Re: how to modify text in html form from python
PS: If my question is not clear, I am trying to share the form between the client and server. just as many sites out there allow you to modify existing data: 1) the server pops up a form with your data in it. 2) the client can modify it and submit. I know this is a _basic_ question, sorry. Philippe Philippe C. Martin wrote: Hi, I am trying to change the data in a form field from python. The following code does not crash but has no effect as if form is just a copy of the original html form. Must I recreate the form order to do that ? My point is for the client to be able to re-read the modified data. Thanks, Philippe #!/usr/bin/python import cgi import os import sys import logging import cgi sys.stderr = sys.stdout print Content-type: text/html\n try: form = cgi.FieldStorage() #logging.warning (form) except: logging.exception(\nEXCEPTION 1) try: form['tosrv'].value = TEST except: logging.exception(\nEXCEPTION 2) pass html body titleSmart Logon/title h1Smart Logon/h1 hr FORM METHOD=POST ACTION=/cgi-bin/scfbweb.py table TRTD INPUT TYPE=HIDDEN NAME=key VALUE=process TO SERVER:BR INPUT type=text NAME=tosrv value=TO size=60 BR FROM SERVERBR INPUT type=text name=fromsrv value=FROM size=60 P INPUT TYPE=SUBMIT VALUE=START /TD/TR/table /FORM /body /html -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Philippe C. Martin wrote: PS: If my question is not clear, I am trying to share the form between the client and server. just as many sites out there allow you to modify existing data: 1) the server pops up a form with your data in it. 2) the client can modify it and submit. I know this is a _basic_ question, sorry. When debugging Python cgi scripts, it is helpful to run the scripts from a command line just to make sure there aren't any compiler errors. Depending on how the server is set up, you'll get a server error or just a blank page if your script won't compile. When I run your script directly as I suggest, here's what I get: [EMAIL PROTECTED]:~$ python test.py File test.py, line 23 html ^ SyntaxError: invalid syntax D'oh! You needed to surround the html with quotes to make it a string, as in: print html ... /html I don't really understand your original problem, but perhaps this will help get you rolling again. -- Paul McNett http://paulmcnett.com http://dabodev.com -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Philippe C. Martin [EMAIL PROTECTED] writes: PS: If my question is not clear, I am trying to share the form between the client and server. Yes, your question is not clear. And this statement doesn't clarify it. That you quoted the share shows you are probably aware of this, if not consciously so. just as many sites out there allow you to modify existing data: 1) the server pops up a form with your data in it. 2) the client can modify it and submit. This doesn't really help, either. The server can't pop up a form; only the client can do that. All the server can do is send data to the client. The client can't modify data on the server. It can send data to the server, but that arrives as *new* data. The server can use that to replace old data, thus modifying that old data. I know this is a _basic_ question, sorry. It's not clear it's a basic question, because it's not clear what you're trying to do. Try answering these questions: Where do you expect the HTML to come from? Where do you expect the data originally in the HTML form to come from? Where do you expect the data the user inputs into the form to be stored? mike Philippe Philippe C. Martin wrote: Hi, I am trying to change the data in a form field from python. The following code does not crash but has no effect as if form is just a copy of the original html form. Must I recreate the form order to do that ? My point is for the client to be able to re-read the modified data. Thanks, Philippe #!/usr/bin/python import cgi import os import sys import logging import cgi sys.stderr = sys.stdout print Content-type: text/html\n try: form = cgi.FieldStorage() #logging.warning (form) except: logging.exception(\nEXCEPTION 1) try: form['tosrv'].value = TEST except: logging.exception(\nEXCEPTION 2) pass html body titleSmart Logon/title h1Smart Logon/h1 hr FORM METHOD=POST ACTION=/cgi-bin/scfbweb.py table TRTD INPUT TYPE=HIDDEN NAME=key VALUE=process TO SERVER:BR INPUT type=text NAME=tosrv value=TO size=60 BR FROM SERVERBR INPUT type=text name=fromsrv value=FROM size=60 P INPUT TYPE=SUBMIT VALUE=START /TD/TR/table /FORM /body /html -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Thanks Paul but I was not clear: the html page is separate from the python script, it calls the python script when the button is clicked. The indentation error must be because of my cut and paste. PS: My goal is to be able to exchange data between the server and the client (browser plugin) as I have not yet found an easier way. Regards, Philippe Paul McNett wrote: Philippe C. Martin wrote: PS: If my question is not clear, I am trying to share the form between the client and server. just as many sites out there allow you to modify existing data: 1) the server pops up a form with your data in it. 2) the client can modify it and submit. I know this is a _basic_ question, sorry. When debugging Python cgi scripts, it is helpful to run the scripts from a command line just to make sure there aren't any compiler errors. Depending on how the server is set up, you'll get a server error or just a blank page if your script won't compile. When I run your script directly as I suggest, here's what I get: [EMAIL PROTECTED]:~$ python test.py File test.py, line 23 html ^ SyntaxError: invalid syntax D'oh! You needed to surround the html with quotes to make it a string, as in: print html ... /html I don't really understand your original problem, but perhaps this will help get you rolling again. