mod_rewrite.html.en

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

      System-view. </p>

      <p>Notice: These variables hold the URI/URL <em>as they were
      initially requested</em>, <em>i.e.</em>, <em>before</em> any
      rewriting. This is important because the rewriting process is
      primarily used to rewrite logical URLs to physical
      pathnames.</p>

<div class="example"><h3>Example</h3><pre>
SCRIPT_NAME=/sw/lib/w3s/tree/global/u/rse/.www/index.html
SCRIPT_FILENAME=/u/rse/.www/index.html
SCRIPT_URL=/u/rse/
SCRIPT_URI=http://en1.engelschall.com/u/rse/
</pre></div>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="Solutions" id="Solutions">Practical Solutions</a></h2>

      <p>We also have an <a href="../misc/rewriteguide.html">URL
      Rewriting Guide</a> available, which provides a collection of
      practical solutions for URL-based problems. There you can
      find real-life rulesets and additional information about
      mod_rewrite.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="RewriteBase" id="RewriteBase">RewriteBase</a> <a name="rewritebase" id="rewritebase">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the base URL for per-directory rewrites</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RewriteBase <em>URL-path</em></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for information.</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_rewrite</td></tr>
</table>
      <p>The <code class="directive">RewriteBase</code> directive explicitly
      sets the base URL for per-directory rewrites. As you will see
      below, <code class="directive"><a href="#rewriterule">RewriteRule</a></code>
      can be used in per-directory config files
      (<code>.htaccess</code>). There it will act locally,
      <em>i.e.</em>, the local directory prefix is stripped at this
      stage of processing and your rewriting rules act only on the
      remainder. At the end it is automatically added back to the
      path. The default setting is; <code class="directive">RewriteBase</code> <em>physical-directory-path</em></p>

      <p>When a substitution occurs for a new URL, this module has
      to re-inject the URL into the server processing. To be able
      to do this it needs to know what the corresponding URL-prefix
      or URL-base is. By default this prefix is the corresponding
      filepath itself. <strong>But at most websites URLs are NOT
      directly related to physical filename paths, so this
      assumption will usually be wrong!</strong> There you have to
      use the <code>RewriteBase</code> directive to specify the
      correct URL-prefix.</p>

<div class="note"> If your webserver's URLs are <strong>not</strong> directly
related to physical file paths, you have to use
<code class="directive">RewriteBase</code> in every <code>.htaccess</code>
files where you want to use <code class="directive"><a href="#rewriterule">RewriteRule</a></code> directives.
</div>

        <p> For example, assume the following per-directory config file:</p>

<div class="example"><pre>
#
#  /abc/def/.htaccess -- per-dir config file for directory /abc/def
#  Remember: /abc/def is the physical path of /xyz, <em>i.e.</em>, the server
#            has a 'Alias /xyz /abc/def' directive <em>e.g.</em>
#

RewriteEngine On

#  let the server know that we were reached via /xyz and not
#  via the physical path prefix /abc/def
RewriteBase   /xyz

#  now the rewriting rules
RewriteRule   ^oldstuff\.html$  newstuff.html
</pre></div>

        <p>In the above example, a request to
        <code>/xyz/oldstuff.html</code> gets correctly rewritten to
        the physical file <code>/abc/def/newstuff.html</code>.</p>

<div class="note"><h3>For Apache Hackers</h3>
<p>The following list gives detailed information about
              the internal processing steps:</p>
<pre>
Request:
  /xyz/oldstuff.html

Internal Processing:
  /xyz/oldstuff.html     -&gt; /abc/def/oldstuff.html  (per-server Alias)
  /abc/def/oldstuff.html -&gt; /abc/def/newstuff.html  (per-dir    RewriteRule)
  /abc/def/newstuff.html -&gt; /xyz/newstuff.html      (per-dir    RewriteBase)
  /xyz/newstuff.html     -&gt; /abc/def/newstuff.html  (per-server Alias)

Result:
  /abc/def/newstuff.html
</pre>
              <p>This seems very complicated but is
              the correct Apache internal processing, because the
              per-directory rewriting comes too late in the
              process. So, when it occurs the (rewritten) request
              has to be re-injected into the Apache kernel! BUT:
              While this seems like a serious overhead, it really
              isn't, because this re-injection happens fully
              internally to the Apache server and the same
              procedure is used by many other operations inside
              Apache. So, you can be sure the design and
              implementation is correct.</p>
</div>


