You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@activemq.apache.org by bu...@apache.org on 2015/02/11 19:20:57 UTC
svn commit: r939838 - in /websites/production/activemq/content:
cache/main.pageCache rest.html
Author: buildbot
Date: Wed Feb 11 18:20:57 2015
New Revision: 939838
Log:
Production update by buildbot for activemq
Modified:
websites/production/activemq/content/cache/main.pageCache
websites/production/activemq/content/rest.html
Modified: websites/production/activemq/content/cache/main.pageCache
==============================================================================
Binary files - no diff available.
Modified: websites/production/activemq/content/rest.html
==============================================================================
--- websites/production/activemq/content/rest.html (original)
+++ websites/production/activemq/content/rest.html Wed Feb 11 18:20:57 2015
@@ -81,7 +81,7 @@
<tbody>
<tr>
<td valign="top" width="100%">
-<div class="wiki-content maincontent"><p>ActiveMQ implements a RESTful API to messaging which allows any web capable device to publish or consume messages using a regular HTTP POST or GET.</p><p>If you are interested in messaging directly from web browsers you might wanna check out our <a shape="rect" href="ajax.html">Ajax</a> or <a shape="rect" href="websockets.html">WebSockets</a> support or try <a shape="rect" href="web-samples.html">running the REST examples</a></p><h2 id="REST-MappingofRESTtoJMS">Mapping of REST to JMS</h2><p>To publish a message use a HTTP POST. To consume a message use HTTP DELETE or GET.</p><p>ActiveMQ has a Servlet that takes care of the integration between HTTP and the ActiveMQ dispatcher.</p><p><span style="color: rgb(255,153,0);">NOTE: The example below requires servlet mapping on the URL. For posting without mapping, see examples further down.</span></p><p>You can map a URI to the servlet and then use the relative part of the URI as the topic or queue n
ame. e.g. you could HTTP POST to</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<div class="wiki-content maincontent"><p>ActiveMQ implements a RESTful API to messaging which allows any web capable device to publish or consume messages using a regular HTTP POST or GET.</p><p>If you are interested in messaging directly from web browsers you might wanna check out our <a shape="rect" href="ajax.html">Ajax</a> or <a shape="rect" href="websockets.html">WebSockets</a> support or try <a shape="rect" href="web-samples.html">running the REST examples</a></p><h2 id="REST-MappingofRESTtoJMS">Mapping of REST to JMS</h2><p>To publish a message use a HTTP POST. To consume a message use HTTP DELETE or GET.</p><p>ActiveMQ has a Servlet that takes care of the integration between HTTP and the ActiveMQ dispatcher.</p><p><span style="color: rgb(255,153,0);">NOTE: The example below requires servlet mapping on the URL. For posting without the servlet mapping, see examples further down.</span></p><p>You can map a URI to the servlet and then use the relative part of the URI as the topi
c or queue name. e.g. you could HTTP POST to</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="theme: Default; brush: java; gutter: false" type="syntaxhighlighter"><![CDATA[http://www.acme.com/orders/input
]]></script>
</div></div><p>which would publish the contents of the HTTP POST to the orders.input queue on JMS. </p><p>Similarly you could perform a HTTP DELETE GET on the above URL to read from the same queue. In this case we will map the MessageServlet from ActiveMQ to the URI</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
@@ -99,7 +99,13 @@
<param-value>false</param-value>
</init-param>
</servlet>]]></script>
-</div></div><h3 id="REST-Timeouts">Timeouts</h3><p>When reading from a queue we might not have any messages. We can use a timeout query parameter to indicate how long we are prepared to wait for a message to arrive. This allows us to poll or block until a message arrives.</p><p>Couple this with HTTP 1.1 keep-alive sockets and pipeline processing we can have efficient access to JMS over HTTP.</p><p>Obviously if your client is Java then using ActiveMQ's JMS API is the fastest and most efficient way to work with the message broker; however, if you are not using Java or prefer the simplicity of HTTP then it should be fairly efficient, especially if your HTTP client supports keep-alive sockets and pipeline processing.</p><h3 id="REST-Consuming">Consuming</h3><p>When consuming messages using the REST API, you have to keep session alive between GET requests, or you'll create a separate consumer for every request and due to prefetch limit your succeeding call will hang.</p><p>For example, y
ou can use <code>wget</code> to consume messages, like this:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+</div></div><h4 class="p1" id="REST-AlternateProducingSyntax"><span class="s1">Alternate Producing Syntax</span></h4><p class="p1"><span class="s1">An alternative syntax for posting is supported, using the destination URL-encoded parameter; here are some examples:</span> </p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="theme: Default; brush: java; gutter: false" type="syntaxhighlighter"><![CDATA[# Send to queue orders.input:
+curl -XPOST -d "body=message" http://admin:admin@localhost:8161/api/message?destination=queue://orders.input
+
+# Send to topic orders.input:
+curl -XPOST -d "body=message" http://admin:admin@localhost:8161/api/message?destination=topic://orders.input]]></script>
+</div></div><h3 id="REST-Timeouts">Timeouts</h3><p>When reading from a queue we might not have any messages. We can use a timeout query parameter to indicate how long we are prepared to wait for a message to arrive. This allows us to poll or block until a message arrives.</p><p>Couple this with HTTP 1.1 keep-alive sockets and pipeline processing we can have efficient access to JMS over HTTP.</p><p>Obviously if your client is Java then using ActiveMQ's JMS API is the fastest and most efficient way to work with the message broker; however, if you are not using Java or prefer the simplicity of HTTP then it should be fairly efficient, especially if your HTTP client supports keep-alive sockets and pipeline processing.</p><h4 class="p1" id="REST-Consuming"><span style="font-size: 16.0px;line-height: 1.5625;">Consuming</span></h4><p>When consuming messages using the REST API, you have to keep session alive between GET requests, or you'll create a separate consumer for every request and due
