Apache Module mod_alias
Summary
The directives contained in this module allow for manipulation
and control of URLs as requests arrive at the server. The
Alias and ScriptAlias directives are used to
map between URLs and filesystem paths. This allows for content
which is not directly under the DocumentRoot served as part of the web
document tree. The ScriptAlias directive has the
additional effect of marking the target directory as containing
only CGI scripts.
The Redirect
directives are used to instruct clients to make a new request with
a different URL. They are often used when a resource has moved to
a new location.
The Alias directive allows documents to
be stored in the local filesystem other than under the
DocumentRoot. URLs with a
(%-decoded) path beginning with url-path will be mapped
to local files beginning with directory-path.
Example:
Alias /image /ftp/pub/image
A request for http://myserver/image/foo.gif would cause the
server to return the file /ftp/pub/image/foo.gif.
Note that if you include a trailing / on the
url-path then the server will require a trailing / in
order to expand the alias. That is, if you use Alias
/icons/ /usr/local/apache/icons/ then the url
/icons will not be aliased.
Note that you may need to specify additional <Directory> sections which
cover the destination of aliases. Aliasing occurs before
<Directory> sections
are checked, so only the destination of aliases are affected.
(Note however <Location>
sections are run through once before aliases are performed, so
they will apply.)
In particular, if you are creating an Alias to a
directory outside of your DocumentRoot, you may need to explicitly
permit access to the target directory.
Example:
Alias /image /ftp/pub/image
<Directory /ftp/pub/image>
Order allow,deny
Allow from all
</Directory>
This directive is equivalent to Alias, but makes use of standard
regular expressions, instead of simple prefix matching. The
supplied regular expression is matched against the URL-path, and
if it matches, the server will substitute any parenthesized
matches into the given string and use it as a filename. For
example, to activate the /icons directory, one might
use:
AliasMatch ^/icons(.*) /usr/local/apache/icons$1
The Redirect directive maps an old URL into a new one. The
new URL is returned to the client which attempts to fetch it
again with the new address. URL-path a (%-decoded)
path; any requests for documents beginning with this path will
be returned a redirect error to a new (%-encoded) URL beginning
with URL.
Example:
Redirect /service http://foo2.bar.com/service
If the client requests http://myserver/service/foo.txt, it
will be told to access http://foo2.bar.com/service/foo.txt
instead.
Note
Redirect directives take precedence over
Alias and ScriptAlias directives, irrespective of their ordering in
the configuration file. Also, URL-path must be a fully
qualified URL, not a relative path, even when used with .htaccess files or
inside of <Directory>
sections.
If no status argument is given, the redirect will
be "temporary" (HTTP status 302). This indicates to the client
that the resource has moved temporarily. The status
argument can be used to return other HTTP status codes:
- permanent
- Returns a permanent redirect status (301) indicating that
the resource has moved permanently.
- temp
- Returns a temporary redirect status (302). This is the
default.
- seeother
- Returns a "See Other" status (303) indicating that the
resource has been replaced.
- gone
- Returns a "Gone" status (410) indicating that the
resource has been permanently removed. When this status is
used the URL argument should be omitted.
Other status codes can be returned by giving the numeric
status code as the value of status. If the status is
between 300 and 399, the URL argument must be present,
otherwise it must be omitted. Note that the status must be
known to the Apache code (see the function
send_error_response in http_protocol.c).
Example:
Redirect permanent /one http://example.com/two
Redirect 303 /three http://example.com/other
This directive is equivalent to Redirect, but makes use of standard
regular expressions, instead of simple prefix matching. The
supplied regular expression is matched against the URL-path, and
if it matches, the server will substitute any parenthesized
matches into the given string and use it as a filename. For
example, to redirect all GIF files to like-named JPEG files on
another server, one might use:
RedirectMatch (.*)\.gif$ http://www.anotherserver.com$1.jpg
This directive makes the client know that the Redirect is
permanent (status 301). Exactly equivalent to Redirect
permanent.
This directive makes the client know that the Redirect is
only temporary (status 302). Exactly equivalent to
Redirect temp.
| Description: | Maps a URL to a filesystem location and designates the
target as a CGI script |
|---|
| Syntax: | ScriptAlias URL-path
file-path|directory-path |
|---|
| Context: | server config, virtual host |
|---|
| Status: | Base |
|---|
| Module: | mod_alias |
|---|
The ScriptAlias directive has the same
behavior as the Alias
directive, except that in addition it marks the target directory
as containing CGI scripts that will be processed by mod_cgi's cgi-script handler. URLs with a
(%-decoded) path beginning with URL-path will be mapped
to scripts beginning with the second argument which is a full
pathname in the local filesystem.
Example:
ScriptAlias /cgi-bin/ /web/cgi-bin/
A request for http://myserver/cgi-bin/foo would cause the
server to run the script /web/cgi-bin/foo.
| Description: | Maps a URL to a filesystem location using a regular expression
and designates the target as a CGI script |
|---|
| Syntax: | ScriptAliasMatch regex
file-path|directory-path |
|---|
| Context: | server config, virtual host |
|---|
| Status: | Base |
|---|
| Module: | mod_alias |
|---|
This directive is equivalent to ScriptAlias, but makes use of standard
regular expressions, instead of simple prefix matching. The
supplied regular expression is matched against the URL-path,
and if it matches, the server will substitute any parenthesized
matches into the given string and use it as a filename. For
example, to activate the standard /cgi-bin, one
might use:
ScriptAliasMatch ^/cgi-bin(.*) /usr/local/apache/cgi-bin$1
