Subversion Repositories Integrator Subversion

Rev

Details | Last modification | View Log | RSS feed

Rev Author Line No. Line
771 blopes 1 
<!DOCTYPE html SYSTEM "about:legacy-compat">
2 
<html lang="en"><head><META http-equiv="Content-Type" content="text/html; charset=UTF-8"><link href="./images/docs-stylesheet.css" rel="stylesheet" type="text/css"><title>Apache Tomcat 9 (9.0.112) - WebSocket How-To</title></head><body><div id="wrapper"><header><div id="header"><div><div><div class="logo noPrint"><a href="https://tomcat.apache.org/"><img alt="Tomcat Home" src="./images/tomcat.png"></a></div><div style="height: 1px;"></div><div class="asfLogo noPrint"><a href="https://www.apache.org/" target="_blank"><img src="./images/asf-logo.svg" alt="The Apache Software Foundation" style="width: 266px; height: 83px;"></a></div><h1>Apache Tomcat 9</h1><div class="versionInfo">
3 
            Version 9.0.112,
4 
            <time datetime="2025-11-06">Nov 6 2025</time></div><div style="height: 1px;"></div><div style="clear: left;"></div></div></div></div></header><div id="middle"><div><div id="mainLeft" class="noprint"><div><nav><div><h2>Links</h2><ul><li><a href="index.html">Docs Home</a></li><li><a href="https://cwiki.apache.org/confluence/display/TOMCAT/FAQ">FAQ</a></li></ul></div><div><h2>User Guide</h2><ul><li><a href="introduction.html">1) Introduction</a></li><li><a href="setup.html">2) Setup</a></li><li><a href="appdev/index.html">3) First webapp</a></li><li><a href="deployer-howto.html">4) Deployer</a></li><li><a href="manager-howto.html">5) Manager</a></li><li><a href="host-manager-howto.html">6) Host Manager</a></li><li><a href="realm-howto.html">7) Realms and AAA</a></li><li><a href="security-manager-howto.html">8) Security Manager</a></li><li><a href="jndi-resources-howto.html">9) JNDI Resources</a></li><li><a href="jndi-datasource-examples-howto.html">10) JDBC DataSources</a></li><li><a href="class-loader-howto.html">11) Classloading</a></li><li><a href="jasper-howto.html">12) JSPs</a></li><li><a href="ssl-howto.html">13) SSL/TLS</a></li><li><a href="ssi-howto.html">14) SSI</a></li><li><a href="cgi-howto.html">15) CGI</a></li><li><a href="proxy-howto.html">16) Proxy Support</a></li><li><a href="mbeans-descriptors-howto.html">17) MBeans Descriptors</a></li><li><a href="default-servlet.html">18) Default Servlet</a></li><li><a href="cluster-howto.html">19) Clustering</a></li><li><a href="balancer-howto.html">20) Load Balancer</a></li><li><a href="connectors.html">21) Connectors</a></li><li><a href="monitoring.html">22) Monitoring and Management</a></li><li><a href="logging.html">23) Logging</a></li><li><a href="apr.html">24) APR/Native</a></li><li><a href="virtual-hosting-howto.html">25) Virtual Hosting</a></li><li><a href="aio.html">26) Advanced IO</a></li><li><a href="maven-jars.html">27) Mavenized</a></li><li><a href="security-howto.html">28) Security Considerations</a></li><li><a href="windows-service-howto.html">29) Windows Service</a></li><li><a href="windows-auth-howto.html">30) Windows Authentication</a></li><li><a href="jdbc-pool.html">31) Tomcat's JDBC Pool</a></li><li><a href="web-socket-howto.html">32) WebSocket</a></li><li><a href="rewrite.html">33) Rewrite</a></li><li><a href="cdi.html">34) CDI 2 and JAX-RS</a></li><li><a href="graal.html">35) AOT/GraalVM Support</a></li></ul></div><div><h2>Reference</h2><ul><li><a href="RELEASE-NOTES.txt">Release Notes</a></li><li><a href="config/index.html">Configuration</a></li><li><a href="api/index.html">Tomcat Javadocs</a></li><li><a href="servletapi/index.html">Servlet 4.0 Javadocs</a></li><li><a href="jspapi/index.html">JSP 2.3 Javadocs</a></li><li><a href="elapi/index.html">EL 3.0 Javadocs</a></li><li><a href="websocketapi/index.html">WebSocket 1.1 Javadocs</a></li><li><a href="jaspicapi/index.html">JASPIC 1.1 Javadocs</a></li><li><a href="annotationapi/index.html">Common Annotations 1.3 Javadocs</a></li><li><a href="https://tomcat.apache.org/connectors-doc/">JK 1.2 Documentation</a></li></ul></div><div><h2>Apache Tomcat Development</h2><ul><li><a href="building.html">Building</a></li><li><a href="changelog.html">Changelog</a></li><li><a href="https://cwiki.apache.org/confluence/display/TOMCAT/Tomcat+Versions">Status</a></li><li><a href="developers.html">Developers</a></li><li><a href="architecture/index.html">Architecture</a></li><li><a href="tribes/introduction.html">Tribes</a></li></ul></div></nav></div></div><div id="mainRight"><div id="content"><h2>WebSocket How-To</h2><h3 id="Table_of_Contents">Table of Contents</h3><div class="text">
5 
<ul><li><a href="#Overview">Overview</a></li><li><a href="#Application_development">Application development</a></li><li><a href="#Tomcat_WebSocket_specific_configuration">Tomcat WebSocket specific configuration</a></li></ul>
6 
</div><h3 id="Overview">Overview</h3><div class="text">
7 
<p>Tomcat provides support for WebSocket as defined by
8 
   <a href="https://tools.ietf.org/html/rfc6455">RFC 6455</a>.</p>
9 
</div><h3 id="Application_development">Application development</h3><div class="text">
10 
<p>Tomcat implements the Java WebSocket 1.1 API defined by <a href="https://www.jcp.org/en/jsr/detail?id=356">JSR-356</a>.</p>
11 
 
