Apache HTTP Server Version 2.5

Apache > HTTP Server > Documentation > Version 2.5 > Modules

# Apache Module mod_dir

Description: | Provides for "trailing slash" redirects and serving directory index files
Status: | Base
Module Identifier: | dir_module
Source File: | mod_dir.c

### Summary

The index of a directory can come from one of two sources:

- A file written by the user, typically called `index.html`. The `DirectoryIndex` directive sets the name of this file. This is controlled by `mod_dir`.
- Otherwise, a listing generated by the server. This is provided by `mod_autoindex`.

The two functions are separated so that you can completely remove (or replace) automatic index generation should you want to.

A "trailing slash" redirect is issued when the server receives a request for a URL `http://servername/foo/dirname` where `dirname` is a directory. Directories require a trailing slash, so `mod_dir` issues a redirect to `http://servername/foo/dirname/`.

### Directives

### Bugfix checklist

- httpd changelog
- Known issues
- Report a bug

## DirectoryCheckHandler Directive ¶

Description: | Toggle how this module responds when another handler is configured
Syntax: | `DirectoryCheckHandler On|Off`
Default: | `DirectoryCheckHandler Off`
Context: | server config, virtual host, directory, .htaccess
Override: | Indexes
Status: | Base
Module: | mod_dir
Compatibility: | Available in 2.4.8 and later. Releases prior to 2.4 implicitly act as if "DirectoryCheckHandler ON" was specified.

The `DirectoryCheckHandler` directive determines whether `mod_dir` should check for directory indexes or add trailing slashes when some other handler has been configured for the current URL. Handlers can be set by directives such as `SetHandler` or by other modules at runtime.

When set to `On`, `mod_dir` will take no action if another handler has already been configured for the URL.

When set to `Off` (the default), `mod_dir` will process the request regardless of any other handler that may be configured. This allows directory indexes to be served even when a `SetHandler` directive is specified for an entire directory, but it can also result in conflicts with other modules.

## DirectoryIndex Directive ¶

Description: | List of resources to look for when the client requests a directory
Syntax: | `DirectoryIndex disabled | local-url [local-url] ...`
Default: | `DirectoryIndex index.html`
Context: | server config, virtual host, directory, .htaccess
Override: | Indexes
Status: | Base
Module: | mod_dir

The `DirectoryIndex` directive sets the list of resources to look for, when the client requests an index of the directory by specifying a / at the end of the directory name. Local-url is the (%-encoded) URL of a document on the server relative to the requested directory; it is usually the name of a file in the directory. Several URLs may be given, in which case the server will return the first one that it finds. If none of the resources exist and the `Indexes` option is set, the server will generate its own listing of the directory.

### Example

    DirectoryIndex index.html

then a request for `http://example.com/docs/` would return `http://example.com/docs/index.html` if it exists, or would list the directory if it did not.

Note that the documents do not need to be relative to the directory;

    DirectoryIndex index.html index.txt  /cgi-bin/index.pl

would cause the CGI script `/cgi-bin/index.pl` to be executed if neither `index.html` or `index.txt` existed in a directory.

A single argument of "disabled" prevents `mod_dir` from searching for an index. An argument of "disabled" will be interpreted literally if it has any arguments before or after it, even if they are "disabled" as well.

Note: Multiple `DirectoryIndex` directives within the same context will add to the list of resources to look for rather than replace:

    # Example A: Set index.html as an index page, then add index.php to that list as well.
    <Directory "/foo">
        DirectoryIndex index.html
        DirectoryIndex index.php
    </Directory>

    # Example B: This is identical to example A, except it's done with a single directive.
    <Directory "/foo">
        DirectoryIndex index.html index.php
    </Directory>

    # Example C: To replace the list, you must explicitly reset it first:
    # In this example, only index.php will remain as an index resource.
    <Directory "/foo">
        DirectoryIndex index.html
        DirectoryIndex disabled
        DirectoryIndex index.php
    </Directory>

## DirectoryIndexRedirect Directive ¶

Description: | Configures an external redirect for directory indexes.
Syntax: | `DirectoryIndexRedirect on | off | permanent | temp | seeother | 3xx-code`
Default: | `DirectoryIndexRedirect off`
Context: | server config, virtual host, directory, .htaccess
Override: | Indexes
Status: | Base
Module: | mod_dir
Compatibility: | Available in version 2.3.14 and later

By default, the `DirectoryIndex` is selected and returned transparently to the client. `DirectoryIndexRedirect` causes an external redirect to instead be issued.

