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- <h1 align="center">Environment Variables in Apache</h1>
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+ --><title>Environment Variables in Apache- Apache HTTP Server</title><link href="./style/manual.css" type="text/css" rel="stylesheet"/></head><body><blockquote><div align="center"><img src="./images/sub.gif" alt="[APACHE DOCUMENTATION]"/><h3>Apache HTTP Server Version 2.0</h3></div><h1 align="center">Environment Variables in Apache</h1>
<p>The Apache HTTP Server provides a mechanism for storing
information in named variables that are called <em>environment
variables</em>. This information can be used to control various
also used as a mechanism to communicate with external programs
such as CGI scripts. This document discusses different ways to
manipulate and use these variables.</p>
-
+
<p>Although these variables are referred to as <em>environment
variables</em>, they are not the same as the environment
variables controlled by the underlying operating system.
server itself runs, you must use the standard environment
manipulation mechanisms provided by your operating system
shell.</p>
-
- <ul>
- <li><a href="#setting">Setting Environment Variables</a></li>
-
- <li><a href="#using">Using Environment Variables</a></li>
-
- <li><a href="#special">Special Purpose Environment
- Variables</a></li>
-
- <li><a href="#examples">Examples</a></li>
- </ul>
- <hr />
-
- <h2><a id="setting" name="setting">Setting Environment
- Variables</a></h2>
-
- <table border="1">
- <tr>
- <td valign="top"><strong>Related Modules</strong><br />
- <br />
- <a href="mod/mod_env.html">mod_env</a><br />
- <a href="mod/mod_rewrite.html">mod_rewrite</a><br />
- <a href="mod/mod_setenvif.html">mod_setenvif</a><br />
- <a href="mod/mod_unique_id.html">mod_unique_id</a><br />
- </td>
-
- <td valign="top"><strong>Related Directives</strong><br />
- <br />
- <a
- href="mod/mod_setenvif.html#BrowserMatch">BrowserMatch</a><br />
- <a
- href="mod/mod_setenvif.html#BrowserMatchNoCase">BrowserMatchNoCase</a><br />
- <a href="mod/mod_env.html#passenv">PassEnv</a><br />
- <a
- href="mod/mod_rewrite.html#RewriteRule">RewriteRule</a><br />
- <a href="mod/mod_env.html#setenv">SetEnv</a><br />
- <a
- href="mod/mod_setenvif.html#SetEnvIf">SetEnvIf</a><br />
- <a
- href="mod/mod_setenvif.html#SetEnvIfNoCase">SetEnvIfNoCase</a><br />
- <a href="mod/mod_env.html#unsetenv">UnsetEnv</a><br />
- </td>
- </tr>
- </table>
-
- <h3>Basic Environment Manipulation</h3>
-
- <p>The most basic way to set an environment variable in Apache
- is using the unconditional <code>SetEnv</code> directive.
- Variables may also be passed from the environment of the shell
- which started the server using the <code>PassEnv</code>
- directive.</p>
-
- <h3>Conditional Per-Request Settings</h3>
-
- <p>For additional flexibility, the directives provided by
- mod_setenvif allow environment variables to be set on a
- per-request basis, conditional on characteristics of particular
- requests. For example, a variable could be set only when a
- specific browser (User-Agent) is making a request, or only when
- a specific Referer [sic] header is found. Even more flexibility
- is available through the mod_rewrite's <code>RewriteRule</code>
- which uses the <code>[E=...]</code> option to set environment
- variables.</p>
-
- <h3>Unique Identifiers</h3>
-
- <p>Finally, mod_unique_id sets the environment variable
- <code>UNIQUE_ID</code> for each request to a value which is
- guaranteed to be unique across "all" requests under very
- specific conditions.</p>
-
- <h3>Standard CGI Variables</h3>
-
- <p>In addition to all environment variables set within the
- Apache configuration and passed from the shell, CGI scripts and
- SSI pages are provided with a set of environment variables
- containing meta-information about the request as required by
- the <a href="http://cgi-spec.golux.com/">CGI
- specification</a>.</p>
-
- <h3>Some Caveats</h3>
-
- <ul>
- <li>It is not possible to override or change the standard CGI
- variables using the environment manipulation directives.</li>
-
- <li>When <a href="suexec.html">suexec</a> is used to launch
- CGI scripts, the environment will be cleaned down to a set of
- <em>safe</em> variables before CGI scripts are launched. The
- list of <em>safe</em> variables is defined at compile-time in
- <code>suexec.c</code>.</li>
-
- <li>For portability reasons, the names of environment
- variables may contain only letters, numbers, and the
- underscore character. In addition, the first character may
- not be a number. Characters which do not match this
- restriction will be replaced by an underscore when passed to
- CGI scripts and SSI pages.</li>
- </ul>
- <hr />
-
- <h2><a id="using" name="using">Using Environment
- Variables</a></h2>
-
- <table border="1">
- <tr>
- <td valign="top"><strong>Related Modules</strong><br />
- <br />
- <a href="mod/mod_access.html">mod_access</a><br />
- <a href="mod/mod_cgi.html">mod_cgi</a><br />
- <a href="mod/mod_headers.html">mod_headers</a><br />
- <a href="mod/mod_include.html">mod_include</a><br />
- <a href="mod/mod_log_config.html">mod_log_config</a><br />
- <a href="mod/mod_rewrite.html">mod_rewrite</a><br />
- </td>
-
- <td valign="top"><strong>Related Directives</strong><br />
- <br />
- <a href="mod/mod_access.html#allow">Allow</a><br />
- <a
- href="mod/mod_log_config.html#customlog">CustomLog</a><br />
- <a href="mod/mod_access.html#deny">Deny</a><br />
- <a href="mod/mod_headers.html#Header">Header</a><br />
- <a
- href="mod/mod_log_config.html#logformat">LogFormat</a><br />
- <a
- href="mod/mod_rewrite.html#RewriteCond">RewriteCond</a><br />
- <a
- href="mod/mod_rewrite.html#RewriteRule">RewriteRule</a><br />
- </td>
- </tr>
- </table>
-
- <h3>CGI Scripts</h3>
-
- <p>One of the primary uses of environment variables is to
- communicate information to CGI scripts. As discussed above, the
- environment passed to CGI scripts includes standard
- meta-information about the request in addition to any variables
- set within the Apache configuration. For more details, see the
- <a href="howto/cgi.html">CGI tutorial</a>.</p>
-
- <h3>SSI Pages</h3>
-
- <p>Server-parsed (SSI) documents processed by mod_include's
- <code>INCLUDES</code> filter can print environment variables
- using the <code>echo</code> element, and can use environment
- variables in flow control elements to makes parts of a page
- conditional on characteristics of a request. Apache also
- provides SSI pages with the standard CGI environment variables
- as discussed above. For more details, see the <a
- href="howto/ssi.html">SSI tutorial</a>.</p>
-
- <h3>Access Control</h3>
-
- <p>Access to the server can be controlled based on the value of
- environment variables using the <code>allow from env=</code>
- and <code>deny from env=</code> directives. In combination with
- <code>SetEnvIf</code>, this allows for flexible control of
- access to the server based on characteristics of the client.
- For example, you can use these directives to deny access to a
- particular browser (User-Agent).</p>
-
- <h3>Conditional Logging</h3>
-
- <p>Environment variables can be logged in the access log using
- the <code>LogFormat</code> option <code>%e</code>. In addition,
- the decision on whether or not to log requests can be made
- based on the status of environment variables using the
- conditional form of the <code>CustomLog</code> directive. In
- combination with <code>SetEnvIf</code> this allows for flexible
- control of which requests are logged. For example, you can
- choose not to log requests for filenames ending in
- <code>gif</code>, or you can choose to only log requests from
- clients which are outside your subnet.</p>
-
- <h3>Conditional Response Headers</h3>
-
- <p>The <code>Header</code> directive can use the presence or
- absence of an environment variable to determine whether or not
- a certain HTTP header will be placed in the response to the
- client. This allows, for example, a certain response header to
- be sent only if a corresponding header is received in the
- request from the client.</p>
-
- <h3>URL Rewriting</h3>
-
- <p>The <code>%{ENV:...}</code> form of <em>TestString</em> in
- the <code>RewriteCond</code> allows mod_rewrite's rewrite
- engine to make decisions conditional on environment variables.