12 
<p>There are several example applications that demonstrate how the WebSocket API
13 
   can be used. You will need to look at both the client side <a href="https://github.com/apache/tomcat/tree/9.0.x/webapps/examples/websocket">
14 
   HTML</a> and the server side <a href="https://github.com/apache/tomcat/tree/9.0.x/webapps/examples/WEB-INF/classes/websocket">
15 
   code</a>.</p>
16 
</div><h3 id="Tomcat_WebSocket_specific_configuration">Tomcat WebSocket specific configuration</h3><div class="text">
17 
 
18 
<p>Tomcat provides a number of Tomcat specific configuration options for
19 
   WebSocket. It is anticipated that these will be absorbed into the WebSocket
20 
   specification over time.</p>
21 
 
22 
<p>The write timeout used when sending WebSocket messages in blocking mode
23 
   defaults to 20000 milliseconds (20 seconds). This may be changed by setting
24 
   the property <code>org.apache.tomcat.websocket.BLOCKING_SEND_TIMEOUT</code>
25 
   in the user properties collection attached to the WebSocket session. The
26 
   value assigned to this property should be a <code>Long</code> and represents
27 
   the timeout to use in milliseconds. For an infinite timeout, use
28 
   <code>-1</code>.</p>
29 
 
30 
<p>The time Tomcat waits for a peer to send a WebSocket session close message
31 
   after Tomcat has sent a close message to the peer defaults to 30000
32 
   milliseconds (30 seconds). This may be changed by setting the property
33 
   <code>org.apache.tomcat.websocket.SESSION_CLOSE_TIMEOUT</code> in the user
34 
   properties collection attached to the WebSocket session. The value assigned
35 
   to this property should be a <code>Long</code> and represents the timeout to
36 
   use in milliseconds. Values less than or equal to zero will be ignored.</p>
37 
 
