Re: Difference between a library and a module...
sophie_newbie wrote: OK this might seem like a retarded question, but what is the difference between a library and a module? If I do: import string am I importing a module or a library? I'm not a guru, but... I think that modules are things that live inside the Python language. In the above case, you are importing a Python module. I think that a library is something that resides on the file system and contains code. But it can be anything, and it exists outside a Python program. I have the feeling that a library is usually lives in compiled form, while a python module can be anything that can be 'import'-ed (py file, pyd file or an so file...) And if i do string.replace() am I using a module or a function or a method or what? What you call here is: string.replace. In the standard string module, replace is a function. But if string refers to a custom module, then string.replace could be a class or an object (or any callable) as well. By the way, modules are not callable at all. Methods can only be called with an object. Class methods can be called with a class. Well, a module is itself a special object, called the 'module object'. Module objects have no class, and they cannot be instantiated or called. http://docs.python.org/ref/types.html#l2h-105 I hope this helps. Laszlo -- http://mail.python.org/mailman/listinfo/python-list
Re: Send email notification
Ernesto wrote: Is there a special module for mail ? I'd like to send an email [to 'n' unique email addresses] from a python script. http://www.justfuckinggoogleit.com/search.pl?python+smtp -- http://mail.python.org/mailman/listinfo/python-list
Re: Convert dictionary to HTTP POST
The values of some inputs are encoded using html entities. How can I decode a string like Bessy#39;s cat in Bessy's cat? this snippet might help: http://effbot.org/zone/re-sub.htm#strip-html Thank you, worked like a charm. :-) Laszlo -- http://mail.python.org/mailman/listinfo/python-list
Re: Calculating md5 checksums.
Rajesh Sathyamoorthy wrote: I tried the script and had to get a hexdigest to get the value provided My test: SimplyMEPIS-3.3.1-1.iso checksum: 41a19060d3bb37bd596708ba77964491 i got: 41a19060d3bb37bd596708ba77964491 Do people normally provide md5 checksum in a *hexadecimal string? *Besides that, is the script reliable? I think the biggest problem is that you read the whole file as one string into memory. This won't work for large files, or at least it is very inefficient. Try to read chunks from the file until EOF and update the hash object with each chunk. Best, Laszlo -- http://mail.python.org/mailman/listinfo/python-list
Convert dictionary to HTTP POST
Hello,
How can I convert a dictionary into a HTTP POST string?
I have an example below, but this is not working correctly for special
characters. ( ' and others). In other words, if I use Bessy's cat
instead of Bessy then the http server will parse that to Bessy#39;s cat
Probably the problem is that I should not use urllib.quote but something
else.
Can you please advise?
Laszlo
form_values = {'name':'Bessy','age':'10','gender':'female'}
for key,value in form_values.iteritems():
values.append('%s=%s' % (urllib.quote(key),urllib.quote(value)) )
values.append('x=33')
values.append('y=14')
post_data = (''.join(values)).replace('/','%2F')
txheaders = {
'Accept':'text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5',
'Accept-Language':'en,hu;q=0.8,en-us;q=0.5,hu-hu;q=0.3',
'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
}
req = urllib2.Request(url, post_data, txheaders)
u = urllib2.build_opener()
req.add_data(post_data)
page2 = self.download(action,post_data,{
'Content-Type': 'application/x-www-form-urlencoded'
})
openerdirector = u.open(req)
data = openerdirector.read()
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Re: Convert dictionary to HTTP POST
See urllib.urlencode(). No idea why they don't include it in urllib2 as
well, but there you go.
from urllib import urlencode
urlencode({'a':' Simple string', 'b': '[EMAIL PROTECTED]*()_+='})
'a=%26+%22Simple+string%22b=%3C%3E%21%40%23%24%25%5E%26%2A%28%29_%2B%3D'
Hmm. urlencode is using quote_plus internally. Looks like there is no
difference in the encoding of the apostrophe.
I tried to create a very basic form and realized that the problem is NOT
with the quoting.
I'm writting a program that puts orders into a wholesaler's database.
They do not have a programatic interface, so I have to login and post
forms using a program.
There are some fields that I must not change, so I have to read the
value from the HTML source and then post it back.
Here is the problem:
html
body
form method=POST
input name=name value=Bessy#39;s cat
input type=submit
/form
/body
/html
The values of some inputs are encoded using html entities.
How can I decode a string like Bessy#39;s cat in Bessy's cat?
Thanks,
Laszlo
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Re: Convert dictionary to HTTP POST
Well I don't understand what's encoding the apostrophe as an encoded entity anyway. That's only supposed to be done for HTML content, not form content. You are right. I was wrong. The problem was not with quote. It was reading out the VALUE of an INPUT from HTML source. How about an RE that turned all #DD; into %DD ? Good idea, but then I still need to examine for nbsp; gt; and the others. I just wonder if there is a standard function in Python that can convert HTML escaped value into plain string. Regards, Laszlo -- http://mail.python.org/mailman/listinfo/python-list
Re: Numerical solver
Robert Kern wrote: In [7]: scipy.optimize.fmin_cobyla? Type: function Base Class: type 'function' String Form:function fmin_cobyla at 0x4fff3b0 Namespace: Interactive File: /Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/scipy- 0.4.7.1607-py2.4-macosx-10.4-ppc.egg/scipy/optimize/cobyla.py Definition: scipy.optimize.fmin_cobyla(func, x0, cons, args=(), consargs=None, rhobeg=1.0, rhoen d=0.0001, iprint=1, maxfun=1000) Docstring: Minimize a function using the Contrained Optimization BY Linear Approximation (COBYLA) method ... Returns: x -- the minimum I'm going to try this. I hope x and x0 can be a vectors. :-) -- http://mail.python.org/mailman/listinfo/python-list
Numerical solver
Hello, I would like to use a numerical solver for a specific problem. My problem looks like this: 1. I have numeric constants, named A,B,C etc. 2. I have numeric variables, named x,y,z etc. 3. I have functions, like f1(x), f2(x), f3(x,y), f4(y) etc. 4. I have constraints like f1(x) A f3(x,y) B etc. Fortunately, all of the variables can be limited to a closed finite interval. (E.g. 0 = x = 100) There is a specific function, called P(x,y,z) that needs to be optimized (need to find its maximum/minimum). I'm looking for a native Python solution: I would like to define the functions and the constraints in Python. I have looked at the cheeseshop and found LogiLab's constraint: http://www.logilab.org/projects/constraint/documentation It is almost perfect for me, but it is working with finite sets. I'm not sure about SciPy or NumPy. Do you have an idea about what is the package I need? I'll gladly read any documentation or tutorial, just I do not know which one is the best to start with. Thanks, Laszlo -- http://mail.python.org/mailman/listinfo/python-list
Re: _bsddb on NetBSD
Miki Tebeka wrote: Hello All, I can't seem to build Python2.4.2 with bsddb on NetBSD. bsddb seems to be missing from the pkg_add installation as well. Please look at the message that you get when you execute pkg_add -r python You will see that tkinter, bsddb, gdbm and some other libs are available as separate packages. Did you try pkg_add -r py24_bsddb pkg_add -r py24_gdbm Best, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Developing a network protocol with Python
Paul Rubin wrote: Laszlo Zsolt Nagy [EMAIL PROTECTED] writes: But how can I transfer pure python objects otherwise? Pyro also uses Pickle and it also transfers bytecode. Pyro in the past used pickle in an insecure way. I'd heard it had been fixed and I didn't realize it still uses pickle. On the features page, you can read this: Mobile objects. Clients and servers can pass objects around - even when the server has never known them before. Pyro will then automatically transfer the needed Python bytecode. I believe that using cPickle and transferring data (but not the code) is still more secure than transferring bytecode. :-) Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Developing a network protocol with Python
Try Pyro http://pyro.sourceforge.net before rolling your own Python-specific protocol. You are right. I wanted to use pyro before, because it is well tested and it has nice features. Unfortunately, it is not good for me. :-( I already have my own classes. My objects are in object ownership trees, and they are referencing to each other (weakly and strongly). These classes have their own streaming methods, and they can be pickled safely. This is something that pyro cannot handle. It cannot handle these ownership object trees with weak references. Pyro can distribute distinct objects only, and it uses an 'object naming scheme'. This is not what I want. My objects do not have a name, and I do not want to create 'technical names' just to force the Pyro style access. (Another problem is that I do not want to rewrite my classes and inherit them from the Pyro base object class.) Thanks for the comment. I'm going to check the Pyro documentation again. I might find something useful. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Developing a network protocol with Python
Paul Rubin wrote: Laszlo Zsolt Nagy [EMAIL PROTECTED] writes: I already have my own classes. My objects are in object ownership trees, and they are referencing to each other (weakly and strongly). These classes have their own streaming methods, and they can be pickled safely. Standard warning: if you're accepting requests from potentially hostile sources, don't use pickle. Yes, I know. Not talking about TLS/SSL - there can be hostile persons, knowing a valid password and using a modified client program. But how can I transfer pure python objects otherwise? Pyro also uses Pickle and it also transfers bytecode. Well, Pyro has an option to use XML messaging, but that is very restricted, you cannot publish arbitrary python objects with XML. :-( I read somewhere that Pickle had a security problem before Python 2.2, but after 2.2 it has been solved. BTW how CORBA or COM does this? They can do object marshaling safely. Can we do the same with Python? Isn't it enough to implement find_global of a cPickler ? Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Developing a network protocol with Python
Tom Anderson wrote: I think to be effective, I need to use TCP_NODELAY, and manually buffered transfers. Why? Because of the big delays when sending small messages (size 1500 bytes). Personally, i'd steer clear of doing it like this, and try to use an existing, language-neutral generic marshalling layer. XML and ASN.1 would be the obvious ones, but i wouldn't advise using either of them, as they're abominations. JSON would be a good choice: http://www.json.org/ I need to send Python objects too. They are too elaborate to convert them to XML. (They are using cyclic weak references and other Python specific stuff.) I can be sure that on both sides, there are Python programs. Is there any advantage in using XML if I already need to send Python objects? Those objects cannot be represented in XML, unless pickled into a CDATA string. And didn't get much in the way of answers. Someone did point to this, though: http://www.internet2.edu/~shalunov/writing/protocol-design.html Hmm, this was very helpful. Thank you! Les -- http://mail.python.org/mailman/listinfo/python-list
Re: instance + classmethod question
Mike Meyer wrote:
Laszlo Zsolt Nagy [EMAIL PROTECTED] writes:
Is it possible to tell, which instance was used to call the
classmethod that is currently running?
