you can refer attach file with this test code.
poem = '\
Programming is fun
When the work is done
if you wanna make your work also fun:
use Python!
'
f = file('poem.txt', 'w') # open for 'w'riting
f.write(poem) # write text to file
f.close() # close the file
f = file('poem.txt')
# if no mode is specified, 'r'ead mode is assumed by default
while True:
line = f.readline()
if len(line) == 0: # Zero length indicates EOF
break
print line,
# Notice comma to avoid automatic newline added by Python
f.close() # close the file
but the datastore limit filesize 1M.it is trashiness.
this code is included my opensource blog ,http://code.google.com/p/woiclub
On 12/19/08, Ross Ridge <rri...@csclub.uwaterloo.ca> wrote:
>
> jeremy wrote:
> > i was hoping to seamlessly virtualize a filesystem on top of
> > datastore. it seems there is no pure-python approach to filesystem
> > virtualization, making this impossible. should i give up on this or
> > have a i overlooked something?
>
> I don't see why you would think it's impossible. It's certainly
> possible to write a filesystem implementation in pure Python, I've
> done it.
>
> >
>
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"""
This is experimental code to provide writable filesystem capability to
App Engine. It can be enabled through importing, just with ``import
filesystem``.
"""
from google.appengine.ext import db
from google.appengine.ext import gql
import os
import sys
import tempfile
from datetime import datetime
import time
from google.appengine.ext import db
import logging
import itertools
from StringIO import StringIO
'''
poem = '\
Programming is fun
When the work is done
if you wanna make your work also fun:
use Python!
'
f = file('poem.txt', 'w') # open for 'w'riting
f.write(poem) # write text to file
f.close() # close the file
f = file('poem.txt')
# if no mode is specified, 'r'ead mode is assumed by default
while True:
line = f.readline()
if len(line) == 0: # Zero length indicates EOF
break
print line,
# Notice comma to avoid automatic newline added by Python
f.close() # close the file
'''
class Files(db.Model):
basename = db.StringProperty()
dir = db.StringProperty()
path = db.StringProperty()
content = db.BlobProperty()
mtime_dt = db.DateTimeProperty(auto_now=True)
ctime_dt = db.DateTimeProperty(auto_now_add=True)
filetype = db.StringProperty()
@property
def is_dir(self):
return not self.basename
@classmethod
def get_file(cls, filename, create=False ,filetype =None):
query = cls.gql('WHERE path = :1', filename)
files = query.fetch(1)
if files:
return files[0]
if not create:
return None
if filename.startswith("/"):
if not filetype:
split = path.rfind('.')
ext = path[split + 1:]
file = cls(
key_name = filename,
basename=os.path.basename(filename),
dir=os.path.dirname(filename),
path=filename,
content='',
mtime_dt=datetime.now(),
ctime_dt=datetime.now(),
filetype=ext,
)
return file
@classmethod
def listdir(cls, dir):
results =[]
files = cls.gql('WHERE dir = :1', dir)
results = [file.basename for file in files]
return results
@classmethod
def mkdir(cls, dir):
pass
@classmethod
def readlink(cls, path):
# path = os.path.abspath(path)
obj = cls.get_file(path)
if obj is None:
return obj
return obj.content
@classmethod
def remove(cls, path):
# path = os.path.abspath(path)
obj = cls.get_file(path)
if not obj:
db.delete(obj)
@classmethod
def rename(cls, src, dest):
obj = cls.get_file(src)
if obj is None:
return False
dest_obj = cls.get_file(dest)
if dest_obj is not None:
if dest_obj.is_dir:
return False
else:
cls.remove(dest)
return True
obj.path = dest
if obj.is_dir:
obj.dir = dest
obj.basename = ''
else:
obj.dir = os.path.dirname(dest)
obj.basename = os.path.basename(dest)
obj.put()
@classmethod
def rmdir(cls, path):
pass
@classmethod
def stat(cls, path):
obj = cls.get_file(path)
if obj is None:
return obj
return os.stat_result((
0, # mode
0, # inode
0, # device
1, # hard links
0, # owner uid
0, # gid
len(obj.content or ''), # size
0, # atime
obj.mtime, # mtime
obj.ctime, # ctime
))
@classmethod
def dump(cls):
"""Returns all the files in a text description
"""
objs = list(cls.all())
objs.sort(key=lambda obj: obj.path)
lines = []
for obj in objs:
if obj.is_dir:
lines.append('Dir: %s' % obj.path)
else:
lines.append('File: %s (%i bytes)' % (obj.path,
len(obj.content or '')))
return '\n'.join(lines)
def open(oldfilename, mode='r', buffering=0):
## FIXME: totally ignore buffering?
create = mode.startswith('w') or mode.startswith('rw') or
mode.startswith('a')
fileobj = Files.get_file(oldfilename, create=create)
if fileobj is None:
return None
if fileobj.is_dir:
return None
return FileWrapper(fileobj, mode=mode)
class FileWrapper(object):
def __init__(self, fileobj, pos=0, mode='r'):
self.fileobj = fileobj
self.pos = pos
mode = mode.replace('U', '').replace('t', '').replace('b', '')
assert mode in ('r', 'w', 'rw', 'a'), (
"Bad mode: %r" % mode)
self.mode = mode
if mode == 'a':
self.pos = len(self.fileobj.content)
self._closed = False
def read(self, size=-1):
if size == -1:
t = self.fileobj.content[self.pos:]
self.pos = len(self.fileobj.content)
return t
else:
t = self.fileobj.content[self.pos:self.pos+size]
self.pos = min(len(self.fileobj.content), self.pos+size)
return t
def readline(self, size=-1):
parts = self.fileobj.content[self.pos:].split('\n', 1)
if len(parts) == 2:
next = parts[0] + '\n'
else:
next = parts[0]
if size == -1 or size <= len(next):
self.pos += len(next)
return next
else:
self.pos += size
return next[:size]
def readlines(self, size=-1):
if size == -1:
rest = self.fileobj.content[self.pos:]
self.pos = len(self.fileobj.content)
else:
rest = self.fileobj.content[self.pos:self.pos+size]
self.pos += size
return rest.splitlines(True)
def write(self, text):
self.fileobj.content = self.fileobj.content[:self.pos] + text +
self.fileobj.content[self.pos+len(text):]
self.pos += len(text)
self.fileobj.mtime_dt = datetime.now()
def writelines(self, lines):
self.write(''.join(lines))
def seek(self, pos):
self.assert_state(None)
self.pos = pos
def tell(self):
self.assert_state(None)
return self.pos
def close(self):
self.fileobj.put()
self._closed = True
def flush(self):
self.assert_state(None)
self.fileobj.put()
