mod_proxy.html.en

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

<div class="directive-section"><h2><a name="ProxyMatch" id="ProxyMatch">&lt;ProxyMatch&gt;</a> <a name="proxymatch" id="proxymatch">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Container for directives applied to regular-expression-matched 
proxied resources</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>&lt;ProxyMatch <var>regex</var>&gt; ...&lt;/ProxyMatch&gt;</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</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_proxy</td></tr>
</table>
    <p>The <code class="directive">&lt;ProxyMatch&gt;</code> directive is
    identical to the <code class="directive"><a href="#proxy">&lt;Proxy&gt;</a></code> directive, except it matches URLs
    using <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expressions</a>.</p>

</div>
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<div class="directive-section"><h2><a name="ProxyMaxForwards" id="ProxyMaxForwards">ProxyMaxForwards</a> <a name="proxymaxforwards" id="proxymaxforwards">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximium number of proxies that a request can be forwarded
through</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyMaxForwards <var>number</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ProxyMaxForwards -1</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</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_proxy</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.0 and later;
	default behaviour changed in 2.2.7</td></tr>
</table>
    <p>The <code class="directive">ProxyMaxForwards</code> directive specifies the
    maximum number of proxies through which a request may pass, if there's no
    <code>Max-Forwards</code> header supplied with the request. This may
    be set to prevent infinite proxy loops, or a DoS attack.</p>

    <div class="example"><h3>Example</h3><p><code>
      ProxyMaxForwards 15
    </code></p></div>

    <p>Note that setting <code class="directive">ProxyMaxForwards</code> is a
    violation of the HTTP/1.1 protocol (RFC2616), which forbids a Proxy
    setting <code>Max-Forwards</code> if the Client didn't set it.
    Earlier Apache versions would always set it.  A negative
    <code class="directive">ProxyMaxForwards</code> value, including the
    default -1, gives you protocol-compliant behaviour, but may
    leave you open to loops.</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="ProxyPass" id="ProxyPass">ProxyPass</a> <a name="proxypass" id="proxypass">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maps remote servers into the local server URL-space</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ProxyPass [<var>path</var>] !|<var>url</var> [<var>key=value</var>
<var>key=value</var> ...]] [nocanon] [interpolate]</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory</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_proxy</td></tr>
</table>
    <p>This directive allows remote servers to be mapped into the
    space of the local server; the local server does not act as a
    proxy in the conventional sense, but appears to be a mirror of the
    remote server. The local server is often called a <dfn>reverse
    proxy</dfn> or <dfn>gateway</dfn>. The <var>path</var> is the name of
    a local virtual path; <var>url</var> is a partial URL for the
    remote server and cannot include a query string.</p>

    <div class="warning">The <code class="directive"><a href="#proxyrequests">ProxyRequests</a></code> directive should
    usually be set <strong>off</strong> when using
    <code class="directive">ProxyPass</code>.</div>

    <p>Suppose the local server has address <code>http://example.com/</code>;
    then</p>

    <div class="example"><p><code>
      ProxyPass /mirror/foo/ http://backend.example.com/
    </code></p></div>

    <p>will cause a local request for
    <code>http://example.com/mirror/foo/bar</code> to be internally converted
    into a proxy request to <code>http://backend.example.com/bar</code>.</p>

    <div class="warning">
    <p>If the first argument ends with a trailing <strong>/</strong>, the second
       argument should also end with a trailing <strong>/</strong> and vice
       versa. Otherwise the resulting requests to the backend may miss some
       needed slashes and do not deliver the expected results.
    </p>
    </div>

    <p>The <code>!</code> directive is useful in situations where you don't want
    to reverse-proxy a subdirectory, <em>e.g.</em></p>

    <div class="example"><p><code>
      ProxyPass /mirror/foo/i !<br />
      ProxyPass /mirror/foo http://backend.example.com
    </code></p></div>

    <p>will proxy all requests to <code>/mirror/foo</code> to
    <code>backend.example.com</code> <em>except</em> requests made to
    <code>/mirror/foo/i</code>.</p>

    <div class="note"><h3>Note</h3>
      <p>Order is important: exclusions must come <em>before</em> the
      general <code class="directive">ProxyPass</code> directive.</p>
    </div>

    <p>As of Apache 2.1, the ability to use pooled connections to a backend
    server is available. Using the <code>key=value</code> parameters it is
    possible to tune this connection pooling. The default for a <code>Hard
    Maximum</code> for the number of connections is the number of threads per
    process in the active MPM. In the Prefork MPM, this is always 1, while with
    the Worker MPM it is controlled by the
    <code class="directive">ThreadsPerChild</code>.</p>

