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| </style></head><body bgcolor="#ffffff" text="#000000" link="#525D76" alink="#525D76" vlink="#525D76"><table border="0" width="100%" cellspacing="0"><!--PAGE HEADER--><tr><td><!--PROJECT LOGO--><a href="http://tomcat.apache.org/"><img src="../images/tomcat.gif" align="right" alt=" | |
| The Apache Tomcat Servlet/JSP Container | |
| " border="0"></a></td><td><h1><font face="arial,helvetica,sanserif">Apache Tomcat 7</font></h1><font face="arial,helvetica,sanserif">Version 7.0.77, Mar 28 2017</font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img src="../images/asf-logo.svg" align="right" alt="Apache Logo" border="0" style="width: 266px;height: 83px;"></a></td></tr></table><table border="0" width="100%" cellspacing="4"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr noshade size="1"></td></tr><tr><!--LEFT SIDE NAVIGATION--><td width="20%" valign="top" nowrap class="noPrint"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Config Ref. Home</a></li><li><a href="http://wiki.apache.org/tomcat/FAQ">FAQ</a></li><li><a href="#comments_section">User Comments</a></li></ul><p><strong>Top Level Elements</strong></p><ul><li><a href="server.html">Server</a></li><li><a href="service.html">Service</a></li></ul><p><strong>Executors</strong></p><ul><li><a href="executor.html">Executor</a></li></ul><p><strong>Connectors</strong></p><ul><li><a href="http.html">HTTP</a></li><li><a href="ajp.html">AJP</a></li></ul><p><strong>Containers</strong></p><ul><li><a href="context.html">Context</a></li><li><a href="engine.html">Engine</a></li><li><a href="host.html">Host</a></li><li><a href="cluster.html">Cluster</a></li></ul><p><strong>Nested Components</strong></p><ul><li><a href="globalresources.html">Global Resources</a></li><li><a href="jar-scanner.html">JarScanner</a></li><li><a href="listeners.html">Listeners</a></li><li><a href="loader.html">Loader</a></li><li><a href="manager.html">Manager</a></li><li><a href="realm.html">Realm</a></li><li><a href="resources.html">Resources</a></li><li><a href="sessionidgenerator.html">SessionIdGenerator</a></li><li><a href="valve.html">Valve</a></li></ul><p><strong>Cluster Elements</strong></p><ul><li><a href="cluster.html">Cluster</a></li><li><a href="cluster-manager.html">Manager</a></li><li><a href="cluster-channel.html">Channel</a></li><li><a href="cluster-membership.html">Channel/Membership</a></li><li><a href="cluster-sender.html">Channel/Sender</a></li><li><a href="cluster-receiver.html">Channel/Receiver</a></li><li><a href="cluster-interceptor.html">Channel/Interceptor</a></li><li><a href="cluster-valve.html">Valve</a></li><li><a href="cluster-deployer.html">Deployer</a></li><li><a href="cluster-listener.html">ClusterListener</a></li></ul><p><strong>web.xml</strong></p><ul><li><a href="filter.html">Filter</a></li></ul><p><strong>Other</strong></p><ul><li><a href="systemprops.html">System properties</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left" id="mainBody"><h1>The Host Container</h1><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Table of Contents"><!--()--></a><a name="Table_of_Contents"><strong>Table of Contents</strong></a></font></td></tr><tr><td><blockquote> | |
| <ul><li><a href="#Introduction">Introduction</a></li><li><a href="#Attributes">Attributes</a><ol><li><a href="#Common_Attributes">Common Attributes</a></li><li><a href="#Standard_Implementation">Standard Implementation</a></li></ol></li><li><a href="#Nested_Components">Nested Components</a></li><li><a href="#Special_Features">Special Features</a><ol><li><a href="#Logging">Logging</a></li><li><a href="#Access_Logs">Access Logs</a></li><li><a href="#Automatic_Application_Deployment">Automatic Application Deployment</a></li><li><a href="#Host_Name_Aliases">Host Name Aliases</a></li><li><a href="#Lifecycle_Listeners">Lifecycle Listeners</a></li><li><a href="#Request_Filters">Request Filters</a></li><li><a href="#Single_Sign_On">Single Sign On</a></li><li><a href="#User_Web_Applications">User Web Applications</a></li></ol></li></ul> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Introduction"><strong>Introduction</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>The <strong>Host</strong> element represents a <em>virtual host</em>, | |
| which is an association of a network name for a server (such as | |
| "www.mycompany.com") with the particular server on which Tomcat is running. | |