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Mike, Here is what I am trying to do: WHAT -) a client opens his/her browser and click on some button which triggers my plugin -) the plugin starts to communicate with a server on some URL. -) the communication between the server and the client involves a few exchanges: data from client to server, then from server to client,. -) just for info (I do not think it's relevant to my problem) on each side (server and client) there is a smart card (that's why I need a plugin) and the information exchanged comes from/go to the smart cards -) The smart card on the server side eventually decides whether or not the smart client on the client side is OK and tells so to the cgi script which acts accordingly * HOW (if there's a better way let me know please) ** As I have not found any better solution yet, I am trying to do the following (on the server there is an html file and a cgi file) -) the plugging opens the correct url which has a form with a click button -) the customer clicks on the button -) the server puts some information in a hidden form field (info from local smart card) -) the pluggin fetches the information from the form field and gives it to its local smart card ... (this a couple of time) -) the cgi script gets the final verdict from the server smart card and acts accordingly. I hope that is clearer. Regards, Philippe Mike Meyer wrote: Philippe C. Martin [EMAIL PROTECTED] writes: PS: If my question is not clear, I am trying to share the form between the client and server. Yes, your question is not clear. And this statement doesn't clarify it. That you quoted the share shows you are probably aware of this, if not consciously so. just as many sites out there allow you to modify existing data: 1) the server pops up a form with your data in it. 2) the client can modify it and submit. This doesn't really help, either. The server can't pop up a form; only the client can do that. All the server can do is send data to the client. The client can't modify data on the server. It can send data to the server, but that arrives as *new* data. The server can use that to replace old data, thus modifying that old data. I know this is a _basic_ question, sorry. It's not clear it's a basic question, because it's not clear what you're trying to do. Try answering these questions: Where do you expect the HTML to come from? Where do you expect the data originally in the HTML form to come from? Where do you expect the data the user inputs into the form to be stored? mike Philippe Philippe C. Martin wrote: Hi, I am trying to change the data in a form field from python. The following code does not crash but has no effect as if form is just a copy of the original html form. Must I recreate the form order to do that ? My point is for the client to be able to re-read the modified data. Thanks, Philippe #!/usr/bin/python import cgi import os import sys import logging import cgi sys.stderr = sys.stdout print Content-type: text/html\n try: form = cgi.FieldStorage() #logging.warning (form) except: logging.exception(\nEXCEPTION 1) try: form['tosrv'].value = TEST except: logging.exception(\nEXCEPTION 2) pass html body titleSmart Logon/title h1Smart Logon/h1 hr FORM METHOD=POST ACTION=/cgi-bin/scfbweb.py table TRTD INPUT TYPE=HIDDEN NAME=key VALUE=process TO SERVER:BR INPUT type=text NAME=tosrv value=TO size=60 BR FROM SERVERBR INPUT type=text name=fromsrv value=FROM size=60 P INPUT TYPE=SUBMIT VALUE=START /TD/TR/table /FORM /body /html -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Philippe C. Martin [EMAIL PROTECTED] writes: Mike, Here is what I am trying to do: WHAT -) a client opens his/her browser and click on some button which triggers my plugin -) the plugin starts to communicate with a server on some URL. -) the communication between the server and the client involves a few exchanges: data from client to server, then from server to client,. -) just for info (I do not think it's relevant to my problem) on each side (server and client) there is a smart card (that's why I need a plugin) and the information exchanged comes from/go to the smart cards -) The smart card on the server side eventually decides whether or not the smart client on the client side is OK and tells so to the cgi script which acts accordingly * HOW (if there's a better way let me know please) ** As I have not found any better solution yet, I am trying to do the following (on the server there is an html file and a cgi file) -) the plugging opens the correct url which has a form with a click button -) the customer clicks on the button -) the server puts some information in a hidden form field (info from local smart card) -) the pluggin fetches the information from the form field and gives it to its local smart card ... (this a couple of time) -) the cgi script gets the final verdict from the server smart card and acts accordingly. I hope that is clearer. Some. To continue clarifying: The phrase cgi script refers to a server-side script that is run in response to the user clicking something