condition is determined to be true only if the the
<em>CondPattern</em> does not match.</p>
- <p><em>TestString</em> is a string which can contain the
+
+
+
+
+ <p><a id="rewritecond-teststring" name="rewritecond-teststring"></a><strong>TestString</strong></p>
+
+ <p><em>TestString</em> is a string which can contain the
following expanded constructs in addition to plain text:</p>
- <ul>
- <li>
- <strong>RewriteRule backreferences</strong>: These are
- backreferences of the form <strong><code>$N</code></strong>
+
+
+ <p><a id="rewritecond-backreferences" name="rewritecond-backreferences"></a><strong>Backreferences</strong></p>
+
+ <dl>
+ <dt><strong><code>$N</code></strong> — RewriteRule backreferences</dt>
+ <dd>Backreferences of the form <code>$N</code>
(0 <= N <= 9). $1 to $9 provide access to the grouped
parts (in parentheses) of the pattern, from the
<code>RewriteRule</code> which is subject to the current
set of <code>RewriteCond</code> conditions. $0 provides
- access to the whole string matched by that pattern.
-
- <div class="note">Backreferences are only defined if the pattern
- matches. Thus, if the pattern is prefixed with
- <code>!</code>, no backreferences are ever defined.</div>
- </li>
- <li>
- <strong>RewriteCond backreferences</strong>: These are
- backreferences of the form <strong><code>%N</code></strong>
+ access to the whole string matched by that pattern.</dd>
+
+ <dt><strong><code>%N</code></strong> — RewriteCond backreferences</dt>
+ <dd>Backreferences of the form <code>%N</code>
(0 <= N <= 9). %1 to %9 provide access to the grouped
parts (again, in parentheses) of the pattern, from the last matched
<code>RewriteCond</code> in the current set
of conditions. %0 provides access to the whole string matched by
- that pattern.
-
- <div class="note">Backreferences are only defined if the pattern
- matches. Thus, if the pattern is prefixed with
- <code>!</code>, no backreferences are ever defined.</div>
- </li>
- <li>
- <strong>RewriteMap expansions</strong>: These are
- expansions of the form <strong><code>${mapname:key|default}</code></strong>.
- See <a href="#mapfunc">the documentation for
- RewriteMap</a> for more details.
- </li>
- <li>
- <strong>Server variables</strong>: These are variables of
- the form
- <strong><code>%{</code> <em>NAME_OF_VARIABLE</em>
- <code>}</code></strong>
- where <em>NAME_OF_VARIABLE</em> can be a string taken
- from the following list:
+ that pattern.</dd>
+ </dl>
+
+ <div class="note">Backreferences are only defined if the pattern
+ matches. Thus, if the pattern is prefixed with
+ <code>!</code>, no backreferences are ever defined.</div>
+
+
+
+ <p><a id="rewritecond-mapexpansions" name="rewritecond-mapexpansions"></a><strong>RewriteMap Expansions</strong></p>
+
+ <p>These are expansions of the form <strong><code>${mapname:key|default}</code></strong>.
+ See <a href="#mapfunc">the documentation for
+ RewriteMap</a> for more details.</p>
+
+
+
+ <p><a id="rewritecond-servervars" name="rewritecond-servervars"></a><strong>Server and CGI Variables</strong></p>
+
+ <p>These are variables of the form
+ <strong><code>%{</code> <em>NAME_OF_VARIABLE</em>
+ <code>}</code></strong>
+ where <em>NAME_OF_VARIABLE</em> can be a string taken
+ from the following list:</p>
<table>
correspond to the similarly named HTTP
MIME-headers, C variables of the Apache HTTP Server or
<code>struct tm</code> fields of the Unix system.
- Most are documented in the
+ Most are documented in the
<a href="../expr.html#vars">Expressions doc</a>, in the
<a href="../env.html">Environment Variables doc</a>,
or the CGI specification (<a href="https://www.rfc-editor.org/rfc/rfc3875">RFC 3875</a>).</p>
<code class="directive"><a href="../mod/core.html#usecanonicalphysicalport">UseCanonicalPhysicalPort</a></code>
respectively.</p>
- <p>Those that are special to <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> include those below.</p>
+ <p>The variables SCRIPT_FILENAME and REQUEST_FILENAME
+ contain the same value - the value of the
+ <code>filename</code> field of the internal
+ <code>request_rec</code> structure of the Apache HTTP Server.
+ The first name is the commonly known CGI variable name
+ while the second is the appropriate counterpart of
+ REQUEST_URI (which contains the value of the
+ <code>uri</code> field of <code>request_rec</code>).</p>
+
+ <p>If a substitution occurred and the rewriting continues,
+ the value of both variables will be updated accordingly.</p>
+
+ <p>If used in per-server context (<em>i.e.</em>, before the
+ request is mapped to the filesystem) SCRIPT_FILENAME and
+ REQUEST_FILENAME cannot contain the full local filesystem
+ path since the path is unknown at this stage of processing.
