REST API : Start an instance providing the key (not the id)

[othmann]

Hi everyone,

  First of all, congratulations for the nice work behind Activiti.

  I need to use the REST API to start a process instance. I chose to use the process definition key instead of the process definition id, so as to start automatically the latest version of the process. It is made clear in the user guide that we can make a POST request on /process-instance with :

{
  "processDefinitionKey":"financialReport:1",
  "businessKey":"order-4711"
}‍‍‍‍‍

   However, the engine keeps telling me :

{
    "status" : 
  {
    "code" : 400,
    "name" : "Bad Request",
    "description" : "Request sent by the client was syntactically incorrect."
  },  
  
  "message" : "02230006 Parameter 'processDefinitionId' is missing",  
  "exception" : "org.springframework.extensions.webscripts.WebScriptException - 02230006 Parameter 'processDefinitionId' is missing",
  
  "callstack" : 
  [ 
       ""      ,"org.springframework.extensions.webscripts.WebScriptException: 02230006 Parameter 'processDefinitionId' is missing"
      ,"org.activiti.rest.util.ActivitiRequest.checkObject(ActivitiRequest.java:383)"
      ,"org.activiti.rest.util.ActivitiRequest.checkString(ActivitiRequest.java:367)"
      ,"org.activiti.rest.util.ActivitiRequest.getMandatoryString(ActivitiRequest.java:291)"
      ,"org.activiti.rest.api.process.ProcessInstancePost.executeWebScript(ProcessInstancePost.java:45)"
      ,"org.activiti.rest.util.ActivitiWebScript.executeImpl(ActivitiWebScript.java:68)"
      ,"org.springframework.extensions.webscripts.DeclarativeWebScript.execute(DeclarativeWebScript.java:64)"
      ,"org.springframework.extensions.webscripts.PresentationContainer.executeScript(PresentationContainer.java:69)"
      ,"org.springframework.extensions.webscripts.AbstractRuntime.executeScript(AbstractRuntime.java:333)"
      ,"org.springframework.extensions.webscripts.AbstractRuntime.executeScript(AbstractRuntime.java:189)"
      ,"org.springframework.extensions.webscripts.servlet.WebScriptServlet.service(WebScriptServlet.java:118)"
      ,"javax.servlet.http.HttpServlet.service(HttpServlet.java:717)"
      ,"org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)"
      ,"org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)"
      ,"org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)"
      ,"org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)"
      ,"org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)"
      ,"org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)"
      ,"org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)"
      ,"org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)"
      ,"org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)"
      ,"org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)"
      ,"org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)"
      ,"java.lang.Thread.run(Thread.java:662)"
 
  ],
  
  "server" : "Spring WebScripts - v1.0.0 (Release Candidate 2 660) schema 1,000",
  "time" : "23-Mar-2011 15:59:36"
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

  When I use the processDefinitionId attribute, it works fine. Any idea ?

Thanks,
Othman

[frederikherema1]

Strange, the code does actually check if the processDefinitionKey is available. If not, the ID is mandatory:

org.activiti.rest.api.process.ProcessInstancePost:41

    String processDefinitionKey = req.getString("processDefinitionKey");
    String processDefinitionId = null;
    if (processDefinitionKey==null) {
      processDefinitionId = req.getMandatoryString(obj, "processDefinitionId");
    }

Are you sure you typed "processDefinitionKey" correct.?

[hrabe]

The problem could be

String processDefinitionKey = req.getString("processDefinitionKey");

public String getString(String param) {
    return checkString(req.getParameter(param), param, false);
}
is called on ActivitiRequest

whereas


processDefinitionId = req.getMandatoryString(obj, "processDefinitionId");

public String getMandatoryString(ActivitiRequestObject obj, String param) {
    return checkString(obj.getString(param), param, true);
}

is called on ActivitiRequestObject

[othmann]

Yes, it works when you give processDefinitionKey as a POST parameter (and not in the JSON body as written in the user guide). But the other parameters still have to be in the JSON body, which, of course, is weird.

Should I report a bug issue ?

[frederikherema1]

Yes, go ahead

[othmann]

Done : http://jira.codehaus.org/browse/ACT-737

[lucassouza1]

I had the same problem and it was solved adding a header content type to application/json

[gumba]

Hi Lucasousa1
I want to do the same but I keep getting error, see my code.
Could you give more tips on how did you managed to do this?
I have this code:
import org.apache.commons.io.IOUtils;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.AuthCache;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.protocol.ClientContext;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.auth.BasicScheme;
import org.apache.http.impl.client.BasicAuthCache;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;

public class RestAPI {

/**
  * @param args
  */
public static void main(String[] args) {
  try {
   // TODO Auto-generated method stub
   DefaultHttpClient client = new DefaultHttpClient();
        client.getCredentialsProvider().setCredentials(new AuthScope("localhost", 8080),
            new UsernamePasswordCredentials("kermit", "kermit"));
                
        // Create AuthCache instance
        AuthCache authCache = new BasicAuthCache();
        // Generate BASIC scheme object and add it to the local auth cache
        BasicScheme basicAuth = new BasicScheme();
        authCache.put(new HttpHost("localhost", 8080, "http"), basicAuth);

        // Add AuthCache to the execution context
        BasicHttpContext localcontext = new BasicHttpContext();
        localcontext.setAttribute(ClientContext.AUTH_CACHE, authCache);
        HttpPost postMethod = new HttpPost("http://localhost:8080/activiti-rest/service/process-instance");
     
           postMethod.setEntity(new StringEntity("{\"processDefinitionKey\":\"MailSender\"}", "UTF-8"));
           HttpResponse response = client.execute(postMethod, localcontext);
           System.out.println(IOUtils.toString(response.getEntity().getContent()));
           client.getConnectionManager().shutdown();
        } catch (Exception e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
        }
 
       
       
}

}

<html>
<head>
   <title>Status page</title>
</head>
<body style="font-family: sans-serif;">
<p style="font-size: 1.2em;font-weight: bold;margin: 1em 0px;">Internal Server Error</p>
<p>Failed to retrieve the process definition parameters</p>
<p>You can get technical details <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.1">here</a>.<br>
Please continue your visit at our <a href="/">home page</a>.
</p>
</body>
</html>