base_url with multiple environments (tracd)

[Olivier Mehani <shtrom-trac@…>]

Context: I'm using Trac 11.6 from OpenBSD's ports. tracd manages several environments using the -e flag. Trac runs behind an Apache proxy which redirects every request to /svn to Trac. For consistency and to simplify proxying rules, Trac serves the content from an identical base path (--base-path) of /svn.

All the environments inherit from a global trac.ini which contains the following:

[trac]
base_url = http://scm.domain.tld/svn/
use_base_url_for_redirect = True

While this may work for single-projects, when serving multiple environments, all of them inherit the same base_url. They then create URLs respective to the Trac root rather than there own. For example, project1 will reference http://scm.domain.tld/svn/log?rev=1, which doesn't exist, rather than http://scm.domain.tld/svn/project1/log?rev=1.

Thus, I think it would be better to consider the base_url to be the base URL from where Trac is accessible. Depending on the configuration, additional path components may be added to it:

• In single project configurations, the base_url can be used directly as it does reference the root of the project as well as that of Trac.
• In multiple environment configuration, the path to the project should be added to the main base_url to actually build the project's base URL http://scm.domain.tld/svn/project1/ (rather that Trac's http://scm.domain.tld/svn/).

This would allow for a more scalable configuration management where the server's base_url is configured only once and each environment derives its own path from there.

Also, I noticed that when use_base_url_for_redirect="False", full URLS (e.g. in the RSS) still use 127.0.0.1, where I understood from the documentation that setting base_url was sufficient to have them replaced, and use_base_url_for_redirect was only necessary with redirect issues, but not document rewriting. Did I misunderstand? Should use_base_url_for_redirect be set for document rewriting to work at all?

[Olivier Mehani <shtrom-trac@…>]

Thinking a bit more about this issue, maybe changing the way base_url is interpreted is not a correct approach. One could imagine a scenario where two Trac environments served by the same tracd are proxyed from two completely different URLS (say http://www.site1.tld and http://www.site2.tld/code). Having a functionality modifying the base_url would mess everything up in that case (e.g. http://www.site2.tld/code/site2project isn't desired).

Maybe the best approach, then, is to add a new configuration directive trac_base_url which can be inherited, and do something like the following Python-like pseudocode.

if base_url is not None:
  project_base_url = base_url
elif trac_base_url is not None:
  if multi_environment:
    project_base_url = trac_base_url + project_name
  else:
    project_base_url = trac_base_url
else:
  project_base_url = HTTP_HOST + path

[Remy Blank]

Duplicate of #7573?

[Olivier Mehani <shtrom-trac@…>]

Indeed, it is a Duplicate of #7573. It didn't come up in my searches.

Thanks for the pointer !