plugin-dispatch.xtp
来自「RESIN 3.2 最新源码」· XTP 代码 · 共 204 行
XTP
204 行
<document> <header> <product>resin</product> <title>How the Plugins Dispatch to Resin</title> <description> <p>When used with another web server, Resin serves JSPs and Servlets and the other web server serves static content like html and images.</p> </description> </header> <body><s1> <p>The web server plugins (mod_caucho and isapi_srun) have two main tasks:</p> <ol> <li>Select urls to dispatch to the Java process </li><li>Pass the request and retrieve the response from the Java process. </li></ol> <note>"mod_caucho" is used to mean all the plugins. All of the plugins work the same, so "mod_caucho" is just a shorthand for "mod_caucho and isapi_srun".</note></s1> <localtoc/><s1 title="ResinConfigServer"><p>mod_caucho discovers its configuration by contactingthe ResinConfigServer specified in the httpd.conf or resin.ini.The ResinConfigServer can be any Resin server. When a user requests a URL,mod_caucho uses the configuration it has determined from the ResinConfigServerto determine whether Resin or Apache should handle the request. That decisionis based on the configuration in the ResinConfigServer's resin.xml.</p></s1><s1 title="servlet-mapping selects URLs"><p>The <a href="webapp-tags.xtp#servlet-mapping">servlet-mapping</a>tag selects the URLs to send to Resin.<a href="host-tags.xtp#host"><host></a> and <a href="webapp-tags.xtp"><web-app></a> group theservlet-mapping tags.</p><s2 title="url-pattern"><p>servlet-mapping's <a href="webapp-tags.xtp#url-pattern">url-pattern</a>selects the URLs to pass to Resin. servlet-mapping and url-patternare part of the Servlet 2.3 standard, so there are many references explaininghow it works.</p><p>url-pattern can take one of four forms:</p><ul><li>"<var>/</var>" matches all URLs. Use this to pass all requests to Resin.</li><li>"<var>/prefix/url/*</var>" matches any URL starting with <var>/prefix/url</var>,including <var>prefix/url</var> itself. It does not match <var>/prefix/urlfoo</var>because any slash must immediately follow <var>url</var></li><li>"<var>/exact/path</var>" matches only the exact path. In other words, itwill not match <var>/exact/path/bogus</var>.</li><li>"<var>*.ext</var>" matches any URL with the extension <var>ext</var>. Resinallows path-infos, so <var>/foo/bar.ext/path/info</var> will also match.</li></ul></s2><s2 title="url-regexp"><note>mod_caucho does not understand regular expressions. If youput regular expressions in your resin.xml, mod_caucho will not sendthe request to Resin. Apache will handle the request itself.</note><p>If you want to use regular expressions in servlet-mapping, web-app, orhosts, you must use Apache-specific configuration to send the requestto Resin. You can see this by looking at /caucho-status. /caucho-statuswill not display any regular expressions.</p></s2><s2 title="special servlet-mappings"><p>There are two special servlet-names which only affect the plugins:<var>plugin_match</var> and <var>plugin_ignore</var>.</p><p><var>plugin_match</var> will direct a request to Resin.The servlet engine itselfwill ignore the plugin_match directive. You can use plugin_match todirect an entire subtree to Resin, e.g. to workaround theregexp limitation, but allow Resin's other servlet-mapping directivesto control which servlets are used.</p><p><var>plugin_ignore</var> keeps the request at on the web server. So youcould create a directory <var>/static</var> where all documents, including JSPs areserved by the web server.</p><example><!-- send everything under /resin to Resin --><servlet-mapping url-pattern='/resin/*' servlet-name='plugin_match'/><!-- keep everything under /static at the web server --><servlet-mapping url-pattern='/static/*' servlet-name='plugin_ignore'/></example></s2><s2 title="<web-app>"><p><a href="webapp-tags.xtp">web-apps</a> collect servlets andJSP files into separate applications. All the servlet-mappings in aweb-app apply only to the URL suffix.</p><p>In the following example, every URL starting with /prefix/url maps tothe web-app. The servlet-mapping only applies to URLs matching the prefix.</p><example>...<web-app id='/prefix/url'> <servlet-mapping url-pattern='*.foo' .../></web-app>..</example><p>In the exaple, mod_caucho will match any URL matching /prefix/url/*.foo./prefix/url/bar.foo will match, but /test/bar.foo will not match.</p><note>Resin standalone allows a <var>regexp</var> attribute instead of anid. Because mod_caucho does not understand regexps, it will ignore anyweb-app with a <var>regexp</var> attribute.</note><note>web.xml files and war files are treated exactly the same as web-appsin the resin.xml.</note></s2><s2 title="<host>"><p><a href="cluster-tags.xtp#host">host</a> blocks configure<a href="virtual-host.xtp">virtual hosts</a>. There's a bit ofextra work for virtual hosts that we'll ignore here. (Basically, youneed to add Apache <var>ServerName</var> directives so Resin knows the nameof the virtual host.)</p><p>For dispatching, a host block gathers a set of web-apps. Each hostwill match a different set of URLs, depending on the web-app configuration.The default host matches any host not matched by a specific rule.</p><p>As usual, /caucho-status will show the URLs matched for each host.</p><note>mod_caucho does not understand the host <var>regexp</var> attribute.It will ignore all hosts using <var>regexp</var>. To get around this, you caneither configure Apache directly (see below), or configure the default hostwith the same set of servlet-mappings. Since mod_caucho will use thedefault host if no others match, it will send the right requests toResin.</note></s2></s1><s1 title="/caucho-status shows mod_caucho's URLs"><p>The special URL <var>/caucho-status</var> is invaluable in debuggingResin configurations. <var>/caucho-status</var> displays all the resin.xmlpatterns, so you can easily scan it to see which URLs mod_caucho is sendingto Resin and which ones are handled by Apache.</p></s1><s1 title="Dispatching using Apache's http.conf"><p>You can configure Apache directly, instead of letting mod_caucho dispatchfrom the resin.xml file. If you use this method, you need to makesure you match the Apache configuration with the Resin configuration.</p><note>This technique uses Apache-specific features, so it's notdirectly applicable to IIS or iPlanet.</note><p>Apache's <var>Location</var> and <var>SetHandler</var> directives send requeststo Resin. The mod_caucho handler is <var>caucho-request</var>.</p><example title="httpd.conf">LoadModule caucho_module libexec/mod_caucho.soAddModule mod_caucho.cCauchoHost localhost 6802AddHandler caucho-request jsp<Location /servlet/*> SetHandler caucho-request</Location></example><p>Because Apache's <var>SetHandler</var> is external to mod_caucho,/caucho-status will not show any <var>SetHandler</var> dispatching.</p></s1> </body></document>⌨️ 快捷键说明
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