WebError#evalerror can't handle malformed URLs

[martinth]

If you have the evalerror defined in you WSGI pipeline and than access a URL with wrongly encoded characters there will be an uncatched UnicodeDecodeError (thrown by WebOb).

Suppose you have this pipleline config:

pipeline =
    egg:WebError#evalerror
    YOURAPP

and then access an invalid URL like http://localhost/%F6 you will get a error trace similar to this:

Traceback (most recent call last):
  File "/home/vagrant/demo/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/httpserver.py", line 1068, in process_request_in_thread
    self.finish_request(request, client_address)
  File "/usr/lib/python2.7/SocketServer.py", line 323, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/lib/python2.7/SocketServer.py", line 638, in __init__
    self.handle()
  File "/home/vagrant/demo/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/httpserver.py", line 442, in handle
    BaseHTTPRequestHandler.handle(self)
  File "/usr/lib/python2.7/BaseHTTPServer.py", line 340, in handle
    self.handle_one_request()
  File "/home/vagrant/demo/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/httpserver.py", line 437, in handle_one_request
    self.wsgi_execute()
  File "/home/vagrant/demo/local/lib/python2.7/site-packages/Paste-1.7.5.1-py2.7.egg/paste/httpserver.py", line 287, in wsgi_execute
    self.wsgi_start_response)
  File "/home/vagrant/demo/local/lib/python2.7/site-packages/WebError-0.10.3-py2.7.egg/weberror/evalexception.py", line 232, in __call__
    if req.path_info_peek() == '_debug':
  File "/home/vagrant/demo/local/lib/python2.7/site-packages/WebOb-1.3.1-py2.7.egg/webob/request.py", line 560, in path_info_peek
    path = self.path_info
  File "/home/vagrant/demo/local/lib/python2.7/site-packages/WebOb-1.3.1-py2.7.egg/webob/descriptors.py", line 68, in fget
    return req.encget(key, encattr=encattr)
  File "/home/vagrant/demo/local/lib/python2.7/site-packages/WebOb-1.3.1-py2.7.egg/webob/request.py", line 178, in encget
    return val.decode(encoding)
  File "/home/vagrant/demo/lib/python2.7/encodings/utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xf6 in position 1: invalid start byte

While I agree that there is nothing you can do about malformed URLs the code inside evalexception.py should still try to catch the error and at least return an standard 400 Bad Request response. This way, at least the wsgi thread won't die.

[digitalresistor]

This is an issue in WebOb. There is some work underway to fix that issue there.