on the client. That's what you expect it to be, right? Do you expect the plugin to display a form? Or to ouput a form that the client will display? You've got lots of stuff going on here. I count at least five programs and three network connections. How much is working, and which parts are you trying to do in Python? mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Mike Meyer wrote: Philippe C. Martin [EMAIL PROTECTED] writes: Some. To continue clarifying: The phrase cgi script refers to a server-side script that is run in response to the user clicking something on the client. That's what you expect it to be, right? Yes, the cgi script on the server side hooks up to the local (server) smart card Do you expect the plugin to display a form? Or to ouput a form that the client will display? No, I want of all the html stuff to be handled by the server You've got lots of stuff going on here. I count at least five programs and three network connections. How much is working, and which parts are you trying to do in Python? I am starting from existing applications (cross-platform - and in python 99% ) that work even through tcp-ip (sockets). I am just trying to apply them to a web environement. So prior to any user interaction with the page, I need some data exchange between the plugin and the server (authentication). So _if_ (I'm a web newbie) the server and the clien(plugin) could exchange data through some form field, my prototype would be much further along. Here is a small picture: Smart Card - driver - cgi - apache .. [NET] browser - plugin - driver - Smart Card Regards, Philippe mike -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
I feel fairly stupid ... but to my defense in the past 17 years of coding, i've only spent 3 days looking at web stuff: I now can understand how writing to an existing form field from a cgi script might not work: how would the browser know ?: unless there is a very sophisticated scheme there (as those used in image transfer), I assume the complete page would have to be sent back: so might as well regenerate/rewrite everything. Yes ? I so, I'm back to finding a way for a browser plugin and a server based cgi script to exchange information. Any idea welcome... I know I don't want to open another socket/port but stick to http:80 Regards, Philippe Mike Meyer wrote: Philippe C. Martin [EMAIL PROTECTED] writes: Mike, Here is what I am trying to do: WHAT -) a client opens his/her browser and click on some button which triggers my plugin -) the plugin starts to communicate with a server on some URL. -) the communication between the server and the client involves a few exchanges: data from client to server, then from server to client,. -) just for info (I do not think it's relevant to my problem) on each side (server and client) there is a smart card (that's why I need a plugin) and the information exchanged comes from/go to the smart cards -) The smart card on the server side eventually decides whether or not the smart client on the client side is OK and tells so to the cgi script which acts accordingly * HOW (if there's a better way let me know please) ** As I have not found any better solution yet, I am trying to do the following (on the server there is an html file and a cgi file) -) the plugging opens the correct url which has a form with a click button -) the customer clicks on the button -) the server puts some information in a hidden form field (info from local smart card) -) the pluggin fetches the information from the form field and gives it to its local smart card ... (this a couple of time) -) the cgi script gets the final verdict from the server smart card and acts accordingly. I hope that is clearer. Some. To continue clarifying: The phrase cgi script refers to a server-side script that is run in response to the user clicking something on the client. That's what you expect it to be, right? Do you expect the plugin to display a form? Or to ouput a form that the client will display? You've got lots of stuff going on here. I count at least five programs and three network connections. How much is working, and which parts are you trying to do in Python? mike -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Philippe C. Martin [EMAIL PROTECTED] writes: You've got lots of stuff going on here. I count at least five programs and three network connections. How much is working, and which parts are you trying to do in Python? I am starting from existing applications (cross-platform - and in python 99% ) that work even through tcp-ip (sockets). I am just trying to apply them to a web environement. So prior to any user interaction with the page, I need some data exchange between the plugin and the server (authentication). I don't know much about plugins. I believe they get started when the page loads, which gives you a chance to do the authentication when you want it done. So _if_ (I'm a web newbie) the server and the clien(plugin) could exchange data through some form field, my prototype would be much further along. That won't work very well. HTML goes to the client to display. The server can put data in hidden form elements that code running on the client side can get to - and change - via the document object model (DOM). However, the only way to send the changed data back to the server is to get the client to submit the form. You can automate that, but the results will be disconcerting to the user: they load a page, and it reloads