+ Both variables will initially contain the value of REQUEST_URI
+ in that case. In order to obtain the full local filesystem
+ path of the request in per-server context, use an URL-based
+ look-ahead <code>%{LA-U:REQUEST_FILENAME}</code> to determine
+ the final value of REQUEST_FILENAME.</p>
+
+ <p>Those that are special to <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
+ include those below.</p>
<dl>
<dt><code>API_VERSION</code></dt>
such as "/index.html". This notably excludes the
query string which is available as its own variable
named <code>QUERY_STRING</code>. The value returned for
- <code>REQUEST_URI</code>
+ <code>REQUEST_URI</code>
has already been %-decoded, to re-encode it pass it through
the "escape" <a href="#mapfunc">mapping-function</a>.
Note that this server variable differs from the CGI
(decoded), unlike most other variables below.</dd>
</dl>
- </li>
- </ul>
- <p>If the <em>TestString</em> has the special value <code>expr</code>,
- the <em>CondPattern</em> will be treated as an
- <a href="../expr.html">ap_expr</a>. HTTP headers referenced in the
- expression will be added to the Vary header if the <code>novary</code>
- flag is not given.</p>
+
- <p>Other things you should be aware of:</p>
+ <p><a id="rewritecond-prefixed" name="rewritecond-prefixed"></a><strong>Prefixed Variable Lookups</strong></p>
- <ol>
- <li>
- <p>The variables SCRIPT_FILENAME and REQUEST_FILENAME
- contain the same value - the value of the
- <code>filename</code> field of the internal
- <code>request_rec</code> structure of the Apache HTTP Server.
- The first name is the commonly known CGI variable name
- while the second is the appropriate counterpart of
- REQUEST_URI (which contains the value of the
- <code>uri</code> field of <code>request_rec</code>).</p>
- <p>If a substitution occurred and the rewriting continues,
- the value of both variables will be updated accordingly.</p>
- <p>If used in per-server context (<em>i.e.</em>, before the
- request is mapped to the filesystem) SCRIPT_FILENAME and
- REQUEST_FILENAME cannot contain the full local filesystem
- path since the path is unknown at this stage of processing.
- Both variables will initially contain the value of REQUEST_URI
- in that case. In order to obtain the full local filesystem
- path of the request in per-server context, use an URL-based
- look-ahead <code>%{LA-U:REQUEST_FILENAME}</code> to determine
- the final value of REQUEST_FILENAME.</p></li>
-
- <li>
- <code>%{ENV:variable}</code>, where <em>variable</em> can be
- any environment variable, is also available.
- This is looked-up via internal
+ <p>In addition to the server variables above, the
+ <code>%{<em>PREFIX</em>:<em>name</em>}</code> syntax provides
+ access to additional sources:</p>
+
+ <dl>
+ <dt><strong><code>%{ENV:variable}</code></strong></dt>
+ <dd>Where <em>variable</em> can be
+ any environment variable. This is looked-up via internal
Apache httpd structures and (if not found there) via
- <code>getenv()</code> from the Apache httpd server process.</li>
+ <code>getenv()</code> from the Apache httpd server process.</dd>
- <li>
- <code>%{SSL:variable}</code>, where <em>variable</em> is the
+ <dt><strong><code>%{SSL:variable}</code></strong></dt>
+ <dd>Where <em>variable</em> is the
name of an <a href="mod_ssl.html#envvars">SSL environment
- variable</a>, can be used whether or not
+ variable</a>. This can be used whether or not
<code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code> is loaded, but will always expand to
the empty string if it is not. Example:
<code>%{SSL:SSL_CIPHER_USEKEYSIZE}</code> may expand to
<code>128</code>. These variables are available even without
setting the <code>StdEnvVars</code> option of the
- <code class="directive"><a href="../mod/mod_ssl.html#ssloptions">SSLOptions</a></code> directive.</li>
+ <code class="directive"><a href="../mod/mod_ssl.html#ssloptions">SSLOptions</a></code> directive.</dd>
- <li>
- <code>%{HTTP:header}</code>, where <em>header</em> can be
- any HTTP MIME-header name, can always be used to obtain the
+ <dt><strong><code>%{HTTP:header}</code></strong></dt>
+ <dd>Where <em>header</em> can be
+ any HTTP MIME-header name. This can always be used to obtain the
value of a header sent in the HTTP request.
Example: <code>%{HTTP:Proxy-Connection}</code> is
the value of the HTTP header
``<code>Proxy-Connection:</code>''.