- Note that the variables accessible in mod_rewrite without the
- <code>ENV:</code> prefix are not actually environment
- variables. Rather, they are variables special to mod_rewrite
- which cannot be accessed from other modules.</p>
- <hr />
-
- <h2><a id="special" name="special">Special Purpose Environment
- Variables</a></h2>
-
- <p>Interoperability problems have led to the introduction of
- mechanisms to modify the way Apache behaves when talking to
- particular clients. To make these mechanisms as flexible as
- possible, they are invoked by defining environment variables,
- typically with <a
- href="mod/mod_setenvif.html#browsermatch">BrowserMatch</a>,
- though <a href="mod/mod_env.html#setenv">SetEnv</a> and <a
- href="mod/mod_env.html#passenv">PassEnv</a> could also be used,
- for example.</p>
-
- <h2>downgrade-1.0</h2>
-
- <p>This forces the request to be treated as a HTTP/1.0 request
- even if it was in a later dialect.</p>
-
- <h2>force-no-vary</h2>
-
- <p>This causes any <code>Vary</code> fields to be removed from
- the response header before it is sent back to the client. Some
- clients don't interpret this field correctly (see the <a
- href="misc/known_client_problems.html">known client
- problems</a> page); setting this variable can work around this
- problem. Setting this variable also implies
- <strong>force-response-1.0</strong>.</p>
-
- <h2>force-response-1.0</h2>
-
- <p>This forces an HTTP/1.0 response when set. It was originally
- implemented as a result of a problem with AOL's proxies. Some
- clients may not behave correctly when given an HTTP/1.1
- response, and this can be used to interoperate with them.</p>
-
- <h2>nokeepalive</h2>
-
- <p>This disables <a
- href="mod/core.html#keepalive">KeepAlive</a> when set.</p>
-
- <h2>redirect-carefully</h2>
-
- <p>This forces the server to be more careful when sending a redirect
- to the client. This is typically used when a client has a known
- problem handling redirects. This was originally implemented as a
- result of a problem with Microsoft's WebFolders software which has
- a problem handling redirects on directory resources via DAV
- methods.</p>
-
- <hr />
- <h2><a id="examples" name="examples">Examples</a></h2>
-
- <h3>Changing protocol behavior with misbehaving clients</h3>
-
- <p>We recommend that the following lines be included in
- httpd.conf to deal with known client problems.</p>
-<pre>
+ <ul><li><a href="#setting">Setting Environment Variables</a><ul><li><a href="#basic-manipulation">Basic Environment Manipulation</a></li><li><a href="#conditional">Conditional Per-Request Settings</a></li><li><a href="#unique-identifiers">Unique Identifiers</a></li><li><a href="#standard-cgi">Standard CGI Variables</a></li><li><a href="#caveats">Some Caveats</a></li></ul></li><li><a href="#using">Using Environment Variables</a><ul><li><a href="#cgi-scripts">CGI Scripts</a></li><li><a href="#ssi-pages">SSI Pages</a></li><li><a href="#access-control">Access Control</a></li><li><a href="#logging">Conditional Logging</a></li><li><a href="#response-headers">Conditional Response Headers</a></li><li><a href="#url-rewriting">URL Rewriting</a></li></ul></li><li><a href="#special">Special Purpose Environment Variables</a><ul><li><a href="#downgrade">downgrade-1.0</a></li><li><a href="#force-no-vary">force-no-vary</a></li><li><a href="#force-response">force-response-1.0</a></li><li><a href="#nokeepalive">nokeepalive</a></li><li><a href="#redirect-carefully">redirect-carefully</a></li></ul></li><li><a href="#examples">Examples</a><ul><li><a href="#misbehaving">Changing protocol behavior with misbehaving clients</a></li><li><a href="#no-img-log">Do not log requests for images in the access log</a></li><li><a href="#image-theft">Prevent "Image Theft"</a></li></ul></li></ul><hr/><h2><a name="setting">Setting Environment Variables</a></h2>
+
+ <table border="1"><tr><td valign="top"><strong>Related Modules</strong><br/><br/><code><a href="./mod/mod_env.html">mod_env</a></code>, <br/><code><a href="./mod/mod_rewrite.html">mod_rewrite</a></code>, <br/><code><a href="./mod/mod_setenvif.html">mod_setenvif</a></code>, <br/><code><a href="./mod/mod_unique_id.html">mod_unique_id</a></code><br/></td><td valign="top"><strong>Related Directives</strong><br/><br/><a href="./mod/mod_setenvif.html#browsermatch" class="directive"><code class="directive">BrowserMatch</code></a><br/><a href="./mod/mod_setenvif.html#browsermatchnocase" class="directive"><code class="directive">BrowserMatchNoCase</code></a><br/><a href="./mod/mod_env.html#passenv" class="directive"><code class="directive">PassEnv</code></a><br/><a href="./mod/mod_rewrite.html#rewriterule" class="directive"><code class="directive">RewriteRule</code></a><br/><a href="./mod/mod_env.html#setenv" class="directive"><code class="directive">SetEnv</code></a><br/><a href="./mod/mod_setenvif.html#setenvif" class="directive"><code class="directive">SetEnvIf</code></a><br/><a href="./mod/mod_setenvif.html#setenvifnocase" class="directive"><code class="directive">SetEnvIfNoCase</code></a><br/><a href="./mod/mod_env.html.html#unsetenv" class="directive"><code class="directive">UnsetEnv</code></a><br/></td></tr></table>
+
+ <h3><a name="basic-manipulation">Basic Environment Manipulation</a></h3>
+
+
+ <p>The most basic way to set an environment variable in Apache
+ is using the unconditional <a href="./mod/mod_env.html#setenv" class="directive"><code class="directive">SetEnv</code></a> directive. Variables may also be passed from
+ the environment of the shell which started the server using the
+ <a href="./mod/mod_env.html#passenv" class="directive"><code class="directive">PassEnv</code></a> directive.</p>
+
+
+ <h3><a name="conditional">Conditional Per-Request Settings</a></h3>
+
+
+ <p>For additional flexibility, the directives provided by
+ mod_setenvif allow environment variables to be set on a
+ per-request basis, conditional on characteristics of particular
+ requests. For example, a variable could be set only when a
+ specific browser (User-Agent) is making a request, or only when
+ a specific Referer [sic] header is found. Even more flexibility
+ is available through the mod_rewrite's <a href="./mod/mod_rewrite.html#rewriterule" class="directive"><code class="directive">RewriteRule</code></a> which uses the
+ <code>[E=...]</code> option to set environment variables.</p>
+
+
+ <h3><a name="unique-identifiers">Unique Identifiers</a></h3>
+
+
+ <p>Finally, mod_unique_id sets the environment variable
+ <code>UNIQUE_ID</code> for each request to a value which is
+ guaranteed to be unique across "all" requests under very
+ specific conditions.</p>
+
+
+ <h3><a name="standard-cgi">Standard CGI Variables</a></h3>
+
+
+ <p>In addition to all environment variables set within the
+ Apache configuration and passed from the shell, CGI scripts and
+ SSI pages are provided with a set of environment variables
+ containing meta-information about the request as required by
+ the <a href="http://cgi-spec.golux.com/">CGI
+ specification</a>.</p>
+
+
+ <h3><a name="caveats">Some Caveats</a></h3>
+
+
+ <ul>
+ <li>It is not possible to override or change the standard CGI
+ variables using the environment manipulation directives.</li>
+
+ <li>When <a href="suexec.html">suexec</a> is used to launch
+ CGI scripts, the environment will be cleaned down to a set of
+ <em>safe</em> variables before CGI scripts are launched. The
+ list of <em>safe</em> variables is defined at compile-time in
+ <code>suexec.c</code>.</li>
+
+ <li>For portability reasons, the names of environment