Ok, I read through what got to my nntp server, and I'm still
completely confused.
A class method isn't necessarilry called by an instance. That's why
it's a class method. What should happen in that case?
Here is the answer (an example):
@ClassOrInstanceMethod
def process_create_table(cls_or_self,tabledef,processor):
Process the CREATE TABLE command.
@param tabledef: a L{TableDefinition} instance.
@param processor: a L{SQLProcessor} instance.
hname = cls_or_self.hashident(tabledef.name)
if (isinstance(cls_or_self,type)) or (not
cls_or_self.istableexists(hname)):
processor.addline(create table %s \n (% hname)
for field in tabledef.fields:
if not (field() is None):
cls_or_self.process_create_table_field(field(),processor)
processor.addline(,)
processor.truncate_last_comma()
processor.addline()
processor.addline())
cls_or_self.addtablespaceclause(tabledef,processor)
processor.processbuffer()
So if the method was called with an instance, it will check if the table
exists and create the table only if it did not exist before.
But if the method was called with a class, it will create the table anyway.
The above method is just a short example. I have many methods for
creating sequences, triggers, constraings etc.
The full pattern is:
def process_XXX(cls_or_self,defobject,processor):
longer code
a condition, depending on the class or the instance
longer code
another condition, depending on the class or the instance
longer code
There are two reasons why I do not want to create two methods (one
instance and one class method).
1. If you look the above pattern, it is clear that the method does the
same thing, just there are some conditions when I call it with an
instance. I do not want to call process_create_table_with_class and
process_create_table_with_instance, because the name of the method
should reflect what it does primarily. (BTW, I also looked at
multimethods, but they are not exactly for this kind of problem.)
2. The pattern above makes it clear that I just can't easily split the
method into elementary parts. Steven wrote this pattern:
class C(object):
...
@classmethod
def do_stuff(cls, *args):
...
def do_instance_stuff(self, *args):
# instance stuff
...
self.do_stuff(*args)
# more instance stuff
But I cannot do this, because primarily I do class stuff, and in some
cases, I can make use of an instance (but do not require it).
Comments welcome
Les
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Developing a network protocol with Python
Hello, I would like to develop a new network protocol, where the server and the clients are Python programs. I think to be effective, I need to use TCP_NODELAY, and manually buffered transfers. I would like to create a general messaging object that has methods like sendinteger recvinteger sendstring recvstring To be more secure, I think I can use this loads function to transfer more elaborate python stuctures: def loads(s): Loads an object from a string. @param s: The string to load the object from. @return: The object loaded from the string. This function will not unpickle globals and instances. f = cStringIO.StringIO(s) p = cPickle.Unpickler(f) p.find_global = None return p.load() Am I on the right way to develop a new protocol? Are there any common mistakes that programmers do? Is there a howto where I can read more about this? Thanks Les -- http://mail.python.org/mailman/listinfo/python-list
instance + classmethod question
Hello, Is it possible to tell, which instance was used to call the classmethod that is currently running? Background: I have a class called DatabaseConnection and it has a classmethod called process_create_tables. This method should create some database tables defined by a database definition object. The DatabaseConnection has many descendants, for example PostgreSQLConnection. Descendants know how to create tables in a given RDBMS type. I also use subclasses of the 'SQLProcessor' class, that processes SQL commands in different ways (print to stdout, write to file, execute directly in the database etc.) I would like to use the process_create_tables classmethod as is, because sometimes I only need to save a SQL script. However, I also want to use the same classmethod to create tables directly into an existing database. That database is presented as a DatabaseConnection instance. In that case, I only want to create the tables that do not exists yet. Examples: processor = SQLProcessors.StdOutProcessor() # Print to stdout PostgreSQLConnection.process_create_tables(processor,dbdef) # This sould create all tables, using the processor processor = SQLProcessors.DirectProcessor(conn) # Execute directly conn.process_create_tables(processor,dbdef) # This should create non-existing tables only, using the processor Is this possible? Maybe there is a better way to achieve this, I'm not sure. I was thinking about this construct: @classsmethod def process_create_tables(cls,processor,dbdef,conn=None) and then calling it as conn.process_create_tables(processor,dbdef,conn) but this looks very ugly to me. It would be much easier if I could tell which instance (if any) was used to call the classmethod. Thanks, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: instance + classmethod question
Hello Steven, I already implemented this using the form @classmethod def methodname(cls,other_params,self=None) but your example code looks so neat! This is exactly what I needed. :-) In my methods, most code is about string manipulation and calling other classmethods. There are only a few places where I can use an instance, but it is not required. I would like to reuse as most code as possible, so I do not want to create two different methods. That would result in duplicating code. Now the only problem is how I name this. It is not a classmethod, but it is also not a normal method. All right, it is a ClassOrInstanceMethod. Amazing! Probably Python is the only language that is flexible enough to do this. :-) Thanks again! Laszlo Steven Bethard wrote: Laszlo Zsolt Nagy wrote: Hello, Is it possible to tell, which instance was used to call the classmethod that is currently running? class ClassOrInstanceMethod(object): ... def __init__(self, func): ... self.func = func ... self.classfunc = classmethod(func) ... def __get__(self, obj, objtype=None): ... func = obj is None and self.classfunc or self.func ... return func.__get__(obj, objtype) ... -- http://mail.python.org/mailman/listinfo/python-list
Re: How to ping in Python?
Michael Schneider wrote: I telnet to port 13 (returns time) The problem is that most modern up-to-date servers use firewalls. They only open the ports that are absolutely necessary. Usually the time service is part of inetd, which is disabled by default, on most of the servers. PING ICMP may work, but sometimes it does not either. In the worst case, all port are closed and you have no way to tell if there is a computer or not. Can you tell more about what kind of server do you need to ping? Example: if you need to know if a web server is alive, you should connect to port 80 (http). If the connection was successful, you can close the connection immeditelly. You can expect a HTTP server to open the HTTP port, but all other ports may be closed. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: extract python install info from registry
rbt wrote: On windows xp, is there an easy way to extract the information that Python added to the registry as it was installed? Using regedit.exe, look at the registry keys and values under HKEY_LOCAL_MACHINE\Software\Python If you need to know how to read the registry from Python: please install the python win32 extensions (or use ActivePython). Les -- http://mail.python.org/mailman/listinfo/python-list
Re: extract python install info from registry
There's more to it than that... isn't there? I've used _winreg and the win32 extensions in the past when working with the registry. I thought perhaps someone had already scripted something to extract this info. Ok, if you need to get all changes in the registry, you can use regdiff. http://p-nand-q.com/download/regdiff.html Take a snapshot before and after installing Python. However, this is not a wise approach. For example: 1. One can have a system drive 'C:\' others 'G:\' 2. One can have Windows installed in \Windows others in \WinNT and others in \MyWinNT 3. For many registry values, you cannot really tell if you need to correct a value or not. As a result, I believe you will only be able to use the 'regdiff' only on the same type of computer, with the same system drive, same system directory, same windows version etc. For other computers, there is no guarantee for that it will work. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: windows installer problems
[EMAIL PROTECTED] wrote: Hi, I'm trying to install Python on Windows 2000 Server using remote desktop. I log as a user that is in administrators group. Instalator starts, I select default installation directory, on the next screen with parts to install I click just next. Than blicks screen with progress bar but it is immediately replaced with screen informing that installation failed. But there's no information why or what is wrong. On remote connection I use 16 colors - can it be the problem? Please try to do the same using Start Menu/Control Panel/AddRemovePrograms. Once I had the same problem and it turned out that when you start the Control Panel, the terminal goes into a different mode where you can install programs. Without that, you will not be able to add new programs. I'm not sure why. Les -- http://mail.python.org/mailman/listinfo/python-list
junk pointer ????
Hi All, I got this while using Python 2.4 under FreeBSD 5.4: python in free(): warning: junk pointer, too high to make sense Segmentation fault (core dumped) What does it mean? Thanks, Les -- http://mail.python.org/mailman/listinfo/python-list
ZSI bug?
Hi All, I'm trying to use ZSI (and SOAP) for the first time. I read somewhere that ZSI is the most compete SOAP implementation. I have ZSI-1.7 and PyXML-0.8.4. This very simple code: import ZSI fname = 'eBaySvc.wsdl' version = 421 url = 'http://developer.ebay.com/webservices/%s/%s' % (version,fname) print Creating proxy... proxy = ZSI.ServiceProxy(url) print proxy Throws me: C:/Python24/pythonw.exe -u T:/Python/Projects/eBay-SOAP/test.py Creating proxy... Traceback (most recent call last): File T:/Python/Projects/eBay-SOAP/test.py, line 6, in ? proxy = ZSI.ServiceProxy(url) File C:\Python24\Lib\site-packages\ZSI\ServiceProxy.py, line 34, in __init__ wsdl = ZSI.wstools.WSDLTools.WSDLReader().loadFromURL(wsdl) File C:\Python24\Lib\site-packages\ZSI\wstools\WSDLTools.py, line 42, in loadFromURL wsdl.load(document) File C:\Python24\Lib\site-packages\ZSI\wstools\WSDLTools.py, line 260, in load schema = reader.loadFromNode(WSDLToolsAdapter(self), item) File C:\Python24\Lib\site-packages\ZSI\wstools\XMLSchema.py, line 80, in loadFromNode schema.load(reader) File C:\Python24\Lib\site-packages\ZSI\wstools\XMLSchema.py, line 1116, in load tp.fromDom(node) File C:\Python24\Lib\site-packages\ZSI\wstools\XMLSchema.py, line 2271, in fromDom self.content.fromDom(contents[indx]) File C:\Python24\Lib\site-packages\ZSI\wstools\XMLSchema.py, line 2328, in fromDom self.derivation.fromDom(i) File C:\Python24\Lib\site-packages\ZSI\wstools\XMLSchema.py, line 2388, in fromDom component = SplitQName(contents[indx].getTagName())[1] IndexError: list index out of range Is this a ZSI bug? Or is it something that is not implemented in ZSI yet? Unfortunately, eBay's simple XML API is deprecated, I do not want to start a new project with that. Also I would not like to use MS .NET or Java because I prefer Python, of course. :-) Thanks, Laszlo Nagy -- http://mail.python.org/mailman/listinfo/python-list
Re: IE Temporary Internet Files Python
The script does not seem to work when used on Temporary Internet Files. Doesn't work well? What does it mean? Is there an exception raised? Les -- http://mail.python.org/mailman/listinfo/python-list
Re: html parser?