- <p>If a HTTP header is used in a condition this header is added to
+ <p>If an HTTP header is used in a condition, this header is added to
the Vary header of the response in case the condition evaluates
to true for the request. It is <strong>not</strong> added if the
condition evaluates to false for the request. Adding the HTTP header
to the Vary header of the response is needed for proper caching.</p>
<p>It has to be kept in mind that conditions follow a short circuit
logic in the case of the '<strong><code>ornext|OR</code></strong>' flag
- so that certain conditions might not be evaluated at all.</p></li>
+ so that certain conditions might not be evaluated at all.</p></dd>
+ </dl>
+
+
- <li>
- <a id="LA-U" name="LA-U"><code>%{LA-U:variable}</code></a>
- can be used for look-aheads which perform
- an internal (URL-based) sub-request to determine the final
+ <p><a id="rewritecond-lookahead" name="rewritecond-lookahead"></a><strong>Look-ahead Sub-requests</strong></p>
+
+ <p>These forms perform an internal sub-request to determine the
+ final value of a variable that is not yet available at the current
+ stage of processing:</p>
+
+ <dl>
+ <dt><a id="LA-U" name="LA-U"><strong><code>%{LA-U:variable}</code></strong></a></dt>
+ <dd>Performs an internal (URL-based) sub-request to determine the final
value of <em>variable</em>. This can be used to access
- variable for rewriting which is not available at the current
+ a variable for rewriting which is not available at the current
stage, but will be set in a later phase.
<p>For instance, to rewrite according to the
<code>REMOTE_USER</code> variable from within the
its <a class="glossarylink" href="../glossary.html#perdirectory" title="see glossary">per-directory</a> context via
the Fixup phase of the API and because the authorization
phases come <em>before</em> this phase, you just can use
- <code>%{REMOTE_USER}</code> in that context.</p></li>
+ <code>%{REMOTE_USER}</code> in that context.</p></dd>
- <li>
- <code>%{LA-F:variable}</code> can be used to perform an internal
- (filename-based) sub-request, to determine the final value
- of <em>variable</em>. Most of the time, this is the same as
- LA-U above.</li>
- </ol>
+ <dt><strong><code>%{LA-F:variable}</code></strong></dt>
+ <dd>Performs an internal (filename-based) sub-request to determine
+ the final value of <em>variable</em>. Most of the time, this is
+ the same as LA-U above.</dd>
+ </dl>
+
+
+
+ <p><a id="rewritecond-expr" name="rewritecond-expr"></a><strong>Expression Syntax</strong></p>
+
+ <p>If the <em>TestString</em> has the special value <code>expr</code>,
+ the <em>CondPattern</em> will be treated as an
+ <a href="../expr.html">ap_expr</a>. HTTP headers referenced in the
+ expression will be added to the Vary header if the <code>novary</code>
+ flag is not given.</p>
+
+
+
+
+
+ <p><a id="rewritecond-condpattern" name="rewritecond-condpattern"></a><strong>CondPattern</strong></p>
<p><em>CondPattern</em> is the condition pattern,
a regular expression which is applied to the
additional syntax available to perform other useful tests against
the <em>Teststring</em>:</p>
- <ol>
- <li>You can prefix the pattern string with a
+
+
+ <p>You can prefix the pattern string with a
'<code>!</code>' character (exclamation mark) to negate the result
of the condition, no matter what kind of <em>CondPattern</em> is used.
- </li>
+ </p>
+
+
- <li>
- You can perform lexicographical string comparisons:
+ <p><a id="rewritecond-stringcomp" name="rewritecond-stringcomp"></a><strong>String Comparisons</strong></p>
+ <dl>
<dt><strong><CondPattern</strong></dt>
<dd>Lexicographically precedes<br>
Treats the <em>CondPattern</em> as a plain string and
if <em>TestString</em> lexicographically follows
<em>CondPattern</em>, or is equal to <em>CondPattern</em>
(the two strings are equal, character for character).</dd>
- </dl>
+ </dl>
+
<div class="note"><h3>Note</h3>
The string comparison operator is part of the <em>CondPattern</em>
argument and must be included in the quotes if those are used. Eg.
-
+
<pre class="prettyprint lang-config">RewriteCond %{HTTP_USER_AGENT} "=This Robot/1.0"</pre>
</div>
-
- </li>
- <li>
- You can perform integer comparisons:
- <dl>
+
+
+ <p><a id="rewritecond-intcomp" name="rewritecond-intcomp"></a><strong>Integer Comparisons</strong></p>
+ <dl>
<dt><strong>-eq</strong></dt>
<dd>Is numerically <strong>eq</strong>ual to<br>
The <em>TestString</em> is treated as an integer, and is
numerically compared to the <em>CondPattern</em>. True if
the two are numerically different. This is equivalent to
<code>!-eq</code>.</dd>
+ </dl>
- </dl>
- </li>
-
- <li>You can perform various file attribute tests:
-
+
- <dl>
+ <p><a id="rewritecond-fileattr" name="rewritecond-fileattr"></a><strong>File Attribute Tests</strong></p>
+ <dl>
<dt><strong>-d</strong></dt>
-
<dd>Is <strong>d</strong>irectory.<br>
Treats the <em>TestString</em> as a pathname and tests
whether or not it exists, and is a directory.