+ variables may contain only letters, numbers, and the
+ underscore character. In addition, the first character may
+ not be a number. Characters which do not match this
+ restriction will be replaced by an underscore when passed to
+ CGI scripts and SSI pages.</li>
+ </ul>
+
+ <h2><a name="using">Using Environment Variables</a></h2>
+
+
+ <table border="1"><tr><td valign="top"><strong>Related Modules</strong><br/><br/><code><a href="./mod/mod_access.html">mod_access</a></code>, <br/><code><a href="./mod/mod_cgi.html">mod_cgi</a></code>, <br/><code><a href="./mod/mod_headers.html">mod_headers</a></code>, <br/><code><a href="./mod/mod_include.html">mod_include</a></code>, <br/><code><a href="./mod/mod_log_config.html">mod_log_config</a></code>, <br/><code><a href="./mod/mod_rewrite.html">mod_rewrite</a></code><br/></td><td valign="top"><strong>Related Directives</strong><br/><br/><a href="./mod/mod_access.html#allow" class="directive"><code class="directive">Allow</code></a><br/><a href="./mod/mod_log_config.html#customlog" class="directive"><code class="directive">CustomLog</code></a><br/><a href="./mod/mod_access.html#deny" class="directive"><code class="directive">Deny</code></a><br/><a href="./mod/mod_headers.html#header" class="directive"><code class="directive">Header</code></a><br/><a href="./mod/mod_log_config.html#logformat" class="directive"><code class="directive">LogFormat</code></a><br/><a href="./mod/mod_rewrite.html#rewritecond" class="directive"><code class="directive">RewriteCond</code></a><br/><a href="./mod/mod_rewrite.html#rewriterule" class="directive"><code class="directive">RewriteRule</code></a><br/></td></tr></table>
+
+ <h3><a name="cgi-scripts">CGI Scripts</a></h3>
+
+
+ <p>One of the primary uses of environment variables is to
+ communicate information to CGI scripts. As discussed above, the
+ environment passed to CGI scripts includes standard
+ meta-information about the request in addition to any variables
+ set within the Apache configuration. For more details, see the
+ <a href="howto/cgi.html">CGI tutorial</a>.</p>
+
+
+ <h3><a name="ssi-pages">SSI Pages</a></h3>
+
+
+ <p>Server-parsed (SSI) documents processed by mod_include's
+ <code>INCLUDES</code> filter can print environment variables
+ using the <code>echo</code> element, and can use environment
+ variables in flow control elements to makes parts of a page
+ conditional on characteristics of a request. Apache also
+ provides SSI pages with the standard CGI environment variables
+ as discussed above. For more details, see the <a href="howto/ssi.html">SSI tutorial</a>.</p>
+
+
+ <h3><a name="access-control">Access Control</a></h3>
+
+
+ <p>Access to the server can be controlled based on the value of
+ environment variables using the <code>allow from env=</code>
+ and <code>deny from env=</code> directives. In combination with
+ <a href="./mod/mod_setenvif.html#setenvif" class="directive"><code class="directive">SetEnvIf</code></a>, this
+ allows for flexible control of access to the server based on
+ characteristics of the client. For example, you can use these
+ directives to deny access to a particular browser (User-Agent).
+ </p>
+
+
+ <h3><a name="logging">Conditional Logging</a></h3>
+
+
+ <p>Environment variables can be logged in the access log using
+ the <a href="./mod/mod_log_config.html#logformat" class="directive"><code class="directive">LogFormat</code></a>
+ option <code>%e</code>. In addition, the decision on whether
+ or not to log requests can be made based on the status of
+ environment variables using the conditional form of the
+ <a href="./mod/mod_log_config.html#customlog" class="directive"><code class="directive">CustomLog</code></a>
+ directive. In combination with <a href="./mod/mod_setenvif.html#setenvif" class="directive"><code class="directive">SetEnvIf</code></a> this allows for flexible control of which
+ requests are logged. For example, you can choose not to log
+ requests for filenames ending in <code>gif</code>, or you can
+ choose to only log requests from clients which are outside your
+ subnet.</p>
+
+
+ <h3><a name="response-headers">Conditional Response Headers</a></h3>
+
+
+ <p>The <a href="./mod/mod_headers.html#header" class="directive"><code class="directive">Header</code></a>
+ directive can use the presence or
+ absence of an environment variable to determine whether or not
+ a certain HTTP header will be placed in the response to the
+ client. This allows, for example, a certain response header to
+ be sent only if a corresponding header is received in the
+ request from the client.</p>
+
+
+ <h3><a name="url-rewriting">URL Rewriting</a></h3>
+
+
+ <p>The <code>%{ENV:...}</code> form of <em>TestString</em> in
+ the <a href="./mod/mod_rewrite.html#rewritecond" class="directive"><code class="directive">RewriteCond</code></a>
+ allows mod_rewrite's rewrite
+ engine to make decisions conditional on environment variables.
+ Note that the variables accessible in mod_rewrite without the
+ <code>ENV:</code> prefix are not actually environment
+ variables. Rather, they are variables special to mod_rewrite
+ which cannot be accessed from other modules.</p>
+
+ <h2><a name="special">Special Purpose Environment Variables</a></h2>
+
+
+ <p>Interoperability problems have led to the introduction of
+ mechanisms to modify the way Apache behaves when talking to
+ particular clients. To make these mechanisms as flexible as
+ possible, they are invoked by defining environment variables,
+ typically with <a href="./mod/mod_setenvif.html#browsermatch" class="directive"><code class="directive">BrowserMatch</code></a>,
+ though <a href="./mod/mod_env.html#setenv" class="directive"><code class="directive">SetEnv</code></a> and
+ <a href="./mod/mod_env.html#passenv" class="directive"><code class="directive">PassEnv</code></a> could also be used,
+ for example.</p>
+
+ <h3><a name="downgrade">downgrade-1.0</a></h3>
+
+
+ <p>This forces the request to be treated as a HTTP/1.0 request
+ even if it was in a later dialect.</p>
+
+
+ <h3><a name="force-no-vary">force-no-vary</a></h3>
+
+
+ <p>This causes any <code>Vary</code> fields to be removed from
+ the response header before it is sent back to the client. Some
+ clients don't interpret this field correctly (see the <a href="misc/known_client_problems.html">known client
+ problems</a> page); setting this variable can work around this
+ problem. Setting this variable also implies
+ <strong>force-response-1.0</strong>.</p>
+
+
+ <h3><a name="force-response">force-response-1.0</a></h3>
+
+
+ <p>This forces an HTTP/1.0 response when set. It was originally
+ implemented as a result of a problem with AOL's proxies. Some
+ clients may not behave correctly when given an HTTP/1.1
+ response, and this can be used to interoperate with them.</p>
+
+
+ <h3><a name="nokeepalive">nokeepalive</a></h3>
+
+
+ <p>This disables <a href="./mod/core.html#keepalive" class="directive"><code class="directive">KeepAlive</code></a> when set.</p>
+
+
+ <h3><a name="redirect-carefully">redirect-carefully</a></h3>
+
+
+ <p>This forces the server to be more careful when sending a redirect
+ to the client. This is typically used when a client has a known
+ problem handling redirects. This was originally implemented as a
+ result of a problem with Microsoft's WebFolders software which has
+ a problem handling redirects on directory resources via DAV
+ methods.</p>
+
+
+ <h2><a name="examples">Examples</a></h2>
+
+
+ <h3><a name="misbehaving">Changing protocol behavior with misbehaving clients</a></h3>