38 
<p>The write timeout Tomcat uses when writing a session close message when the
39 
   close is abnormal defaults to 50 milliseconds. This may be changed by setting
40 
   the property
41 
   <code>org.apache.tomcat.websocket.ABNORMAL_SESSION_CLOSE_SEND_TIMEOUT</code>
42 
   in the user properties collection attached to the WebSocket session. The
43 
   value assigned to this property should be a <code>Long</code> and represents
44 
   the timeout to use in milliseconds. Values less than or equal to zero will be
45 
   ignored.</p>
46 
 
47 
<p>In addition to the <code>Session.setMaxIdleTimeout(long)</code> method which
48 
   is part of the Java WebSocket API, Tomcat provides greater control of the
49 
   timing out the session due to lack of activity. Setting the property
50 
   <code>org.apache.tomcat.websocket.READ_IDLE_TIMEOUT_MS</code> in the user
51 
   properties collection attached to the WebSocket session will trigger a
52 
   session timeout if no WebSocket message is received for the specified number
53 
   of milliseconds. Setting the property
54 
   <code>org.apache.tomcat.websocket.WRITE_IDLE_TIMEOUT_MS</code> will trigger a
55 
   session timeout if no WebSocket message is sent for the specified number of
56 
   milliseconds. These can be used separately or together, with or without
57 
   <code>Session.setMaxIdleTimeout(long)</code>. If the associated property is
58 
   not specified, the read and/or write idle timeout will be applied.</p>
59 
 
60 
<p>If the application does not define a <code>MessageHandler.Partial</code> for
61 
   incoming binary messages, any incoming binary messages must be buffered so
62 
   the entire message can be delivered in a single call to the registered
63 
   <code>MessageHandler.Whole</code> for binary messages. The default buffer
64 
   size for binary messages is 8192 bytes. This may be changed for a web
65 
   application by setting the servlet context initialization parameter
66 
   <code>org.apache.tomcat.websocket.binaryBufferSize</code> to the desired
67 
   value in bytes.</p>
68 
 
69 
<p>If the application does not define a <code>MessageHandler.Partial</code> for
70 
   incoming text messages, any incoming text messages must be buffered so the
71 
   entire message can be delivered in a single call to the registered
72 
   <code>MessageHandler.Whole</code> for text messages. The default buffer size
73 
   for text messages is 8192 bytes. This may be changed for a web application by
74 
   setting the servlet context initialization parameter
75 
   <code>org.apache.tomcat.websocket.textBufferSize</code> to the desired value
76 
   in bytes.</p>
77 
 
78 
<p>The Java WebSocket specification 1.0 does not permit programmatic deployment
79 
   after the first endpoint has started a WebSocket handshake. By default,
80 
   Tomcat continues to permit additional programmatic deployment. This
81 
   behavior is controlled by the
82 
   <code>org.apache.tomcat.websocket.noAddAfterHandshake</code> servlet context
83 
   initialization parameter. The default may be changed by setting the
84 
   <code>org.apache.tomcat.websocket.STRICT_SPEC_COMPLIANCE</code> system
85 
   property to <code>true</code> but any explicit setting on the servlet context
86 
   will always take priority.</p>
87 
 
88 
<p>When using the WebSocket client to connect to server endpoints, the timeout
89 
   for IO operations while establishing the connection is controlled by the
90 
   <code>userProperties</code> of the provided
91 
   <code>javax.websocket.ClientEndpointConfig</code>. The property is
92 
   <code>org.apache.tomcat.websocket.IO_TIMEOUT_MS</code> and is the
93 
   timeout as a <code>String</code> in milliseconds. The default is 5000 (5
94 
   seconds).</p>
95 
 
96 
<p>When using the WebSocket client to connect to secure server endpoints, the
97 
   client SSL configuration is controlled by the <code>userProperties</code>
98 
   of the provided <code>javax.websocket.ClientEndpointConfig</code>. The
99 
   following user properties are supported:</p>
100 
   <ul>
101 
     <li><code>org.apache.tomcat.websocket.SSL_CONTEXT</code></li>
102 
     <li><code>org.apache.tomcat.websocket.SSL_PROTOCOLS</code></li>
103 
     <li><code>org.apache.tomcat.websocket.SSL_TRUSTSTORE</code></li>
104 
     <li><code>org.apache.tomcat.websocket.SSL_TRUSTSTORE_PWD</code></li>
105 
   </ul>
106 
   <p>The default truststore password is <code>changeit</code>.</p>
107 
 