</dd>
<dt><strong>-f</strong></dt>
-
<dd>Is regular <strong>f</strong>ile.<br>
-
Treats the <em>TestString</em> as a pathname and tests
whether or not it exists, and is a regular file.
- </dd>
+ </dd>
<dt><strong>-F</strong></dt>
-
<dd>Is existing file, via subrequest.<br>
Checks whether or not <em>TestString</em> is a valid file,
accessible via all the server's currently-configured
</dd>
<dt><strong>-l</strong></dt>
-
<dd>Is symbolic <strong>l</strong>ink.<br>
Treats the <em>TestString</em> as a pathname and tests
whether or not it exists, and is a symbolic link. May also
whether or not it exists, and has executable permissions.
These permissions are determined according to
the underlying OS.</dd>
+ </dl>
- </dl>
-
- For example:
+ <p>For example:</p>
<pre class="prettyprint lang-config">RewriteCond /var/www/%{REQUEST_URI} !-f
RewriteRule ^(.+) /other/archive/$1 [R]</pre>
- </li>
+
+
+ <p><a id="rewritecond-expr-pattern" name="rewritecond-expr-pattern"></a><strong>Expression Evaluation</strong></p>
- <li>
<p>If the <em>TestString</em> has the special value <code>expr</code>, the
<em>CondPattern</em> will be treated as an
<a href="../expr.html">ap_expr</a>.</p>
<pre class="prettyprint lang-config">RewriteCond expr "! %{HTTP_REFERER} -strmatch '*://%{HTTP_HOST}/*'"
RewriteRule "^/images" "-" [F]</pre>
- </li>
- </ol>
- <p>You can also set special flags for <em>CondPattern</em> by appending
+
+
+
+
+ <p><a id="rewritecond-flags" name="rewritecond-flags"></a><strong>Flags</strong></p>
+
+ <p>You can set special flags for <em>CondPattern</em> by appending
<strong><code>[</code><em>flags</em><code>]</code></strong>
as the third argument to the <code class="directive">RewriteCond</code>
directive, where <em>flags</em> is a comma-separated list of any of the
following flags:</p>
-
- <ul>
- <li>'<strong><code>nocase|NC</code></strong>'
- (<strong>n</strong>o <strong>c</strong>ase)<br>
+
+ <dl>
+ <dt>'<strong><code>nocase|NC</code></strong>'</dt>
+ <dd>(<strong>n</strong>o <strong>c</strong>ase)<br>
This makes the test case-insensitive - differences
between 'A-Z' and 'a-z' are ignored, both in the
expanded <em>TestString</em> and the <em>CondPattern</em>.
This flag is effective only for comparisons between
<em>TestString</em> and <em>CondPattern</em>. It has no
- effect on filesystem and subrequest checks.</li>
+ effect on filesystem and subrequest checks.</dd>
- <li>
- '<strong><code>ornext|OR</code></strong>'
- (<strong>or</strong> next condition)<br>
+ <dt>'<strong><code>ornext|OR</code></strong>'</dt>
+ <dd>(<strong>or</strong> next condition)<br>
Use this to combine rule conditions with a local OR
instead of the implicit AND. Typical example:
Without this flag you would have to write the condition/rule
pair three times.
- </li>
+ </dd>
- <li>'<strong><code>novary|NV</code></strong>'
- (<strong>n</strong>o <strong>v</strong>ary)<br>
- If a HTTP header is used in the condition, this flag prevents
+ <dt>'<strong><code>novary|NV</code></strong>'</dt>
+ <dd>(<strong>n</strong>o <strong>v</strong>ary)<br>
+ If an HTTP header is used in the condition, this flag prevents
this header from being added to the Vary header of the response. <br>
Using this flag might break proper caching of the response if
the representation of this response varies on the value of this header.
So this flag should be only used if the meaning of the Vary header
is well understood.
- </li>
- </ul>
+ </dd>
+ </dl>
+
+
+
+
- <p><strong>Example:</strong></p>
+ <p><a id="rewritecond-examples" name="rewritecond-examples"></a><strong>Example</strong></p>
<p>To rewrite the Homepage of a site according to the
``<code>User-Agent:</code>'' header of the request, you can
condition is determined to be true only if the the
<em>CondPattern</em> does not match.</p>
- <p><em>TestString</em> is a string which can contain the
+ <!-- ============================================================ -->
+ <!-- TestString -->
+ <!-- ============================================================ -->
+
+ <p><a id="rewritecond-teststring" name="rewritecond-teststring"
+ ></a><strong>TestString</strong></p>
+
+ <p><em>TestString</em> is a string which can contain the
following expanded constructs in addition to plain text:</p>
- <ul>
- <li>
- <strong>RewriteRule backreferences</strong>: These are
- backreferences of the form <strong><code>$N</code></strong>
+ <!-- Backreferences -->
+
+ <p><a id="rewritecond-backreferences" name="rewritecond-backreferences"
+ ></a><strong>Backreferences</strong></p>
+
+ <dl>
+ <dt><strong><code>$N</code></strong> — RewriteRule backreferences</dt>
+ <dd>Backreferences of the form <code>$N</code>
(0 <= N <= 9). $1 to $9 provide access to the grouped
parts (in parentheses) of the pattern, from the
<code>RewriteRule</code> which is subject to the current
set of <code>RewriteCond</code> conditions. $0 provides
- access to the whole string matched by that pattern.
