Traceback on 404 status code for quickstart project

[khorn]

as of: TG [3946], Pylons [1293:28eed5438061]

Using a new quickstarted project, when requesting a page that does not exist, the following traceback occurs:

----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 3080)
Traceback (most recent call last):
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\httpserver.py", line 1046, in process_request_in_thread
    self.finish_request(request, client_address)
  File "C:\Python25\lib\SocketServer.py", line 254, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "C:\Python25\lib\SocketServer.py", line 522, in __init__
    self.handle()
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\httpserver.py", line 425, in handle
    BaseHTTPRequestHandler.handle(self)
  File "C:\Python25\lib\BaseHTTPServer.py", line 316, in handle
    self.handle_one_request()
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\httpserver.py", line 420, in handle_one_request
    self.wsgi_execute()
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\httpserver.py", line 287, in wsgi_execute
    self.wsgi_start_response)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\cascade.py", line 119, in __call__
    return self.apps[-1](environ, start_response)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\registry.py",line 334, in __call__
    app_iter = self.application(environ, start_response)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\recursive.py", line 84, in __call__
    return middleware(environ, start_response)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\recursive.py", line 47, in __call__
    return self.app(environ, start_response)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\errordocument.py", line 84, in __call__
    return self.app(environ, keep_status_start_response)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\recursive.py", line 80, in __call__
    return self.application(environ, start_response)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\errordocument.py", line 185, in __call__
    app_iter = self.application(environ, change_response)
  File "c:\python25\lib\site-packages\weberror-0.8dev_20071111-py2.5.egg\weberror\evalexception\middleware.py", line 213, in __call__
    return self.respond(environ, start_response)
  File "c:\python25\lib\site-packages\weberror-0.8dev_20071111-py2.5.egg\weberror\evalexception\middleware.py", line 324, in respond
    return self.application(environ, start_response)
  File "c:\python25\lib\site-packages\toscawidgets-0.2rc3dev_r3795-py2.5.egg\toscawidgets\middleware.py", line 40, in __call__
    return self.wsgi_app(environ, start_response)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\registry.py",line 334, in __call__
    app_iter = self.application(environ, start_response)
  File "c:\python25\lib\site-packages\toscawidgets-0.2rc3dev_r3795-py2.5.egg\toscawidgets\middleware.py", line 55, in wsgi_app
    app_iter = self.application(environ, start_response)
  File "c:\python25\lib\site-packages\Beaker-0.9-py2.5.egg\beaker\middleware.py", line 73, in __call__
    return self.app(environ, start_response)
  File "c:\python25\lib\site-packages\Beaker-0.9-py2.5.egg\beaker\middleware.py", line 145, in __call__
    response = self.wrap_app(environ, session_start_response)
  File "c:\documents and settings\ittemp2\desktop\mine_ph\pystuff\tg2\tg\__init__.py", line 79, in __call__
    return self.root(environ, start_response)
  File "C:\Documents and Settings\ittemp2\Desktop\mine_ph\pystuff\authtest\authtest\lib\base.py", line 39, in __call__
    return TurboGearsController.__call__(self, environ, start_response)
  File "c:\documents and settings\ittemp2\desktop\mine_ph\pystuff\pylons\pylons\controllers\core.py", line 218, in __call__
    return response(environ, self.start_response)
  File "c:\python25\lib\site-packages\webob-0.8.5-py2.5.egg\webob\exc.py", line228, in __call__
    return self.generate_response(environ, start_response)
  File "c:\python25\lib\site-packages\webob-0.8.5-py2.5.egg\webob\exc.py", line220, in generate_response
    start_response(self.status, headerlist)
  File "c:\python25\lib\site-packages\Beaker-0.9-py2.5.egg\beaker\middleware.py", line 143, in session_start_response
    return start_response(status, headers, exc_info)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\errordocument.py", line 183, in change_response
    return start_response(status, headers, exc_info)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\errordocument.py", line 75, in keep_status_start_response
    replace_header(self.headers, header, value)
  File "c:\python25\lib\site-packages\Paste-1.5.1-py2.5.egg\paste\response.py", line 155, in replace_header
    assert not result, "two values for the header '%s' found" % name
AssertionError: two values for the header 'content-type' found
----------------------------------------

It seems that something changed during the sprint which is now preventing HTTP exception handling from working properly. I suspect the new WebOb? stuff is causing problems with ErroDocuments? middleware, but I can't prove it yet.

[khorn]

OK, here's what the headers look like in the replace_headers function:

[('content-type', 'text/html'), 
 ('content-type', 'text/html; charset=utf-8'), 
 ('Pragma', 'no-cache'), 
 ('Cache-Control', 'no-cache'), 
 ('Content-Length', '154')]

Now, where do they get set?

[percious]

I wanted to add that I ran into the same problem in Python 2.5 on mac OS X.

[khorn]

This also appears to happen when raising other HTTPExceptions, such as HTTPUnauthorized (401), etc.

[khorn]

This is essentially blocking work on #1665

[khorn]

I've verified that this problem DOES NOT occur when the ErrorDocument? middleware is disabled.

I think something with the new webob functionality is driving it nuts.

[khorn]

Just for completeness, I'm seeing this on Win32 with Python 2.4 and 2.5.

[khorn]

Pylons 0.9.7 seems to be moving to using WebError? instead of ErrorDocuments?, which will probably affect this ticket.

see the Error Handling section here:  http://wiki.pylonshq.com/pages/viewpage.action?pageId=11174779

[mramm]

I had a few min to look at this, and a simple update to midleware.py_tmpl should fix this. We just need to use StatusCodeRedirect? rather than ErrorDocument? as seen in this snippet from the current pylons template.

    if asbool(full_stack):
        # Handle Python exceptions
        app = ErrorHandler(app, global_conf, **config['pylons.errorware'])

        # Display error documents for 401, 403, 404 status codes (and
        # 500 when debug is disabled)
        if asbool(config['debug']):
            app = StatusCodeRedirect(app)
        else:
            app = StatusCodeRedirect(app, [401, 403, 404, 500])

[khorn]

I mentioned this on the mailing list a while back, but we were waiting on the 2.4 compatibility fixes to investigate this further.

[mramm]

Submited a fix for this in trunk. Kevin, can you test this and make sure we're on the same page. Thanks!

[khorn]

shouldn't the ErrorDocuments? call also be removed?

I was under the impression that StatusCodeRedirect? did the same thing...

Also, StatusCodeRedirect? needs to be imported at the top of middleware.py_tmpl. a la:

from pylons.middleware import StatusCodeRedirect

as it is right now I get an import error when starting the quickstarted project

[khorn]

fixed by Mark Ramm in [4113]

[anonymous]

Milestone 2.0-preview-1 deleted