Thorsten Kampe wrote: * Christoph Söllner (2005-10-18 12:20 +0100) right, that's what I was looking for. Thanks very much. For simple things like that BeautifulSoup might be overkill. import formatter, \ htmllib, \ urllib url = 'http://python.org' htmlp = htmllib.HTMLParser(formatter.NullFormatter()) The problem with HTMLParser is that does not handle unclosed tags and/or attirbutes given with invalid syntax. Unfortunately, many sites on the internet use malformed HTML pages. You are right, BeautifulSoup is an overkill (it is rather slow) but I'm affraid this is the only fault-tolerant solution. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: html parser?
Christoph Söllner wrote:
Hi *,
is there a html parser available, which could i.e. extract all links from a
given text like that:
a href=foo.php?param1=testBARimg src=none.gif/a
a href=foo2.php?param1=testparam2=testBAR2/a
and return a set of dicts like that:
{
['foo.php','BAR','param1','test'],
['foo2.php','BAR2','param1','test','param2','test']
}
thanks,
Chris
I asked the same question a week ago, and the answer I got was a really
beautiful one. :-)
http://www.crummy.com/software/BeautifulSoup/
Les
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Outdated documentation
Hi All, This is from the documentation of the dbhash module: Returns the key next key/value pair in a database traversal. The following code prints every key in the database |db|, without having to create a list in memory that contains them all: print db.first() for i in xrange(1, len(db)): print db.next() Apparently, it is different for gdbm: k = db.firstkey() while k != None: print k k = db.nextkey(k) I think both of them is outdated. This should be: for key,value in db.iteritems(): print key,value Is this the good place to post? Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Need a spider library
Fredrik Lundh wrote: Laszlo Zsolt Nagy wrote: The question: is there a good library for Python for extraction links and images out of (possibly malformed) HTML soucre code? http://www.crummy.com/software/BeautifulSoup/ Thanks a lot! This is just what I wanted. Why it is not part of the standard Python library yet? :-) -- http://mail.python.org/mailman/listinfo/python-list
Very dumb question
I have a program with this code fragment: print len(data) print data[:50] raise SystemExit This prints: 20381 !DOCTYPE html PUBLIC -//W3C//DTD XHTML 1.1//EN But if I change 50 to 51 print len(data) print data[:51] raise SystemExit then it prints 20381 !DOCTYPE html PUBLIC -//W3C//DTD XHTML 1.1//EN After all, only the last 50 bytes are printed. The string is the same (length 20381) in both cases. Surprisingly, I can print more than 50 characters, this works: print 012345678901234567890123456789012345678901234567890123456789A I'm sure it is my mistake, but I don't know what am I doing wrong. Do you have an idea? Thanks, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Very dumb question
I assume the code snippets are exact copy/paste so this is not a typo (like print data[51:] ...) - and I can't reproduce it here... even with a string of 20381 characters. Yes, they were cut out. type(data) returns 'type str'. The data was downloaded from a website, it starts with !DOCTYPE html PUBLIC -//W3C//DTD XHTML 1.1//EN http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd; Even if it had special control characters in it, I do not understand the effect (printing only the first 50 chars). But probably it is an issue with the terminal, since it is working fine on Windows. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Very dumb question
i. e. a character after a 'carriage return' ('\r') overwrites part of the
string which therefore doesn't seem to grow. Try
print repr(data[:51])
to see what's really in your data string.
Yes, that was it! Thanks for you help. I thought it will be something
obvious.
The server returned carriage returns in the HTML source code, and I
tried to print that. :-)
Les
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Re: Send password over TCP connection
dcrespo wrote: ¡Beautiful and elegant solution! Two copies of the password: one on the client, the other on the server. 1. Client wants to connect 2. Server generates a random_alphanumeric_string and sends it to the client 3. Both Client and Server creates a hash string from password+random_alphanumeric_string 4. Client sends the hash string to the server 5. Server compares his hash result with the hash string received from de client. I think it is a very good solution, Isn't it? In fact this is almost an OTP but be aware! A man-in-the-middle attack can crack your algorithm. This is beacuse you create a random string only on one side. You cannot trust in the connection you are using. You can modify you algorigthm to be more secure: 1. Client wants to connect 2. Server generates a server_random_alphanumeric_string and sends it to the client 3. Client generates a client_random_alphanumeric_string and sends it to the client too 3. Both Client and Server creates a hash string from server_random_alphanumeric_string+password+client_random_alphanumeric_string 4. Client sends the hash string to the server 5. Server compares his hash result with the hash string received from de client. This is only a bit difference, but is makes sense. An intuder (who knows the your algorithm, because getting the code is not as difficult) could make a fake server to you, and send back HIS string (that is not random). Suppose we have a weakness in the hash function. The intuder can exploit this weakness by sending you his special string. The modified version has the advantage of sending two random strings, this way the intuder cannot take advantage of possible hash function weaknesses, because the hash function will be called on a string that is random for sure. Best, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Send password over TCP connection
Ignoring all the other issues, any solution which actually requires the password to be stored on the server is a bad solution. Administrators should not have access to user passwords, and in addition users should not be put in the position of having to trust your server-side security to keep their passwords (which they might have used on other systems) from being grabbed by hackers. Users will always need to trust in the server. The authentication process ensures that the client is really talking with the desired server and vice versa. But even if you know that you are talking to the right server, you need to trust in the server. The administrator of the server has access to all data. Possibly other persons and softwares too. Passwords are not different from this point of view. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Send password over TCP connection
If you really want to do it right, use SRP, http://srp.stanford.edu. This is a bit offtopic here. I read the RFC and I do not see why SRP is not vulnerable to dictionary attacks. If I have a working client software then I can use it to reveal passwords. Isn't it a dictionary attack? Can you please enlighten me? Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Send password over TCP connection
Paul Rubin wrote: Laszlo Zsolt Nagy [EMAIL PROTECTED] writes: This is a bit offtopic here. I read the RFC and I do not see why SRP is not vulnerable to dictionary attacks. If I have a working client software then I can use it to reveal passwords. Isn't it a dictionary attack? Dictionary attack in this context means an eavesdropper records a session, then compares all the hashed passwords against a word list offline. If the attacker is allowed to make unlimited online queries, then he can guess at SRP passwords too. But the host should notice that and prevent it. I see. So the eavesdropper records the random strings and the password hash value sent. Having these values, he can try to find a suitable password in his list that will result in the same communication. He can do this without having to connect to the server again, just by replaying the algorithm for a given password (and the same 'random' strings). The difference in SRP is that the random strings are private, they will never be sent over the network. So they cannot be eavesdropped. Cracking SRP would require to calculate the dividers of a product of two very big primes (like in RSA). This is why it is hard to use dictionary attacks - you cannot replay the algorithm for a given password. Thank you, I think I understand now. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Send password over TCP connection
If you're saying that people have no choice but to trust that their passwords, stored in the clear on the server of some idiot who didn't know better, are safe from casual administrator observation and safe from hackers stealing the password file, then you shouldn't be allowed anywhere near a supposedly secure system... Of course I would not say this. :-) If you're just saying that one has to trust that the server you are talking to at this instant in time is really the one you thought it was, then that's an entirely different issue and I agree. Not just this. one has to trust that the server you are talking to at this instant in time is really the one you thought it was - this is just authentication. I'm saying that even if the authentication is secure and the server is really the one that you wanted to talk with, the server can still be vulnerable to other kinds of attacks. Since users are storing data on the server, they need to trust in its security. Storing the clear passwords is not a good idea, I agree. But having a secure authentication method and not storing clear passwords doesn't automatically mean that the server is secured. :-) I'm sorry, I was not clear. I think we were talking about the same thing. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Comparing lists
Odd-R. wrote: I have to lists, A and B, that may, or may not be equal. If they are not identical, I want the output to be three new lists, X,Y and Z where X has all the elements that are in A, but not in B, and Y contains all the elements that are B but not in A. Z will then have the elements that are in both A and B. These are set operations. One way of doing this is of course to iterate throug the lists and compare each of the element, but is there a more efficient way? Maybe, using sets? L1 = [1,2,3,4] L2=[3,4,5,6] diff1 = list(set(L1)-set(L2)) # [1,2] diff2 = list(set(L2)-set(L1)) # [5,6] symdiff = diff1+diff2 # Symmetric difference [1,2,5,6] intersect = set(L1+L2) - set(symdiff) # Intersect [3,4] Best, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Send password over TCP connection
How about an OTP (One Time Password) algorithm? It is described in RFC2289. http://www.faqs.org/rfcs/rfc2289.html I have a working implementation in Messlib. You can download it an look at the MessageSocket.SecureMessageSocket class. That is a modified version where a good random generator is used instead of a finite sequence of passwords. But it is just example implementation - you can get the idea there and develop your own. In fact, my class also has support for encrypting the communication channel, but the OTP algorithm itself only requires a cryptographically secure hash algorithm and a good random number generator. These are all included in Python. ;-) I also tried to use SSL before, but I realized that for secure password type authentication, OTP is much easier to understand and use. Of course, SSL can be used for securing the communication line WITHOUT AUTHENTICATION, and it is harder to understand and use. Best, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Python's Performance
Dave wrote: Hello All, I would like to gather some information on Python's runtime performance. As far as I understand, it deals with a lot of string objects. Does it require a lot string processing during program execution? How does it handle such time-consuming operations? Is there a way to find out how many string operations (perhaps in the underlying system) ) it does during program execution? Do you want to know how many internal string operations are done inside the Python interpreter? I believe it is not a useful information. There are benchmarks testing the *real performance* of Python. For example: http://www.osnews.com/story.php?news_id=5602 Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Help-log in to a web page
Murugesh wrote:
Hi all,
I'm a newbie to python.I need to login to a webpage after supplying
usename and password.
import urllib
sock = urllib.urlopen(http://xop-pc.main.com;)
htmlSource = sock.read()
sock.close()
print htmlSource
In the above code how can i supply username and password to that URL.
