[Python-Dev] HTTP responses and errors (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Tue Mar 27 16:48:02 CEST 2007

Why only 200 and 206?

This kind of question can often be answered through the revision history. If you do 'svn annotate', you see that the line testing for 206 was last changed in r36262. Comparing that to the previous revision, you see that it before said

 if r.status == 200:

and that amk changed it with the log message

[Bug #912845] urllib2 only checks for a 200 return code, but 206 is also legal if a Range: header was supplied. (Actually, should the first 'if' statement be modified to allow any 2xx status code?)

Going to bugs.python.org/912845, you see that the current form was proposed by Ahmed F. (oneofone), apparently because it crashed for him with 206. In 2006, heresiarch ask the same question that you are now asking and that amk asked before.

Going further back, you see that HTTPErrorProcessor (along with the handling of 200) as added by jhylton in 34909, which in turn originates from #852995, where jjlee introduced the handlers in order to support cookie handling. Looking at the change, you see that it is just refactoring; the special-casing of 200 was present before.

In earlier versions, the error handling was done using this block:

14267 jhylton if code == 200: 14267 jhylton return addinfourl(fp, hdrs, req.get_full_url()) 14267 jhylton else: 14267 jhylton return self.parent.error('http', req, fp, code, msg, hdrs)

You then find that 14267 is the initial revision, checked in with the comment

EXPERIMENTAL

An extensible library for opening URLs using a variety protocols.

Intended as a replacement for urllib.

So it seems that it only tests for 200 and 206 because the experiments never produced a need for anything else.

Regards, Martin

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