+
+
+ <p>We recommend that the following lines be included in
+ httpd.conf to deal with known client problems.</p>
+<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code><pre>
#
# The following directives modify normal HTTP response behavior.
# The first directive disables keepalive for Netscape 2.x and browsers that
#
BrowserMatch "RealPlayer 4\.0" force-response-1.0
BrowserMatch "Java/1\.0" force-response-1.0
-BrowserMatch "JDK/1\.0" force-response-1.0
-</pre>
-
- <h3>Do not log requests for images in the access log</h3>
-
- <p>This example keeps requests for images from appearing in the
- access log. It can be easily modified to prevent logging of
- particular directories, or to prevent logging of requests
- coming from particular hosts.</p>
-<pre>
- SetEnvIf Request_URI \.gif image-request
- SetEnvIf Request_URI \.jpg image-request
- SetEnvIf Request_URI \.png image-request
- CustomLog logs/access_log common env=!image-request
-</pre>
-
- <h3>Prevent "Image Theft"</h3>
-
- <p>This example shows how to keep people not on your server
- from using images on your server as inline-images on their
- pages. This is not a recommended configuration, but it can work
- in limited circumstances. We assume that all your images are in
- a directory called /web/images.</p>
-<pre>
- SetEnvIf Referer "^http://www.example.com/" local_referal
- # Allow browsers that do not send Referer info
- SetEnvIf Referer "^$" local_referal
- <Directory /web/images>
- Order Deny,Allow
- Deny from all
- Allow from env=local_referal
- </Directory>
-</pre>
-
- <p>For more information about this technique, see the
- ApacheToday tutorial " <a
- href="http://apachetoday.com/news_story.php3?ltsn=2000-06-14-002-01-PS">
+BrowserMatch "JDK/1\.0" force-response-1.0</pre></code></td></tr></table></blockquote>
+
+
+ <h3><a name="no-img-log">Do not log requests for images in the access log</a></h3>
+
+
+ <p>This example keeps requests for images from appearing in the
+ access log. It can be easily modified to prevent logging of
+ particular directories, or to prevent logging of requests
+ coming from particular hosts.</p>
+ <blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code><pre>
+SetEnvIf Request_URI \.gif image-request
+SetEnvIf Request_URI \.jpg image-request
+SetEnvIf Request_URI \.png image-request
+CustomLog logs/access_log common env=!image-request</pre></code></td></tr></table></blockquote>
+
+
+ <h3><a name="image-theft">Prevent "Image Theft"</a></h3>
+
+
+ <p>This example shows how to keep people not on your server
+ from using images on your server as inline-images on their
+ pages. This is not a recommended configuration, but it can work
+ in limited circumstances. We assume that all your images are in
+ a directory called /web/images.</p>
+ <blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code><pre>
+SetEnvIf Referer "^http://www.example.com/" local_referal
+# Allow browsers that do not send Referer info
+SetEnvIf Referer "^$" local_referal
+<Directory /web/images>
+ Order Deny,Allow
+ Deny from all
+ Allow from env=local_referal
+</Directory></pre></code></td></tr></table></blockquote>
+
+ <p>For more information about this technique, see the
+ ApacheToday tutorial " <a href="http://apachetoday.com/news_story.php3?ltsn=2000-06-14-002-01-PS">
Keeping Your Images from Adorning Other Sites</a>".</p>
- <!--#include virtual="footer.html" -->
- </body>
-</html>
-
+
+ </blockquote><h3 align="center">Apache HTTP Server Version 2.0</h3><a href="./"><img src="./images/index.gif" alt="Index"/></a><a href="./"><img src="./images/home.gif" alt="Home"/></a></body></html>
\ No newline at end of file
--- /dev/null
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE manualpage SYSTEM "./style/manualpage.dtd">
+<?xml-stylesheet type="text/xsl" href="./style/manual.en.xsl"?>
+
+<manualpage>
+ <relativepath href="."/>
+
+ <title>Environment Variables in Apache</title>
+
+ <summary>
+ <p>The Apache HTTP Server provides a mechanism for storing
+ information in named variables that are called <em>environment
+ variables</em>. This information can be used to control various
+ operations such as logging or access control. The variables are
+ also used as a mechanism to communicate with external programs
+ such as CGI scripts. This document discusses different ways to
+ manipulate and use these variables.</p>
+
+ <p>Although these variables are referred to as <em>environment
+ variables</em>, they are not the same as the environment
+ variables controlled by the underlying operating system.
+ Instead, these variables are stored and manipulated in an
+ internal Apache structure. They only become actual operating
+ system environment variables when they are provided to CGI
+ scripts and Server Side Include scripts. If you wish to
+ manipulate the operating system environment under which the
+ server itself runs, you must use the standard environment
+ manipulation mechanisms provided by your operating system
+ shell.</p>
+ </summary>
+
+ <section id="setting">
+ <title>Setting Environment Variables</title>
+ <related>
+ <modulelist>
+ <module>mod_env</module>
+ <module>mod_rewrite</module>
+ <module>mod_setenvif</module>
+ <module>mod_unique_id</module>
+ </modulelist>
+ <directivelist>
+ <directive module="mod_setenvif">BrowserMatch</directive>
+ <directive module="mod_setenvif">BrowserMatchNoCase</directive>
+ <directive module="mod_env">PassEnv</directive>
+ <directive module="mod_rewrite">RewriteRule</directive>
+ <directive module="mod_env">SetEnv</directive>
+ <directive module="mod_setenvif">SetEnvIf</directive>
+ <directive module="mod_setenvif">SetEnvIfNoCase</directive>
+ <directive module="mod_env.html">UnsetEnv</directive>
+ </directivelist>
+ </related>
+
+ <section id="basic-manipulation">
+ <title>Basic Environment Manipulation</title>
+
+ <p>The most basic way to set an environment variable in Apache
+ is using the unconditional <directive module="mod_env"
+ >SetEnv</directive> directive. Variables may also be passed from
+ the environment of the shell which started the server using the
+ <directive module="mod_env">PassEnv</directive> directive.</p>
+
+ </section>
+ <section id="conditional">
+ <title>Conditional Per-Request Settings</title>
+
+ <p>For additional flexibility, the directives provided by
+ mod_setenvif allow environment variables to be set on a
+ per-request basis, conditional on characteristics of particular
+ requests. For example, a variable could be set only when a
+ specific browser (User-Agent) is making a request, or only when
+ a specific Referer [sic] header is found. Even more flexibility
+ is available through the mod_rewrite's <directive
+ module="mod_rewrite">RewriteRule</directive> which uses the
+ <code>[E=...]</code> option to set environment variables.</p>
+
+ </section>
+ <section id="unique-identifiers">
+ <title>Unique Identifiers</title>
+
+ <p>Finally, mod_unique_id sets the environment variable
+ <code>UNIQUE_ID</code> for each request to a value which is
+ guaranteed to be unique across "all" requests under very
+ specific conditions.</p>
+
+ </section>
+ <section id="standard-cgi">
+ <title>Standard CGI Variables</title>
+
+ <p>In addition to all environment variables set within the
+ Apache configuration and passed from the shell, CGI scripts and
+ SSI pages are provided with a set of environment variables
+ containing meta-information about the request as required by
+ the <a href="http://cgi-spec.golux.com/">CGI
+ specification</a>.</p>
+
+ </section>
+ <section id="caveats">
+ <title>Some Caveats</title>
+
+ <ul>
+ <li>It is not possible to override or change the standard CGI
+ variables using the environment manipulation directives.</li>
+
+ <li>When <a href="suexec.html">suexec</a> is used to launch
