[Tutor] Remove last newline only in print / open / read function
davea at davea.name
Fri Apr 25 12:14:31 CEST 2014
Chris <ch2009 at arcor.de> Wrote in message:
> I'm a Python Newbie. Probably, this is a simple question.
But what is your context? Your Python version (apparently 2.x,
since you're using print as a statement, rather than a function)?
What os, and what is stdout pointing to, since you're pretending
that you can write binary data to it?
> I've a function that offers a ZIP-file for download:
> def download_cert(form, config):
> cn = form['cn'].value
> serial = pki.util.serial_from_cn(config, cn)
> files = pki.util.cert_files(config, cn, serial, True)
> name = path.join(tempfile.mkdtemp(), cn + '.zip')
> zip = zipfile.ZipFile(name, 'w')
> for file in files:
> zip.write(file, path.basename(file))
> zip.close() (1)
> pki.cgi.start_html('Internal error', True)
> pki.cgi.show_link('Go Back')
> print 'Content-Type: application/zip'
> print 'Content-Disposition: attachment;filename=' + cn + '.zip'
> print open(name).read() (2)
print adds a newline. Use write () instead.
sys.stdout.write (open (name).read ())
This assumes stdout is opened in binary mode, so that bytes that
happen to look like a newline are not corrupted.
> The ZIP file on the server is okay (1), but when it's sent to the client
> (2), there's a linefeed in the last line. This makes the zip invalid. So
> how can I remove the last linefeed only?
Minimum change is to add a comma at the end of the print
statement. But I'd prefer write method, to be parallel with the
Do you know that memory is not a problem, since you're reading
the entire temp file in before writing any of it to stdout? If
you're not sure, replace this with a loop.
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