D2774: hgweb: remove support for retrieving parameters from POST form data

[indygreg (Gregory Szorc)]

indygreg created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  Previously, we called out to cgi.parse(), which for POST requests
  parsed multipart/form-data and application/x-www-form-urlencoded
  Content-Type requests for form data, combined it with query string
  parameters, returned a union of the values.
  
  As far as I know, nothing in Mercurial actually uses this mechanism
  to submit data to the HTTP server. The wire protocol has its own
  mechanism for passing parameters. And the web interface only does
  GET requests. Removing support for parsing POST data doesn't break
  any tests.
  
  Another reason to not like this feature is that cgi.parse() may
  modify the QUERY_STRING environment variable as a side-effect.
  In addition, it merges both POST data and the query string into
  one data structure. This prevents consumers from knowing whether
  a variable came from the query string or POST data. That can matter
  for some operations.
  
  I suspect we use cgi.parse() because back when this code was
  initially implemented, it was the function that was readily
  available. In other words, I don't think there was conscious
  choice to support POST data: we just got it because cgi.parse()
  supported it.
  
  Since nothing uses the feature and it is untested, let's remove
  support for parsing POST form data. We can add it back in easily
  enough if we need it in the future.
  
  .. bc::
  
    Hgweb no longer reads form data in POST requests from
    multipart/form-data and application/x-www-form-urlencoded
    requests. Arguments should be specified as URL path components
    or in the query string in the URL instead.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D2774

AFFECTED FILES
  mercurial/hgweb/request.py

CHANGE DETAILS

diff --git a/mercurial/hgweb/request.py b/mercurial/hgweb/request.py
--- a/mercurial/hgweb/request.py
+++ b/mercurial/hgweb/request.py
@@ -8,7 +8,6 @@
 
 from __future__ import absolute_import
 
-import cgi
 import errno
 import socket
 import wsgiref.headers as wsgiheaders
@@ -258,15 +257,12 @@
         self.multiprocess = wsgienv[r'wsgi.multiprocess']
         self.run_once = wsgienv[r'wsgi.run_once']
         self.env = wsgienv
-        self.form = normalize(cgi.parse(inp,
-                                        self.env,
-                                        keep_blank_values=1))
+        self.req = parserequestfromenv(wsgienv, inp)
+        self.form = normalize(self.req.querystringdict)
         self._start_response = start_response
         self.server_write = None
         self.headers = []
 
-        self.req = parserequestfromenv(wsgienv, inp)
-
     def respond(self, status, type, filename=None, body=None):
         if not isinstance(type, str):
             type = pycompat.sysstr(type)



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