multiple times as the plugin exchanges data with the server. Here is a small picture: Smart Card - driver - cgi - apache .. [NET] browser - plugin - driver - Smart Card The problem with this is that the apache-browser connection isn't a connection, it's a series of HTTP request/repsonse pairs. Originally, this implied tearing down and setting up a TCP connection for every request. Modern software will leave the link open and reuse it - but modern software also tends to have multiple connetions open, so it can fetch images and other embedded objects in parallel. You can make this work, but doing it like that requires making multiple HTTP requests via the browser, which will be disconcerting. I'd recommend taking the browser out of the loop. Have the plugin talk directly to the server to do the authentication. That's what the latest web buzzword (AJAX) does: client-side software makes independent requests of the server (or *any* server) to get data, and possibly updates the document the browser is viewing as a result of that. So here's a scenario: the first cgi script gets info from the smart card that puts it in a hidden form element and sends the page to the browser. The plugin - started when the page loads - uses the DOM to get that data, then makes an *independent* HTTP request to the server, thus passing whatever it generated from the data in the form field to a second cgi script. This happens several times, then the plugin changes the HTML form to put whatever the cgi script generated into the form, so that when the user finally submits the form, the third cgi script - the one that handles the submitted form - sees the data from the second script. Actually, the exchanges between the plugin and the server don't need to be HTTP requests. If you've got this working over some other TCP protocol, there's no reason you can't keep doing it that way. A word of warning: authentication protocols are fragile; they tend to stop being resistant to attacks after even relatively minor changes, so you want to be very carefull about changing the protocol. Web-based things are very open. You can't really do much to prevent the client end from doing *whatever they want* with the HTML you send them, or you generate for them on the fly. This also has serious security implications. Think carefully about what happens when the user pulls one of your forms out of the browser history, or bookmarks a page. Then make sure you get a thorough audit of the resulting system/protocol done by people who know what they're doing. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Philippe C. Martin [EMAIL PROTECTED] writes: I feel fairly stupid ... but to my defense in the past 17 years of coding, i've only spent 3 days looking at web stuff: I now can understand how writing to an existing form field from a cgi script might not work: how would the browser know ?: unless there is a very sophisticated scheme there (as those used in image transfer), I assume the complete page would have to be sent back: so might as well regenerate/rewrite everything. Yes ? I so, I'm back to finding a way for a browser plugin and a server based cgi script to exchange information. Any idea welcome... I know I don't want to open another socket/port but stick to http:80 Then you're out of luck. You can't even depend on their being an open http connection available to use when the plugin runs. The browser may well do: Load all data. Close connections. Render page as far as we can. Launch code objects that we loaded. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Philippe C. Martin [EMAIL PROTECTED] writes: * HOW (if there's a better way let me know please) ** As I have not found any better solution yet, I am trying to do the following (on the server there is an html file and a cgi file) If I understand it, you're trying to use a smart card to authenticate a web site login. The major browsers already have smart card interfaces (Windows CAPI for MSIE, or PKCS11 for Netscape/Moz*) so you shouldn't need a plugin. On the other hand, smart cards are very slow. The typical approach is as follows (MSIE version). Stop using special smart card programs and just use a card that implements CAPI with a from the vendor and that can sign against an X509 certificate. The CSP will have a special signature that makes it less scary to install than a browser plugin. You'll have to issue a cert for the smart card and there's various approaches to that, so I'll skip that part. Set up a TLS server to require a client cert from the CA that signed the smart card. The browser should recognize the challenge and select the right cert. The CSP will have its own interface for the user entering a PIN along with inserting the card. Once you have the TLS connection established, set a secure cookie in the client session and then redirect the browser to another URL that doesn't require the smart card (because otherwise the card will have to re-authenticate every click, which is very slow). From then on, use the cookie for authentication (it can have a timeout or whatever). -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Paul, That won't cut it: The cards I use/code do not have RSA capabilities but only symmetrical algorithms (AES, 3DES, ). I use the same type of authentication you would see between a POS and a Smart Card (ex: B0' in France) So I cannot hookup to one of the standards (PKCS11 or CSP). Thanks anyway. Regards, Philippe Paul Rubin wrote: