Digest Authentication; Using .htaccess files - From Apache: The Definitive Guide

Using .htaccess Files

We experimented with putting configuration directives in a file called ... /htdocs/.htaccess rather than in httpd.conf. It worked, but how do you decide whether to do things this way rather than the other?

The point of the .htaccess mechanism is that you can change configuration directives without having to restart the server. This is especially valuable on a site where a lot of people maintain their own home pages but are not authorized to bring the server down or, indeed, to modify its Config files. The drawback to the .htaccess method is that the files are parsed for each access to the server, rather than just once at startup, so there is a substantial performance penalty.

The httpd1.conf (from ... /site.htaccess) file contains the following:

User webuser Group webgroup ServerName www.butterthlies.com AccessFileName .myaccess ServerAdmin sales@butterthlies.com DocumentRoot /usr/www/APACHE3/site.htaccess/htdocs/salesmen ErrorLog /usr/www/APACHE3/site.htaccess/logs/error_log TransferLog /usr/www/APACHE3/site.htaccess/logs/access_log ServerName sales.butterthlies.com

Access control, as specified by AccessFileName, is now in ... /htdocs/salesmen/.myaccess:

AuthType Basic AuthName darkness AuthUserFile /usr/www/APACHE3/ok_users/sales AuthGroupFile /usr/www/APACHE3/ok_users/groups require group cleaners

If you run the site with ./go 1 and access http://sales.butterthlies.com /, you are asked for an ID and a password in the usual way. You had better be daphne or sonia if you want to get in, because only members of the group cleaners are allowed.

You can then edit ... /htdocs/salesmen/.myaccess to require group directors instead. Without reloading Apache, you now have to be bill or ben.

AccessFileName

AccessFileName gives authority to the files specified. If a directory is given, authority is given to all files in it and its subdirectories.

AccessFileName filename, filename|direcory and subdirectories ...
Server config, virtual host

Include the following line in httpd.conf:

AccessFileName .myaccess1, myaccess2 ...

Restart Apache (since the AccessFileName has to be read at startup). You might expect that you could limit AccessFileName to .myaccess in some particular directory, but not elsewhere. You can't — it is global (well, more global than per-directory). Try editing ... /conf/httpd.conf to read:

<Directory /usr/www/APACHE3/site.htaccess/htdocs/salesmen>
AccessFileName .myaccess
</Directory>

Apache complains:

Syntax error on line 2 of /usr/www/APACHE3/conf/srm.conf: AccessFileName not allowed 
here

As we have said, this file is found and parsed on each access, and this takes time. When a client requests access to a file /usr/www/APACHE3/site.htaccess/htdocs/salesmen/index.html, Apache searches for the following:

/.myaccess
/usr/.myaccess
/usr/www/APACHE3/.myaccess
/usr/www/APACHE3/site.htaccess/.myaccess
/usr/www/APACHE3/site.htaccess/htdocs/.myaccess
/usr/www/APACHE3/site.htaccess/htdocs/salesmen/.myaccess

This multiple search also slows business down. You can turn multiple searching off, making a noticeable difference to Apache's speed, with the following directive:

<Directory />
AllowOverride none
</Directory>

It is important to understand that / means the real, root directory (because that is where Apache starts searching) and not the server's document root.