+ CGI scripts, the environment will be cleaned down to a set of
+ <em>safe</em> variables before CGI scripts are launched. The
+ list of <em>safe</em> variables is defined at compile-time in
+ <code>suexec.c</code>.</li>
+
+ <li>For portability reasons, the names of environment
+ variables may contain only letters, numbers, and the
+ underscore character. In addition, the first character may
+ not be a number. Characters which do not match this
+ restriction will be replaced by an underscore when passed to
+ CGI scripts and SSI pages.</li>
+ </ul>
+ </section>
+ </section>
+ <section id="using">
+ <title>Using Environment Variables</title>
+
+ <related>
+ <modulelist>
+ <module>mod_access</module>
+ <module>mod_cgi</module>
+ <module>mod_headers</module>
+ <module>mod_include</module>
+ <module>mod_log_config</module>
+ <module>mod_rewrite</module>
+ </modulelist>
+ <directivelist>
+ <directive module="mod_access">Allow</directive>
+ <directive module="mod_log_config">CustomLog</directive>
+ <directive module="mod_access">Deny</directive>
+ <directive module="mod_headers">Header</directive>
+ <directive module="mod_log_config">LogFormat</directive>
+ <directive module="mod_rewrite">RewriteCond</directive>
+ <directive module="mod_rewrite">RewriteRule</directive>
+ </directivelist>
+ </related>
+
+ <section id="cgi-scripts">
+ <title>CGI Scripts</title>
+
+ <p>One of the primary uses of environment variables is to
+ communicate information to CGI scripts. As discussed above, the
+ environment passed to CGI scripts includes standard
+ meta-information about the request in addition to any variables
+ set within the Apache configuration. For more details, see the
+ <a href="howto/cgi.html">CGI tutorial</a>.</p>
+
+ </section>
+ <section id="ssi-pages">
+ <title>SSI Pages</title>
+
+ <p>Server-parsed (SSI) documents processed by mod_include's
+ <code>INCLUDES</code> filter can print environment variables
+ using the <code>echo</code> element, and can use environment
+ variables in flow control elements to makes parts of a page
+ conditional on characteristics of a request. Apache also
+ provides SSI pages with the standard CGI environment variables
+ as discussed above. For more details, see the <a
+ href="howto/ssi.html">SSI tutorial</a>.</p>
+
+ </section>
+ <section id="access-control">
+ <title>Access Control</title>
+
+ <p>Access to the server can be controlled based on the value of
+ environment variables using the <code>allow from env=</code>
+ and <code>deny from env=</code> directives. In combination with
+ <directive module="mod_setenvif">SetEnvIf</directive>, this
+ allows for flexible control of access to the server based on
+ characteristics of the client. For example, you can use these
+ directives to deny access to a particular browser (User-Agent).
+ </p>
+
+ </section>
+ <section id="logging">
+ <title>Conditional Logging</title>
+
+ <p>Environment variables can be logged in the access log using
+ the <directive module="mod_log_config">LogFormat</directive>
+ option <code>%e</code>. In addition, the decision on whether
+ or not to log requests can be made based on the status of
+ environment variables using the conditional form of the
+ <directive module="mod_log_config">CustomLog</directive>
+ directive. In combination with <directive module="mod_setenvif"
+ >SetEnvIf</directive> this allows for flexible control of which
+ requests are logged. For example, you can choose not to log
+ requests for filenames ending in <code>gif</code>, or you can
+ choose to only log requests from clients which are outside your
+ subnet.</p>
+
+ </section>
+ <section id="response-headers">
+ <title>Conditional Response Headers</title>
+
+ <p>The <directive module="mod_headers">Header</directive>
+ directive can use the presence or
+ absence of an environment variable to determine whether or not
+ a certain HTTP header will be placed in the response to the
+ client. This allows, for example, a certain response header to
+ be sent only if a corresponding header is received in the
+ request from the client.</p>
+
+ </section>
+ <section id="url-rewriting">
+ <title>URL Rewriting</title>
+
+ <p>The <code>%{ENV:...}</code> form of <em>TestString</em> in
+ the <directive module="mod_rewrite">RewriteCond</directive>
+ allows mod_rewrite's rewrite
+ engine to make decisions conditional on environment variables.
+ Note that the variables accessible in mod_rewrite without the
+ <code>ENV:</code> prefix are not actually environment
+ variables. Rather, they are variables special to mod_rewrite
+ which cannot be accessed from other modules.</p>
+ </section>
+ </section>
+
+ <section id="special">
+ <title>Special Purpose Environment Variables</title>
+
+ <p>Interoperability problems have led to the introduction of
+ mechanisms to modify the way Apache behaves when talking to
+ particular clients. To make these mechanisms as flexible as
+ possible, they are invoked by defining environment variables,
+ typically with <directive module="mod_setenvif">BrowserMatch</directive>,
+ though <directive module="mod_env">SetEnv</directive> and
+ <directive module="mod_env">PassEnv</directive> could also be used,
+ for example.</p>
+
+ <section id="downgrade">
+ <title>downgrade-1.0</title>
+
+ <p>This forces the request to be treated as a HTTP/1.0 request
+ even if it was in a later dialect.</p>
+
+ </section>
+ <section id="force-no-vary">
+ <title>force-no-vary</title>
+
+ <p>This causes any <code>Vary</code> fields to be removed from
+ the response header before it is sent back to the client. Some
+ clients don't interpret this field correctly (see the <a
+ href="misc/known_client_problems.html">known client
+ problems</a> page); setting this variable can work around this
+ problem. Setting this variable also implies
+ <strong>force-response-1.0</strong>.</p>
+
+ </section>
+ <section id="force-response">
+ <title>force-response-1.0</title>
+
+ <p>This forces an HTTP/1.0 response when set. It was originally
+ implemented as a result of a problem with AOL's proxies. Some
+ clients may not behave correctly when given an HTTP/1.1
+ response, and this can be used to interoperate with them.</p>
+
+ </section>
+ <section id="nokeepalive">
+ <title>nokeepalive</title>
+
+ <p>This disables <directive module="core">KeepAlive</directive> when set.</p>
+
+ </section>
+ <section id="redirect-carefully">
+ <title>redirect-carefully</title>
+
+ <p>This forces the server to be more careful when sending a redirect
+ to the client. This is typically used when a client has a known
+ problem handling redirects. This was originally implemented as a
+ result of a problem with Microsoft's WebFolders software which has
+ a problem handling redirects on directory resources via DAV
+ methods.</p>
+
+ </section>
+ </section>
+
+ <section id="examples">
+ <title>Examples</title>
+
+ <section id="misbehaving">
+ <title>Changing protocol behavior with misbehaving clients</title>
+
+ <p>We recommend that the following lines be included in
+ httpd.conf to deal with known client problems.</p>
+<example><pre>
+#
+# The following directives modify normal HTTP response behavior.
+# The first directive disables keepalive for Netscape 2.x and browsers that
+# spoof it. There are known problems with these browser implementations.
+# The second directive is for Microsoft Internet Explorer 4.0b2
+# which has a broken HTTP/1.1 implementation and does not properly
+# support keepalive when it is used on 301 or 302 (redirect) responses.
+#
+BrowserMatch "Mozilla/2" nokeepalive
+BrowserMatch "MSIE 4\.0b2;" nokeepalive downgrade-1.0 force-response-1.0
+
+#
+# The following directive disables HTTP/1.1 responses to browsers which
+# are in violation of the HTTP/1.0 spec by not being able to grok a
+# basic 1.1 response.