| For clients to be able to connect to a Tomcat server using its network name, | |
| this name must be registered in the <em>Domain Name Service</em> (DNS) server | |
| that manages the Internet domain you belong to - contact your Network | |
| Administrator for more information.</p> | |
| <p>In many cases, System Administrators wish to associate more than | |
| one network name (such as <code>www.mycompany.com</code> and | |
| <code>company.com</code>) with the same virtual host and applications. | |
| This can be accomplished using the <a href="#Host_Name_Aliases">Host | |
| Name Aliases</a> feature discussed below.</p> | |
| <p>One or more <strong>Host</strong> elements are nested inside an | |
| <a href="engine.html">Engine</a> element. Inside the Host element, you | |
| can nest <a href="context.html">Context</a> elements for the web | |
| applications associated with this virtual host. Exactly one of the Hosts | |
| associated with each Engine MUST have a name matching the | |
| <code>defaultHost</code> attribute of that Engine.</p> | |
| <p>Clients normally use host names to identify the server they wish to connect | |
| to. This host name is also included in the HTTP request headers. Tomcat | |
| extracts the host name from the HTTP headers and looks for a | |
| <strong>Host</strong> with a matching name. If no match is found, the request | |
| is routed to the default host. The name of the default host does not have to | |
| match a DNS name (although it can) since any request where the DNS name does | |
| not match the name of a <strong>Host</strong> element will be routed to the | |
| default host.</p> | |
| <p><em>The description below uses the variable name $CATALINA_BASE to refer the | |
| base directory against which most relative paths are resolved. If you have | |
| not configured Tomcat for multiple instances by setting a CATALINA_BASE | |
| directory, then $CATALINA_BASE will be set to the value of $CATALINA_HOME, | |
| the directory into which you have installed Tomcat.</em></p> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Attributes"><strong>Attributes</strong></a></font></td></tr><tr><td><blockquote> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Common Attributes"><!--()--></a><a name="Common_Attributes"><strong>Common Attributes</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>All implementations of <strong>Host</strong> | |
| support the following attributes:</p> | |
| <table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Attribute</font></th><th width="85%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><strong><code class="attributeName">appBase</code></strong></td><td align="left" valign="center"> | |
| <p>The <em>Application Base</em> directory for this virtual host. | |
| This is the pathname of a directory that may contain web applications | |
| to be deployed on this virtual host. You may specify an | |
| absolute pathname, or a pathname that is relative to the | |
| <code>$CATALINA_BASE</code> directory. See | |
| <a href="#Automatic_Application_Deployment">Automatic Application | |
| Deployment</a> for more information on automatic recognition and | |
| deployment of web applications. If not specified, the default of | |
| <code>webapps</code> will be used.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">xmlBase</code></td><td align="left" valign="center"> | |
| <p>The <em>XML Base</em> directory for this virtual host. | |
| This is the pathname of a directory that may contain context XML | |
| descriptors to be deployed on this virtual host. You may specify an | |
| absolute pathname for this directory, or a pathname that is relative | |
| to the <code>$CATALINA_BASE</code> directory. See | |
| <a href="#Automatic_Application_Deployment">Automatic Application | |
| Deployment</a> for more information on automatic recognition and | |
| deployment of web applications. If not specified the default of | |
| <code>conf/<engine_name>/<host_name></code> will be used.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">createDirs</code></td><td align="left" valign="center"> | |
| <p>If set to true, Tomcat will attempt to create the directories defined | |
| by the attributes <code>appBase</code> and <code>xmlBase</code> during | |
| the startup phase. The default value is <code>true</code>. If set to | |
| true, and directory creation fails, an error message will be printed out | |
| but will not halt the startup sequence.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">autoDeploy</code></td><td align="left" valign="center"> | |
