Access uploaded file in Groovy Script

[jvaidya]

I'm trying to Base64 encode a file that a user uploads in an Activiti form, and then save the resulting encoding as a string to be accessed by other parts of the business process. I thought a Groovy Script in a Script task would be the best way to do this. How do I access the file in the script? 

Would something like: 

execution.getVariable('file'); 

give me access to the raw file? 

Thanks!

[gdharley]

Nope, When you upload a file it is registered as related content (Enterprise Edition) or as an attachment (Community Edition).

You will need to use the relatedContentService to retrieve the uploaded files for the process instance (Enterprise Edition).
More details here:  

if using Community Edition you can get to the attachments you use taskService.getTaskAttachments(taskid).

This will return a list of atachments from which you can retrieve the content.

Greg

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[jvaidya]

Thanks Greg! Very helpful! I tried calling the API from a Script Task, but I can't use jQuery or vanilla JavaScript AJAX calls. The error I get from Activiti is: 

Caused by: <eval>:5 ReferenceError: "XMLHttpRequest" is not defined

How do I access this API if I can't use XML Http Requests? 

EDIT: I tried following this : What is the best way to call REST API from Activiti? Can I use JavaScript's URL redirection?  but I get an "'importPackage' is not defined" error. 

[gdharley]

Hi Jay,

Script tasks actually run on the server side, even though they use Javascript (via embedded Nashorn/Rhino engine) or groovy.

Therefore you dont need to access the Ajax request.

Look up script tasks here: Activiti User Guide - Script Task 

[jvaidya]

How do I access the file using relatedContentService? The link you pointed me to in the original answer uses REST API calls, so I got a little confused! Sorry about that. 

Can you point me to the documentation for relatedContentService? 

[gdharley]

Unfortunately there is no documentation on related content service.
You can check for example use here:
 

Greg

[jvaidya]

Hi Greg,

Can you do something like this in a script task, or would you have to use a service task? The example you pointed me to seems to use Java, but script tasks can only take JavaScript or Groovy, correct? 

Thanks,

Jay

[gdharley]

Yes, it is java code, but if you set the script task language to groovy then you can effectively write java code in a script task.

Obviously if the code is complex you would use a service task, but for simple things like pulling the instance/task attachments it is only a few lines of code (<10) so a script task if ok.
The only real downside to a script task is the fact that you cannot debug your code and dont have the toot support you would have with a java IDE.

Greg

[jvaidya]

Thanks Greg. I'm a little lost without documentation, so not sure how to use relatedContentService. Would something like this work? 

fileVar = "content"

file = relatedContentService.getFieldContentForProcessInstance( execution.getProcessInstanceId(), fileVar, 1, 0).getContent(); <- what format would file be in and what methods of relatedContentService do I use? 

is = file.getStream() <- Another questionable line 
val = is.read()
output = ""
while(val != -1){
output += val
}
execution.setVariable('raw', output)

[gdharley]

Try this in a groovy script task.

import com.activiti.service.runtime.RelatedContentService;
import com.activiti.service.runtime.RelatedContentStreamProvider;
import com.activiti.domain.runtime.RelatedContent;
import java.io.InputStream;
import org.apache.commons.io.IOUtils;
import java.nio.charset.StandardCharsets;

String fileVariableName = "myFile";
List<RelatedContent> contentList = relatedContentService.getFieldContentForProcessInstance(execution.getProcessInstanceId(), fileVariableName, 1, 0).getContent();
RelatedContent content = contentList.get(0);
out.println("GDH :" + content.getName());
InputStream is = relatedContentStreamProvider.getContentStream(content);
String result = IOUtils.toString(is, StandardCharsets.UTF_8);
out.println("GDH:" + result);

Apologies but ALfresco has not documented any of these services.

Greg

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