Iterating an array using Mule's foreach scope - foreach

Question

I would like to iterate through an array and use the value taken from the array to put it within an http inbound endpoint. How would I be able to iterate through this array and take the value from the array to place it as a variable within the http inbound endpoint?
The code that I used to try was:
<flow name="foreachFlow1" doc:name="foreachFlow1">
<poll frequency="2000">
<foreach collection="#[groovy:['localhost:8082', 'localhost:8083']]"
doc:name="For Each">
<http:outbound-endpoint exchange-pattern="request-response"
address="http://#[payload]" method="GET" doc:name="HTTP" />
</foreach>
</poll>
</flow>
and I get the error
Invalid content was found starting with element 'poll'

Answer 1

Inbound endpoints are message sources and can not be parametrized the way you're describing.
To achieve your goal, trying a <poll> message source to wrap a foreach that uses http:outbound-endpoint to perform GET (#method) request-response (#exchange-apttern) interactions.
The trick is to bring the results for the HTTP calls back through the foreach, which by default do not do it. The following illustrate a potential approach:
<flow name="foreachFlow1">
<poll frequency="2000">
<processor-chain>
<set-variable variableName="httpResponses" value="#[[]]" />
<foreach collection="#[groovy:['localhost:8082', 'localhost:8083']]">
<http:outbound-endpoint
exchange-pattern="request-response" address="http://#[payload]"
method="GET" />
<expression-component>httpResponses.add(message.payloadAs(java.lang.String))
</expression-component>
</foreach>
</processor-chain>
</poll>
<logger level="INFO" message="#[httpResponses]" />
</flow>
<!-- Test server stubs -->
<flow name="server8082">
<http:inbound-endpoint exchange-pattern="request-response"
address="http://localhost:8082" />
<set-payload value="This is 8082" />
</flow>
<flow name="server8083">
<http:inbound-endpoint exchange-pattern="request-response"
address="http://localhost:8083" />
<set-payload value="This is 8083" />
</flow>