| <p>This flag value indicates if Tomcat should check periodically for new | |
| or updated web applications while Tomcat is running. If true, Tomcat | |
| periodically checks the <code>appBase</code> and <code>xmlBase</code> | |
| directories and deploys any new web applications or context XML | |
| descriptors found. Updated web applications or context XML descriptors | |
| will trigger a reload of the web application. The flag's value defaults | |
| to true. See | |
| <a href="#Automatic_Application_Deployment">Automatic Application | |
| Deployment</a> for more information.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">backgroundProcessorDelay</code></td><td align="left" valign="center"> | |
| <p>This value represents the delay in seconds between the | |
| invocation of the backgroundProcess method on this host and | |
| its child containers, including all contexts. | |
| Child containers will not be invoked if their delay value is not | |
| negative (which would mean they are using their own processing | |
| thread). Setting this to a positive value will cause | |
| a thread to be spawn. After waiting the specified amount of time, | |
| the thread will invoke the backgroundProcess method on this host | |
| and all its child containers. A host will use background processing to | |
| perform live web application deployment related tasks. If not | |
| specified, the default value for this attribute is -1, which means | |
| the host will rely on the background processing thread of its parent | |
| engine.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">className</code></td><td align="left" valign="center"> | |
| <p>Java class name of the implementation to use. This class must | |
| implement the <code>org.apache.catalina.Host</code> interface. | |
| If not specified, the standard value (defined below) will be used.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">deployIgnore</code></td><td align="left" valign="center"> | |
| <p>A regular expression defining paths to ignore when | |
| <code>autoDeploy</code> and <code>deployOnStartup</code> are set. This | |
| allows you to keep your configuration in a version control system, for | |
| example, and not deploy a .svn or CVS folder that happens to be in the | |
| <code>appBase</code>.</p> | |
| <p>This regular expression is relative to <code>appBase</code>. It is | |
| also <em>anchored</em>, meaning the match is performed against the | |
| entire file/directory name. So, <code>foo</code> matches only a file or | |
| directory named <code>foo</code> but not <code>foo.war</code>, | |
| <code>foobar</code>, or <code>myfooapp</code>. To match anything with | |
| "foo", you could use <code>.*foo.*</code>.</p> | |
| <p>See <a href="#Automatic_Application_Deployment">Automatic Application | |
| Deployment</a> for more information.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">deployOnStartup</code></td><td align="left" valign="center"> | |
| <p>This flag value indicates if web applications from this host should | |
| be automatically deployed when Tomcat starts. The flag's value defaults | |
| to true. See | |
| <a href="#Automatic_Application_Deployment">Automatic Application | |
| Deployment</a> for more information.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">failCtxIfServletStartFails</code></td><td align="left" valign="center"> | |
| <p>Set to <code>true</code> to have each child contexts fail its startup | |
| if any of its servlet that has load-on-startup >=0 fails its own | |
| startup.</p> | |
| <p>Each child context may override this attribute.</p> | |
| <p>If not specified, the default value of <code>false</code> is | |
| used.</p> | |
| </td></tr><tr><td align="left" valign="center"><strong><code class="attributeName">name</code></strong></td><td align="left" valign="center"> | |
| <p>Usually the network name of this virtual host, as registered in your | |
| <em>Domain Name Service</em> server. Regardless of the case used to | |
| specify the host name, Tomcat will convert it to lower case internally. | |
| One of the Hosts nested within an <a href="engine.html">Engine</a> MUST | |
| have a name that matches the <code>defaultHost</code> setting for that | |
| Engine. See <a href="#Host_Name_Aliases">Host Name Aliases</a> for | |
| information on how to assign more than one network name to the same | |
