How can I find if URI parameter exists in Mule? - mule

Question

I want to check if a URI parameter exists in the URL using Mule 3.8.3 and also need to make sure that inboundProperties is not empty either when using the Choice component in Anypoint Studio 6.2 and Mule 3.8.3.
I have tried:
#[message.inboundProperties.'http.uri.params'.code != empty]
#[org.mule.util.StringUtils.isNotEmpty(message.inboundProperties.'http.uri.params'.code)]
For both I get
org.mule.api.expression.ExpressionRuntimeException: Execution of the
expression
"org.mule.util.StringUtils.isNotEmpty(message.inboundProperties.'http.query.params'.code)"
failed.
Is there any other way to try?

Answer 1

There are two "Expression" in palate.
1.Expression-transformer
Example : <expression-transformer expression="#[message.inboundProperties.'http.uri.params'.param != empty]" doc:name="Expression"/>
2.Expression-component
Example : <expression-component doc:name="Expression"/>
Make sure you use "Expression-transformer" as shown below
Try below flow in Anypoint Studio.It works for me.
<http:listener-config name="HTTP_Listener_Configuration" host="0.0.0.0" port="8082" basePath="/testapi" doc:name="HTTP Listener Configuration"/>
<flow name="uri">
<http:listener path="uri/{param}/resource" config-ref="HTTP_Listener_Configuration" doc:name="HTTP"/>
<expression-transformer expression="#[message.inboundProperties.'http.uri.params'.param != empty]" doc:name="Expression"/>
<object-to-string-transformer doc:name="Object to String"/>
<set-payload value="#[payload]" doc:name="Set Payload"/>
</flow>
Test above with below url in your browser
http://localhost:8082/testapi/uri/testUriParam/resource
This could be used with Choice component component as well.
Try below code :
<http:listener-config name="HTTP_Listener_Configuration" host="0.0.0.0" port="8082" basePath="/testapi" doc:name="HTTP Listener Configuration"/>
<flow name="uri">
<http:listener path="uri/{param}/resource" config-ref="HTTP_Listener_Configuration" doc:name="HTTP"/>
<choice doc:name="Choice">
<when expression="#[message.inboundProperties.'http.uri.params'.param != empty]">
<logger message="Found URI Param" level="INFO" doc:name="Logger"/>
<set-payload value="Found URI Param" doc:name="Set Payload"/>
</when>
<otherwise>
<logger level="INFO" doc:name="Logger" message="URI Param not found"/>
<set-payload value="URI Param not found" doc:name="Set Payload"/>
</otherwise>
</choice>
</flow>