How do you accumulate values within a ForEach loop in Mule?

问题

I have the below json output:

{
  "results": [
    {
      "ID": "1",
      "ImageID": "2",
      "Name": "Test1",
      "Owner": "sysadmin",
      "Author": "sysadmin",
      "Creator": "sysadmin"
	},
	{
      "ID": "2",
      "ImageID": "23",
      "Name": "Test2",
      "Owner": "sysadmin",
      "Author": "sysadmin",
      "Creator": "sysadmin"
	}
  ]
}

For each ID in above response, i need to invoke the rest service passing ID as a parameter and the rest service will send me a response back. I have to consolidate all the output into a single json response in mule. I have tried using for each and enricher but could not able to build it. Below is the code which i am using.

 <foreach doc:name="For Each Loop">
  <logger level="INFO" message="#[payload]" doc:name="Logger" category="INFO"/>
            <json:json-to-object-transformer doc:name="JSON to Object"/>
   <enricher doc:name="Message Enricher">
                <http:request config-ref="SAM" path="/abc/#[payload.ID]" method="GET" doc:name="HTTP"/>
<enrich target="#[flowVars.ID]" source="#[payload[0].ID]"/>
 </enricher>
 <logger level="INFO" message="#[flowVars.ID]" doc:name="Logger" />
 <expression-component doc:name="Expression"><![CDATA[payload.ID = flowVars.ID;    ]]></expression-component> 
 </foreach>

Kindly help me with the way to fix this !!

Thanks

回答1:

You need to initialize an empty array before the for-each loop and add to that array within the for-each:

<set-variable variableName="idList" value="#[[]]" doc:name="Variable - Init idList"/>
<foreach doc:name="For Each Loop">
  <logger level="INFO" message="#[payload]" doc:name="Logger" category="INFO"/>
  <json:json-to-object-transformer doc:name="JSON to Object"/>
  <enricher doc:name="Message Enricher">
    <http:request config-ref="SAM" path="/abc/#[payload.ID]" method="GET" doc:name="HTTP"/>
    <enrich target="#[flowVars.ID]" source="#[payload[0].ID]"/>
  </enricher>
  <logger level="INFO" message="#[flowVars.ID]" doc:name="Logger" />
  <expression-component doc:name="Expression"><![CDATA[flowVars.idList.add(flowVars.ID);]]></expression-component> 
</foreach>

I cover this topic in this video.

回答2:

Thanks Jerney !!

I made it working by doing the following:

<set-variable variableName="outputList" value="#[new java.util.ArrayList()]" doc:name="SetEmptyArray"/>
 <foreach collection="json:packshots" doc:name="ForEachDocument">
            <set-variable variableName="docName" value="#[json:Name]" doc:name="docName"/>
            <http:request config-ref="AH_DAM_API_Configuration" path="${ah.dam.api.get.renditions.path}#[json:Name]" method="GET" doc:name="InvokeAHDamService"/>
            <set-payload value="#[xpath3('//*:service/*:document',payload,'NODE')]" doc:name="fetchRenditionInfo"/>
     <expression-transformer expression="#[flowVars.outputList.add(payload)]" doc:name="AppendResponseToArray"/>
 </foreach>

回答3:

I have used from the savedOutput for array variable.

来源：https://stackoverflow.com/questions/52027993/how-do-you-accumulate-values-within-a-foreach-loop-in-mule

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