Thanks for you time.
xop-pc.main.com is not an existing site.
Can you tell me what kind of authentication method it is using?
If that is the basic authentication (defined the standard HTTP
protocol) then you need to read this:
http://docs.python.org/lib/urlopener-objs.html
Basically, you need to subclass URLopener or FancyURLopener, and
overwrite its prompt_user_passwd method.
That method will be then called whenever the server needs authentication.
Here is a template for you (untested):
from urllib import FancyURLOpener
class MyOpener(FancyURLOpener):
def prompt_user_passwd(host,realm):
return ('myusername','mypassword')
opener = MyOpener({})
f = opener.open(http://xop-pc.main.com;)
try:
html_source = f.read()
finally:
f.close()
Best,
Les
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Class property (was: Class methods)
Hughes, Chad O wrote: Is there any way to create a class method? I can create a class variable like this: Hmm, seeing this post, I have decided to implement a 'classproperty' descriptor. But I could not. This is what I imagined: class A(object): _x = 0 @classmethod def get_x(cls): print Getting x... return cls._x @classmethod def set_x(cls,value): print Setting x... cls._x = value x = classproperty(get_x,set_x) Usage example: print A.x Getting x 0 A.x = 8 Setting x print A.x Getting x 8 I was trying for a while, but I could not implement a 'classproperty' function. Is it possible at all? Thanks, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Help-log in to a web page
I tried to view the source,it has, src=/em/cabo/images /t.gif height=80/tdtdtable align=center border=0 cellspacing=2 cellpadding=0tr id=username __xc_td align=right nowrapspan class=x8span title=Required class=xc*/spannbsp;*User Name/s pan/tdtd width=12img src=/em/cabo/images/t.gif width=12/tdtd valign=top nowrapinput id=username class=x4 onkeypress=return _submitOnEnter(event, 'User'); name=j_username size=30 type=text value=myadmin/td/trtrtd align=right nowrapspan class=x8span title=Required class=xc*/spannbsp;Password/span/tdtd width=12img src=/em/cabo/images/t.gif width=12/td td valign=top nowrapinput id=M__Id class=x4 name=j_password size=30* autocomplete=off type=p ... ... Either it is a javascript or a form. Most likely this will be a normal form, like: form method=POST action=login.php input name=login type=text input name=pwd type=text /form This is another authentication method that is used frequently. You need to POST the login/password and other parameters to the URL specified by the action attribute of the form tag. Say, if you download the above HTML page from http://here.net/there then you should POST your login data to http://here.net/there/login.php The response may contain cookies - you need to use them to keep yourself logged in. Please read documentation about these: - HTML forms - HTTP cookies and then read the docs of the urllib module here: http://www.python.org/doc/current/lib/module-urllib.html It has parts where you can learn how to POST or GET data. If you need to handle cookies as well (probably, this is true in your case), you might want to change to urllib2 http://www.python.org/doc/current/lib/module-urllib2.html because it has support for cookies. Don't do anything until you understand what cookies and HTML forms are. (And don't ask about them here - it is not about Python programming...) Best, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: /usr/bin/env python, force a version
[EMAIL PROTECTED] wrote: I've got a trouble, and i think that anybody there can help me I've got a python script which i distribute in somes packages for *nix. This script is full of python and need python 2.4 ! And i'd like to display a message when the user doesn't have a python2.4 version. import sys sys.version '2.4.1 (#65, Mar 30 2005, 09:13:57) [MSC v.1310 32 bit (Intel)]' There is also sys.hexversion sys.api_version sys.version_info* Read this: *http://docs.python.org/lib/module-sys.html Les ** -- http://mail.python.org/mailman/listinfo/python-list
Re: /usr/bin/env python, force a version
Roel Schroeven wrote: Laszlo Zsolt Nagy wrote: [EMAIL PROTECTED] wrote: I've got a trouble, and i think that anybody there can help me I've got a python script which i distribute in somes packages for *nix. This script is full of python and need python 2.4 ! And i'd like to display a message when the user doesn't have a python2.4 version. import sys sys.version '2.4.1 (#65, Mar 30 2005, 09:13:57) [MSC v.1310 32 bit (Intel)]' Yes, but the problem is also that Debian (not only Sid, but also stable and testing) has python 2.4 but it is not the default, i.e. /usr/bin/python is a symlink to /usr/bin/python2.3 even if /usr/bin/python2.4 is available to. Hmm. Idea one: Create a list of possible locations. First of all, use your PATH, and then add common locations: ['/bin','/usr/bin','/opt/bin','/usr/local/bin'] # etc. Then use a list of the possible executable names: ['python','python2.3','python2.4'] # etc Finally using these combinations, execute each executeable with python -V and examine its output. This may work, but I'm affraid there is no general solution. The system administrator can install different python versions to virtually any location. But I don't think you should be affraid of that. If a system admin installs different versions into strange locations, then he will take the responsibility to fix python programs that need a specific version. But in most cases, looking for a python executable on your PATH should be enough; and it is the most I would expect from an application. :-) Last idea: - create a configuration file that resides beside your Python program - take the path to the good executeable there - if the program was started with the wrong version, but you have the path to the good one (from the config file), then re-execute - otherwise print an error message telling the required version AND how the user can set it up in the config file Third idea (for Windows only): read available versions from the registry. ;-) Best, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Class property
Peter Otten wrote: Laszlo Zsolt Nagy wrote: I was trying for a while, but I could not implement a 'classproperty' function. Is it possible at all? You could define a normal property in the metaclass: The only way I could do this is: class MyXMetaClass(type): _x = 0 def get_x(cls): print Getting x return cls._x def set_x(cls,value): cls._x = value print Set %s.x to %s % (cls.__name__,value) x = property(get_x,set_x) class A(object): __metaclass__ = MyXMetaClass print A.x A.x = 8 Results in: Getting x 0 Set A.x to 8 But of course this is bad because the class attribute is not stored in the class. I feel it should be. Suppose we want to create a class property, and a class attribute; and we would like the property get/set methods to use the values of the class attributes. A real example would be a class that keeps track of its direct and subclassed instances: class A(object): cnt = 0 a_cnt = 0 def __init__(self): A.cnt += 1 if self.__class__ is A: A.a_cnt += 1 class B(A): pass print A.cnt,A.a_cnt # 0,0 b = B() print A.cnt,A.a_cnt # 1,0 a = A() print A.cnt,A.a_cnt # 2,1 But then, I may want to create read-only class property that returns the cnt/a_cnt ratio. This now cannot be implemented with a metaclass, because the metaclass cannot operate on the class attributes: class A(object): cnt = 0 a_cnt = 0 ratio = a_class_property_that_returns_the_cnt_per_a_cnt_ratio() # def __init__(self): A.cnt += 1 if self.__class__ is A: A.a_cnt += 1 Any ideas? Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Python, Mysql, insert NULL
Python_it wrote: Python 2.4 MySQL-python.exe-1.2.0.win32-py2.4.zip How can I insert a NULL value in a table (MySQL-database). I can't set a var to NULL? Or is there a other possibility? My var must be variable string or NULL. Becaus i have a if statement: if cursor.execute(.insert NULL ..) if cursor.execute(.insert string ..) Use parameters! For example, did you try: cursor.execute( insert into tablename(fieldname) values (%s),[value]) None will be converted to NULL, any other value will be quoted as neccesary. BTW, you did not write which driver are you using. Usage of parameters is different for each driver, but it is standardized. If it is DB API 2.0 compatible, then parametrized queries should work as desicribed in PEP 0249: http://www.python.org/peps/pep-0249.html Under 'cursor objects' section, look for the '.execute' method. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python, Mysql, insert NULL
BTW, you did not write which driver are you using. Oh, you did. Sorry. :-( Import your DB module 'yourmodule' and then print yourmodule.paramstyle Description of paramstyle is also in PEP249: paramstyle String constant stating the type of parameter marker formatting expected by the interface. Possible values are [2]: 'qmark' Question mark style, e.g. '...WHERE name=?' 'numeric' Numeric, positional style, e.g. '...WHERE name=:1' 'named' Named style, e.g. '...WHERE name=:name' 'format'ANSI C printf format codes, e.g. '...WHERE name=%s' 'pyformat' Python extended format codes, e.g. '...WHERE name=%(name)s' Best, Les e.g. '...WHERE name=%(name)s' -- http://mail.python.org/mailman/listinfo/python-list
Re: How to get the output from os.system() into a variable?
alexLIGO wrote:
Hi,
I would like to execute some command in python on the bash, e.g.
os.system('globus-job-run mike4.cct.lsu.edu/jobmanager-pbs -l
/bin/date')
and want the result of the output in a vector, so something like:
result=python_command(' command_on_the_bash ')
Is that possible? And how to do that?
You can use one of these:
the subprocess module: http://docs.python.org/lib/module-subprocess.html
the popen2 module: http://docs.python.org/lib/module-popen2.html
popen and spawn variants from the os module:
http://docs.python.org/lib/os-process.html
pexpect (it is not in the standard library):
http://pexpect.sourceforge.net/
I believe that if you do not need the extended functionality of
pexpect, then you should start with the subprocess module.
It is the newest.