    <p>Setting <code>min</code> will determine how many connections will always 
    be open to the backend server. Upto the Soft Maximum or <code>smax</code> 
    number of connections will be created on demand. Any connections above 
    <code>smax</code> are subject to a time to live or <code>ttl</code>.  Apache
    will never create more than the Hard Maximum or <code>max</code> connections
    to the backend server.</p>

    <div class="example"><p><code>
        ProxyPass /example http://backend.example.com smax=5 max=20 ttl=120 retry=300
    </code></p></div>

    <table>
    <tr><th>Parameter</th>
        <th>Default</th>
        <th>Description</th></tr>
    <tr><td>min</td>
        <td>0</td>
        <td>Minimum number of connections that will always
            be open to the backend server.</td></tr>
    <tr><td>max</td>
        <td>1...n</td>
        <td>Hard Maximum number of connections that will be
    allowed to the backend server. The default for a Hard Maximum
    for the number of connections is the number of threads per process in the 
    active MPM. In the Prefork MPM, this is always 1, while with the Worker MPM
    it is controlled by the <code class="directive">ThreadsPerChild</code>.
    Apache will never create more than the Hard Maximum connections
    to the backend server.</td></tr>
    <tr><td>smax</td>
        <td>max</td>
        <td>Upto the Soft Maximum
    number of connections will be created on demand. Any connections above 
    <code>smax</code> are subject to a time to live or <code>ttl</code>.
    </td></tr>
    <tr><td>acquire</td>
        <td>-</td>
        <td>If set this will be the maximum time to wait for a free
    connection in the connection pool, in milliseconds. If there are no free
    connections in the pool the Apache will return <code>SERVER_BUSY</code>
    status to the client.
    </td></tr>
    <tr><td>connectiontimeout</td>
        <td>timeout</td>
        <td>Connect timeout in seconds.
        The number of seconds Apache waits for the creation of a connection to
        the backend to complete. By adding a postfix of ms the timeout can be
        also set in milliseconds.
    </td></tr>
    <tr><td>disablereuse</td>
        <td>Off</td>
        <td>This parameter should be used when you want to force mod_proxy
    to immediately close a connection to the backend after being used, and
    thus, disable its persistent connection and pool for that backend.
    This helps in various situations where a firewall between Apache and
    the backend server (regardless of protocol) tends to silently
    drop connections or when backends themselves may be under round-
    robin DNS. To disable connection pooling reuse,
    set this property value to <code>On</code>. 
    </td></tr>
    <tr><td>flushpackets</td>
        <td>off</td>
        <td>Determines whether the proxy module will auto-flush the output
        brigade after each "chunk" of data. 'off' means that it will flush
        only when needed, 'on' means after each chunk is sent and
        'auto' means poll/wait for a period of time and flush if
        no input has been received for 'flushwait' milliseconds.
        Currently this is in effect only for AJP.
    </td></tr>
    <tr><td>flushwait</td>
        <td>10</td>
        <td>The time to wait for additional input, in milliseconds, before
        flushing the output brigade if 'flushpackets' is 'auto'.
    </td></tr>
    <tr><td>keepalive</td>
        <td>Off</td>
        <td>This parameter should be used when you have a firewall between your
    Apache and the backend server, who tend to drop inactive connections.
    This flag will tell the Operating System to send <code>KEEP_ALIVE</code>
    messages on inactive connections (interval depends on global OS settings,
    generally 120ms), and thus prevent the firewall to drop the connection.
    To enable keepalive set this property value to <code>On</code>. 
    </td></tr>
    <tr><td>lbset</td>
        <td>0</td>
        <td>Sets the load balancer cluster set that the worker is a member
         of. The load balancer will try all members of a lower numbered
         lbset before trying higher numbered ones.
    </td></tr>
    <tr><td>ping</td>
        <td>0</td>
        <td>Ping property tells webserver to send a <code>CPING</code>
        request on ajp13 connection before forwarding a request.
        The parameter is the delay in seconds to wait for the
        <code>CPONG</code> reply.
        This features has been added to avoid problem with hung and
        busy Tomcat's and require ajp13 ping/pong support which has
        been implemented on Tomcat 3.3.2+, 4.1.28+ and 5.0.13+.
        This will increase the network traffic during the normal operation
        which could be an issue, but it will lower the
        traffic in case some of the cluster nodes are down or busy.
        Currently this has an effect only for AJP.
        By adding a postfix of ms the delay can be also set in
        milliseconds.
    </td></tr>
    <tr><td>loadfactor</td>
        <td>1</td>
        <td>Worker load factor. Used with BalancerMember.
         It is a number between 1 and 100 and defines the normalized weighted
         load applied to the worker.
    </td></tr>
    <tr><td>redirect</td>
        <td>-</td>
        <td>Redirection Route of the worker. This value is usually
        set dynamically to enable safe removal of the node from
        the cluster. If set all requests without session id will be
        redirected to the BalancerMember that has route parametar
        equal as this value.