| virtual host.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">startStopThreads</code></td><td align="left" valign="center"> | |
| <p>The number of threads this <strong>Host</strong> will use to start | |
| child <a href="context.html">Context</a> elements in parallel. The same | |
| thread pool will be used to deploy new | |
| <a href="context.html">Context</a>s if automatic deployment is being | |
| used. The special value of 0 will result in the value of | |
| <code>Runtime.getRuntime().availableProcessors()</code> being used. | |
| Negative values will result in | |
| <code>Runtime.getRuntime().availableProcessors() + value</code> being | |
| used unless this is less than 1 in which case 1 thread will be used. If | |
| not specified, the default value of 1 will be used.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">undeployOldVersions</code></td><td align="left" valign="center"> | |
| <p>This flag determines if Tomcat, as part of the auto deployment | |
| process, will check for old, unused versions of web applications | |
| deployed using parallel deployment and, if any are found, remove them. | |
| This flag only applies if <code>autoDeploy</code> is true. If not | |
| specified the default value of false will be used.</p> | |
| </td></tr></table> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Standard Implementation"><!--()--></a><a name="Standard_Implementation"><strong>Standard Implementation</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>The standard implementation of <strong>Host</strong> is | |
| <strong>org.apache.catalina.core.StandardHost</strong>. | |
| It supports the following additional attributes (in addition to the | |
| common attributes listed above):</p> | |
| <table border="1" cellpadding="5"><tr><th width="15%" bgcolor="#023264"><font color="#ffffff">Attribute</font></th><th width="85%" bgcolor="#023264"><font color="#ffffff">Description</font></th></tr><tr><td align="left" valign="center"><code class="attributeName">copyXML</code></td><td align="left" valign="center"> | |
| <p>Set to <code>true</code> if you want a context XML descriptor | |
| embedded inside the application (located at | |
| <code>/META-INF/context.xml</code>) to be copied to <code>xmlBase</code> | |
| when the application is deployed. On subsequent starts, the copied | |
| context XML descriptor will be used in preference to any context XML | |
| descriptor embedded inside the application even if the descriptor | |
| embedded inside the application is more recent. The flag's value | |
| defaults to <code>false</code>. Note if <strong>deployXML</strong> | |
| is <code>false</code>, this attribute will have no effect.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">deployXML</code></td><td align="left" valign="center"> | |
| <p>Set to <code>false</code> if you want to disable parsing the context | |
| XML descriptor embedded inside the application (located at | |
| <code>/META-INF/context.xml</code>). Security conscious environments | |
| should set this to <code>false</code> to prevent applications from | |
| interacting with the container's configuration. The administrator will | |
| then be responsible for providing an external context configuration | |
| file, and putting it in the location defined by the | |
| <strong>xmlBase</strong> attribute. If this flag is <code>false</code>, | |
| a descriptor is located at <code>/META-INF/context.xml</code> and no | |
| descriptor is present in <strong>xmlBase</strong> then the context will | |
| fail to start in case the descriptor contains necessary configuration | |
| for secure deployment (such as a RemoteAddrValve) which should not be | |
| ignored. The flag's value defaults to <code>true</code> unless a | |
| security manager is enabled when the default is <code>false</code>.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">errorReportValveClass</code></td><td align="left" valign="center"> | |
| <p>Java class name of the error reporting valve which will be used | |
| by this Host. The responsibility of this valve is to output error | |
| reports. Setting this property allows to customize the look of the | |
| error pages which will be generated by Tomcat. This class must | |
| implement the | |
| <code>org.apache.catalina.Valve</code> interface. If none is specified, | |
| the value <code>org.apache.catalina.valves.ErrorReportValve</code> | |
| will be used by default.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">unpackWARs</code></td><td align="left" valign="center"> | |