+#
+BrowserMatch "RealPlayer 4\.0" force-response-1.0
+BrowserMatch "Java/1\.0" force-response-1.0
+BrowserMatch "JDK/1\.0" force-response-1.0</pre></example>
+
+ </section>
+ <section id="no-img-log">
+ <title>Do not log requests for images in the access log</title>
+
+ <p>This example keeps requests for images from appearing in the
+ access log. It can be easily modified to prevent logging of
+ particular directories, or to prevent logging of requests
+ coming from particular hosts.</p>
+ <example><pre>
+SetEnvIf Request_URI \.gif image-request
+SetEnvIf Request_URI \.jpg image-request
+SetEnvIf Request_URI \.png image-request
+CustomLog logs/access_log common env=!image-request</pre></example>
+
+ </section>
+ <section id="image-theft">
+ <title>Prevent "Image Theft"</title>
+
+ <p>This example shows how to keep people not on your server
+ from using images on your server as inline-images on their
+ pages. This is not a recommended configuration, but it can work
+ in limited circumstances. We assume that all your images are in
+ a directory called /web/images.</p>
+ <example><pre>
+SetEnvIf Referer "^http://www.example.com/" local_referal
+# Allow browsers that do not send Referer info
+SetEnvIf Referer "^$" local_referal
+<Directory /web/images>
+ Order Deny,Allow
+ Deny from all
+ Allow from env=local_referal
+</Directory></pre></example>
+
+ <p>For more information about this technique, see the
+ ApacheToday tutorial " <a
+ href="http://apachetoday.com/news_story.php3?ltsn=2000-06-14-002-01-PS">
+ Keeping Your Images from Adorning Other Sites</a>".</p>
+ </section>
+ </section>
+</manualpage>
+
+
+
+
-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
- "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-
-<html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <meta name="generator" content="HTML Tidy, see www.w3.org" />
-
- <title>Filters - Apache HTTPD</title>
- </head>
- <!-- Background white, links blue (unvisited), navy (visited), red (active) -->
-
- <body bgcolor="#FFFFFF" text="#000000" link="#0000FF"
- vlink="#000080" alink="#FF0000">
- <!--#include virtual="header.html" -->
-
- <h1 align="center">Filters</h1>
-
- <table border="1">
- <tr>
- <td valign="top"><strong>Related Modules</strong><br />
- <br />
- <a href="mod/mod_deflate.html">mod_deflate</a><br />
- <a href="mod/mod_ext_filter.html">mod_ext_filter</a><br />
- <a href="mod/mod_include.html">mod_include</a><br />
- </td>
-
- <td valign="top"><strong>Related Directives</strong><br />
- <br />
- <a
- href="mod/mod_mime.html#addinputfilter">AddInputFilter</a><br />
- <a
- href="mod/mod_mime.html#addoutputfilter">AddOutputFilter</a><br />
- <a
- href="mod/mod_ext_filter.html#extfilterdefine">ExtFilterDefine</a><br />
- <a
- href="mod/mod_ext_filter.html#extfilteroptions">ExtFilterOptions</a><br />
- <a
- href="mod/core.html#setinputfilter">SetInputFilter</a><br />
- <a
- href="mod/core.html#setoutputfilter">SetOutputFilter</a><br />
- </td>
- </tr>
- </table>
-
+<html xmlns="http://www.w3.org/TR/xhtml1/strict"><head><!--
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ This file is generated from xml source: DO NOT EDIT
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ --><title>Filters- Apache HTTP Server</title><link href="./style/manual.css" type="text/css" rel="stylesheet"/></head><body><blockquote><div align="center"><img src="./images/sub.gif" alt="[APACHE DOCUMENTATION]"/><h3>Apache HTTP Server Version 2.0</h3></div><h1 align="center">Filters</h1>
+ <p>This document describes the use of filters in Apache.</p>
+ <ul><li><a href="#filters">Filters</a></li></ul><hr/><h2><a name="filters">Filters</a></h2>
+
+ <table border="1"><tr><td valign="top"><strong>Related Modules</strong><br/><br/><code><a href="./mod/mod_deflate.html">mod_deflate</a></code>, <br/><code><a href="./mod/mod_ext_filter.html">mod_ext_filter</a></code>, <br/><code><a href="./mod/mod_include.html">mod_include</a></code><br/></td><td valign="top"><strong>Related Directives</strong><br/><br/><a href="./mod/mod_mime.html#addinputfilter" class="directive"><code class="directive">AddInputFilter</code></a><br/><a href="./mod/mod_mime.html#addoutputfilter" class="directive"><code class="directive">AddOutputFilter</code></a><br/><a href="./mod/mod_ext_filter.html#extfilterdefine" class="directive"><code class="directive">ExtFilterDefine</code></a><br/><a href="./mod/mod_ext_filter.html#extfilteroptions" class="directive"><code class="directive">ExtFilterOptions</code></a><br/><a href="./mod/core.html.html#setinputfilter" class="directive"><code class="directive">SetInputFilter</code></a><br/><a href="./mod/core.html.html#setoutputfilter" class="directive"><code class="directive">SetOutputFilter</code></a><br/></td></tr></table>
+
<p>A <em>filter</em> is a process that is applied to data that
is sent or received by the server. Data sent by clients to the
server is processed by <em>input filters</em> while data sent
as chunking and byte-range request handling. In addition, modules
can provide filters that are selectable using run-time
configuration directives. The set of filters that apply to data
- can be manipulated with the <code>SetInputFilter</code>,
- <code>SetOutputFilter</code>, <code>AddInputFilter</code>, and
- <code>AddOutputFilter</code> directives.</p>
+ can be manipulated with the <a href="./mod/core.html.html#setinputfilter" class="directive"><code class="directive">SetInputFilter</code></a>, <a href="./mod/core.html.html#setoutputfilter" class="directive"><code class="directive">SetOutputFilter</code></a>, <a href="./mod/mod_mime.html#addinputfilter" class="directive"><code class="directive">AddInputFilter</code></a>, and <a href="./mod/mod_mime.html#addoutputfilter" class="directive"><code class="directive">AddOutputFilter</code></a> directives.</p>
<p>The following user-selectable filters are currently provided
with the Apache HTTP Server distribution.</p>
-<dl>
-<dt>INCLUDES</dt> <dd>Server-Side Includes processing by <a
-href="mod/mod_include.html">mod_include</a></dd>
-<dt>DEFLATE</dt> <dd>Compress output before sending it to
-the client using <a href="mod/mod_deflate.html">mod_deflate</a></dd>
-</dl>
+ <dt>INCLUDES</dt>
+ <dd>Server-Side Includes processing by <code><a href="./mod/mod_include.html">mod_include</a></code></dd>
+ <dt>DEFLATE</dt>
+ <dd>Compress output before sending it to the client using <code><a href="./mod/mod_include.html">mod_include</a></code></dd>
+ </dl>
- <p>In addition, the module <a
- href="mod/mod_ext_filter.html">mod_ext_filter</a> allows
+ <p>In addition, the module <code><a href="./mod/mod_ext_filter.html">mod_ext_filter</a></code> allows
for external programs to be defined as filters.</p>
-
- <!--#include virtual="footer.html" -->
- </body>
-</html>
-
+ </blockquote><h3 align="center">Apache HTTP Server Version 2.0</h3><a href="./"><img src="./images/index.gif" alt="Index"/></a><a href="./"><img src="./images/home.gif" alt="Home"/></a></body></html>
\ No newline at end of file
--- /dev/null
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE manualpage SYSTEM "./style/manualpage.dtd">
+<?xml-stylesheet type="text/xsl" href="./style/manual.en.xsl"?>
+
+<manualpage>
+ <relativepath href="."/>
+
+ <title>Filters</title>
+
+ <summary>
+ <p>This document describes the use of filters in Apache.</p>
+ </summary>
+
+ <section id="filters">
+ <title>Filters</title>
+ <related>
+ <modulelist>
+ <module>mod_deflate</module>
+ <module>mod_ext_filter</module>
+ <module>mod_include</module>
+ </modulelist>
+ <directivelist>
+ <directive module="mod_mime">AddInputFilter</directive>
+ <directive module="mod_mime">AddOutputFilter</directive>
+ <directive module="mod_ext_filter">ExtFilterDefine</directive>
+ <directive module="mod_ext_filter">ExtFilterOptions</directive>