The argument can be:

- `on`: issues a 302 redirection to the index resource.
- `off`: does not issue a redirection. This is the legacy behavior of mod_dir.
- `permanent`: issues a 301 (permanent) redirection to the index resource.
- `temp`: this has the same effect as `on`
- `seeother`: issues a 303 redirection (also known as "See Other") to the index resource.
- 3xx-code: issues a redirection marked by the chosen 3xx code.

### Example

    DirectoryIndexRedirect on

A request for `http://example.com/docs/` would return a temporary redirect to `http://example.com/docs/index.html` if it exists.

## DirectorySlash Directive ¶

Description: | Toggle trailing slash redirects on or off
Syntax: | `DirectorySlash On|Off|NotFound`
Default: | `DirectorySlash On`
Context: | server config, virtual host, directory, .htaccess
Override: | Indexes
Status: | Base
Module: | mod_dir
Compatibility: | Argument NotFound added in 2.5.1

The `DirectorySlash` directive determines how `mod_dir` should fixup URLs pointing to a directory or not.

Typically if a user requests a resource without a trailing slash, which points to a directory, `mod_dir` redirects them to the same resource, but with trailing slash for some good reasons:

- The user is finally requesting the canonical URL of the resource
- `mod_autoindex` works correctly. Since it doesn't emit the path in the link, it would point to the wrong path.
- `DirectoryIndex` will be evaluated only for directories requested with trailing slash.
- Relative URL references inside html pages will work correctly.

If you don't want this effect and the reasons above don't apply to you, you can turn off the redirect as shown below. However, be aware that there are possible security implications to doing this.

    # see security warning below!
    <Location "/some/path">
        DirectorySlash Off
        SetHandler some-handler
    </Location>

### Security Warning

Turning off the trailing slash redirect may result in an information disclosure. Consider a situation where `mod_autoindex` is active (`Options +Indexes`) and `DirectoryIndex` is set to a valid resource (say, `index.html`) and there's no other special handler defined for that URL. In this case a request with a trailing slash would show the `index.html` file. But a request without trailing slash would list the directory contents.

Also note that some browsers may erroneously change POST requests into GET (thus discarding POST data) when a redirect is issued.

To avoid the risks of the "off" behavior above, or to avoid disclosing that a directory is present via the behavior of "on", an argument of "NotFound" can be used to tell `mod_dir` to return an HTTP 404 status code instead of redirecting the request to include a trailing slash.

## FallbackResource Directive ¶

Description: | Define a default URL for requests that don't map to a file or handler
Syntax: | `FallbackResource disabled | local-url`
Default: | `disabled - httpd will return 404 (Not Found)`
Context: | server config, virtual host, directory, .htaccess
Override: | Indexes
Status: | Base
Module: | mod_dir
Compatibility: | The `disabled` argument is available in version 2.4.4 and later

Use this to set a handler for any URL that doesn't map to anything in your filesystem, and would otherwise return HTTP 404 (Not Found). For example

    FallbackResource /not-404.php

will cause requests for non-existent files to be handled by `not-404.php`, while requests for files that exist are unaffected.

It is frequently desirable to have a single file or resource handle all requests to a particular directory, except those requests that correspond to an existing file or script. This is often referred to as a 'front controller.'

In earlier versions of httpd, this effect typically required `mod_rewrite`, and the use of the `-f` and `-d` tests for file and directory existence. This now requires only one line of configuration.

    FallbackResource /index.php

Existing files, such as images, css files, and so on, will be served normally.

Use the `disabled` argument to disable that feature if inheritance from a parent directory is not desired.

In a sub-URI, such as http://example.com/blog/ this sub-URI has to be supplied as local-url:

    <Directory "/web/example.com/htdocs/blog">
        FallbackResource /blog/index.php
    </Directory>
    <Directory "/web/example.com/htdocs/blog/images">
        FallbackResource disabled
    </Directory>

A fallback handler (in the above case, `/blog/index.php`) can access the original requested URL via the server variable `REQUEST_URI`. For example, to access this variable in PHP, use `$_SERVER['REQUEST_URI']`.

### Interaction with other handlers

`FallbackResource` only takes effect when no other handler has been assigned to the request. If a directive such as `SetHandler` or `AddHandler` has already assigned a handler to a URL or file extension, `FallbackResource` will not override it. For example, if you use `SetHandler application/x-httpd-php` in a `<Directory>` section, that handler applies to all requests in that directory — even requests for non-existent files — so `FallbackResource` will never be invoked.

### See also

- `SetHandler`
- `AddHandler`
- `DirectoryCheckHandler`