Les
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Re: How to get the output from os.system() into a variable?
result=python_command(' command_on_the_bash ')
Is that possible? And how to do that?
Check out the commands module.
http://docs.python.org/lib/module-commands.html
Hmm, I forgot this one. It is only working from UNIX, am I right?
Les
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Re: change a value to NULL?
Bell, Kevin wrote: I'm pulling a list of numbers from MS Excel, but occasionally if there is no data from excel, the value is an asterisk, but I need to make it null. What is the best way to do that? Thus far, I'm using: for value in myRange: try: intV = int(value) print intV except: print its an asterisk I'm affraid I did not understand what is your real problem. Here is an answer, anyway. When converting a string intoto an int, you should use TypeError to trap type errors only: try: intV = int(value) except TypeError: intV = None print intV # It will be None if 'value' is not an int Best, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: how to keep collection of existing instances and return one on instantiation
I've removed all references to the object, except for the cache. Do I
have to implement my own garbage collecting is or there some magical
way of doing this within Python? I pretty much want to get rid of the
cache as soon as there are no other references (other than the cache).
Store weak references to instances.
from weakref import ref
class Spam(object):
cache = {}
def __new__(cls, x):
instance = None
if cls.cache.has_key(x):
instance = cls.cache[x]()
if instance is None:
instance = object.__new__(cls, x)
cls.cache[x] = ref(instance )
return instance
def __init__(self, x):
self.x = x
Then:
a = Spam('foo')
b = Spam('foo')
a is b
True
print Spam.cache
{'foo': weakref at 00A1F690; to 'Spam' at 00A2A650}
del a
del b
print Spam.cache
{'foo': weakref at 00A1F690; dead}
Well, of course this is still not thread safe, and weak references will
use some memory (but it can be much less expensive).
You can grabage collect dead weak references periodically, if you wish.
Best,
Les
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Re: Class methods
Hughes, Chad O wrote: Is there any way to create a class method? I can create a class variable like this: ... Any ideas? Oh man, it has been a long time I have read such an disturbing question. RTMF here: http://docs.python.org/lib/built-in-funcs.html#l2h-14 Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Class methods
Oh man, it has been a long time I have read such an disturbing question. RTMF here: http://docs.python.org/lib/built-in-funcs.html#l2h-14 I feel I was a bit harsh. class A(object): x = 0 @classmethod def f(cls): cls.x += 1 print x is,cls.x A.f() x is 1 A.f() x is 2 A.f() x is 3 Ashes to my head. :-( Les -- http://mail.python.org/mailman/listinfo/python-list
email module, redirecting to stdout
Hello, I have this code: s = smtplib.SMTP() s.set_debuglevel(1) s.connect(host=smtp_host) s.set_debuglevel(0) log(Connected, sending e-mail) sys.stdout.flush() s.sendmail( consts.EMAIL_FROMADDRESS, [to], msg.as_string() ) log(E-mail sent OK) s.quit() The problem is that whenever I set the debuglevel to 1, messages will go to stderr. I would like them to go to stdout. Using sys.stderr = sys.stdout has no effect. Redirecting stderr to stdout from the shell is not an option for me, because I need to use stderr for other messages. Thanks, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: @staticmethod, backward compatibility?
Neal Becker wrote: How can I write code to take advantage of new decorator syntax, while allowing backward compatibility? I almost want a preprocessor. #if PYTHON_VERSION = 2.4 @staticmethod ... Since python 2.4 will just choke on @staticmethod, how can I do this? Decorators are there because class MyClass: @staticmethod def my_method(arg1, arg2, ...): whatever is nicer than class MyClass: def my_method(arg1, arg2, ...): whatever my_method = staticmethod(my_method) I'm affraid, if you need to be 2.3 compatible then you need to use the later form. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem subclassing (Newbie)
Then I have an instance of class Button called obj. My probelm is that the test isinstance(obj, Widget) resturns False! You must have a typo somewhere. Please try this little test program. class Widget(object): ... pass ... class Button(Widget): ... pass ... b = Button() isinstance(b,Widget) True isinstance(b,Button) True issubclass(Widget,Button) False issubclass(Button,Widget) True -- http://mail.python.org/mailman/listinfo/python-list
Re: Indexed variables
a1=a2=0 def f(x): if x == a1: a1 = a1 + 1 elif x == a2: a2 = a2 + 1 Now if I call f with f(a2) only a1, of course, is incremented because the if-clause does only check for the value of the input and the values of a1 and a2 are identical. So how do I define the function such as to discrimate wheter I call it by f(a1) or f(a2) ? What you are trying to do is to create a function with a side effect. (Side effect is when a function changes its environment. The environment of a function is everything that is not local to that function, plus the actual parameters and I/O devices.) If you really want to change an actual parameter inside an object, then you should use a mutable object. In Python, there are two kinds of objects: mutable and immutable. Immutable objects cannot change their value. Integers are immutable. The object zero will always be zero. You can add another integer to it, but it will create another object, while the zero object will remain zero. There are other immutable objects. For example, tuples are immutable. t = (1,2,3) This object is an immutable tuple. You cannot change its value. Mutable objects can change their values. For example, lists are mutable. L = [1,2,3] Usually, mutable objects have methods to change their value. L.append(4) print L [1,2,3,4] So if you really want to create a function with a side effect, do something like this: a1 = [0] a2 = [0] def f(x): ... if x is a1: ... a1[0] += 1 ... elif x is a2: ... a2[0] += 1 ... a1 [0] f(a1) a1 [1] a2 [0] But please note that having side effect is generally considered harmful. Please read the tutorial, these things are explained quite well. http://docs.python.org/tut/tut.html Best, Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Indexed variables
If you really want to change an actual parameter inside an object, then inside a function, I mean -- http://mail.python.org/mailman/listinfo/python-list
Re: win32 service and time.sleep()
rbt wrote:
I have a win32 service written in Python. It works well. It sends a
report of the status of the machine via email periodically. The one
problem I have is this... while trying to send an email, the script
loops until a send happens and then it breaks. Should it be unable to
send, it sleeps for 10 minutes with time.sleep(600) and then wakes and
tries again. This is when the problem occurs. I can't stop the service
while the program is sleeping. When I try, it just hangs until a reboot.
Can some suggest how to fix this?
Yes. Generally, most of the win32 services work like this:
- the main thread listens to win32 service commands
- when starting the service, you should create a new worker thread that
does the job for you
- when stopping the service, your service should report
win32service.SERVICE_STOP_PENDING immediately, and ask the worker thread
to terminate
- you should be continuously reporting win32service.SERVICE_STOP_PENDING
until your workder thread has stopped
Here is a simple module that uses a 'Processor' class and a new thread
to do the work.
(The full program is here: http://mess.hu/download/SimpleHTTPService.zip )
class Service(win32serviceutil.ServiceFramework):
_svc_name_ = SERVICE_NAME
_svc_display_name_ = SERVICE_DISPLAY
def __init__(self, args):
win32serviceutil.ServiceFramework.__init__(self, args)
self.stopped = threading.Event()
self.stopped.clear()
self.logger = getLogger(SERVICE_NAME)
def SvcStop(self):
self.logger.info(Got SvcStop, trying to stop service...)
self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
self.stopped.set()
def SvcDoRun(self):
Write an event log record - in debug mode we will also see
this message printed.
try:
import servicemanager
servicemanager.LogMsg(
servicemanager.EVENTLOG_INFORMATION_TYPE,
servicemanager.PYS_SERVICE_STARTED,
(self._svc_name_, '')
)
self.logger.info(Started.)
self.logger.debug(Creating processor instance)
processor = Processor(self.stopped)
self.logger.debug(Starting processor thread)
thread.start_new_thread(processor.Process,())
self.logger.debug(Waiting for the processor thread to finish)
self.stopped.wait()
self.logger.debug(Stopping)
time.sleep(1)
while not processor.stopped.isSet():
self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING, 5000)
time.sleep(5)
servicemanager.LogMsg(
servicemanager.EVENTLOG_INFORMATION_TYPE,
servicemanager.PYS_SERVICE_STOPPED,
(self._svc_name_, )
)
self.logger.info(Stopped)
except:
self.logger.error('',exc_info = sys.exc_info())
if __name__=='__main__':
win32serviceutil.HandleCommandLine(Service)
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Where is my exception
I have this code in a wxWidgets program: class HtmlHintWindow(wx.Frame): def __init__(self,pos,hint,config): global _current_hint_window # Determine the size of the screen self.screensize = wx.ClientDisplayRect()[2:] # Calculate the size of the hint ;-) self.renderer = MegaXMLRenderer() self.renderer.LoadStyle(config.style) self.cookie, self.parsed_xml = self.renderer.Parse(hint) print point 1 try: self.image = self.renderer.Render( self.cookie, self.parsed_xml, (0,0,self.screensize[0],self.screensize[1]), draw=True ) finally: print point 2 raise The program prints out point 1 but it does not print point 2. What am I missing? Les -- http://mail.python.org/mailman/listinfo/python-list
Re: testing a website from python
M.N.A.Smadi wrote: hi; I just want to test that a given website is up or not from a python script. I thought of using wget as an os command. Any better ideas? urllib http://www.python.org/doc/current/lib/module-urllib.html If you only want to test if the HTTP port is open or not: socket http://docs.python.org/lib/module-socket.html Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Where is my exception
The program prints out point 1 but it does not print point 2. What am I missing? Sorry from all. I should have been looked at the processor before I posted. There is no exception. It was an infinite loop inside the try block, but it was called from an event handler. I did not notice that my CPU is at 100%. :-( Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Doc Problem Example: os.path.split
is the doc writer, trying to write the doc with some austereness, but is confused about the behavior of split, or confused about expressing it? Did his pretension fucked him up? Dear Xah Lee, The Python community is very sorry because we have a very bad documentation. You are right. The documentation is bad, and the language is bad etc. The mailing list itself is not helpful and you cannot use it for anything. We will try to follow all of your glorious suggestions. But we have so many things to do, I'm affraid you need to wait until Python 5000 is released. Until that, I can recommend you the Visual Basic language. Its documentation is much more perfect. MSDN is really really well structured and easy to use! It is commercial, and - as you would expect - you will get immediate fixes after you make a kind suggestion like this. I think this is the best thing you can do. For more information about this fabolous ClosedSource commercial product, please visit this link: http://msdn.microsoft.com/vbasic/ Good Luck! Les -- http://mail.python.org/mailman/listinfo/python-list
Re: How to clear screen in Python interactive shell mode?
