Q:

unpack bz2 url without temporary file in python

I want to unpack data from bz2 url directly to target file.  Here is the code: 
filename = 'temp.file'  
req = urllib2.urlopen('http://example.com/file.bz2')
CHUNK = 16 * 1024
with open(filename, 'wb') as fp:
  while True:
    chunk = req.read(CHUNK)
    if not chunk: break
    fp.write(bz2.decompress(chunk)) 
fp.close()

Error on bz2.decompress(chunk)  - ValueError: couldn't find end of stream

A:

Use bz2.BZ2Decompressor to do sequential decompression:
filename = 'temp.file'  
req = urllib2.urlopen('http://example.com/file.bz2')
CHUNK = 16 * 1024

decompressor = bz2.BZ2Decompressor()
with open(filename, 'wb') as fp:
    while True:
        chunk = req.read(CHUNK)
        if not chunk:
            break
        fp.write(decompressor.decompress(chunk))
req.close()

BTW, you don't need to call fp.close() as long as you use with statement.