Posting gzip'd image file - server says Malformed Upload?

[Paul Hubert]

On Wednesday, June 17, 2015 at 9:46:25 PM UTC-4, Chris Angelico wrote:
> On Thu, Jun 18, 2015 at 10:45 AM, Paul Hubert <phbrt25 at gmail.com> wrote:
> > On Wednesday, June 17, 2015 at 8:24:17 PM UTC-4, Chris Angelico wrote:
> >
> >> Are you sure you want iteration and writelines() here? I would be
> >> inclined to avoid those for any situation that isn't plain text. If
> >> the file isn't too big, I'd just read it all in a single blob and then
> >> write it all out at once.
> >>
> >> ChrisA
> >
> > Do you think that would fix my issue? Could you give me an example?
> 
> Sorry for the abrupt and terse previous email; I had a student arrive
> just as I was posting that, and hit Ctrl-Enter when I should really
> have just left the email as a draft. Here's what I'm thinking:
> 
> # Was:
> f_in = open(dafile, 'rb')
> f_out = gzip.open('/Users/Paul/Desktop/scripts/pic.jpg.gz', 'wb')
> f_out.writelines(f_in)
> f_out.close()
> f_in.close()
> 
> # Now:
> gz = '/Users/Paul/Desktop/scripts/pic.jpg.gz'
> with open(dafile, 'rb') as f_in, gzip.open(gz, 'wb') as f_out:
>     f_out.write(f_in.read())
> 
> You might actually be able to write to a StringIO rather than to a
> file, given that you appear to be just reading the data back again
> straight away. But in case you want to keep the file around for some
> other reason, this still works the exact same way you had it.
> 
> The main difference is that this version swallows the entire file in a
> single gulp, then passes it all to the gzip writer. If your file is
> tiny (under 1MB), this is perfect. If it's huge (over 1GB), you may
> have problems. In between, it'll probably work, but might be
> inefficient.
> 
> Hope that helps!
> 
> ChrisA

Same result - server says malformed upload. :/