+ <directive module="core.html">SetInputFilter</directive>
+ <directive module="core.html">SetOutputFilter</directive>
+ </directivelist>
+ </related>
+
+ <p>A <em>filter</em> is a process that is applied to data that
+ is sent or received by the server. Data sent by clients to the
+ server is processed by <em>input filters</em> while data sent
+ by the server to the client is processed by <em>output
+ filters</em>. Multiple filters can be applied to the data, and
+ the order of the filters can be explicitly specified.</p>
+
+ <p>Filters are used internally by Apache to perform functions such
+ as chunking and byte-range request handling. In addition, modules
+ can provide filters that are selectable using run-time
+ configuration directives. The set of filters that apply to data
+ can be manipulated with the <directive module="core.html"
+ >SetInputFilter</directive>, <directive module="core.html"
+ >SetOutputFilter</directive>, <directive module="mod_mime"
+ >AddInputFilter</directive>, and <directive module="mod_mime"
+ >AddOutputFilter</directive> directives.</p>
+
+ <p>The following user-selectable filters are currently provided
+ with the Apache HTTP Server distribution.</p>
+
+ <dl>
+ <dt>INCLUDES</dt>
+ <dd>Server-Side Includes processing by <module>mod_include</module></dd>
+ <dt>DEFLATE</dt>
+ <dd>Compress output before sending it to the client using <module
+ >mod_include</module></dd>
+ </dl>
+
+ <p>In addition, the module <module>mod_ext_filter</module> allows
+ for external programs to be defined as filters.</p>
+ </section>
+</manualpage>
+
+
+
+
-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
- "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
-
-<html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <meta name="generator" content="HTML Tidy, see www.w3.org" />
-
- <title>Apache's Handler Use</title>
- </head>
- <!-- Background white, links blue (unvisited), navy (visited), red (active) -->
-
- <body bgcolor="#FFFFFF" text="#000000" link="#0000FF"
- vlink="#000080" alink="#FF0000">
- <!--#include virtual="header.html" -->
-
- <h1 align="center">Apache's Handler Use</h1>
-
- <ul>
- <li><a href="#definition">What is a Handler</a></li>
-
- <li><a href="#examples">Examples</a></li>
-
- <li><a href="#programmer">Programmer's Note</a></li>
- </ul>
- <hr />
-
- <h2><a id="definition" name="definition">What is a
- Handler</a></h2>
-
- <table border="1">
- <tr>
- <td valign="top"><strong>Related Modules</strong><br />
- <br />
- <a href="mod/mod_actions.html">mod_actions</a><br />
- <a href="mod/mod_asis.html">mod_asis</a><br />
- <a href="mod/mod_cgi.html">mod_cgi</a><br />
- <a href="mod/mod_imap.html">mod_imap</a><br />
- <a href="mod/mod_info.html">mod_info</a><br />
- <a href="mod/mod_mime.html">mod_mime</a><br />
- <a
- href="mod/mod_negotiation.html">mod_negotiation</a><br />
- <a href="mod/mod_status.html">mod_status</a><br />
- </td>
-
- <td valign="top"><strong>Related Directives</strong><br />
- <br />
- <a href="mod/mod_actions.html#action">Action</a><br />
- <a
- href="mod/mod_mime.html#addhandler">AddHandler</a><br />
- <a
- href="mod/mod_mime.html#removehandler">RemoveHandler</a><br />
- <a
- href="mod/mod_mime.html#sethandler">SetHandler</a><br />
- </td>
- </tr>
- </table>
+<html xmlns="http://www.w3.org/TR/xhtml1/strict"><head><!--
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ This file is generated from xml source: DO NOT EDIT
+ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ --><title>Apache's Handler Use- Apache HTTP Server</title><link href="./style/manual.css" type="text/css" rel="stylesheet"/></head><body><blockquote><div align="center"><img src="./images/sub.gif" alt="[APACHE DOCUMENTATION]"/><h3>Apache HTTP Server Version 2.0</h3></div><h1 align="center">Apache's Handler Use</h1>
+ <p>This document describes the use of Apache's Handlers.</p>
+ <ul><li><a href="#definition">What is a Handler</a></li><li><a href="#examples">Examples</a><ul><li><a href="#example1">Modifying static content using a CGI script</a></li><li><a href="#example2">Files with HTTP headers</a></li></ul></li><li><a href="#programmer">Programmer's Note</a></li></ul><hr/><h2><a name="definition">What is a Handler</a></h2>
+
+ <table border="1"><tr><td valign="top"><strong>Related Modules</strong><br/><br/><code><a href="./mod/mod_actions.html">mod_actions</a></code>, <br/><code><a href="./mod/mod_asis.html">mod_asis</a></code>, <br/><code><a href="./mod/mod_cgi.html">mod_cgi</a></code>, <br/><code><a href="./mod/mod_imap.html">mod_imap</a></code>, <br/><code><a href="./mod/mod_info.html">mod_info</a></code>, <br/><code><a href="./mod/mod_mime.html">mod_mime</a></code>, <br/><code><a href="./mod/mod_negotiation.html">mod_negotiation</a></code>, <br/><code><a href="./mod/mod_status.html">mod_status</a></code><br/></td><td valign="top"><strong>Related Directives</strong><br/><br/><a href="./mod/mod_actions.html#action" class="directive"><code class="directive">Action</code></a><br/><a href="./mod/mod_mime.html#addhandler" class="directive"><code class="directive">AddHandler</code></a><br/><a href="./mod/mod_mime.html#removehandler" class="directive"><code class="directive">RemoveHandler</code></a><br/><a href="./mod/mod_mime.html#sethandler" class="directive"><code class="directive">SetHandler</code></a><br/></td></tr></table>
+
<p>A "handler" is an internal Apache representation of the
action to be performed when a file is called. Generally, files
can be specified without relation to file type. This is
advantageous both because it is a more elegant solution, and
because it also allows for both a type <strong>and</strong> a
- handler to be associated with a file. (See also <a
- href="mod/mod_mime.html#multipleext">Files with Multiple
+ handler to be associated with a file. (See also <a href="mod/mod_mime.html#multipleext">Files with Multiple
Extensions</a>.)</p>
<p>Handlers can either be built into the server or included in
- a module, or they can be added with the <a
- href="mod/mod_actions.html#action">Action</a> directive. The
+ a module, or they can be added with the <a href="./mod/mod_actions.html#action" class="directive"><code class="directive">Action</code></a> directive. The
built-in handlers in the standard distribution are as
follows:</p>
default to handle static content. (core)</li>
<li><strong>send-as-is</strong>: Send file with HTTP headers
- as is. (<a href="mod/mod_asis.html">mod_asis</a>)</li>
+ as is. (<code><a href="./mod/mod_asis.html">mod_asis</a></code>)</li>
<li><strong>cgi-script</strong>: Treat the file as a CGI
- script. (<a href="mod/mod_cgi.html">mod_cgi</a>)</li>
+ script. (<code><a href="./mod/mod_cgi.html">mod_cgi</a></code>)</li>
<li><strong>imap-file</strong>: Parse as an imagemap rule
- file. (<a href="mod/mod_imap.html">mod_imap</a>)</li>
+ file. (<code><a href="./mod/mod_imap.html">mod_imap</a></code>)</li>
<li><strong>server-info</strong>: Get the server's
- configuration information. (<a
- href="mod/mod_info.html">mod_info</a>)</li>
+ configuration information. (<code><a href="./mod/mod_info.html">mod_info</a></code>)</li>
<li><strong>server-status</strong>: Get the server's status
- report. (<a href="mod/mod_status.html">mod_status</a>)</li>
+ report. (<code><a href="./mod/mod_status.html">mod_status</a></code>)</li>
<li><strong>type-map</strong>: Parse as a type map file for
- content negotiation. (<a
- href="mod/mod_negotiation.html">mod_negotiation</a>)</li>
+ content negotiation. (<code><a href="./mod/mod_negotiation.html">mod_negotiation</a></code>)</li>
</ul>
- <hr />
-
- <h2><a id="examples" name="examples">Examples</a></h2>
-
- <h3>Modifying static content using a CGI script</h3>
-
- <p>The following directives will cause requests for files with