to prefetch limit your succeeding call will hang.</p><p>For example, you can use <code>wget</code> to consume messages, like this:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="theme: Default; brush: java; gutter: false" type="syntaxhighlighter"><![CDATA[wget --user admin --password admin --save-cookies cookies.txt --load-cookies cookies.txt --keep-session-cookies http://localhost:8161/api/message/TEST1?type=queue
]]></script>
</div></div><p>Also, if you plan to have multiple consumer using REST, it's advisable to set prefetch size to 1 so all consumers have an equal chance of getting the message. You can do that by passing a special parameter to the <code>MessageServlet</code></p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
@@ -113,7 +119,13 @@
</init-param>
</servlet>
]]></script>
-</div></div><p>in the <code>webapps/demo/WEB-INF/web.xml</code></p><h3 id="REST-Consumingwithoutsessions">Consuming without sessions</h3><p>Since 5.2.0 you can use <code>clientId</code> parameter to avoid storing actual JMS consumer in the request session. When using this approach, you don't need to keep sessions alive between requests, you just need to use the same <code>clientId</code> every time.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+</div></div><p>in the <code>webapps/demo/WEB-INF/web.xml</code></p><h4 class="p1" id="REST-AlternateConsumingSyntax"><span class="s1">Alternate Consuming Syntax</span></h4><p class="p1"><span class="s1">As with producing, an alternative syntax for consuming messages is also supported, using the destination URL-encoded parameter; here are some examples:</span> </p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="theme: Default; brush: java; gutter: false" type="syntaxhighlighter"><![CDATA[# Send to queue orders.input:
+curl -XGET http://admin:admin@localhost:8161/api/message?destination=queue://orders.input
+
+# Send to topic orders.input:
+curl -XGET http://admin:admin@localhost:8161/api/message?destination=topic://orders.input]]></script>
+</div></div><h4 class="p1" id="REST-Consumingwithoutsessions"><span style="font-size: 16.0px;line-height: 1.5625;">Consuming without sessions</span></h4><p>Since 5.2.0 you can use <code>clientId</code> parameter to avoid storing actual JMS consumer in the request session. When using this approach, you don't need to keep sessions alive between requests, you just need to use the same <code>clientId</code> every time.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="theme: Default; brush: java; gutter: false" type="syntaxhighlighter"><![CDATA[wget --user admin --password admin http://localhost:8161/api/message/test?type=queue&clientId=consumerA
]]></script>
</div></div><p>Every such call will use the same JMS consumer and deliver messages send to it by the broker.</p><p>In 5.4.1 it's also possible to unsubscribe the client. It's done by sending a POST call with <code>clientId</code> and <code>action=unsubscribe</code> parameters to the server, like</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
@@ -127,7 +139,9 @@
<param-value>activemq-selector</param-value>
</context-param>
]]></script>
-</div></div><p>For more info, take a look at <a shape="rect" class="external-link" href="http://fisheye6.atlassian.com/browse/activemq/trunk/activemq-web-demo/src/test/java/org/apache/activemq/web/RestTest.java?r=HEAD" rel="nofollow">RestTest</a></p><h3 id="REST-ContentTypes">Content Types</h3><p>By default messages are sent to the consumers with <code>text/xml</code> content type. Your REST-based application may expect JSON response instead of XML one. In that case, you can configure the servlet to send responses back by adding something like this</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+</div></div><p>For more info, take a look at <a shape="rect" class="external-link" href="http://fisheye6.atlassian.com/browse/activemq/trunk/activemq-web-demo/src/test/java/org/apache/activemq/web/RestTest.java?r=HEAD" rel="nofollow">RestTest</a></p><h3 id="REST-ConsumingwithOneShotConsumers">Consuming with One Shot Consumers</h3><p>One shot consumption allows a REST call to receive a single message and then immediately close the associated consumer.</p><p>All of the examples so far lead to the servlet creating and holding on to consumers of the destination across multiple HTTP requests. Without care, these consumers could easily lead to confusion as messages are dispatched to them but then sit unused because the consuming HTTP session, or clientId, fails to connect to continue requesting the messages. One way around that problem is the use of one-shot consumers.  Simple add the <code>?oneShot=true</code> option and the consumer is removed once the consumption completes; a
s follows:</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="theme: Default; brush: java; gutter: false" type="syntaxhighlighter"><![CDATA[curl -XGET http://admin:admin@localhost:8161/api/message?destination=queue://orders.input&oneShot=true]]></script>
+</div></div><p>Note that interrupting the call while the consumer is waiting for a message, the consumer may remain until the server times out the HTTP request, or until a message finally arrives.</p><h3 id="REST-ContentTypes">Content Types</h3><p>By default messages are sent to the consumers with <code>text/xml</code> content type. Your REST-based application may expect JSON response instead of XML one. In that case, you can configure the servlet to send responses back by adding something like this</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
<script class="theme: Default; brush: java; gutter: false" type="syntaxhighlighter"><![CDATA[ <servlet>
<servlet-name>MessageServlet</servlet-name>
<servlet-class>org.apache.activemq.web.MessageServlet</servlet-class>