-
- <note>Backreferences are only defined if the pattern
- matches. Thus, if the pattern is prefixed with
- <code>!</code>, no backreferences are ever defined.</note>
- </li>
- <li>
- <strong>RewriteCond backreferences</strong>: These are
- backreferences of the form <strong><code>%N</code></strong>
+ access to the whole string matched by that pattern.</dd>
+
+ <dt><strong><code>%N</code></strong> — RewriteCond backreferences</dt>
+ <dd>Backreferences of the form <code>%N</code>
(0 <= N <= 9). %1 to %9 provide access to the grouped
parts (again, in parentheses) of the pattern, from the last matched
<code>RewriteCond</code> in the current set
of conditions. %0 provides access to the whole string matched by
- that pattern.
-
- <note>Backreferences are only defined if the pattern
- matches. Thus, if the pattern is prefixed with
- <code>!</code>, no backreferences are ever defined.</note>
- </li>
- <li>
- <strong>RewriteMap expansions</strong>: These are
- expansions of the form <strong><code
- >${mapname:key|default}</code></strong>.
- See <a href="#mapfunc">the documentation for
- RewriteMap</a> for more details.
- </li>
- <li>
- <strong>Server variables</strong>: These are variables of
- the form
- <strong><code>%{</code> <em>NAME_OF_VARIABLE</em>
- <code>}</code></strong>
- where <em>NAME_OF_VARIABLE</em> can be a string taken
- from the following list:
+ that pattern.</dd>
+ </dl>
+
+ <note>Backreferences are only defined if the pattern
+ matches. Thus, if the pattern is prefixed with
+ <code>!</code>, no backreferences are ever defined.
+ See <a href="../rewrite/tech.html#InternalRuleset">How the
+ Ruleset is Applied</a> for more details on the order in which
+ patterns are matched and backreferences populated.</note>
+
+ <!-- RewriteMap Expansions -->
+
+ <p><a id="rewritecond-mapexpansions" name="rewritecond-mapexpansions"
+ ></a><strong>RewriteMap Expansions</strong></p>
+
+ <p>These are expansions of the form <strong><code
+ >${mapname:key|default}</code></strong>.
+ See <a href="#mapfunc">the documentation for
+ RewriteMap</a> for more details.</p>
+
+ <!-- Server and CGI Variables -->
+
+ <p><a id="rewritecond-servervars" name="rewritecond-servervars"
+ ></a><strong>Server and CGI Variables</strong></p>
+
+ <p>These are variables of the form
+ <strong><code>%{</code> <em>NAME_OF_VARIABLE</em>
+ <code>}</code></strong>
+ where <em>NAME_OF_VARIABLE</em> can be a string taken
+ from the following list:</p>
<table>
<columnspec><column width=".3"/><column width=".3"/>
correspond to the similarly named HTTP
MIME-headers, C variables of the Apache HTTP Server or
<code>struct tm</code> fields of the Unix system.
- Most are documented in the
+ Most are documented in the
<a href="../expr.html#vars">Expressions doc</a>, in the
<a href="../env.html">Environment Variables doc</a>,
or the CGI specification (<rfc>3875</rfc>).</p>
<directive module="core">UseCanonicalPhysicalPort</directive>
respectively.</p>
- <p>Those that are special to <module>mod_rewrite</module> include those below.</p>
+ <p>The variables SCRIPT_FILENAME and REQUEST_FILENAME
+ contain the same value - the value of the
+ <code>filename</code> field of the internal
+ <code>request_rec</code> structure of the Apache HTTP Server.
+ The first name is the commonly known CGI variable name
+ while the second is the appropriate counterpart of
+ REQUEST_URI (which contains the value of the
+ <code>uri</code> field of <code>request_rec</code>).</p>
+
+ <p>If a substitution occurred and the rewriting continues,
+ the value of both variables will be updated accordingly.</p>
+
+ <p>If used in per-server context (<em>i.e.</em>, before the
+ request is mapped to the filesystem) SCRIPT_FILENAME and
+ REQUEST_FILENAME cannot contain the full local filesystem
+ path since the path is unknown at this stage of processing.