- the <code>html</code> extension to trigger the launch of the
- <code>footer.pl</code> CGI script.</p>
-<pre>
- Action add-footer /cgi-bin/footer.pl
- AddHandler add-footer .html
-</pre>
-
- <p>Then the CGI script is responsible for sending the
- originally requested document (pointed to by the
- <code>PATH_TRANSLATED</code> environment variable) and making
- whatever modifications or additions are desired.</p>
-
- <h3>Files with HTTP headers</h3>
-
- <p>The following directives will enable the
- <code>send-as-is</code> handler, which is used for files which
- contain their own HTTP headers. All files in the
- <code>/web/htdocs/asis/</code> directory will be processed by
- the <code>send-as-is</code> handler, regardless of their
- filename extensions.</p>
-<pre>
- <Directory /web/htdocs/asis>
- SetHandler send-as-is
- </Directory>
-</pre>
- <hr />
-
- <h2><a id="programmer" name="programmer">Programmer's
- Note</a></h2>
+ <h2><a name="examples">Examples</a></h2>
+
+
+ <h3><a name="example1">Modifying static content using a CGI script</a></h3>
+
+
+ <p>The following directives will cause requests for files with
+ the <code>html</code> extension to trigger the launch of the
+ <code>footer.pl</code> CGI script.</p>
+
+ <blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code><code>
+ Action add-footer /cgi-bin/footer.pl<br>
+ AddHandler add-footer .html
+ </code></code></td></tr></table></blockquote>
+
+ <p>Then the CGI script is responsible for sending the
+ originally requested document (pointed to by the
+ <code>PATH_TRANSLATED</code> environment variable) and making
+ whatever modifications or additions are desired.</p>
+
+
+ <h3><a name="example2">Files with HTTP headers</a></h3>
+
+
+ <p>The following directives will enable the
+ <code>send-as-is</code> handler, which is used for files which
+ contain their own HTTP headers. All files in the
+ <code>/web/htdocs/asis/</code> directory will be processed by
+ the <code>send-as-is</code> handler, regardless of their
+ filename extensions.</p>
+
+ <blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code><code>
+ <Directory /web/htdocs/asis><br>
+ SetHandler send-as-is<br>
+ </Directory>
+ </code></code></td></tr></table></blockquote>
+
+
+ <h2><a name="programmer">Programmer's Note</a></h2>
+
<p>In order to implement the handler features, an addition has
been made to the <a href="developer/API.html">Apache API</a> that
type. While it is not necessary, the naming convention for
handlers is to use a dash-separated word, with no slashes, so
as to not invade the media type name-space.</p>
- <!--#include virtual="footer.html" -->
- </body>
-</html>
-
+ </blockquote><h3 align="center">Apache HTTP Server Version 2.0</h3><a href="./"><img src="./images/index.gif" alt="Index"/></a><a href="./"><img src="./images/home.gif" alt="Home"/></a></body></html>
\ No newline at end of file
--- /dev/null
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE manualpage SYSTEM "./style/manualpage.dtd">
+<?xml-stylesheet type="text/xsl" href="./style/manual.en.xsl"?>
+
+<manualpage>
+ <relativepath href="."/>
+
+ <title>Apache's Handler Use</title>
+
+ <summary>
+ <p>This document describes the use of Apache's Handlers.</p>
+ </summary>
+
+ <section id="definition">
+ <title>What is a Handler</title>
+ <related>
+ <modulelist>
+ <module>mod_actions</module>
+ <module>mod_asis</module>
+ <module>mod_cgi</module>
+ <module>mod_imap</module>
+ <module>mod_info</module>
+ <module>mod_mime</module>
+ <module>mod_negotiation</module>
+ <module>mod_status</module>
+ </modulelist>
+ <directivelist>
+ <directive module="mod_actions">Action</directive>
+ <directive module="mod_mime">AddHandler</directive>
+ <directive module="mod_mime">RemoveHandler</directive>
+ <directive module="mod_mime">SetHandler</directive>
+ </directivelist>
+ </related>
+
+
+ <p>A "handler" is an internal Apache representation of the
+ action to be performed when a file is called. Generally, files
+ have implicit handlers, based on the file type. Normally, all
+ files are simply served by the server, but certain file types
+ are "handled" separately.</p>
+
+ <p>Apache 1.1 adds the ability to use handlers explicitly.
+ Based on either filename extensions or on location, handlers
+ can be specified without relation to file type. This is
+ advantageous both because it is a more elegant solution, and
+ because it also allows for both a type <strong>and</strong> a
+ handler to be associated with a file. (See also <a
+ href="mod/mod_mime.html#multipleext">Files with Multiple
+ Extensions</a>.)</p>
+
+ <p>Handlers can either be built into the server or included in
+ a module, or they can be added with the <directive
+ module="mod_actions">Action</directive> directive. The
+ built-in handlers in the standard distribution are as
+ follows:</p>
+
+ <ul>
+ <li><strong>default-handler</strong>: Send the file using the
+ <code>default_handler()</code>, which is the handler used by
+ default to handle static content. (core)</li>
+
+ <li><strong>send-as-is</strong>: Send file with HTTP headers
+ as is. (<module>mod_asis</module>)</li>
+
+ <li><strong>cgi-script</strong>: Treat the file as a CGI
+ script. (<module>mod_cgi</module>)</li>
+
+ <li><strong>imap-file</strong>: Parse as an imagemap rule
+ file. (<module>mod_imap</module>)</li>
+
+ <li><strong>server-info</strong>: Get the server's
+ configuration information. (<module>mod_info</module>)</li>
+
+ <li><strong>server-status</strong>: Get the server's status
+ report. (<module>mod_status</module>)</li>
+
+ <li><strong>type-map</strong>: Parse as a type map file for
+ content negotiation. (<module>mod_negotiation</module>)</li>
+ </ul>
+ </section>
+ <section id="examples">
+ <title>Examples</title>
+
+ <section id="example1">
+ <title>Modifying static content using a CGI script</title>
+
+ <p>The following directives will cause requests for files with
+ the <code>html</code> extension to trigger the launch of the
+ <code>footer.pl</code> CGI script.</p>
+
+ <example><code>
+ Action add-footer /cgi-bin/footer.pl<br/>
+ AddHandler add-footer .html
+ </code></example>
+
+ <p>Then the CGI script is responsible for sending the
+ originally requested document (pointed to by the
+ <code>PATH_TRANSLATED</code> environment variable) and making
+ whatever modifications or additions are desired.</p>
+
+ </section>
+ <section id="example2">
+ <title>Files with HTTP headers</title>
+
+ <p>The following directives will enable the
+ <code>send-as-is</code> handler, which is used for files which
+ contain their own HTTP headers. All files in the
+ <code>/web/htdocs/asis/</code> directory will be processed by
+ the <code>send-as-is</code> handler, regardless of their
+ filename extensions.</p>
+
+ <example><code>
+ <Directory /web/htdocs/asis><br/>
+ SetHandler send-as-is<br/>
+ </Directory>
+ </code></example>
+
+ </section>
+ </section>
+ <section id="programmer">
+ <title>Programmer's Note</title>
+
+ <p>In order to implement the handler features, an addition has
+ been made to the <a href="developer/API.html">Apache API</a> that
+ you may wish to make use of. Specifically, a new record has
+ been added to the <code>request_rec</code> structure:</p>
+<pre>
+ char *handler
+</pre>
+
+ <p>If you wish to have your module engage a handler, you need
+ only to set <code>r->handler</code> to the name of the
+ handler at any time prior to the <code>invoke_handler</code>
+ stage of the request. Handlers are implemented as they were
+ before, albeit using the handler name instead of a content
+ type. While it is not necessary, the naming convention for
+ handlers is to use a dash-separated word, with no slashes, so
+ as to not invade the media type name-space.</p>
+ </section>
+</manualpage>
+
+
+
+
+
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