HTTP protocol

Feature description

HTTP form-based remote invocation protocol, implemented by Spring’s HttpInvoker, supported by versions above 2.3.0.

• Number of connections: multiple connections
• Connection method: short connection
• Transmission protocol: HTTP
• Transmission method: synchronous transmission
• Serialization: form serialization
• Scope of application: The size of incoming and outgoing parameter data packets is mixed, the number of providers is more than that of consumers, it can be viewed with a browser, and parameters can be passed in by form or URL, and file transfer is not supported for now.
• Applicable scenarios: services that need to be used by both application and browser JS.

Constraints

• Parameters and return values must conform to the Bean specification

scenes to be used

HTTP short connection, standardized and easy-to-read protocol, easy to connect to external systems, suitable for upper-level business modules.

How to use

Starting from Dubbo 3, the Http protocol is no longer embedded in Dubbo, and an independent module needs to be introduced separately.

<dependency>
    <groupId>org.apache.dubbo.extensions</groupId>
    <artifactId>dubbo-rpc-http</artifactId>
    <version>1.0.0</version>
</dependency>

Configuration protocol

<dubbo:protocol name="http" port="8080" />

Configure Jetty Server (default)

<dubbo:protocol ... server="jetty" />

Configure Servlet Bridge Server (recommended)

<dubbo:protocol ... server="servlet" />

Configure DispatcherServlet

<servlet>
         <servlet-name>dubbo</servlet-name>
         <servlet-class>org.apache.dubbo.remoting.http.servlet.DispatcherServlet</servlet-class>
         <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
         <servlet-name>dubbo</servlet-name>
         <url-pattern>/*</url-pattern>
</servlet-mapping>

If a servlet is used to dispatch the request

• The protocol port <dubbo:protocol port="8080" /> must be the same as the port of the servlet container,
• The context path of the protocol <dubbo:protocol contextpath="foo" /> must be the same as the context path of the servlet application.