Philippe C. Martin [EMAIL PROTECTED] writes: * HOW (if there's a better way let me know please) ** As I have not found any better solution yet, I am trying to do the following (on the server there is an html file and a cgi file) If I understand it, you're trying to use a smart card to authenticate a web site login. The major browsers already have smart card interfaces (Windows CAPI for MSIE, or PKCS11 for Netscape/Moz*) so you shouldn't need a plugin. On the other hand, smart cards are very slow. The typical approach is as follows (MSIE version). Stop using special smart card programs and just use a card that implements CAPI with a from the vendor and that can sign against an X509 certificate. The CSP will have a special signature that makes it less scary to install than a browser plugin. You'll have to issue a cert for the smart card and there's various approaches to that, so I'll skip that part. Set up a TLS server to require a client cert from the CA that signed the smart card. The browser should recognize the challenge and select the right cert. The CSP will have its own interface for the user entering a PIN along with inserting the card. Once you have the TLS connection established, set a secure cookie in the client session and then redirect the browser to another URL that doesn't require the smart card (because otherwise the card will have to re-authenticate every click, which is very slow). From then on, use the cookie for authentication (it can have a timeout or whatever). -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Mike Meyer wrote: Philippe C. Martin [EMAIL PROTECTED] writes: I feel fairly stupid ... but to my defense in the past 17 years of coding, i've only spent 3 days looking at web stuff: I now can understand how writing to an existing form field from a cgi script might not work: how would the browser know ?: unless there is a very sophisticated scheme there (as those used in image transfer), I assume the complete page would have to be sent back: so might as well regenerate/rewrite everything. Yes ? I so, I'm back to finding a way for a browser plugin and a server based cgi script to exchange information. Any idea welcome... I know I don't want to open another socket/port but stick to http:80 Then you're out of luck. You can't even depend on their being an open http connection available to use when the plugin runs. The browser may well do: Load all data. Close connections. Render page as far as we can. Launch code objects that we loaded. mike But the plugin opened the connection: var l_w = window.open(l_url,); Philippe -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Mike Meyer wrote: I don't know much about plugins. I believe they get started when the page loads, which gives you a chance to do the authentication when you want it done. Well not in this case actually: the user triggers the plugin which in turn open the url, so the connection is owned by the plugin That won't work very well. HTML goes to the client to display. The server can put data in hidden form elements that code running on the client side can get to - and change - via the document object model (DOM). However, the only way to send the changed data back to the server is to get the client to submit the form. You can automate that, but the results will be disconcerting to the user: they load a page, and it reloads multiple times as the plugin exchanges data with the server. Here again, I'm not dying for any page data to be visible: cannot the cgi script and the plugin do their business before that ? The problem with this is that the apache-browser connection isn't a connection, it's a series of HTTP request/repsonse pairs. Originally, this implied tearing down and setting up a TCP connection for every request. Modern software will leave the link open and reuse it - but modern software also tends to have multiple connetions open, so it can fetch images and other embedded objects in parallel. I'm lost here, better do some more reading You can make this work, but doing it like that requires making multiple HTTP requests via the browser, which will be disconcerting. I'd recommend taking the browser out of the loop. Have the plugin talk directly to the server to do the authentication. That's what the latest web buzzword (AJAX) does: client-side software makes independent requests of the server (or *any* server) to get data, and possibly updates the document the browser is viewing as a result of that. Here I think it's OK as the plugin can talk to server prior to the browser showing anything. So here's a scenario: the first cgi script gets info from the smart card that puts it in a hidden form element and sends the page to the browser. The plugin - started when the page loads - uses the DOM to get that data, then makes an *independent* HTTP request to the server, thus passing whatever it generated from the data in the form field to a second cgi script. This happens several times, then the plugin changes the HTML form to put whatever the cgi script generated into the form, so that when the user finally submits the form, the third cgi script - the one that handles the submitted form - sees the data from the second script. Actually, the exchanges between the plugin and the server don't need to be HTTP requests. If you've got this working over some other TCP protocol, there's no reason you can't keep doing it that way. Maybe that's my clue: can a cgi script, once triggered by a (let's say) POST request, use back and forth file transfer with the client ? through the _existing_ connection. A word of warning: authentication protocols are fragile; they tend to stop being resistant to attacks after even relatively minor changes, so you want to be very carefull about changing the protocol. Web-based things are very open. You can't really do much to prevent the client end from doing *whatever they want* with the HTML you send them, or you generate for them on the fly. This also has serious security implications. Think carefully about what happens when the user pulls one of your forms out of the browser history, or bookmarks a page. Then make sure you get a thorough audit of the resulting system/protocol done by people who know what they're doing. Even if the data when seen, there would not be any security breach as the cards have the keys + algo to understand the data. I realy just need of few tens of bytes to go back and forth (I'm frustrated ;-) Thanks Philippe mike -- http://mail.python.org/mailman/listinfo/python-list
Re: how to modify text in html form from python
Philippe C. Martin [EMAIL PROTECTED] writes: Mike Meyer wrote: I don't know much about plugins. I believe they get started when the page loads, which gives you a chance to do the authentication when you want it done. Well not in this case actually: the user triggers the plugin which in turn open the url, so the connection is owned by the plugin I think we don't mean the same thing when we say plugin. To me, a plugin is a bit of code that gets executed when the page is rendered to provide custom content with it's own behavior. Flash is probably the most popular example. Like I said, I don't know much about plugins, so they may be usable in other ways. That won't work very well. HTML goes to the client to display. The server can put data in hidden form elements that code running on the client side can get to - and change - via the document object model (DOM). However, the only way to send the changed data back to the server is to get the client to submit the form. You can automate that, but the results will be disconcerting to the user: they load a page, and it reloads multiple times as the plugin exchanges data with the server. Here again, I'm not dying for any page data to be visible: cannot the cgi script and the plugin do their business before that ? Not if you're using plugin as defined above. Pretty much anything that happens on the browser end is triggered by things happening in HTML - which means it has to be displayed. I don't know of any way to download something to the browser to run without rendering *something* in the browser window - even if it's only a blank plage. The problem with this is that the apache-browser connection isn't a connection, it's a series of HTTP request/repsonse pairs. Originally, this implied tearing down and setting up a TCP connection for every request. Modern software will leave the link open and reuse it - but modern software also tends to have multiple connetions open, so it can fetch images and other embedded objects in parallel. I'm lost here, better do some more reading HTTP is a stateless protocol. Every HTTP request goes the same: the client sends a request saying what object it wants from the server. The server reads the request, and sends back the response, which is a collection of HTTP headers and a string of bytes. There's lots more details invovled, and various things you can do to enhance the performance of the system, but functionally they all boil down to that. You can make this work, but doing it like that requires making multiple HTTP requests via the browser, which will be disconcerting. I'd recommend taking the browser out of the loop. Have the plugin talk directly to the server to do the authentication. That's what the latest web buzzword (AJAX) does: client-side software makes independent requests of the server (or *any* server) to get data, and possibly updates the document the browser is viewing as a result of that. Here I think it's OK as the plugin can talk to server prior to the browser showing anything. If you say so. But certainly not through the browser. So here's a scenario: the first cgi script gets info from the smart card that puts it in a hidden form element and sends the page to the browser. The plugin - started when the page loads - uses the DOM to get that data, then makes an *independent* HTTP request to the server, thus passing whatever it generated from the data in the form field to a second cgi script. This happens several times, then the plugin changes the HTML form to put whatever the cgi script generated into the form, so that when the user finally submits the form, the third cgi script - the one that handles the submitted form - sees the data from the second script. Actually, the exchanges between the plugin and the server don't need to be HTTP requests. If you've got this working over some other TCP protocol, there's no reason you can't keep doing it that way. Maybe that's my clue: can a cgi script, once triggered by a (let's say) POST request, use back and forth file transfer with the client ? through the _existing_ connection. I honestly don't know. HTTP does a strict onetime turnaround - the client sends, then the server sends, then you're done. There are hooks in the protocol to allow a connection to be resused, but that's a different request/response pair, and generally handled by the server, not the cgi script. After all, the next request from the client may be for some static file instead of the output of a cgi script. Having a cgi script start two-way communications on the connection may well work. But it won't be HTTP, and I wouldn't be at all surprised if one or more of the components in some web connections - proxies, caches, firewalls, etc. - choked on it. You're liable to get apparently random failures depending on all kinds of exotic things. mike -- Mike Meyer [EMAIL PROTECTED] http://www.mired.org/home/mwm/ Independent
