Ability to override SCRIPT_NAME from base_url

[oetiker@…]

I am using mod_rewrite to hide the fcgi trac script … this works fine, except that trac uses absolte urls in its generated content … so the name of the fcgi script will be exposed all the same … with this patch I can set the TRAC_BASE_URL environment variable to tell trac what base URL it should be using.

--- temp/trac/trac-0.9/trac/web/cgi_frontend.py 2005-10-31 19:37:51.000000000 +0100
+++ pack/trac-0.9/lib/python2.3/site-packages/trac/web/cgi_frontend.py  2005-11-02 23:30:52.393286000 +0100
@@ -49,6 +49,10 @@
         self.args = self._getFieldStorage()
 
         self.cgi_location = self.__environ.get('SCRIPT_NAME')
+
+        if 'TRAC_BASE_URL' in os.environ:
+            self.cgi_location = os.environ['TRAC_BASE_URL'];
+
         self.idx_location = self.cgi_location
 
         self.path_info = self.__environ.get('PATH_INFO', '')

[Matthew Good]

Instead of mod_rewrite, use a ScriptAlias command to point to the fcgi script and the CGI SCRIPT_NAME variable will be set appropriately.

To run Trac at the root URL:

ScriptAlias / /usr/share/trac/cgi-bin/trac.fcgi

[jo@…]

But if one uses RewriteEngine to hide user names in suexec configurations, ScriptAlias does not work. It breaks the suexec mechansim. In such a situation BASE_URL would be a good idea.

[sid]

Patch attached, so should be reviewed.

[Christopher Lenz]

1. the patch is outdated (would need to be updated for 0.10)
2. this functionality is available by use of the base_url option in trac.ini

[tobi@…]

base_url in trac.ini does not allow to override what SCRIPT_NAME returns … which is necessary when working without ScriptAlias (see above). The following patch adds the necessary functionallity for trac 0.10:

--- trac/web/api.py.orig        2006-09-21 20:32:16.000000000 +0200
+++ trac/web/api.py     2006-10-22 14:00:07.000000000 +0200
@@ -223,7 +223,15 @@
                                'has not logged in using HTTP authentication')
     scheme = property(fget=lambda self: self.environ['wsgi.url_scheme'],
                       doc='The scheme of the request URL')
-    base_path = property(fget=lambda self: self.environ.get('SCRIPT_NAME', ''),
+
+    def _get_base_url(self):
+       from urlparse import urlparse
+       if self.base_url:
+               return urlparse(self.base_url.encode('latin-1'))[2]
+       else:
+               return self.environ.get('SCRIPT_NAME')
+
+    base_path = property(fget=_get_base_url,
                          doc='The root path of the application')
     server_name = property(fget=lambda self: self.environ['SERVER_NAME'],
                            doc='Name of the server')
                                                                                                                                                                                              

[dom@…]

I would like this patch to make it in - it is as far as I can see the only way to make nice URLs with fcgi and mod_rewrite. I am currently manually patching to achieve this aim.

[Christian Boos]

Could someone familiar with fcgi review this?

[Tim Hatch]

A slightly related ticket is #2418, which strangely shows up in searches while this one initially didn't.

I run Trac under mod_python and thus can't have this issue (modpython_frontend bails if TRAC_URI_ROOT and base_url don't match), however if this issue still needs fixing I came up with a patch with tests that doesn't reimport urlparse.

[Matthew Good]

Replying to cboos:

Could someone familiar with fcgi review this?

Yeah, I'll do it.

[Matthew Good]

This has been fixed with r4718:4719 and r4720.

This uses Apache's SCRIPT_URL variable which is specifically intended for reconstructing the logical URL when rewriting has been used, so I think this a cleaner solution.

[James Teh <jamie@…>]

If you are using Apache mod_rewrite and the script path is still exposed, be aware that the SCRIPT_URL variable is not set by mod_rewrite if the RewriteEngine on directive is used in .htaccess or directory context. SCRIPT_URL is only set if RewriteEngine on is used in the server or VirtualHost context. This is an extremely frustrating issue in mod_rewrite. I thought this worth noting here to hopefully save others some agony in the future. :)

[James Teh <jamie@…>]

Err… it'd be nice if I didn't change all the properties by mistake. I think I just found a Firefox bug. :) Sorry people. I can't change the milestone back to 0.10.4, which is what it should be.

[Christian Boos]

(fixing milestone)

[Carsten Fuchs <CarstenFuchs@…>]

I have been experiencing the same situation as the ticket reporter, see my mails to the ​trac-users mailing list.

After long and daunting research I found that James Teh is right in his previous comment and that this ticket addresses the root of the problem and thus should be reopened:

When you use mod_rewrite for pretty Trac URLs as described at TracPrettyUrls, and SCRIPT_URL is not set as described by James Teh, then SCRIPT_NAME is always the rewritten name, which in turn causes "unprettied" or "absolute" URLs in the generated content page.

Work-around: Insert line

os.environ['SCRIPT_NAME'] = ""

into file trac.fcgi.

I'm unfortunately not safe enough in Python in order to know better or even to provide a patch, but wouldn't using REQUEST_URI instead of SCRIPT_NAME help here? Alternatively, please apply the above original patch.

[Carsten Fuchs <CarstenFuchs@…>]

Work-around: Insert line os.environSCRIPT_NAME = "" into file trac.fcgi.

The above work-around unfortunately works only for trac.cgi, not for trac.fcgi, sorry.

[Martin.vGagern@…]

Replying to Carsten Fuchs <CarstenFuchs@…>:

wouldn't using REQUEST_URI instead of SCRIPT_NAME help here?

One problem is that REQUEST_URI is URL-encoded while SCRIPT_NAME and PATH_INFO are not. So in order to find the base of the Trac environment, one would have to strip the query from REQUEST_URI, URL-decode the rest, strip off PATH_INFO, and probably URL-encode the remainder again. So it's not easy, as I learned the hard way in comment:4:ticket:8328.

[Remy Blank]

We currently don't have a complete solution, and we're a bit short on the testing side for frontends other than mod_python or mod_wsgi. Postponing…

[Mike Kelly <pioto@…>]

Replying to rblank:

We currently don't have a complete solution, and we're a bit short on the testing side for frontends other than mod_python or mod_wsgi. Postponing…

If you need volunteers to test patches on mod_fcgi, I can help with that. I'm not familiar enough with the trac codebase to develop a patch myself, but if you gave me pointers I could try to hack something up.

I think a solution to this would be helpful for use in shared hosting environments, where using ScriptAlias or adding anything to the apache config isn't an option, but .htaccess is.