A. L. wrote: In Python interactive mode, is there some function acting like 'clear' command in bash? Could somebody here give some advice? Under Linux/UNIX system (on x86 at least) you can use the CTRL+L combination to clear the screen. I do not now similar for Windows and MACs. Les -- http://mail.python.org/mailman/listinfo/python-list
Re: Self reordering list in Python
I wonder why you don't use a dictionary? The only time I used a move-front algorithm I stored algorithms and had to evaluate a condition to select the correct algo. That means no constant search key was available for accessing the correct one. In case of an image list I would implement a self-ordering list if I have to do some pattern recognition in order to select the correct image. Holding a reference as a search key a Python hash-table will always have a better average time complexity no matter which language is used to implement move-front. You are right in that holding a reference will have a better time complexity. But holding a reference makes it impossible to free the object. :-) As I said, my list has a maximum length. I just can't store any number of images in memory. I need to keep only the most frequently used ones. I do not know which ones will be used the most frequently, this is why I need a self reordering list. Accessing an element makes it more imporant than the others. I already implemented this in Python and it was ten times faster compared to the original version. (200 frames per sec instead of 20 fps) Probably my problem was a no-problem. I realized that it does not matter how fast is my list. The most time consuming part is still the rendering of the images that are not in the cache. I need to speed up rendering and have more RAM, of course. :-) Les -- http://mail.python.org/mailman/listinfo/python-list
Self reordering list in Python
Hello, Do you know how to implement a really efficient self reordering list in Python? (List with a maximum length. When an item is processed, it becomes the first element in the list.) I would like to use this for caching of rendered images. Of course I could implement this in pure Python, I just wonder if there is a faster implementation that uses some cool feature of the standard library. (Maybe a C implementation could be added to the collections module?) Les -- http://mail.python.org/mailman/listinfo/python-list
Distutils question
How how can I install my .mo files from a distutil script into its default location? sys.prefix + os.sep + 'share' + os.sep + 'locale' -- http://mail.python.org/mailman/listinfo/python-list
Re: popen in thread on QNX
Jacek Popławski wrote: I am still in the process of creating my script which will run command received from socket. My scripts works perfectly on Linux, but doesn't work on QNX! File /usr/lib/python2.4/popen2.py, line 108, in __init__ self.pid = os.fork() OSError: [Errno 89] Function not implemented When I try to use os.popen3 - it works. But when I try to use it in new thread - I see that error message. Do you see any solution? This script must work on QNX, command must be on thread, because I need to stop it after timeout. I need popen to see stdout and stderr. Any ideas? os.popen already creates a new process. So what if you try to call os.popen from your main thread, then pass the file descriptors to your thread? It is just an idea... Les -- http://mail.python.org/mailman/listinfo/python-list
Re: popen in thread on QNX
os.popen already creates a new process. So what if you try to call os.popen from your main thread, then pass the file descriptors to your thread? It is just an idea... But I need to run command from thread, that's the main reason to create new thread :) Ok, but can't your main thread be a server thread with a queue? Workflow example: - one of your worker threads wants to run a command - it creates the argument list and puts it into a message queue - woker thread starts to sleep - main thread processes the message queue - it will run popen, put back the file descriptors into the message and wake up the worker thread - the worker thread starts to work with the files Or, if you create the new thread just to interact with that new process, why don't you call popen before you start the thread? Well, of course this would increase the time needed to start up a new worker. Les -- http://mail.python.org/mailman/listinfo/python-list
Distutils extension proposal (was: Re: Distutils question)
Peter Hansen wrote: How how can I install my .mo files from a distutil script into its default location? sys.prefix + os.sep + 'share' + os.sep + 'locale' I can't answer the first question, but the latter should be written this way instead os.path.join(sys.prefix, 'share', 'locale') for greater portability and maintainability. Of course. :-) I know that Peter is a big Python guru, and he could not answer the question. I also read the archives in the i18n-sig. There were questions about the same problem and the answer was that there is no standard way to include message files with a distribution. I would like to propose an extension in distutils. Most of the packages contain messages and they should be i18n-ed. The proposal itself contains two parts. 1. We should extend the distutils interface to allow message files to be installed to the default location os.path.join(sys.prefix, 'share', 'locale') 2. Domain names for packages should be somehow standardized, especially in conjunction with PEP 301 (Package Index and Metadata for Distutils). Somehow, the package name and version should identify the message files that can be used. Les -- http://mail.python.org/mailman/listinfo/python-list
The right way to do i18n
Hello,
I wonder if there is a standard for making i18n in Python projects. I
have several Python projects that are internationalized. I also have
Python packages with i18n. But it is still not clean to me what is the
recommended way to do it. Currently, I use a module called
'localization.py' with this code:
from i18n_domain import DOMAIN
import gettext
t = gettext.translation(DOMAIN,'messages',languages=['hu'])
t.install()
But I believe this is not the best way to do it. Problem one: I cannot
do unit testing and I cannot use pydoc/epydoc for my libraries. They all
use the _() function but it is installed in the main program only. What
I do now is this:
import pydoc
import sys
import __builtin__
import os
sys.argv.append('-g')
def _(s):
return str(s)
__builtin__._ = _
pydoc.cli()
But this is very very ugly.
Another problem is with libraries. I have a common library 'LibFoo' and
several projects 'Project1', 'Project2' etc. I would like to distribute
my projects and my library as distinct Python (distutil) packages. Of
course, I would like to include all messages (po, pot and mo files) with
my distributions. Is there a standard way to do it? I mean, there are
many packages out there and most of them need i18n. Also there are many
projects and they also need i18n. But how these two come together? There
should be a standard way to unify gettext messages from various
libraries. I'm thinking about a general i18n protocol, where each
package or module has a standard way to add its own messages to the whole.
Les
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Re: simple question: $1, $2 in py ?
Oh, yes. Right : ) It feels that I miss-looked it. thank You very much for an advice : ) Also try the OptParse module. http://www.python.org/doc/2.4/lib/module-optparse.html It handles the GNU/POSIX syntax very well. Les -- http://mail.python.org/mailman/listinfo/python-list
epydoc CLI and many files
Hello, I have a problem under Windows. I use the cli.py program included with epydoc. I wrote a small program that lists all of my modules after the cli. Something like this: cli.py --html --inheritance=grouped module1.py module2.py module3.py .. The problem is that now I have so many modules that the shell (cmd.exe) cannot interpret this as a one command. It truncates the command line and gives me and error message. (cli.py does not start). Unfortunately, I cannot split the documentation into parts, because there are many crossreferences. How to overcome this problem? Les -- http://mail.python.org/mailman/listinfo/python-list
pexpect.exitstatus not working?
This function:
def scp(from_path,to_path,pwd):
Copy a file with scp.
cmd = '/bin/csh -c scp -q %s %s ; echo XXX' %(from_path,to_path)
print cmd
child = pexpect.spawn(cmd)
child.expect('Password:')
child.sendline(pwd)
child.expect('XXX')
return child.exitstatus
always returns None. This one:
def scp(from_path,to_path,pwd):
Copy a file with scp.
cmd = 'scp -q %s %s ' %(from_path,to_path)
print cmd
child = pexpect.spawn(cmd)
child.expect('Password:')
child.sendline(pwd)
child.interact()
return child.exitstatus
will return the correct exit status. The big problem is that I would
like to run this function from a cron job. Inside a cron job, interact()
will not work because it is not connected to a real terminal. How can I
get the exit status code? Please help me.
Les
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Re: pexpect.exitstatus not working?
Laszlo Zsolt Nagy wrote:
This function:
def scp(from_path,to_path,pwd):
Copy a file with scp.
cmd = '/bin/csh -c scp -q %s %s ; echo XXX' %(from_path,to_path)
print cmd
child = pexpect.spawn(cmd)
child.expect('Password:')
child.sendline(pwd)
child.expect('XXX')
return child.exitstatus
always returns None.
How can I
get the exit status code? Please help me.
I could develop a workaround, but this is a real hack, using bourne
shell and the $? variable.
def scp(from_path,to_path,pwd):
Copy a file with scp.
Return the exit code.
cmd = '/bin/sh -c scp -q %s %s ; echo $? ; echo XXX '
%(from_path,to_path)
print cmd
child = pexpect.spawn(cmd)
child.expect('Password:')
child.sendline(pwd)
child.expect(XXX)
parts = []
for item in child.before.split('\n'):
if item.strip() != :
parts.append(item.strip())
code = int(parts[-1])
print exit code:, code
if (code != 0):
print parts[0]
return code
Is there a platform independent solution?
