Overview of Mulesoft's Expression Filter. Presentation Includes sample code and output. Includes sample Mule expressions which can be used. Overview of Use cases

1. Using Expression Filter
- By Rahul Kumar

2. Expression Filter
Expression Filter filters against a range of expressions
Accepts Mule Expressions which results in boolean value
Lets the messages pass through the filter only if the expression is evaluated
to true otherwise it drops it silently.

3. Configuration
Expression : Accepts Mule Expressions which results in boolean value
nullReturnsTrue parameter : Returns True if the expression provided is Null

4. Sample Expressions
1. #[payload.endsWith('!!')]
2. #[message.inboundProperties['http.query.params']['priority'] > 2]
3. #[payload.endsWith('!!') &&
message.inboundProperties['http.query.params']['priority'] > 2]

5. Sample Flow
<http:listener-config name="HTTP_Listener_Configuration1" host="0.0.0.0"
port="8081" doc:name="HTTP Listener Configuration"/>
<flow name="filtersFlow">
<http:listener config-ref="HTTP_Listener_Configuration1" path="/filter"
doc:name="HTTP"/>
<logger message="HTTP Listener invoked" level="INFO"
doc:name="Logger"/>
<object-to-string-transformer doc:name="Object to String"/>
<expression-filter expression="#[payload.endsWith('!!') &amp;&amp;
message.inboundProperties['http.query.params']['priority'] &gt; 2]"
doc:name="Expression"/>
<set-payload value="#['Filter Passed']" doc:name="Set Payload"/>
</flow>

6. Sample Flow Contd..
Expression used is :
#[payload.endsWith('!!') && message.inboundProperties['http.query.params']['priority'] > 2]
Which means that it will allow the Mule Message to pass through it only if
Payload contains “!!” at the end and has Query parameter “priority” of value
more than 2

7. Sample Flow Test 1,2
Result : Does not Passes the
Expression Filter
Result : Does not Passes the
Expression Filter

8. Sample Flow Test 3
TH
Result : Passes the Expression Filter

9. Thank You !