256 character limitation in REST API response

[bhartig]

In an attempt to use jBPM console REST API to query the process variable values of a particular process instance, the variable value appears to get truncated when it reaches 256 characters. For example, when we make a call /history/instance/{procInstId: [0-9]+}/{oper: [a-zA-Z]+}"), the content within <value> appears to be limited to 256 characters.

<variable-instance-log id="1635">

---

<value>

<?xml version="1.0" encoding="UTF-8"?><RequestStatusSummary RequestLabel="Post-Action"><RequestActionName>Commission VM</RequestActionName><RequestStatusDescription>Completed</RequestStatusDescription></RequestStatusSummary>

</value>

----

</variable-instance-log>

It would be of great help to know if it is a known limitation or if there is any other way to look at the full value of a process variable using REST API?

[ctkcin]

I think you need to update server configuration.

For Jboss7, add below to standalone.xml

    <system-properties>

        <property name="org.apache.tomcat.util.http.Parameters.MAX_COUNT" value="10000"/>

    </system-properties>

[swiderski.maciej]

What version of jbpm do you use?

please check the hint above and if this is still an issue please file jira for it.

HTH

[bhartig]

I am using jBPM6.0.0.CR2.

I tried adding org.apache.tomcat.util.http.Parameters.MAX_COUNT property but that did not seem to change the behavior. The process variable value is still getting truncated after 256 characters.

[swiderski.maciej]

could you check with newer version available in jboss maven repository? Final is about to be released so you can wait day or two to get that checked on final.

HTH

[bhartig]

It still appears to be an issue in jBPM 6.0.0.Final also. The process variable value is getting truncated after 256 characters. It would be of great help to know if there is any other way to look at the process variable values such that it is not truncated after 256 characters.

[swiderski.maciej]

Actually this is a limitation of the audit component (VariableInstanceLog entity) that saves only up to 255 characters for history purpose. You might want to file a jira for this to remove that limitation. In meantime (with v6) if you embed jbpm in your system you can override that behavior by implementing extension of the VariableInstanceLog and then providing implementation of AuditEventBuilder.

HTH

[bhartig]

Thanks for your confirming this limitation. I have already filed a jira for it at https://issues.jboss.org/i#browse/JBPM-4221. Since we are not embedding jbpm in our solution, so we probably have to wait until it gets fixed.

[cegi]

Hi Maciej,

looks like the REST API is not really functional, my team is trying to promote jbpm inside our company but we need to be able to create our own custom front-end web applications.

Can I create a pull request for this on GitHub? It would be my first, though.

Thanks.

[swiderski.maciej]

Carlos, what do you mean is not really functional?

and when it comes to pull requests, it's more than welcome to receive pull requests so go ahead, please file a jira issue for any pull request you submit.

HTH

[cegi]

Maciej,

Besides this character limitation I ran into another issue, the REST API documentation reads: "Except for the Execute calls, all other REST calls described below can use either JAXB or JSON" but I tried the rest/task/query call like this:

http://localhost:8080/jbpm-console/rest/task/query?potentialOwner=krisv

and it will not return the correct information when you ask for JSON. This is not a show stopper like the character limitation but I just wanted to know if the documentation is incorrect. I'm using 6.0.0.final

Thanks

[swiderski.maciej]

Carlos,

please file a jira issue for the wrong response for json content over REST.

when it comes to character limitation, why do you see it as show stopper? The history of the variable is not intended to be use to recreated the object but more like informational what has happened. Limitation is actually due to the default column size for varchar columns. Although we plan to make it configurable where you can decide yourself if the data base that you use allows to store bigger content and you have configured database properly.

HTH

[cegi]

Maciej,

I tried different REST calls and could only get truncated process variables.

What is the right REST call to use?

Thank you for your help, really appreciated.

[swiderski.maciej]

when it comes to variable history that is true, it can store only up to 255 characters at the moment. We consider to remove (make it configurable) so you can change how much data you would like to store in the variable history log.

Could you elaborate on the use case that you have in mind that this limitation is causing issues?

HTH

[cegi]

I'm creating a basic AngularJS client application.We want to provide a custom UI for our users and keep jbpm-console for design, repository, runtime, etc.

I tried using the "withvars" process REST call but I get truncated values for variables containing long strings or lists of strings. For instance I keep a list of employee names involve in a document sign off workflow, I want to show this list to the user but it gets truncated.

What is the right approach for this?

Thank you.