Is there a Java client for the REST API?

ieugen · September 10, 2019, 12:00am

Hello,

I was wondering if there is a Java client for the REST API?
I am trying to make type safe calls.

From my knowledge it should be possible to have a JAX-RS client. If there isn’t one yet, do you know if it is possible to reuse the annotations used on the server side?

https://docs.jboss.org/resteasy/docs/4.3.0.Final/userguide/html/RESTEasy_Client_Framework.html

Thanks,
Eugen

Miklas · September 10, 2019, 7:47am

Hi @ieugen,

apart from the external task client (which is a REST client for parts of the API), there is no official Java client. There is a project aiming to integrate swagger with the REST API, however, I think this is not up-to-date. You can find it on GitHub: https://github.com/camunda/camunda-bpm-swagger

Also, have a look into this topic.

Cheers,
Miklas

zambrovski · October 1, 2019, 9:59pm

Please have a look on a new project, just started:

Simon

falko.menge · November 19, 2019, 5:36pm

The following example shows how to run Java Delegates as External Task implementations:
Java Process Application for a Remote Camunda BPM Engine

@zambrovski The following classes might be helpful for your project as well:

github.com

camunda-consulting/code/blob/master/snippets/remote-process-engine/src/main/java/com/camunda/bpm/demo/remote_process_engine/SimpleVariableScope.java

package com.camunda.bpm.demo.remote_process_engine;

import java.util.Collections;
import java.util.List;
import java.util.Map;

import org.camunda.bpm.engine.impl.core.variable.CoreVariableInstance;
import org.camunda.bpm.engine.impl.core.variable.scope.AbstractVariableScope;
import org.camunda.bpm.engine.impl.core.variable.scope.SimpleVariableInstance;
import org.camunda.bpm.engine.impl.core.variable.scope.SimpleVariableInstance.SimpleVariableInstanceFactory;
import org.camunda.bpm.engine.impl.core.variable.scope.VariableInstanceFactory;
import org.camunda.bpm.engine.impl.core.variable.scope.VariableInstanceLifecycleListener;
import org.camunda.bpm.engine.impl.core.variable.scope.VariableStore;

/**
 * Simple VariableScope implementation that can be initialized with a Map and
 * provides all variable methods required for implementing a DelegateExecution.
 *
 * @author Falko Menge (Camunda)
 */

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github.com

camunda-consulting/code/blob/master/snippets/remote-process-engine/src/main/java/com/camunda/bpm/demo/remote_process_engine/AbstractExternalTaskDelegateExecution.java

package com.camunda.bpm.demo.remote_process_engine;

import java.util.Map;

import org.camunda.bpm.engine.ProcessEngine;
import org.camunda.bpm.engine.ProcessEngineServices;
import org.camunda.bpm.engine.RepositoryService;
import org.camunda.bpm.engine.delegate.DelegateExecution;
import org.camunda.bpm.engine.runtime.Incident;
import org.camunda.bpm.model.bpmn.BpmnModelInstance;
import org.camunda.bpm.model.bpmn.instance.FlowElement;

/**
 * Abstract DelegateExecution that can be used for as base for DelegateExecution
 * implementations for executing a JavaDelegate as part of an External Task.
 * 
 * It contains all methods that have to be implemented with additional REST API
 * calls or wrapper classes that emulate the Camunda Java API. 
 *
 * @author Falko Menge (Camunda)

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zambrovski · December 5, 2019, 11:56am

Feel free to contribute / start a discussion via issue…

falko.menge · July 14, 2020, 2:29pm

OpenAPI support is available since Camunda 7.13: https://docs.camunda.org/manual/latest/reference/rest/openapi/

It covers the following features: https://docs.camunda.org/manual/latest/reference/rest/openapi/#coverage

Here is an example Java client for OpenAPI: https://twitter.com/falko_menge/status/1283045391123058694

zambrovski · July 16, 2020, 10:14pm

The advantage of the Camunda REST client Spring-Boot over the generated API is that it is an implementation of the Camunda Java API (and not a generated client from the REST API). So in using the https://camunda.github.io/camunda-rest-client-spring-boot/ extension you don’t have to distinguish between local API call and remote API call.

The disadvantage is currently the poor coverage - only a small part is implemented yet, and we are looking for you as contributors or/and for feature request / priorisation.