Les
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Re: FileIO problem
Try this: gclas = raw_input(What is the class:) def Princlas(): count = 0 while count != 1000: count = count + 1 return Admin forceclass %s %s % ( count , gclas ) #asks for file name a = raw_input(What is new file name:) out_file = open(a,w) #this is the input of text out_file.write(Princlas()) out_file.close() i know i need to get it to a string but i dont know how? Your functions should RETURN a string, with the return statement. Another issue: you cannot write the function itself, only its result: out_file.write(Princlas()) instead of out_file.write(Princlas) -- http://mail.python.org/mailman/listinfo/python-list
Re: zlib + Windows 32 service problem (ImportError)
| | C:\Python24;C:\Python24\DLLs;c:\Python24\Lib\site-packages\win32;c:\oracle\product\10.1.0\db_1\bin;c:\oracle\product\10.1.0\db_1\jre\1.4.2\bin\client;c:\oracle\product\10.1.0\db_1\jre\1.4.2\bin;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;C:\Program | Files\Common Files\GTK\2.0\bin | | Then I restarted my computer. It is still missing initzlib. :-( | Please note that I can run the same program as an application, logged in | as the same user. | | Les Changing the Windows dll search path doesn't make any difference. It is sys.path (Python's search path) that's causing you the headache. Please see the mentioned thread for proposed solutions. Great. I could make my service working with this snippet: import sys sys.path.insert(0,r'C:\Python24\DLLs') But this is very ugly. Primarily, I do not want to use absolute path names in a this program. I want to use the same code on different computers and operating systems, but this code is not portable. Secondly, I do not understand why sys.path is different when I start python interactively. I believe that sys.path should be the same when starting the program as a service. The only difference between the application and the service is that the 'main' program of the service imports some additional modules. See them below. iT:\Python\Projects\NamedConnectorpython Python 2.4.1 (#65, Mar 30 2005, 09:13:57) [MSC v.1310 32 bit (Intel)] on win32 Type help, copyright, credits or license for more information. import sys s1 = str(sys.path) import win32serviceutil, win32service import pywintypes, win32con, winerror from win32event import * from win32file import * from win32pipe import * from win32api import * from ntsecuritycon import * s2 = str(sys.path) print s1 == s2 True I cannot distribute my service until I make it independent of the python installation directory. Why sys.path is different when starting the code as a windows service? How can I make this code portable? By the way, you have been a great help. Thank you very much. I can now continue working. :-) Les -- http://mail.python.org/mailman/listinfo/python-list
sys.path and win32 services (was: importerror)
Why do you think str() is needed here? Because I'm not sure if sys.path was overwritten or changed. Some bad modules could overwrite sys.path with another list. I know I'm paranoid. :-) Possibly because sys.path can start with '' which is interpreted as the current directory. Perhaps when the code is started as a windows service [I know nothing about windows services], the current directory is set to %windir%\system32 (where lots of DLLs hang out), and if there is a zlib.dll there, it will get picked up first. Try printing the current directory (see above). Okay, I did so. I wrote a service that prints out sys.path into a logfile. Here is the result: sys.path=['C:\\Python24\\lib\\site-packages\\win32', 'T:\\Python\\Lib', 'C:\\WINDOWS\\system32\\python24.zip', 'C:\\WINDOWS\\system32', 'C:\\Python24\\DLLs', 'C:\\Python24\\lib', 'C:\\Python24\\lib\\plat-win', 'C:\\Python24\\lib\\lib-tk', 'C:\\Python24\\lib\\site-packages\\win32', 'C:\\Python24', 'C:\\Python24\\lib\\site-packages', 'C:\\Python24\\lib\\site-packages\\PIL', 'C:\\Python24\\lib\\site-packages\\win32\\lib', 'C:\\Python24\\lib\\site-packages\\Pythonwin', 'C:\\Python24\\lib\\site-packages\\wx-2.6-msw-ansi', 'T:\\Python\\Projects\\NamedConnector'] The empty string is not on sys.path. This is very strange, because it is different when I start the python interactively. The problem was caused by C:\WINDOWS\system32, not the empty string. I'm still not sure why it is included in sys.path, and why '' is not there? I also checked the Python documentation about sys.path, and read the thread mentioned before but still sys.path is magical, and magic is not Pythonic. :-) Anyway, I think I have found the most platform independent solution. Here it is: import _socket import os import sys dyndir = os.path.split(_socket.__file__)[0] # This can be /usr/local/lib/python2.4/lib-dynload or C:\Python24\DLLs or whatever sys.path.append(dyndir) In most cases, '_socket.pyd' will be the first module that can be imported, and it will by in the dynaload directory for sure. I feel this is still unclean code. Do you think that it would be nice to add new features to the sys module? sys.dlpath - could be the path to the lib-dynload or DLLs folder sys.libpath - could be the path to the lib folder Setting the PYTHONVERBOSE environment variable may assist in showing where modules are being loaded from. This cannot be used in conjunction with a windows service, because its output cannot be seen. :-( -- http://mail.python.org/mailman/listinfo/python-list
Re: zlib + Windows 32 service problem (ImportError)
vincent wehren wrote: Laszlo Zsolt Nagy [EMAIL PROTECTED] schrieb im Newsbeitrag news:[EMAIL PROTECTED] | Sorry, I realized that the import zlib was not executed from my | (working) service. | So here is the question: why can't I use zlib from a win32 service? Is | there any way to make it working? | | - | Python could not import the service's module | File T:\Python\Projects\NamedConnector\Service.py, line 17, in ? | from Processor import * | File c:\Python\Projects\NamedConnector\Processor.py, line 35, in ? | from mess import MessageSocket | File T:\Python\Lib\mess\MessageSocket.py, line 31, in ? | import zlib | exceptions.ImportError: dynamic module does not define init function | (initzlib) | - | | | I had a similar problem where a zlib.dll that is *not a Python extension* is in sys.path *before* zlib.pyd. Python will try to import this zlib.dll and find the dll doesn't export a initzlib: for more info see http://mail.python.org/pipermail/python-list/2004-October/thread.html#248107 Thanks. I set my system environment variable 'PATH' to this: C:\Python24;C:\Python24\DLLs;c:\Python24\Lib\site-packages\win32;c:\oracle\product\10.1.0\db_1\bin;c:\oracle\product\10.1.0\db_1\jre\1.4.2\bin\client;c:\oracle\product\10.1.0\db_1\jre\1.4.2\bin;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;C:\Program Files\Common Files\GTK\2.0\bin Then I restarted my computer. It is still missing initzlib. :-( Please note that I can run the same program as an application, logged in as the same user. Les -- http://mail.python.org/mailman/listinfo/python-list
Windows 32 service problem (ImportError)
Hi All! I have a running service (a small web server) implemented in python, running as a win32 service. I wrote another program that is very similar to the web server but I cannot start the service. From the event log, I can read this traceback: - Python could not import the service's module File T:\Python\Projects\NamedConnector\Service.py, line 17, in ? from Processor import * File c:\Python\Projects\NamedConnector\Processor.py, line 35, in ? from mess import MessageSocket File T:\Python\Lib\mess\MessageSocket.py, line 31, in ? import zlib exceptions.ImportError: dynamic module does not define init function (initzlib) - Facts: 1. I'm using the same module (MessageSocket) for my web server 2. The web server runs fine as a service Where is the problem? Please help. Les -- http://mail.python.org/mailman/listinfo/python-list
zlib + Windows 32 service problem (ImportError)
Sorry, I realized that the import zlib was not executed from my (working) service. So here is the question: why can't I use zlib from a win32 service? Is there any way to make it working? - Python could not import the service's module File T:\Python\Projects\NamedConnector\Service.py, line 17, in ? from Processor import * File c:\Python\Projects\NamedConnector\Processor.py, line 35, in ? from mess import MessageSocket File T:\Python\Lib\mess\MessageSocket.py, line 31, in ? import zlib exceptions.ImportError: dynamic module does not define init function (initzlib) - -- http://mail.python.org/mailman/listinfo/python-list
Re: About size of Unicode string
Frank Abel Cancio Bello wrote:
Hi all!
I need know the size of string object independently of its encoding. For
example:
len('123') == len('123'.encode('utf_8'))
while the size of '123' object is different of the size of
'123'.encode('utf_8')
More:
I need send in HTTP request a string. Then I need know the length of the
string to set the header content-length independently of its encoding.
Any idea?
This is from the RFC:
The Content-Length entity-header field indicates the size of the
entity-body, in decimal number of OCTETs, sent to the recipient or, in
the case of the HEAD method, the size of the entity-body that would
have been sent had the request been a GET.
Content-Length= Content-Length : 1*DIGIT
An example is
Content-Length: 3495
Applications SHOULD use this field to indicate the transfer-length of
the message-body, unless this is prohibited by the rules in section
4.4 http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.4.
Any Content-Length greater than or equal to zero is a valid value.
Section 4.4 describes how to determine the length of a message-body if
a Content-Length is not given.
Looks to me that the Content-Length header has nothing to do with the
encoding. It is a very low levet stuff. The content length is given in
OCTETs and it represents the size of the body. Clearly, it has nothing
to do with MIME/encoding etc. It is about the number of bits transferred
in the body. Try to write your unicode strings into a StringIO and take
its length
Laci
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Re: idiom for constructor?
Mac wrote: Is there a nice Python idiom for constructors which would expedite the following? class Foo: def __init__(self, a,b,c,d,...): self.a = a self.b = b self.c = c self.d = d ... I would like to keep the __init__ parameter list explicit, as is, rather than passing in a dictionary, as I want the code to be explicit about what arguments it expects... in effect enforcing the right number of arguments. I could list the parameter names programatically: classA(object): def __init__(self,a,b,c,d,e,f,): varnames = self.__init__.im_func.func_code.co_varnames for varname in varnames[1:7]: print varname a = A(1,2,3,4,5,6) But I could not get their values. -- http://mail.python.org/mailman/listinfo/python-list
Re: idiom for constructor?
