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23 <modulesynopsis metafile="mod_proxy_http.xml.meta">
25 <name>mod_proxy_http</name>
26 <description>HTTP support module for
27 <module>mod_proxy</module></description>
28 <status>Extension</status>
29 <sourcefile>mod_proxy_http.c</sourcefile>
30 <identifier>proxy_http_module</identifier>
32 <summary>
33 <p>This module <em>requires</em> the service of <module
34 >mod_proxy</module>. It provides the features used for
35 proxying HTTP requests. <module>mod_proxy_http</module>
36 supports HTTP/0.9, HTTP/1.0 and HTTP/1.1. It does <em>not</em>
37 provide any caching abilities. If you want to set up a caching
38 proxy, you might want to use the additional service of the
39 <module>mod_cache</module> module.</p>
41 <p>Thus, in order to get the ability of handling HTTP proxy requests,
42 <module>mod_proxy</module> and <module>mod_proxy_http</module>
43 have to be present in the server.</p>
45 <note type="warning"><title>Warning</title>
46 <p>Do not enable proxying until you have <a
47 href="mod_proxy.html#access">secured your server</a>. Open proxy
48 servers are dangerous both to your network and to the Internet at
49 large.</p>
50 </note>
51 </summary>
52 <seealso><module>mod_proxy</module></seealso>
53 <seealso><module>mod_proxy_connect</module></seealso>
55 <section id="env"><title>Environment Variables</title>
56 <p>In addition to the configuration directives that control the
57 behaviour of <module>mod_proxy</module>, there are a number of
58 <dfn>environment variables</dfn> that control the HTTP protocol
59 provider:</p>
60 <dl>
61 <dt>proxy-sendextracrlf</dt>
62 <dd>Causes proxy to send an extra CR-LF newline on the end of a
63 request. This is a workaround for a bug in some browsers.</dd>
64 <dt>force-proxy-request-1.0</dt>
65 <dd>Forces the proxy to send requests to the backend as HTTP/1.0
66 and disables HTTP/1.1 features.</dd>
67 <dt>proxy-nokeepalive</dt>
68 <dd>Forces the proxy to close the backend connection after
69 each request.</dd>
70 <dt>proxy-chain-auth</dt>
71 <dd>If the proxy requires authentication, it will read and
72 consume the proxy authentication credentials sent by the client.
73 With <var>proxy-chain-auth</var> it will <em>also</em> forward
74 the credentials to the next proxy in the chain. This may
75 be necessary if you have a chain of proxies that share
76 authentication information. <strong>Security Warning:</strong>
77 Do not set this unless you know you need it, as it forwards
78 sensitive information!</dd>
79 <dt>proxy-sendcl</dt>
80 <dd>HTTP/1.0 required all HTTP requests that include a body
81 (e.g. POST requests) to include a <var>Content-Length</var>
82 header. This environment variable forces the Apache proxy to
83 send this header to the backend server, regardless of what the
84 Client sent to the proxy. It ensures compatibility when
85 proxying for an HTTP/1.0 or unknown backend. However, it
86 may require the entire request to be buffered by the proxy,
87 so it becomes very inefficient for large requests.</dd>
88 <dt>proxy-sendchunks or proxy-sendchunked</dt>
89 <dd>This is the opposite of <var>proxy-sendcl</var>. It allows
90 request bodies to be sent to the backend using chunked transfer
91 encoding. This allows the request to be efficiently streamed,
92 but requires that the backend server supports HTTP/1.1.</dd>
93 <dt>proxy-interim-response</dt>
94 <dd>This variable takes values <code>RFC</code> or
95 <code>Suppress</code>. Earlier httpd versions would suppress
96 HTTP interim (1xx) responses sent from the backend. This is
97 technically a violation of the HTTP protocol. In practice,
98 if a backend sends an interim response, it may itself be
99 extending the protocol in a manner we know nothing about,
100 or just broken. So this is now configurable: set
101 <code>proxy-interim-response RFC</code> to be fully protocol
102 compliant, or <code>proxy-interim-response Suppress</code>
103 to suppress interim responses.</dd>
104 <dt>proxy-initial-not-pooled</dt>
105 <dd>If this variable is set no pooled connection will be reused
106 if the client connection is an initial connection. This avoids
107 the "proxy: error reading status line from remote server" error message
108 caused by the race condition that the backend server closed the
109 pooled connection after the connection check by the proxy and
110 before data send by the proxy reached the backend. It has to be
111 kept in mind that setting this variable downgrades performance,
112 especially with HTTP/1.0 clients.
113 </dd>
114 </dl>
115 </section>
117 </modulesynopsis>