Using .htaccess Files with Apache Page 2

By Ken Coar (Send Email)
Posted Jul 19, 2000


The name '.htaccess' isn't universally acceptable, though. Sometimes it can quite difficult to persuade a system to let you create or edit a file with such a name. For this reason, you can change the name that Apache will use when looking for these per-directory config files by using the AccessFileName directive in your server's httpd.conf file. For instance,


  
    AccessFileName ht.acl
  

will cause Apache to look for files named ht.acl instead of .htaccess. They'll be treated the same way, though, and they're still called '.htaccess files' for convenience.

Locating and Merging .htaccess Files

When Apache determines that a requested resource actually represents a file on the disk, it starts a process called the 'directory walk.' This involves checking through its internal list of <Directory> containers to find those that apply, and possibly searching the directories on the filesystem for .htaccess files.

Each time the directory walk finds a new set of directives that apply to the request, they are merged with the settings already accumulated. The result is a collection of settings that apply to the final document, culled from all of its ancestor directories and the server's config files.

When searching for .htaccess files, Apache starts at the top of the filesystem. (On Windows, that usually means 'C:\'; otherwise, the root directory '/'.) It then walks down the directories to the one containing the final document, processing and merging any .htaccess files it finds that the config files say should be processed. (See the section on overrides for more information on how the server determines whether an .htaccess file should be processed or not.)

This can be an intensive process. Consider a request for <URI:http://your.host.com/foo/bar/gritch/x.html> which resolves to the file

    C:\Program Files\Apache Group\Apache\htdocs\foo\bar\gritch\x.html
  

Unless instructed otherwise, Apache is going to look for each of the following .htaccess files, and process any it finds:

  1. C:\.htaccess
  2. C:\Program Files\.htaccess
  3. C:\Program Files\Apache Group\.htaccess
  4. C:\Program Files\Apache Group\Apache\.htaccess
  5. C:\Program Files\Apache Group\Apache\htdocs\.htaccess
  6. C:\Program Files\Apache Group\Apache\htdocs\foo\.htaccess
  7. C:\Program Files\Apache Group\Apache\htdocs\foo\bar\.htaccess
  8. C:\Program Files\Apache Group\Apache\htdocs\foo\bar\gritch\.htaccess

That's a lot of work just to return a single file! And the server will repeat this process each and every time the file is requested. See the overrides section for a way to reduce this overhead with the AllowOverride None directive.



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