ServiceMix HTTP

ServiceMix HTTP

HTTP

HTTP is the World Wide Web (www) protocol for information exchange. HTTP is based on character-oriented streams and is firewall-friendly. Hence, we can also exchange XML streams (which are XML encoded character streams) over HTTP.

In a web service we exchange XML in the SOAP (Simple Object Access Protocol) format over HTTP. Hence, the HTTP headers exchanged will be slightly different than a normal web page interaction. A sample web service request header is shown as follows:

GET /AxisEndToEnd/services/HelloWebService?WSDL HTTP/1.1
User-Agent: Java/1.6.0-rc
Host: localhost:8080
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
POST /AxisEndToEnd/services/HelloWebService HTTP/1.0
Content-Type: text/xml; charset=utf-8
Accept: application/soap+xml, application/dime, multipart/related,
text/*
User-Agent: Axis/1.4
Host: localhost:8080
Cache-Control: no-cache
Pragma: no-cache
SOAPAction: ""
Content-Length: 507

The first line contains a method, a URI and an HTTP version, each separated by one or more blank spaces. The succeeding lines contain more information regarding the web service exchanged.

ESB-based integration heavily leverages the HTTP protocol due to its open nature, maturity, and acceptability. We will now look at the support provided by the ServiceMix in using HTTP.

ServiceMix's servicemix-http

Binding external web services at the ESB layer can be done in multiple ways but the best way is to leverage JBI components such as the servicemix-http component within ServiceMix. We will look in detail at how to bind the web services onto the JBI bus.

servicemix-http in Detail

servicemix-http is used for HTTP or SOAP binding of services and components into the ServiceMix NMR. For this ServiceMix uses an embedded HTTP server based on the Jetty.

In Chapter 3, you have already seen the following two ServiceMix components:

• org.apache.servicemix.components.http.HttpInvoker
• org.apache.servicemix.components.http.HttpConnector

As of today, these components are deprecated and the functionality is replaced by the servicemix-http standard JBI component. A few of the features of the servicemix-http are as follows:

• Supports SOAP 1.1 and 1.2
• Supports MIME with attachments
• Supports SSL
• Supports WS-Addressing and WS-Security
• Supports WSDL-based and XBean-based deployments
• Support for all MEPs as consumers or providers

Since servicemix-http can function both as a consumer and a provider, it can effectively replace the previous HttpInvoker and HttpConnector component.