+ Both variables will initially contain the value of REQUEST_URI
+ in that case. In order to obtain the full local filesystem
+ path of the request in per-server context, use an URL-based
+ look-ahead <code>%{LA-U:REQUEST_FILENAME}</code> to determine
+ the final value of REQUEST_FILENAME.</p>
+
+ <p>Those that are special to <module>mod_rewrite</module>
+ include those below.</p>
<dl>
<dt><code>API_VERSION</code></dt>
such as "/index.html". This notably excludes the
query string which is available as its own variable
named <code>QUERY_STRING</code>. The value returned for
- <code>REQUEST_URI</code>
+ <code>REQUEST_URI</code>
has already been %-decoded, to re-encode it pass it through
the "escape" <a href="#mapfunc">mapping-function</a>.
Note that this server variable differs from the CGI
(decoded), unlike most other variables below.</dd>
</dl>
- </li>
- </ul>
- <p>If the <em>TestString</em> has the special value <code>expr</code>,
- the <em>CondPattern</em> will be treated as an
- <a href="../expr.html">ap_expr</a>. HTTP headers referenced in the
- expression will be added to the Vary header if the <code>novary</code>
- flag is not given.</p>
+ <!-- Prefixed Variable Lookups -->
- <p>Other things you should be aware of:</p>
+ <p><a id="rewritecond-prefixed" name="rewritecond-prefixed"
+ ></a><strong>Prefixed Variable Lookups</strong></p>
- <ol>
- <li>
- <p>The variables SCRIPT_FILENAME and REQUEST_FILENAME
- contain the same value - the value of the
- <code>filename</code> field of the internal
- <code>request_rec</code> structure of the Apache HTTP Server.
- The first name is the commonly known CGI variable name
- while the second is the appropriate counterpart of
- REQUEST_URI (which contains the value of the
- <code>uri</code> field of <code>request_rec</code>).</p>
- <p>If a substitution occurred and the rewriting continues,
- the value of both variables will be updated accordingly.</p>
- <p>If used in per-server context (<em>i.e.</em>, before the
- request is mapped to the filesystem) SCRIPT_FILENAME and
- REQUEST_FILENAME cannot contain the full local filesystem
- path since the path is unknown at this stage of processing.
- Both variables will initially contain the value of REQUEST_URI
- in that case. In order to obtain the full local filesystem
- path of the request in per-server context, use an URL-based
- look-ahead <code>%{LA-U:REQUEST_FILENAME}</code> to determine
- the final value of REQUEST_FILENAME.</p></li>
-
- <li>
- <code>%{ENV:variable}</code>, where <em>variable</em> can be
- any environment variable, is also available.
- This is looked-up via internal
+ <p>In addition to the server variables above, the
+ <code>%{<em>PREFIX</em>:<em>name</em>}</code> syntax provides
+ access to additional sources:</p>
+
+ <dl>
+ <dt><strong><code>%{ENV:variable}</code></strong></dt>
+ <dd>Where <em>variable</em> can be
+ any environment variable. This is looked-up via internal
Apache httpd structures and (if not found there) via
- <code>getenv()</code> from the Apache httpd server process.</li>
+ <code>getenv()</code> from the Apache httpd server process.</dd>
- <li>
- <code>%{SSL:variable}</code>, where <em>variable</em> is the
+ <dt><strong><code>%{SSL:variable}</code></strong></dt>
+ <dd>Where <em>variable</em> is the
name of an <a href="mod_ssl.html#envvars">SSL environment
- variable</a>, can be used whether or not
+ variable</a>. This can be used whether or not
<module>mod_ssl</module> is loaded, but will always expand to
the empty string if it is not. Example:
<code>%{SSL:SSL_CIPHER_USEKEYSIZE}</code> may expand to
<code>128</code>. These variables are available even without
setting the <code>StdEnvVars</code> option of the
- <directive module="mod_ssl">SSLOptions</directive> directive.</li>
+ <directive module="mod_ssl">SSLOptions</directive> directive.</dd>
- <li>
- <code>%{HTTP:header}</code>, where <em>header</em> can be
- any HTTP MIME-header name, can always be used to obtain the
+ <dt><strong><code>%{HTTP:header}</code></strong></dt>
+ <dd>Where <em>header</em> can be
+ any HTTP MIME-header name. This can always be used to obtain the
value of a header sent in the HTTP request.
Example: <code>%{HTTP:Proxy-Connection}</code> is
the value of the HTTP header
``<code>Proxy-Connection:</code>''.