108 
<p>If the <code>org.apache.tomcat.websocket.SSL_CONTEXT</code> property is
109 
   set then the <code>org.apache.tomcat.websocket.SSL_TRUSTSTORE</code> and
110 
   <code>org.apache.tomcat.websocket.SSL_TRUSTSTORE_PWD</code> properties
111 
   will be ignored.</p>
112 
 
113 
<p>For secure server end points, host name verification is enabled by default.
114 
   To bypass this verification (not recommended), it is necessary to provide a
115 
   custom <code>SSLContext</code> via the
116 
   <code>org.apache.tomcat.websocket.SSL_CONTEXT</code> user property. The
117 
   custom <code>SSLContext</code> must be configured with a custom
118 
   <code>TrustManager</code> that extends
119 
   <code>javax.net.ssl.X509ExtendedTrustManager</code>. The desired verification
120 
   (or lack of verification) can then be controlled by appropriate
121 
   implementations of the individual abstract methods.</p>
122 
 
123 
<p>When using the WebSocket client to connect to server endpoints, the number of
124 
   HTTP redirects that the client will follow is controlled by the
125 
   <code>userProperties</code> of the provided
126 
   <code>javax.websocket.ClientEndpointConfig</code>. The property is
127 
   <ocde>org.apache.tomcat.websocket.MAX_REDIRECTIONS</ocde>. The default value
128 
   is 20. Redirection support can be disabled by configuring a value of zero.
129 
   </p>
130 
 
131 
<p>When using the WebSocket client to connect to a server endpoint that requires
132 
   BASIC or DIGEST authentication, the following user properties must be set:
133 
   </p>
134 
   <ul>
135 
     <li><code>org.apache.tomcat.websocket.WS_AUTHENTICATION_USER_NAME</code>
136 
     </li>
137 
     <li><code>org.apache.tomcat.websocket.WS_AUTHENTICATION_PASSWORD</code>
138 
     </li>
139 
   </ul>
140 
   <p>Optionally, the WebSocket client can be configured only to send
141 
   credentials if the server authentication challenge includes a specific realm
142 
   by defining that realm in the optional user property:</p>
143 
   <ul>
144 
     <li><code>org.apache.tomcat.websocket.WS_AUTHENTICATION_REALM</code></li>
145 
   </ul>
146 
 
147 
<p>When using the WebSocket client to connect to a server endpoint via a forward
148 
   proxy (also known as a gateway) that requires BASIC or DIGEST authentication,
149 
   the following user properties must be set:
150 
   </p>
151 
   <ul>
152 
     <li><code>org.apache.tomcat.websocket.WS_PROXY_AUTHENTICATION_USER_NAME
153 
     </code></li>
154 
     <li><code>org.apache.tomcat.websocket.WS_PROXY_AUTHENTICATION_PASSWORD
155 
     </code></li>
156 
   </ul>
157 
   <p>Optionally, the WebSocket client can be configured only to send
158 
   credentials if the server authentication challenge includes a specific realm
159 
   by defining that realm in the optional user property:</p>
160 
   <ul>
161 
     <li><code>org.apache.tomcat.websocket.WS_PROXY_AUTHENTICATION_REALM</code>
162 
     </li>
163 
   </ul>
164 
 
165 
</div></div></div></div></div><footer><div id="footer">
166 
    Copyright &copy; 1999-2025, The Apache Software Foundation
167 
    <br>
168 
    Apache Tomcat, Tomcat, Apache, the Apache Tomcat logo and the Apache logo
169 
    are either registered trademarks or trademarks of the Apache Software
170 
    Foundation.
171 
    </div></footer></div></body></html>