| <p>Set to <code>true</code> if you want web applications that are | |
| placed in the <code>appBase</code> directory as web application | |
| archive (WAR) files to be unpacked into a corresponding disk directory | |
| structure, <code>false</code> to run such web applications directly | |
| from a WAR file. WAR files located outside of the Host's | |
| <strong>appBase</strong> will not be expanded. See | |
| <a href="#Automatic_Application_Deployment">Automatic Application | |
| Deployment</a> for more information.</p> | |
| </td></tr><tr><td align="left" valign="center"><code class="attributeName">workDir</code></td><td align="left" valign="center"> | |
| <p>Pathname to a scratch directory to be used by applications for | |
| this Host. Each application will have its own sub directory with | |
| temporary read-write use. Configuring a Context workDir will override | |
| use of the Host workDir configuration. This directory will be made | |
| visible to servlets in the web application by a servlet context | |
| attribute (of type <code>java.io.File</code>) named | |
| <code>javax.servlet.context.tempdir</code> as described in the | |
| Servlet Specification. If not specified, a suitable directory | |
| underneath <code>$CATALINA_BASE/work</code> will be provided.</p> | |
| </td></tr></table> | |
| </blockquote></td></tr></table> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Nested Components"><!--()--></a><a name="Nested_Components"><strong>Nested Components</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>You can nest one or more <a href="context.html">Context</a> elements | |
| inside this <strong>Host</strong> element, each representing a different web | |
| application associated with this virtual host.</p> | |
| <p>You can nest at most one instance of the following utility components | |
| by nesting a corresponding element inside your <strong>Host</strong> | |
| element:</p> | |
| <ul> | |
| <li><a href="realm.html"><strong>Realm</strong></a> - | |
| Configure a realm that will allow its | |
| database of users, and their associated roles, to be shared across all | |
| <a href="context.html">Contexts</a> nested inside this Host (unless | |
| overridden by a <a href="realm.html">Realm</a> configuration | |
| at a lower level).</li> | |
| </ul> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Special Features"><!--()--></a><a name="Special_Features"><strong>Special Features</strong></a></font></td></tr><tr><td><blockquote> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Logging"><strong>Logging</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>A host is associated with the | |
| <code>org.apache.catalina.core.ContainerBase.[engine_name].[host_name]</code> | |
| log category. Note that the brackets are part of the name, | |
| don't omit them.</p> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Access Logs"><!--()--></a><a name="Access_Logs"><strong>Access Logs</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>When you run a web server, one of the output files normally generated | |
| is an <em>access log</em>, which generates one line of information for | |
| each request processed by the server, in a standard format. Catalina | |
| includes an optional <a href="valve.html">Valve</a> implementation that | |
| can create access logs in the same standard format created by web servers, | |
| or in any number of custom formats.</p> | |
| <p>You can ask Catalina to create an access log for all requests | |
| processed by an <a href="engine.html">Engine</a>, | |
| <a href="host.html">Host</a>, or <a href="context.html">Context</a> | |
| by nesting a <a href="valve.html">Valve</a> element like this:</p> | |
| <div class="codeBox"><pre><code><Host name="localhost" ...> | |
| ... | |
| <Valve className="org.apache.catalina.valves.AccessLogValve" | |
| prefix="localhost_access_log." suffix=".txt" | |
| pattern="common"/> | |
| ... | |
| </Host></code></pre></div> | |
| <p>See <a href="valve.html#Access_Logging">Access Logging Valves</a> | |
| for more information on the configuration attributes that are | |
| supported.</p> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Automatic Application Deployment"><!--()--></a><a name="Automatic_Application_Deployment"><strong>Automatic Application Deployment</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>If you are using the standard <strong>Host</strong> implementation with | |
