BPMN REST tasks allow you to invoke rest endpoints within your BPMN processes. This can be achieved by adding a Service Task and handling the REST invocation part in a level implementation. BPS has provided this functionality out of the box to avoid the hassle of doing implementations by process developers.
Adding a REST task to a process
To add a REST task, you need to add a Java task in place of the process where you need to do the invocation.
Pre-requisite
This guide demonstrates adding a REST task using the Eclipse BPMN Designer. Use the update site, to add this plugin to your eclipse. You can do the same in any other editor by adding the same property values.
- Add a “Service task” from the tools palette in the place where you need to invoke the endpoint.
- Go to the properties panel of Service Task and open the main config tab.
- Select Java Task as the Task Type
Add the following fields with names, under the Documentation section by clicking the New button.
Field Name String Value Expression serviceURL <REST ENDPOINT URL> method HTTP method (GET or POST only) outputVariable Name of the variable to save response basicAuthUsername Username if the endpoints are secured basicAuthPassword Password for the username above input Request payload headers header values in the format "headerName1:headerValue1,headerName2:header Value2"
The following code block provides an example service task definition to use as the REST task.
<serviceTask id="servicetask1" name="REST task1" activiti:class="org.wso2.carbon.bpmn.extensions.rest.RESTTask">
<extensionElements>
<activiti:field name="serviceURL">
<activiti:expression>http://10.0.3.1:9773/restSample1_1.0.0/services/rest_sample1/${m ethod}
</activiti:expression>
</activiti:field>
<activiti:field name="basicAuthUsername">
<activiti:expression>bobcat</activiti:expression>
</activiti:field>
<activiti:field name="basicAuthPassword">
<activiti:expression>bobcat</activiti:expression>
</activiti:field>
<activiti:field name="method">
<activiti:string>
<![CDATA[POST]]>
</activiti:string>
</activiti:field>
<activiti:field name="input">
<activiti:expression>Input for task1</activiti:expression>
</activiti:field>
<activiti:field name="outputVariable">
<activiti:string>
<![CDATA[v1]]>
</activiti:string>
</activiti:field>
<activiti:field name="headers">
<activiti:string>
<![CDATA[key1:value1,key2:value2]]>
</activiti:string>
</activiti:field>
</extensionElements>
</serviceTask>