Apache HTTP Server Tutorial: .htaccess files

files completely if you have access to httpd main server config file. Using .htaccess

files slows down your Apache http server. Any directive that you can include in a .htaccess

block, as it will have the same effect with better performance..htaccess

If you want to call your .htaccess

file something else, you can change the name of the file using the

files use the same syntax as the main configuration files. What you can put in these files is determined by the

directive. This directive specifies, in categories, what directives will be honored if they are found in a AllowOverride.htaccess

file, the documentation for that directive will contain an Override section, specifying what value must be in

directive, you will find that it is permitted in AddDefaultCharset.htaccess

files. (See the Context line in the directive summary.) The Override line reads FileInfo

. Thus, you must have at least AllowOverride FileInfo

If you are unsure whether a particular directive is permitted in a .htaccess

file, look at the documentation for that directive, and check the Context line for ".htaccess".

files. This is simply not the case. You can put user authentication configurations in the main server configuration, and this is, in fact, the preferred way to do things. Likewise, mod_rewrite

directives work better, in many respects, in the main server configuration.

files should be used in a case where the content providers need to make configuration changes to the server on a per-directory basis, but do not have root access on the server system. In the event that the server administrator is not willing to make frequent configuration changes, it might be desirable to permit individual users to make these changes in .htaccess

files for themselves. This is particularly true, for example, in cases where ISPs are hosting multiple user sites on a single machine, and want their users to be able to alter their configuration.

files should be avoided when possible. Any configuration that you would consider putting in a .htaccess

file, can just as effectively be made in a

There are two main reasons to avoid the use of .htaccess

files causes a performance hit, whether or not you actually even use them! Also, the .htaccess

file is loaded every time a document is requested.

files in all higher-level directories, in order to have a full complement of directives that it must apply. (See section on how directives are applied.) Thus, if a file is requested out of a directory /www/htdocs/example

And so, for each file access out of that directory, there are 4 additional file-system accesses, even if none of those files are present. (Note that this would only be the case if .htaccess

files were enabled for /

context these regular expressions must be re-compiled with every request to the directory, whereas in main server configuration context they are compiled once and cached. Additionally, the rules themselves are more complicated, as one must work around the restrictions that come with per-directory context and mod_rewrite

. Consult the Rewrite Guide for more detail on this subject.

The second consideration is one of security. You are permitting users to modify server configuration, which may result in changes over which you have no control. Carefully consider whether you want to give your users this privilege. Note also that giving users less privileges than they need will lead to additional technical support requests. Make sure you clearly tell your users what level of privileges you have given them. Specifying exactly what you have set

to, and pointing them to the relevant documentation, will save yourself a lot of confusion later.AllowOverride

AddType text/example .exm

However, putting this configuration in your server configuration file will result in less of a performance hit, as the configuration is loaded once when httpd starts, rather than every time a file is requested.

files can be disabled completely by setting the

files found higher up in the directory tree. And those, in turn, may have overridden directives found yet higher up, or in the main server configuration file itself.

In the directory /www/htdocs/example1/example2

is in effect, which completely overrides any earlier setting that may have been in place.

As discussed in the documentation on Configuration Sections, .htaccess

sections for the corresponding directory, but will be overridden by other types of configuration sections from the main configuration files. This fact can be used to enforce certain configurations, even in the presence of a liberal

setting. For example, to prevent script execution while allowing anything else to be set in AllowOverride.htaccess

AllowOverride All Options +IncludesNoExec -ExecCGI

files should be used only if you don't have access to the main server configuration file. See above for a discussion of when you should and should not use .htaccess

Having said that, if you still think you need to use a .htaccess

AuthType Basic AuthName "Password Required" AuthUserFile /www/passwords/password.file AuthGroupFile /www/passwords/group.file Require Group admins

Please see the authentication tutorial for a more complete discussion of authentication and authorization.

Options +Includes AddType text/html shtml AddHandler server-parsed shtml

Alternately, if you wish to have all files in the given directory be considered to be CGI programs, this may be done with the following configuration:

Most commonly, the problem is that

is not set such that your configuration directives are being honored. Make sure that you don't have a AllowOverrideAllowOverride None

in effect for the file scope in question. A good test for this is to put garbage in your .htaccess

file and reload the page. If a server error is not generated, then you almost certainly have AllowOverride None

If, on the other hand, you are getting server errors when trying to access documents, check your httpd error log. It will likely tell you that the directive used in your .htaccess

[Fri Sep 17 18:43:16 2010] [alert] [client 192.168.200.51] /var/www/html/.htaccess: DirectoryIndex not allowed here

This will indicate either that you've used a directive that is never permitted in .htaccess

set to a level sufficient for the directive you've used. Consult the documentation for that particular directive to determine which is the case.AllowOverride

[Sat Aug 09 16:22:34 2008] [alert] [client 192.168.200.51] /var/www/html/.htaccess: RewriteCond: bad flag delimiters

In this case, the error message should be specific to the particular syntax error that you have committed.

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