</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="RewriteCond" id="RewriteCond">RewriteCond</a> <a name="rewritecond" id="rewritecond">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Defines a condition under which rewriting will take place
</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code> RewriteCond
      <em>TestString</em> <em>CondPattern</em></code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_rewrite</td></tr>
</table>
      <p>The <code class="directive">RewriteCond</code> directive defines a
      rule condition. Precede a <code class="directive"><a href="#rewriterule">RewriteRule</a></code> directive with one
      or more <code class="directive">RewriteCond</code> directives. The following
      rewriting rule is only used if its pattern matches the current
      state of the URI <strong>and</strong> if these additional
      conditions apply too.</p>

      <p><em>TestString</em> is a string which can contains the
      following expanded constructs in addition to plain text:</p>

      <ul>
        <li>
          <strong>RewriteRule backreferences</strong>: These are
          backreferences of the form 

          <p class="indent">
            <strong><code>$N</code></strong>
          </p>
          (0 &lt;= N &lt;= 9) which provide access to the grouped
          parts (parenthesis!) of the pattern from the
          corresponding <code>RewriteRule</code> directive (the one
          following the current bunch of <code>RewriteCond</code>
          directives).
        </li>

        <li>
          <strong>RewriteCond backreferences</strong>: These are
          backreferences of the form 

          <p class="indent">
            <strong><code>%N</code></strong>
          </p>
          (1 &lt;= N &lt;= 9) which provide access to the grouped
          parts (parentheses!) of the pattern from the last matched
          <code>RewriteCond</code> directive in the current bunch
          of conditions.
        </li>

        <li>
          <strong>RewriteMap expansions</strong>: These are
          expansions of the form 

          <p class="indent">
            <strong><code>${mapname:key|default}</code></strong>
          </p>
          See <a href="#mapfunc">the documentation for
          RewriteMap</a> for more details.
        </li>

        <li>
          <strong>Server-Variables</strong>: These are variables of
          the form 

          <p class="indent">
            <strong><code>%{</code> <em>NAME_OF_VARIABLE</em>
            <code>}</code></strong>
          </p>
          where <em>NAME_OF_VARIABLE</em> can be a string taken
          from the following list: 

          <table>
          
            <tr>
              <th>HTTP headers:</th> <th>connection &amp; request:</th> <th />
	    </tr>

            <tr>
	      <td>
		 HTTP_USER_AGENT<br />
                 HTTP_REFERER<br />
                 HTTP_COOKIE<br />
                 HTTP_FORWARDED<br />
                 HTTP_HOST<br />
                 HTTP_PROXY_CONNECTION<br />
                 HTTP_ACCEPT<br />
              </td>

              <td>
                 REMOTE_ADDR<br />
                 REMOTE_HOST<br />
                 REMOTE_USER<br />
                 REMOTE_IDENT<br />
                 REQUEST_METHOD<br />
                 SCRIPT_FILENAME<br />
                 PATH_INFO<br />
                 QUERY_STRING<br />
                 AUTH_TYPE<br />
              </td>
	      
	      <td />
            </tr>

            <tr>
              <th>server internals:</th> <th>system stuff:</th> <th>specials:</th>
	    </tr>

            <tr>
	      <td>
	         DOCUMENT_ROOT<br />
                 SERVER_ADMIN<br />
                 SERVER_NAME<br />
                 SERVER_ADDR<br />
                 SERVER_PORT<br />
                 SERVER_PROTOCOL<br />
                 SERVER_SOFTWARE<br />
              </td>

              <td>
                 TIME_YEAR<br />
                 TIME_MON<br />
                 TIME_DAY<br />
                 TIME_HOUR<br />
                 TIME_MIN<br />
                 TIME_SEC<br />
                 TIME_WDAY<br />
                 TIME<br />
              </td>

              <td>
                 API_VERSION<br />
                 THE_REQUEST<br />
                 REQUEST_URI<br />
                 REQUEST_FILENAME<br />
                 IS_SUBREQ<br />
                 HTTPS<br />
              </td>
            </tr>
          </table>

<div class="note">
                <p>These variables all
                correspond to the similarly named HTTP
                MIME-headers, C variables of the Apache server or
                <code>struct tm</code> fields of the Unix system.
                Most are documented elsewhere in the Manual or in
                the CGI specification. Those that are special to
                mod_rewrite include:</p>

                <dl>
                  <dt><code>IS_SUBREQ</code></dt>

                  <dd>Will contain the text "true" if the request
                  currently being processed is a sub-request,
                  "false" otherwise. Sub-requests may be generated
                  by modules that need to resolve additional files
                  or URIs in order to complete their tasks.</dd>

                  <dt><code>API_VERSION</code></dt>

                  <dd>This is the version of the Apache module API
                  (the internal interface between server and
                  module) in the current httpd build, as defined in