I’ve been fighting with apache during the past few days to try to accomplish something that has never been done until now.
Apache has some nice included modules, for example mod_vhost_alias. This module allows someone to configure vhosts by just creating directories however it has some limitations:
- It will cause problems with some other modules like mod_rewrite
- You can’t configure stuff (php options, etc) by host (only with .htaccess files, but you can’t alter all settings)
- It can’t handle variable kinds of domains
I decided to do something better, even with the people on #apache-modules (freenode) saying it’s not possible. It was even no possible to do this cleanly, however looking in apache’s code allowed me to reach my goal without too many problems, but with some really dirty parts.
#define CORE_PRIVATE
To reach my goal I needed to use some functions from Apache2′s core. I just wanted to say that I am really sorry, and won’t do it again (maybe). The functions I used are not meant to be used the way I used them, however I had no choice has there is no publicly available function to change the document root, or to inject configuration directives in the current request.
Anyway don’t do this at home, kids!
ap_get_module_config(…, &core_module)
One of the keys to play with core config dynamically is to fetch it. This is the way to modify ap_document_root. I just return DECLINED after completing my dirty work to let apache think it still has to do its work. Yes this is dirty. But it works.
ap_walk_config()
Ever wanted to do bad things in a per-config context? Now you can. I won’t comment this too much, but I’ll just say that it saved me big time (this one is not part of CORE_PRIVATE, so you can use it freely I guess).
The final step was to make logging easier. I decided to throw all the logging info through a udg socket which is then collected by a daemon, stored locally, and transferred to the logging server at the same time.
