Documentation updates
This commit is contained in:
Mark Fisher
@@ -1,43 +1,99 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
|
||||
<chapter id="resources">
|
||||
<title>HttpInvoker</title>
|
||||
<chapter id="httpinvoker">
|
||||
<title>HttpInvoker Support</title>
|
||||
|
||||
<section id="http-intro">
|
||||
<section id="httpinvoker-intro">
|
||||
<title>Introduction</title>
|
||||
<para>
|
||||
HttpInvoker is a Spring-specific remoting option that essentially enables Remote Procedure Calls (RPC) over HTTP.
|
||||
In order to accomplish this, an outbound representation of a method invocation is serialized using standard Java
|
||||
serialization and then passed within an HTTP POST request. After being invoked on the target system, the method's
|
||||
return value is then serialized and written to the HTTP response. There are two main requirements. First, you
|
||||
must be using Spring on both sides since the marshalling to and from HTTP requests and responses is handled by
|
||||
the client-side invoker and server-side exporter. Second, the Objects that you are passing must implement
|
||||
<interfacename>Serializable</interfacename> and be available on both the client and server.
|
||||
</para>
|
||||
<para>
|
||||
While traditional RPC provides <emphasis>physical</emphasis> decoupling, it does not offer nearly the same degree
|
||||
of <emphasis>logical</emphasis> decoupling as a messaging-based system. In other words, both participants in an
|
||||
RPC-based invocation must be aware of a specific interface and specific argument types. Interestingly, in Spring
|
||||
Integration, the "parameter" being sent is a Spring Integration Message, and the interface is an internal detail
|
||||
of Spring Integration's implementation. Therefore, the RPC mechanism is being used as a
|
||||
<emphasis>transport</emphasis> so that from the end user's perspective, it is not necessary to consider the
|
||||
interface and argument types. It's just another adapter to enable messaging between two systems.
|
||||
</para>
|
||||
</section>
|
||||
|
||||
<section id="http-outbound">
|
||||
<title>Outbound HttpInvoker</title>
|
||||
<section id="httpinvoker-inbound">
|
||||
<title>HttpInvoker Inbound Gateway</title>
|
||||
<para>
|
||||
To receive messages over http you need to use an <classname>HttpInvokerInboundGateway</classname>. Here is an
|
||||
example bean definition:
|
||||
<programlisting language="xml"><![CDATA[<bean id="inboundGateway" class="org.springframework.integration.httpinvoker.HttpInvokerInboundGateway">
|
||||
<property name="requestChannel" ref="requestChannel"/>
|
||||
<property name="replyChannel" ref="replyChannel"/>
|
||||
<property name="requestTimeout" value="30000"/>
|
||||
<property name="replyTimeout" value="10000"/>
|
||||
</bean>]]></programlisting>
|
||||
Because the inbound gateway must be able to receive HTTP requests, it must be configured within a Servlet
|
||||
container. The easiest way to do this is to provide a servlet definition in <emphasis>web.xml</emphasis>:
|
||||
<programlisting language="xml"><![CDATA[<servlet>
|
||||
<servlet-name>inboundGateway</servlet-name>
|
||||
<servlet-class>org.springframework.web.context.support.HttpRequestHandlerServlet</servlet-class>
|
||||
</servlet>]]></programlisting>
|
||||
Notice that the servlet name matches the bean name.
|
||||
<note>
|
||||
If you are running within a Spring MVC application and using the BeanNameHandlerMapping, then the servlet
|
||||
definition is not necessary. In that case, the bean name for your gateway can be matched against the URL
|
||||
path just like a Spring MVC Controller bean.
|
||||
</note>
|
||||
</para>
|
||||
</section>
|
||||
|
||||
<section id="httpinvoker-outbound">
|
||||
<title>HttpInvoker Outbound Gateway</title>
|
||||
<para>
|
||||
</para>
|
||||
<para>
|
||||
To configure the outbound gateway write a bean definition like this:
|
||||
<programlisting language="xml"><![CDATA[]]>
|
||||
</programlisting>
|
||||
To configure the <classname>HttpInvokerOutboundGateway</classname> write a bean definition like this:
|
||||
<programlisting language="xml"><![CDATA[<bean id="outboundGateway" class="org.springframework.integration.httpinvoker.HttpInvokerOutboundGateway">
|
||||
<property name="replyChannel" ref="replyChannel"/>
|
||||
</bean>]]></programlisting>
|
||||
The outbound gateway is a <interfacename>MessageConsumer</interfacename> and can therefore be registered with
|
||||
either a <classname>PollingConsumerEndpoint</classname> or <classname>SubscribingConsumerEndpoint</classname>.
|
||||
The URL must match that defined by an inbound HttpInvoker Gateway as described in the previous section.
|
||||
</para>
|
||||
</section>
|
||||
|
||||
<section id="http-inbound">
|
||||
<title>Inbound HttpInvoker</title>
|
||||
<para>
|
||||
To receive messages over http you need to use a <classname>TODO</classname>. This gateway can be configured like this
|
||||
<programlisting language="xml"><![CDATA[]]>
|
||||
</programlisting>
|
||||
</para>
|
||||
</section>
|
||||
|
||||
<section id="http-namespace">
|
||||
<title>HttpInvoker namespace support</title>
|
||||
<section id="httpinvoker-namespace">
|
||||
<title>HttpInvoker Namespace Support</title>
|
||||
<para>
|
||||
Spring Integration provides an "httpinvoker" namespace and schema definition. To include it in your
|
||||
configuration, simply provide the following URI within a namespace declaration:
|
||||
'http://www.springframework.org/schema/integration/httpinvoker'. The schema location should then map to
|
||||
'http://www.springframework.org/schema/integration/httpinvoker/spring-integration-httpinvoker-1.0.xsd'.
|
||||
</para>
|
||||
<para>
|
||||
To configure the inbound gateway you can choose to use the namespace support for it. The following code snippet shows the different configuration options that are supported.
|
||||
<programlisting language="xml"><![CDATA[]]></programlisting>
|
||||
<programlisting language="xml"><![CDATA[<httpinvoker:inbound-gateway id="inboundGateway"
|
||||
request-channel="requestChannel"
|
||||
request-timeout="10000"
|
||||
expect-reply="false"
|
||||
reply-timeout="30000"/>]]></programlisting>
|
||||
<note>
|
||||
A 'reply-channel' may also be provided, but it is recommended to rely on the temporary anonymous channel
|
||||
that will be created automatically for handling replies.
|
||||
</note>
|
||||
</para>
|
||||
<para>
|
||||
To configure the outbound gateway you can use the namespace support as well. The following code snippet shows the different configuration for an outbound HttpInvoker gateway.
|
||||
<programlisting language="xml"><![CDATA[]]></programlisting>
|
||||
To configure the outbound gateway you can use the namespace support as well. The following code snippet shows the different configuration for an outbound HttpInvoker gateway. Only the 'url' and 'request-channel' are required.
|
||||
<programlisting language="xml"><![CDATA[<httpinvoker:outbound-gateway id="outboundGateway"
|
||||
url="http://localhost:8080/example"
|
||||
request-channel="requestChannel"
|
||||
request-timeout="5000"
|
||||
reply-channel="replyChannel"
|
||||
reply-timeout="10000"/>]]></programlisting>
|
||||
</para>
|
||||
</section>
|
||||
</chapter>
|
||||
Reference in New Issue
Block a user