4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore<?xml version="1.0"?>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore<!DOCTYPE modulesynopsis SYSTEM "/style/modulesynopsis.dtd">

6b5e5868e7ebf1aff3a5abd7d0c4ef0e5fbf3648Garrett D'Amore<?xml-stylesheet type="text/xsl" href="/style/manual.en.xsl"?>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore<modulesynopsis metafile="mod_substitute.xml.meta">

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore<name>mod_substitute</name>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore<description>Perform search and replace operations on response bodies</description>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore<status>Extension</status>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore<sourcefile>mod_substitute.c</sourcefile>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore<identifier>substitute_module</identifier>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore<summary>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore <p><module>mod_substitute</module> provides a mechanism to perform

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore both regular expression and fixed string substitutions on

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore response bodies.</p>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore</summary>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore<directivesynopsis>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore<name>Substitute</name>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore<description>Pattern to filter the response content</description>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore<syntax>Substitute <var>s/pattern/substitution/[infq]</var></syntax>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore<contextlist><context>directory</context>

aa64fa16549f13233681f4b40e50fb5b1c18a97cGarrett D'Amore<context>.htaccess</context></contextlist>

aa64fa16549f13233681f4b40e50fb5b1c18a97cGarrett D'Amore<override>FileInfo</override>

aa64fa16549f13233681f4b40e50fb5b1c18a97cGarrett D'Amore

aa64fa16549f13233681f4b40e50fb5b1c18a97cGarrett D'Amore<usage>

aa64fa16549f13233681f4b40e50fb5b1c18a97cGarrett D'Amore <p>The <directive>Substitute</directive> directive specifies a

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore search and replace pattern to apply to the response body.</p>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore <p>The meaning of the pattern can be modified by using any

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore combination of these flags:</p>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore <dl>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore <dt><code>i</code></dt>

2d08521bd15501c8370ba2153b9cca4f094979d0Garrett D'Amore <dd>Perform a case-insensitive match.</dd>

4297a3b0d0a35d80f86fff155e288e885a100e6dGarrett D'Amore <dt><code>n</code></dt>

<dd>By default the pattern is treated as a regular expression.

Using the <code>n</code> flag forces the pattern to be treated

as a fixed string.</dd>

<dt><code>f</code></dt>

<dd>The <code>f</code> flag causes mod_substitute to flatten the

result of a substitution allowing for later substitutions to

take place on the boundary of this one. This is the default.</dd>

<dt><code>q</code></dt>

<dd>The <code>q</code> flag causes mod_substitute to not

flatten the buckets after each substitution. This can

result in much faster response and a decrease in memory

utilization, but should only be used if there is no possibility

that the result of one substitution will ever match a pattern

or regex of a subsequent one.</dd>

</dl>

<example><title>Example</title>

<highlight language="config">

&lt;Location /&gt;

AddOutputFilterByType SUBSTITUTE text/html

Substitute s/foo/bar/ni

&lt;/Location&gt;

</highlight>

</example>

<p>If either the pattern or the substitution contain a slash

character then an alternative delimiter should be used:</p>

<example><title>Example of using an alternate delimiter</title>

<highlight language="config">

&lt;Location /&gt;

AddOutputFilterByType SUBSTITUTE text/html

Substitute "s|&lt;BR */?&gt;|&lt;br /&gt;|i"

&lt;/Location&gt;

</highlight>

</example>

<p>Backreferences can be used in the comparison and in the substitution,

when regular expressions are used, as illustrated in the following example: </p>

<example><title>Example of using backreferences and captures</title>

<highlight language="config">

&lt;Location /&gt;

AddOutputFilterByType SUBSTITUTE text/html

# "foo=k,bar=k" -> "foo/bar=k"

Substitute "s|foo=(\w+),bar=\1|foo/bar=$1"

&lt;/Location&gt;

</highlight>

</example>

<p>A common use scenario for <code>mod_substitute</code> is the

situation in which a front-end server proxies requests to a back-end

server which returns HTML with hard-coded embedded URLs that refer

to the back-end server. These URLs don't work for the end-user,

since the back-end server is unreachable.</p>

<p>In this case, <code>mod_substutite</code> can be used to rewrite

those URLs into something that will work from the front end:</p>

<example><title>Rewriting URLs embedded in proxied content</title>

<highlight language="config">

ProxyPass /blog/ http://internal.blog.example.com

ProxyPassReverse /blog/ http://internal.blog.example.com/

Substitute "s|http://internal.blog.example.com/|http://www.example.com/blog/|i"

</highlight>

</example>

<p><directive module="mod_proxy">ProxyPassReverse</directive>

modifies any <code>Location</code> (redirect) headers that are sent

by the back-end server, and, in this example,

<code>Substitute</code> takes care of the rest of the problem by

fixing up the HTML response as well.</p>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>SubstituteMaxLineLength</name>

<description>Set the maximum line size</description>

<syntax>SubstituteMaxLineLength <var>bytes</var>(b|B|k|K|m|M|g|G)</syntax>

<default>SubstituteMaxLineLength 1m</default>

<contextlist><context>directory</context>

<context>.htaccess</context></contextlist>

<override>FileInfo</override>

<compatibility>Available in httpd 2.5-dev and later</compatibility>

<usage>

<p>The maximum line size handled by <module>mod_substitute</module>

is limited to restrict memory use. The limit can be configured

using <directive>SubstituteMaxLineLength</directive>.

The value can be given as the number of bytes and can be suffixed

with a single letter <code>b</code>, <code>B</code>, <code>k</code>,

<code>K</code>, <code>m</code>, <code>M</code>, <code>g</code>,

<code>G</code> to provide the size in bytes, kilobytes, megabytes

or gigabytes respectively.</p>

<example><title>Example</title>

<highlight language="config">

&lt;Location /&gt;

AddOutputFilterByType SUBSTITUTE text/html

SubstituteMaxLineLength 10m

Substitute s/foo/bar/ni

&lt;/Location&gt;

</highlight>

</example>

</usage>

</directivesynopsis>

</modulesynopsis>