Re: how to modify text in html form from python
Mike, Again, thanks. By plugin I mean the browsers' extensions: ex: http://roachfiend.com/archives/2004/12/08/how-to-create-firefox-extensions/#more-4. IE has the same type or resorts also to activeX components. Right now I know how to program that guy to open a url I guess I need to some thinking before I ask more questions. Regards, Philippe Mike Meyer wrote: Philippe C. Martin [EMAIL PROTECTED] writes: Mike Meyer wrote: I don't know much about plugins. I believe they get started when the page loads, which gives you a chance to do the authentication when you want it done. Well not in this case actually: the user triggers the plugin which in turn open the url, so the connection is owned by the plugin I think we don't mean the same thing when we say plugin. To me, a plugin is a bit of code that gets executed when the page is rendered to provide custom content with it's own behavior. Flash is probably the most popular example. Like I said, I don't know much about plugins, so they may be usable in other ways. That won't work very well. HTML goes to the client to display. The server can put data in hidden form elements that code running on the client side can get to - and change - via the document object model (DOM). However, the only way to send the changed data back to the server is to get the client to submit the form. You can automate that, but the results will be disconcerting to the user: they load a page, and it reloads multiple times as the plugin exchanges data with the server. Here again, I'm not dying for any page data to be visible: cannot the cgi script and the plugin do their business before that ? Not if you're using plugin as defined above. Pretty much anything that happens on the browser end is triggered by things happening in HTML - which means it has to be displayed. I don't know of any way to download something to the browser to run without rendering *something* in the browser window - even if it's only a blank plage. The problem with this is that the apache-browser connection isn't a connection, it's a series of HTTP request/repsonse pairs. Originally, this implied tearing down and setting up a TCP connection for every request. Modern software will leave the link open and reuse it - but modern software also tends to have multiple connetions open, so it can fetch images and other embedded objects in parallel. I'm lost here, better do some more reading HTTP is a stateless protocol. Every HTTP request goes the same: the client sends a request saying what object it wants from the server. The server reads the request, and sends back the response, which is a collection of HTTP headers and a string of bytes. There's lots more details invovled, and various things you can do to enhance the performance of the system, but functionally they all boil down to that. You can make this work, but doing it like that requires making multiple HTTP requests via the browser, which will be disconcerting. I'd recommend taking the browser out of the loop. Have the plugin talk directly to the server to do the authentication. That's what the latest web buzzword (AJAX) does: client-side software makes independent requests of the server (or *any* server) to get data, and possibly updates the document the browser is viewing as a result of that. Here I think it's OK as the plugin can talk to server prior to the browser showing anything. If you say so. But certainly not through the browser. So here's a scenario: the first cgi script gets info from the smart card that puts it in a hidden form element and sends the page to the browser. The plugin - started when the page loads - uses the DOM to get that data, then makes an *independent* HTTP request to the server, thus passing whatever it generated from the data in the form field to a second cgi script. This happens several times, then the plugin changes the HTML form to put whatever the cgi script generated into the form, so that when the user finally submits the form, the third cgi script - the one that handles the submitted form - sees the data from the second script. Actually, the exchanges between the plugin and the server don't need to be HTTP requests. If you've got this working over some other TCP protocol, there's no reason you can't keep doing it that way. Maybe that's my clue: can a cgi script, once triggered by a (let's say) POST request, use back and forth file transfer with the client ? through the _existing_ connection. I honestly don't know. HTTP does a strict onetime turnaround - the client sends, then the server sends, then you're done. There are hooks in the protocol to allow a connection to be resused, but that's a different request/response pair, and generally handled by the server, not the cgi script. After all, the next request from the client may be for some static file instead of the output of a cgi script. Having a cgi script start