- <p>If a HTTP header is used in a condition this header is added to
+ <p>If an HTTP header is used in a condition, this header is added to
the Vary header of the response in case the condition evaluates
to true for the request. It is <strong>not</strong> added if the
condition evaluates to false for the request. Adding the HTTP header
to the Vary header of the response is needed for proper caching.</p>
<p>It has to be kept in mind that conditions follow a short circuit
logic in the case of the '<strong><code>ornext|OR</code></strong>' flag
- so that certain conditions might not be evaluated at all.</p></li>
+ so that certain conditions might not be evaluated at all.</p></dd>
+ </dl>
+
+ <!-- Look-ahead Sub-requests -->
+
+ <p><a id="rewritecond-lookahead" name="rewritecond-lookahead"
+ ></a><strong>Look-ahead Sub-requests</strong></p>
- <li>
- <a id="LA-U" name="LA-U"><code>%{LA-U:variable}</code></a>
- can be used for look-aheads which perform
- an internal (URL-based) sub-request to determine the final
+ <p>These forms perform an internal sub-request to determine the
+ final value of a variable that is not yet available at the current
+ stage of processing:</p>
+
+ <dl>
+ <dt><a id="LA-U" name="LA-U"><strong><code>%{LA-U:variable}</code></strong></a></dt>
+ <dd>Performs an internal (URL-based) sub-request to determine the final
value of <em>variable</em>. This can be used to access
- variable for rewriting which is not available at the current
+ a variable for rewriting which is not available at the current
stage, but will be set in a later phase.
<p>For instance, to rewrite according to the
<code>REMOTE_USER</code> variable from within the
its <glossary ref="perdirectory">per-directory</glossary> context via
the Fixup phase of the API and because the authorization
phases come <em>before</em> this phase, you just can use
- <code>%{REMOTE_USER}</code> in that context.</p></li>
+ <code>%{REMOTE_USER}</code> in that context.</p></dd>
- <li>
- <code>%{LA-F:variable}</code> can be used to perform an internal
- (filename-based) sub-request, to determine the final value
- of <em>variable</em>. Most of the time, this is the same as
- LA-U above.</li>
- </ol>
+ <dt><strong><code>%{LA-F:variable}</code></strong></dt>
+ <dd>Performs an internal (filename-based) sub-request to determine
+ the final value of <em>variable</em>. Most of the time, this is
+ the same as LA-U above.</dd>
+ </dl>
+
+ <!-- Expression Syntax -->
+
+ <p><a id="rewritecond-expr" name="rewritecond-expr"
+ ></a><strong>Expression Syntax</strong></p>
+
+ <p>If the <em>TestString</em> has the special value <code>expr</code>,
+ the <em>CondPattern</em> will be treated as an
+ <a href="../expr.html">ap_expr</a>. HTTP headers referenced in the
+ expression will be added to the Vary header if the <code>novary</code>
+ flag is not given.</p>
+
+ <!-- ============================================================ -->
+ <!-- CondPattern -->
+ <!-- ============================================================ -->
+
+ <p><a id="rewritecond-condpattern" name="rewritecond-condpattern"
+ ></a><strong>CondPattern</strong></p>
<p><em>CondPattern</em> is the condition pattern,
a regular expression which is applied to the
additional syntax available to perform other useful tests against
the <em>Teststring</em>:</p>
- <ol>
- <li>You can prefix the pattern string with a
+ <!-- Negation -->
+
+ <p>You can prefix the pattern string with a
'<code>!</code>' character (exclamation mark) to negate the result
of the condition, no matter what kind of <em>CondPattern</em> is used.
- </li>
+ </p>
+
+ <!-- String Comparisons -->
- <li>
- You can perform lexicographical string comparisons:
+ <p><a id="rewritecond-stringcomp" name="rewritecond-stringcomp"
+ ></a><strong>String Comparisons</strong></p>
+ <dl>
<dt><strong><CondPattern</strong></dt>
<dd>Lexicographically precedes<br />
Treats the <em>CondPattern</em> as a plain string and
if <em>TestString</em> lexicographically follows
<em>CondPattern</em>, or is equal to <em>CondPattern</em>
(the two strings are equal, character for character).</dd>
- </dl>
+ </dl>
+
<note><title>Note</title>
The string comparison operator is part of the <em>CondPattern</em>
argument and must be included in the quotes if those are used. Eg.
-
+
<highlight language="config">
RewriteCond %{HTTP_USER_AGENT} "=This Robot/1.0"
</highlight>
</note>
-
- </li>
- <li>
- You can perform integer comparisons:
- <dl>
+ <!-- Integer Comparisons -->
+
+ <p><a id="rewritecond-intcomp" name="rewritecond-intcomp"
+ ></a><strong>Integer Comparisons</strong></p>
+ <dl>
<dt><strong>-eq</strong></dt>
<dd>Is numerically <strong>eq</strong>ual to<br />
The <em>TestString</em> is treated as an integer, and is
numerically compared to the <em>CondPattern</em>. True if
the two are numerically different. This is equivalent to
<code>!-eq</code>.</dd>
+ </dl>
- </dl>
- </li>
-
- <li>You can perform various file attribute tests:
-
+ <!-- File Attribute Tests -->
- <dl>
+ <p><a id="rewritecond-fileattr" name="rewritecond-fileattr"
+ ></a><strong>File Attribute Tests</strong></p>
+ <dl>
<dt><strong>-d</strong></dt>
-
<dd>Is <strong>d</strong>irectory.<br />
Treats the <em>TestString</em> as a pathname and tests
whether or not it exists, and is a directory.