| default settings then applications in the <em>appBase</em> or with context | |
| files in the <em>configBase</em> are automatically deployed when Tomcat | |
| starts (the <code>deployOnStartup</code> property defaults to | |
| <code>true</code>) and reloaded or redeployed (as appropriate) when a change | |
| is detected while Tomcat is running (the <code>autoDeploy</code> attribute | |
| also defaults to <code>true</code>).</p> | |
| <p><code>deployOnStartup</code> and <code>autoDeploy</code> trigger | |
| execution of exactly the same code so the behaviour is very similar. | |
| However, there is one key difference. When Tomcat starts it has no knowledge | |
| of which files are the same, which have been changed and which are new. It | |
| therefore treats all files as new. While Tomcat is running, it can | |
| differentiate between unchanged, modified and new files. This leads to some | |
| differences in behaviour between files being modified while Tomcat is | |
| running and files being modified while Tomcat is stopped.</p> | |
| <p>When you use automatic deployment, related files (a web application may | |
| have a context.xml file, a WAR and a directory) that exist in the | |
| <strong>Host</strong>'s <em>appBase</em> and/or <em>configBase</em> | |
| must conform to the expected <a href="context.html#Naming">naming | |
| convention</a>. In short, this means files for the same web application must | |
| share the same <em>base name</em>.</p> | |
| <p>The automatic deployment process identifies new and/or modified web | |
| applications using the following search order:</p> | |
| <ol> | |
| <li>Web applications with a context.xml file located in the Host's | |
| <em>configBase</em>.</li> | |
| <li>Web applications with a WAR file located in the Host's | |
| <em>appBase</em> that have not already been identified during the scan for | |
| context.xml files.</li> | |
| <li>Web applications with a directory located in the Host's | |
| <em>appBase</em> that have not already been identified during the scans | |
| for context.xml and/or WAR files.</li> | |
| </ol> | |
| <p>When <code>autoDeploy</code> is <code>true</code>, the automatic | |
| deployment process will monitor the deployed web applications for changes. | |
| Depending on exactly what changes, the web application will either be | |
| re-deployed or reloaded. Re-deployment involves the creation of a new web | |
| application and, if using the standard session manager, user sessions will | |
| not be retained. Reloading uses the existing web application but re-parses | |
| the web.xml and reloads any classes. If using the standard session manager, | |
| user sessions will be persisted.</p> | |
| <p>Users may add to the files that the automatic deployment process monitors | |
| for reloading (i.e. any change to one of these files triggers a reload of | |
| the web application) by adding a <em>WatchedResources</em> element to the | |
| context.xml file. See the | |
| <a href="context.html#Nested_Components">Context</a> documentation for | |
| further details.</p> | |
| <p>When using automatic deployment, the <code>docBase</code> defined by | |
| an XML <a href="context.html">Context</a> file should be outside of the | |
| <code>appBase</code> directory. If this is not the case, difficulties | |
| may be experienced deploying the web application or the application may | |
| be deployed twice. The <code>deployIgnore</code> attribute can be used | |
| to avoid this situation.</p> | |
| <p>Note that if you are defining contexts explicitly in server.xml, you | |
| should probably turn off automatic application deployment or specify | |
| <code>deployIgnore</code> carefully. Otherwise, the web applications | |
| will each be deployed twice, and that may cause problems for the | |
| applications.</p> | |
| <p>There are many possible combinations of settings, new files, changed | |
| files and deleted files. A separate page describes the | |
| <a href="automatic-deployment.html">expected behaviour of the automatic | |
| deployment process</a> in many of these scenarios.</p> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Host Name Aliases"><!--()--></a><a name="Host_Name_Aliases"><strong>Host Name Aliases</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>In many server environments, Network Administrators have configured | |
| more than one network name (in the <em>Domain Name Service</em> (DNS) | |
| server), that resolve to the IP address of the same server. Normally, | |
