Question

I made a script to download a file, but it only works on Unix/Linux/OSX when I’m downloading binary executables, swf’s, images, etc

\#Modfied section from PWB.py  
import sys  
if sys.version_info<(2,8):  
    import urllib as request  
else:  
    import urllib.request as request  
x=request.urlopen("http://homestarrunner.com/intro.swf")  
y=x.read()  
x.close()  
z=open("intro.swf","w")  
z.write(y)  
z.close() 

I will get the the file, and the usual unreadable garbage in the file, but it will be unreadable.

It seems binary files always have these sorts of problem on Windows.
Why is this?

PS. How could I write my python code so that it will download?

Answer 1

From the Python 2 documentation:

On Windows, ‘b’ appended to the mode
opens the file in binary mode, so
there are also modes like ‘rb’, ‘wb’,
and ‘r+b’. Python on Windows makes a
distinction between text and binary
files; the end-of-line characters in
text files are automatically altered
slightly when data is read or written.
This behind-the-scenes modification to
file data is fine for ASCII text
files, but it’ll corrupt binary data
like that in JPEG or EXE files. Be
very careful to use binary mode when
reading and writing such files. On
Unix, it doesn’t hurt to append a ‘b’
to the mode, so you can use it
platform-independently for all binary
files.