You could try: class Foo: def __init__(self,a,b,c,d): args = locals() for arg in args.keys(): if name!='self': self.__dict__[arg] = args[arg] Should be: if arg!='self' Also it is not perfect. For example: class Foo: def __init__(self,a,b,c,d): temp = 12 self.foo2 = temp + 4 args = locals() for arg in args.keys(): if arg!='self': self.__dict__[arg] = args[arg] a = Foo(1,2,3,4) print dir(a) Results in: ['__doc__', '__init__', '__module__', 'a', 'b', 'c', 'd', 'foo2', 'temp'] E.g. not only the parameters but all local variables are used... -- http://mail.python.org/mailman/listinfo/python-list
Manipulating mailboxes
Hi All, I need to create a daemon that sits on a server and forwards some e-mails. (Well not only that, it needs to change header information before forwarding and also insert messages into a database). The mailbox module is fine but I do not see a way to delete/add messages - it is ready only. The other possiblity is IMAP4 but it is bad because my program should not store passwords for all users. I can only see one solution right now: 1. Make a copy of the mailbox 2. Truncate the mailbox 3. Process the messages in the copy and forward the e-mails by sending out real e-mails. But this looks so clumsy. Is there a way to delete/add messages to mailboxes of different users, directly? Thanks, Laci 2.0 -- http://mail.python.org/mailman/listinfo/python-list
Re: Manipulating mailboxes
Maksim Kasimov wrote: change header information, insert messages into a database, delete/add messages, should not store passwords for all users, ... and any things else you wish to do - if your OS is UNIX - just forward mail messages of some users to your python script (you don't need to write a daemon for this) All you need is to place file .forward in users home directory, and write like this: |/path/myscript.py and chmod the script: chmod 777 /path/myscript.py Oh, fantastic. :-) Then I can open stdin and read the e-mail message from there. Thank you so much Laci 2.0 -- http://mail.python.org/mailman/listinfo/python-list
minidom and DTD
Hi All, How can I put the !DOCTYPE collection SYSTEM recipes.dtd thing into an XML created by xml.dom.minidom? Of course I can parse the generated XML file and insert the DOCTYPE string but there must be a standard way to do this... Best, Laci 2.0 -- http://mail.python.org/mailman/listinfo/python-list
Re: minidom and DTD
Martin v. Löwis wrote: Laszlo Zsolt Nagy wrote: How can I put the !DOCTYPE collection SYSTEM recipes.dtd thing into an XML created by xml.dom.minidom? You should put a DocumentType node into your DocumentNode, and pass a qualifiedName of collection and a systemId of recipes.dtd to the createDocumentType call. That worked, thank you. -- http://mail.python.org/mailman/listinfo/python-list
Re: EpyDoc problem
EpyDoc is hosted in Sourceforge. This alone may answer your question about a bug-tracker: http://sourceforge.net/tracker/?atid=405618group_id=32455func=browse Well, I wrote to the bug tracker some days ago but no answer so far. -- http://mail.python.org/mailman/listinfo/python-list
Re: super() and automatic method combination
I have the impression that this is supposed to call the f method
in both A and B, so it should print
Not really true. The first parameter of 'super' should be a type, not an
instance.
A
B
C
or maybe
B
A
C
depending on the resolution order. However, it only calls A.f and not B.f.
I also notice that if I say
class B(object):
def f(self):
super(B,self).f()
print 'b'
then
test(B)
raises an exception since B has no superclass with an f method.
Correct. When you use super(B,self) it accesses the current instance as
the class B. If it has no method named 'f' then this will end up in an
exception.
That doesn't seem like such a good thing necessarily.
But yes, it is. When you try to call a nonexistent method, it should
raise an exception.
Anyway, is there a preferred way of writing this example so that C.f
automatically calls both A.f and B.f?
I do not know a preferred way. However, I made this example for you, I
hope it helps.
class CallSupersMixin(object):
def callsupers(self,fname,*args,**kwargs):
l = self.__class__.__bases__
for cls in l:
if hasattr(cls,fname):
getattr(cls,fname)(self,*args,**kwargs)
elif cls == CallSupersMixin:
pass
else:
raise AttributeError(Base class %s does not have a
method named %s % ( str(cls),fname ) )
class A(object):
def f(self):
print 'A.f called'
class B(object):
def f(self):
print 'B.f called'
class AB(A,B,CallSupersMixin):
def f(self,*args,**kwargs):
self.callsupers('f',*args,**kwargs)
ab = AB()
ab.f()
Of course you can remove the raise AttributeError part. Then it will
call only the classes that have the given method.
I know it is not a very good example but you can go from here.
Best,
Laci 2.0
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Re: super() and automatic method combination
The trick is that C.f only calls A.f, but A.f needs to end up calling B.f when it is used in a C. I believe your response only applies to single inheritance. For classes with muliple bases classes, you need to call the base methods one by one. BTW I prefer to call the base methods in this form: class AB(A,B): def f(self): A.f(self) B.f(self) This arises the question: is there a difference between these: super(A,self).f() # I do not use to use this A.f(self) -- _ Laszlo Nagy web: http://designasign.biz IT Consultant mail: [EMAIL PROTECTED] Python forever! -- http://mail.python.org/mailman/listinfo/python-list
Re: super() and automatic method combination
Which is fine so long as nobody else tries to add further subclasses later:
class C(B): ...
class Mine(AB,C): ...
Mine().f()
Using super throughout this works (it calls f in Mine, AB, A, C, B, and
then Base), but your explicit call to the base classes means that if you
don't call C.f() explicitly from Mine it never gets called, and if you do
call it explicitly from Mine it gets called *after* B.f() has been called
(and B.f() probably ends up being called twice).
Okay, I understand now. It was a good learning session for me. :-)
At this moment I do not see a problem where I would need a diamond
shaped inheritance graph but
I'll keep in mind the difference between super and direct calls. :-)
I tested this and I realized that if you change the parameter list in
the descendants then it is not wise to use super.
I'm going to publish the example below, I hope others can learn from it too.
Example (good):
class A(object):
def f(self):
print A.f called
class B(A):
def f(self):
super(B,self).f()
print B.f called
class C(A):
def f(self):
super(C,self).f()
print C.f called
class D(B,C):
def f(self):
super(D,self).f()
print D.f called
d = D()
d.f()
Results in:
A.f called
C.f called
B.f called
D.f called
Example (bad):
class B(A):
def f(self,what):
super(B,self).f()
print B.f called (%s) % what
Will result in:
C:/Python24/pythonw.exe -u C:/Python/Projects/Test4/test4.py
Traceback (most recent call last):
File C:/Python/Projects/Test4/test4.py, line 22, in ?
d.f()
File C:/Python/Projects/Test4/test4.py, line 17, in f
super(D,self).f()
TypeError: f() takes exactly 2 arguments (1 given)
Of course you cannot tell if super(C,self).f() will call A.f or not
(when add another
subclass under class A, it will change the MRO...)
If you do not want to add any other subclasses then probably you can use
super(C,self).f('foo')
but in that case it is equivalent to
A.f(self,'foo')
Best,
Laci 2.0
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Re: EpyDoc problem
Looks like it is a problem with wxWidgets. There is no problem if I do not import wx. How to overcome this problem? Currently I cannot document modules that import wx. :-( I found the answer on the wxPython-users list. It is disappointing that the standard documentation tool has no support. :-( I had to patch EpyDoc. The author was not responding and there is no mailing list for EpyDoc. Is it still a live project? -- _ Laszlo Nagy web: http://designasign.biz IT Consultant mail: [EMAIL PROTECTED] Python forever! -- http://mail.python.org/mailman/listinfo/python-list
EpyDoc problem
Hello, I would like to create documentation for my lib using EpyDoc. I do not see how to report bugs on the EpyDoc home page. When I try to create documentation, I get this error: Internal error: Expected a pointer Unhandled exception in thread started by function document at 0x00A44C30 At the end of the traceback: wx\_misc.py line 3665, in _eq_ return _misc_.DateTime.__eq__(*args) TypeError: Expected a pointer I have no clue what does it mean but I guess it is an EpyDoc bug. Does anyone ran into the same problem? Any ideas? -- _ Laszlo Nagy web: http://designasign.biz IT Consultant mail: [EMAIL PROTECTED] Python forever! -- http://mail.python.org/mailman/listinfo/python-list
Re: EpyDoc problem
At the end of the traceback: wx\_misc.py line 3665, in _eq_ return _misc_.DateTime.__eq__(*args) TypeError: Expected a pointer I have no clue what does it mean but I guess it is an EpyDoc bug. Does anyone ran into the same problem? Any ideas? Looks like it is a problem with wxWidgets. There is no problem if I do not import wx. How to overcome this problem? Currently I cannot document modules that import wx. :-( -- _ Laszlo Nagy web: http://designasign.biz IT Consultant mail: [EMAIL PROTECTED] Python forever! -- http://mail.python.org/mailman/listinfo/python-list
Re: Python instances
Guess i shouldn't think of the __init__(self) function as a constructor then. __init__ is THE constructor in Python -- _ Laszlo Nagy web: http://designasign.biz IT Consultantmail: [EMAIL PROTECTED] Python forever! -- http://mail.python.org/mailman/listinfo/python-list
Re: Faster os.walk()
fuzzylollipop wrote: I am trying to get the number of bytes used by files in a directory. I am using a large directory ( lots of stuff checked out of multiple large cvs repositories ) and there is lots of wasted time doing multiple os.stat() on dirs and files from different methods. Do you need a precise value, or are you satisfied with approximations too? Under which operating system? The 'du' command can be your firend. man du Best, Laci 2.0 -- _ Laszlo Nagy web: http://designasign.biz IT Consultantmail: [EMAIL PROTECTED] Python forever! -- http://mail.python.org/mailman/listinfo/python-list
Re: logging to two files
Tor Erik Sønvisen wrote: Hi Have the following code: import logging logging.basicConfig(level = logging.DEBUG, format = '[%(levelname)-8s %(asctime)s] %(message)s', filename = 'rfs.log', filemode = 'w') When using logging.(debug, info etc) stuff is logged to rfs.log. How may I specify another log with different charateristics, such as a different file regards I'm not sure if I understood your problem. However, just a tip for you: is it possible to create your own handler object? (See section 6.29.5 in the library reference). You could setup a handler object that holds a list of other handler objects and distribute all logging events to them. This way you should be able to add/remove handlers at runtime. Best, Laci 2.0 -- _ Laszlo Nagy web: http://designasign.biz IT Consultantmail: [EMAIL PROTECTED] Python forever! -- http://mail.python.org/mailman/listinfo/python-list
Re: modules and namespaces
However it doesn't work until I import the string module into m1 and m2
modules. I found in the manual that imported modules will be searched in
the container module first. Is it more efficient to import the string
module into main and m1 and m2 than importing only into m1 and m2?
I bet the most efficient is
str.join( ('a','b'))
The reason is that 'str' is a built-in type. But since new style classes
were introduced, they are also real objects with methods. :-)
p.s.: Hello Mage. I'm also known as nagylzs at enternet dot hu. Do you
remember me from the SQL list? Good to see you here. :-)
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IT Consultantmail: [EMAIL PROTECTED]
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