| each such network name would be configured as a separate | |
| <strong>Host</strong> element in <code>conf/server.xml</code>, each | |
| with its own set of web applications.</p> | |
| <p>However, in some circumstances, it is desirable that two or more | |
| network names should resolve to the <strong>same</strong> virtual host, | |
| running the same set of applications. A common use case for this | |
| scenario is a corporate web site, where it is desirable that users | |
| be able to utilize either <code>www.mycompany.com</code> or | |
| <code>company.com</code> to access exactly the same content and | |
| applications.</p> | |
| <p>This is accomplished by utilizing one or more <strong>Alias</strong> | |
| elements nested inside your <strong>Host</strong> element. For | |
| example:</p> | |
| <div class="codeBox"><pre><code><Host name="www.mycompany.com" ...> | |
| ... | |
| <Alias>mycompany.com</Alias> | |
| ... | |
| </Host></code></pre></div> | |
| <p>In order for this strategy to be effective, all of the network names | |
| involved must be registered in your DNS server to resolve to the | |
| same computer that is running this instance of Catalina.</p> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Lifecycle Listeners"><!--()--></a><a name="Lifecycle_Listeners"><strong>Lifecycle Listeners</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>If you have implemented a Java object that needs to know when this | |
| <strong>Host</strong> is started or stopped, you can declare it by | |
| nesting a <strong>Listener</strong> element inside this element. The | |
| class name you specify must implement the | |
| <code>org.apache.catalina.LifecycleListener</code> interface, and | |
| it will be notified about the occurrence of the corresponding | |
| lifecycle events. Configuration of such a listener looks like this:</p> | |
| <div class="codeBox"><pre><code><Host name="localhost" ...> | |
| ... | |
| <Listener className="com.mycompany.mypackage.MyListener" ... > | |
| ... | |
| </Host></code></pre></div> | |
| <p>Note that a Listener can have any number of additional properties | |
| that may be configured from this element. Attribute names are matched | |
| to corresponding JavaBean property names using the standard property | |
| method naming patterns.</p> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Request Filters"><!--()--></a><a name="Request_Filters"><strong>Request Filters</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>You can ask Catalina to check the IP address, or host name, on every | |
| incoming request directed to the surrounding | |
| <a href="engine.html">Engine</a>, <a href="host.html">Host</a>, or | |
| <a href="context.html">Context</a> element. The remote address or name | |
| will be checked against configured "accept" and/or "deny" | |
| filters, which are defined using <code>java.util.regex</code> Regular | |
| Expression syntax. Requests that come from locations that are | |
| not accepted will be rejected with an HTTP "Forbidden" error. | |
| Example filter declarations:</p> | |
| <div class="codeBox"><pre><code><Host name="localhost" ...> | |
| ... | |
| <Valve className="org.apache.catalina.valves.RemoteHostValve" | |
| allow=".*\.mycompany\.com|www\.yourcompany\.com"/> | |
| <Valve className="org.apache.catalina.valves.RemoteAddrValve" | |
| deny="192\.168\.1\.\d+"/> | |
| ... | |
| </Host></code></pre></div> | |
| <p>See <a href="valve.html#Remote_Address_Filter">Remote Address Filter</a> | |
| and <a href="valve.html#Remote_Host_Filter">Remote Host Filter</a> for | |
| more information about the configuration options that are supported.</p> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Single Sign On"><!--()--></a><a name="Single_Sign_On"><strong>Single Sign On</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>In many environments, but particularly in portal environments, it | |
| is desirable to have a user challenged to authenticate themselves only | |
| once over a set of web applications deployed on a particular virtual | |
| host. This can be accomplished by nesting an element like this inside | |
| the Host element for this virtual host:</p> | |
| <div class="codeBox"><pre><code><Host name="localhost" ...> | |
| ... | |
| <Valve className="org.apache.catalina.authenticator.SingleSignOn"/> | |
| ... | |
| </Host></code></pre></div> | |
| <p>The Single Sign On facility operates according to the following rules: | |
| </p> | |