</dd>
<dt><strong>-f</strong></dt>
-
<dd>Is regular <strong>f</strong>ile.<br />
-
Treats the <em>TestString</em> as a pathname and tests
whether or not it exists, and is a regular file.
- </dd>
+ </dd>
<dt><strong>-F</strong></dt>
-
<dd>Is existing file, via subrequest.<br />
Checks whether or not <em>TestString</em> is a valid file,
accessible via all the server's currently-configured
</dd>
<dt><strong>-l</strong></dt>
-
<dd>Is symbolic <strong>l</strong>ink.<br />
Treats the <em>TestString</em> as a pathname and tests
whether or not it exists, and is a symbolic link. May also
whether or not it exists, and has executable permissions.
These permissions are determined according to
the underlying OS.</dd>
+ </dl>
- </dl>
-
- For example:
+ <p>For example:</p>
<highlight language="config">
RewriteCond /var/www/%{REQUEST_URI} !-f
RewriteRule ^(.+) /other/archive/$1 [R]
</highlight>
- </li>
+ <!-- Expression Evaluation in CondPattern -->
+
+ <p><a id="rewritecond-expr-pattern" name="rewritecond-expr-pattern"
+ ></a><strong>Expression Evaluation</strong></p>
- <li>
<p>If the <em>TestString</em> has the special value <code>expr</code>, the
<em>CondPattern</em> will be treated as an
<a href="../expr.html">ap_expr</a>.</p>
RewriteCond expr "! %{HTTP_REFERER} -strmatch '*://%{HTTP_HOST}/*'"
RewriteRule "^/images" "-" [F]
</highlight>
- </li>
- </ol>
- <p>You can also set special flags for <em>CondPattern</em> by appending
+ <!-- ============================================================ -->
+ <!-- Flags -->
+ <!-- ============================================================ -->
+
+ <p><a id="rewritecond-flags" name="rewritecond-flags"
+ ></a><strong>Flags</strong></p>
+
+ <p>You can set special flags for <em>CondPattern</em> by appending
<strong><code>[</code><em>flags</em><code>]</code></strong>
as the third argument to the <directive>RewriteCond</directive>
directive, where <em>flags</em> is a comma-separated list of any of the
following flags:</p>
-
- <ul>
- <li>'<strong><code>nocase|NC</code></strong>'
- (<strong>n</strong>o <strong>c</strong>ase)<br />
+
+ <dl>
+ <dt>'<strong><code>nocase|NC</code></strong>'</dt>
+ <dd>(<strong>n</strong>o <strong>c</strong>ase)<br />
This makes the test case-insensitive - differences
between 'A-Z' and 'a-z' are ignored, both in the
expanded <em>TestString</em> and the <em>CondPattern</em>.
This flag is effective only for comparisons between
<em>TestString</em> and <em>CondPattern</em>. It has no
- effect on filesystem and subrequest checks.</li>
+ effect on filesystem and subrequest checks.</dd>
- <li>
- '<strong><code>ornext|OR</code></strong>'
- (<strong>or</strong> next condition)<br />
+ <dt>'<strong><code>ornext|OR</code></strong>'</dt>
+ <dd>(<strong>or</strong> next condition)<br />
Use this to combine rule conditions with a local OR
instead of the implicit AND. Typical example:
Without this flag you would have to write the condition/rule
pair three times.
- </li>
+ </dd>
- <li>'<strong><code>novary|NV</code></strong>'
- (<strong>n</strong>o <strong>v</strong>ary)<br />
- If a HTTP header is used in the condition, this flag prevents
+ <dt>'<strong><code>novary|NV</code></strong>'</dt>
+ <dd>(<strong>n</strong>o <strong>v</strong>ary)<br />
+ If an HTTP header is used in the condition, this flag prevents
this header from being added to the Vary header of the response. <br />
Using this flag might break proper caching of the response if
the representation of this response varies on the value of this header.
So this flag should be only used if the meaning of the Vary header
is well understood.
- </li>
- </ul>
+ </dd>
+ </dl>
- <p><strong>Example:</strong></p>
+ <!-- ============================================================ -->
+ <!-- Example -->
+ <!-- ============================================================ -->
+
+ <p><a id="rewritecond-examples" name="rewritecond-examples"
+ ></a><strong>Example</strong></p>
<p>To rewrite the Homepage of a site according to the
``<code>User-Agent:</code>'' header of the request, you can
</directivesynopsis>
+
<directivesynopsis>
<name>RewriteRule</name>
<description>Defines rules for the rewriting engine</description>
projects / thirdparty / apache / httpd.git / commitdiff