| <ul> | |
| <li>All web applications configured for this virtual host must share the | |
| same <a href="realm.html">Realm</a>. In practice, that means you can | |
| nest the Realm element inside this Host element (or the surrounding | |
| <a href="engine.html">Engine</a> element), but not inside a | |
| <a href="context.html">Context</a> element for one of the involved | |
| web applications.</li> | |
| <li>As long as the user accesses only unprotected resources in any of the | |
| web applications on this virtual host, they will not be challenged | |
| to authenticate themselves.</li> | |
| <li>As soon as the user accesses a protected resource in | |
| <strong>any</strong> web application associated with this virtual | |
| host, the user will be challenged to authenticate himself or herself, | |
| using the login method defined for the web application currently | |
| being accessed.</li> | |
| <li>Once authenticated, the roles associated with this user will be | |
| utilized for access control decisions across <strong>all</strong> | |
| of the associated web applications, without challenging the user | |
| to authenticate themselves to each application individually.</li> | |
| <li>As soon as the user logs out of one web application (for example, | |
| by invalidating the corresponding session if form | |
| based login is used), the user's sessions in <strong>all</strong> | |
| web applications will be invalidated. Any subsequent attempt to | |
| access a protected resource in any application will require the | |
| user to authenticate himself or herself again.</li> | |
| <li>The Single Sign On feature utilizes HTTP cookies to transmit a token | |
| that associates each request with the saved user identity, so it can | |
| only be utilized in client environments that support cookies.</li> | |
| </ul> | |
| </blockquote></td></tr></table> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="User Web Applications"><!--()--></a><a name="User_Web_Applications"><strong>User Web Applications</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>Many web servers can automatically map a request URI starting with | |
| a tilde character ("~") and a username to a directory (commonly named | |
| <code>public_html</code>) in that user's home directory on the server. | |
| You can accomplish the same thing in Catalina by using a special | |
| <strong>Listener</strong> element like this (on a Unix system that | |
| uses the <code>/etc/passwd</code> file to identify valid users):</p> | |
| <div class="codeBox"><pre><code><Host name="localhost" ...> | |
| ... | |
| <Listener className="org.apache.catalina.startup.UserConfig" | |
| directoryName="public_html" | |
| userClass="org.apache.catalina.startup.PasswdUserDatabase"/> | |
| ... | |
| </Host></code></pre></div> | |
| <p>On a server where <code>/etc/passwd</code> is not in use, you can | |
| request Catalina to consider all directories found in a specified base | |
| directory (such as <code>c:\Homes</code> in this example) to be | |
| considered "user home" directories for the purposes of this directive:</p> | |
| <div class="codeBox"><pre><code><Host name="localhost" ...> | |
| ... | |
| <Listener className="org.apache.catalina.startup.UserConfig" | |
| directoryName="public_html" | |
| homeBase="c:\Homes" | |
| userClass="org.apache.catalina.startup.HomesUserDatabase"/> | |
| ... | |
| </Host></code></pre></div> | |
| <p>If a user home directory has been set up for a user named | |
| <code>craigmcc</code>, then its contents will be visible from a | |
| client browser by making a request to a URL like:</p> | |
| <div class="codeBox"><pre><code>http://www.mycompany.com:8080/~craigmcc</code></pre></div> | |
| <p>Successful use of this feature requires recognition of the following | |
| considerations:</p> | |
| <ul> | |
| <li>Each user web application will be deployed with characteristics | |
| established by the global and host level default context settings.</li> | |
| <li>It is legal to include more than one instance of this Listener | |
| element. This would only be useful, however, in circumstances | |
| where you wanted to configure more than one "homeBase" directory.</li> | |
| <li>The operating system username under which Catalina is executed | |
| MUST have read access to each user's web application directory, | |
| and all of its contents.</li> | |
| </ul> | |
| </blockquote></td></tr></table> | |
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