How do check if the variable exist in Mule 3.2?
How create or replace a variable?
My Flow Exception is
<choice doc:name="Choice">
<when expression="#[myVar==null]">
<processor-chain>
<set-variable variableName="myVar" value="value1" doc:name="myVar"/>
</processor-chain>
</when>
<otherwise>
<processor-chain>
<set-variable variableName="myVar" value="#[variable:myVar]" doc:name="myVar"/>
</processor-chain>
</otherwise>
</choice>
"myVar==null" does not work
if the variable is an invocation variable please try
flowVars['myVar'] == null
Worst case scenario you could do:
message.getProperty('myVar', org.mule.api.transport.PropertyScope.INVOCATION).
Please notice the scope is an enum so you should provide the canonical in a MEL expression.
HTH
You can use this MEL to print in log or use in Choice component
#[message.invocationProperties('myVar')] == null
There is a component "Message Property" which will help you remove or replace or create Mule message properties. You should use that to perform your operation.
To best find it use keyword "propert" in the search of pallets in the Mule studio and explore the various components there to suit your needs.
Related
I have two queries
Suppose if I declared two variables inside a forEach like flowVars.ABC and flowVars.DEF, how can I access those 2 variables outside that forEach block?
And each variable has a JSON payload, how can I add those 2 variable's data into single JSON payload?
Can anyone assist me? I unable to access the variables inside of foreach and adding 2 JSON.
This is my sample code
<flow name="test">
<foreach doc:name="For Each">
<scatter-gather doc:name="Scatter-Gather">
<set-variable variableName="ABC" value="#[payload]" mimeType="application/json" doc:name="ABC"/>
<set-variable variableName="DEF" value="#[payload]" mimeType="application/json" doc:name="DEF"/>
</scatter-gather>
</foreach>
<set-payload value="#[flowVars.ABC + flowVars.DEF]" mimeType="application/json" doc:name="adding 2 vars"/>
</flow>
You need to understand how scoping works with foreach. Any variables set inside the foreach scope will NOT be available outside of that scope. However, variables set outside of the foreach scope (e.g. a set-variable before the foreach) will be available inside the foreach scope. This should help you get around your issue. I'm taking out the scatter-gather because it really doesn't serve any purpose in your example:
<flow name="test">
<set-variable variableName="ABC value="#[payload] mimeType="application/json" doc:name="ABC"/>
<set-variable variableName="DEF value="#[payload] mimeType="application/json" doc:name="DEF"/>
<foreach doc:name="For Each">
<set-variable variableName="ABC" value="#[payload]" mimeType="application/json" doc:name="ABC"/>
<set-variable variableName="DEF" value="#[payload]" mimeType="application/json" doc:name="DEF"/>
</foreach>
<set-payload value="#[flowVars.ABC ++ flowVars.DEF]" mimeType="application/json" doc:name="adding 2 vars"/>
</flow>
Beyond this, I'm not sure if your code is a simplification or not, but as it stands now there are a couple things that are questionable:
Why are you using a scatter-gather? If you don't really need to do multiple things asynchronously (like making calls to multiple services), it's just a complication in your code. Setting two vars doesn't qualify, in my opinion.
What is your code supposed to do? From my perspective it looks like you're just setting the payload to a duplicate of the last element in the original payload. If so you could just do this in a transformer:
%dw 2.0
output application/json
---
if (not isEmpty(payload))
payload[-1] ++ payload[-1]
else
[]
I want to perform some string operation on MEL I have following expression in MEL
<logger message="#[json:xy/PID/xy.3/AC]" level="INFO" doc:name="Logger"/>
OUTPUT IS
19901026000000
I want to extract 1st 4 digit then 6,7 digit .
How can I do this ??
Thanks
What about trying it in two steps?
<set-variable variableName="result" value="#[json:ADT_A01/PID/PID.3/CX.1]" />
<set-variable variableName="result" value="#[result.substring(0,4)]#[result.substring(5,7)]" />
As noted in the comments in #Ryan Hoegg answer, the JSON expression evaluator has been deprecated since Mule 3.3 and hence the best way to do this would be to use a json to object transformer
<json:json-to-object-transformer doc:name="JSON to Object" returnClass="java.util.HashMap"/>
and then use conventional MEL to traverse the Map
JsonPath expression are depreciated for now and you will even not get enough document on it for doing ..
So, currently you need to use either :- <json:json-to-object-transformer returnClass="java.lang.Object" doc:name="JSON to Object" />
or <json:json-to-object-transformer returnClass="java.util.HashMap" doc:name="JSON to Object" />
or even <json:json-to-object-transformer returnClass="java.util.List" doc:name="JSON to Object" /> to extract data from JSON depending on the JSON data
I'm not sure, how can we extract the flow-name and message-processor Name through MEL. For example I have multiple message processor. For logging, i need to extract the flow Name and Message-processor, so that I can find out transaction has crossed this particular flow and its message processor. Is there any simple way to find out. Please guide me. Please find the screenshot below. Here i need to Extract - set payload and its flowName (flow1)
Thanks in advance.
For mule 3.8+ version onwards #[flow.name] don't work.
Use #[mule:context.serviceName] expression in logger or component to extract the name of the flow
I know this post is old but I have been trying to find a way to do this in MEL for error handling emails.
For the flow name you can use #[exception.event.flowConstruct.name]
for the failing message processor you can use #[exception.failingMessageProcessor].
Both of these work in MEL without the need to use an flowVar.
Please note however, that the failing processor does not always come back with a value but comes back with null, I'm not sure why.
You can extract the flow-name with MEL : #[flow.name]
<flow name="name" doc:name="name">
<http:inbound-endpoint address="http://localhost:8090/resources" doc:name="HTTP" />
<logger message="name of flow: #[flow.name]" level="INFO" doc:name="Logger"/>
<set-payload value="name" doc:name="Set Payload"/>
</flow>
or
flowConstruct.getName() in a Message Processor
Two ways to acthive this (from current flow name)
First one is -
<logger message="Current flowName: #[flow.name]" level="INFO" doc:name="Logger"/>
and the second one is -
<logger message="Current flowName: #[context:serviceName]" level="INFO" doc:name="Logger"/>
I have a flow where I want to evealuate an expression on the smtp subject attribute but always get mvel parse expression though the logger give me the right values.
<json:object-to-json-transformer doc:name="Object to JSON"/>
<logger message="MYRequestPayloadID #[json:RequestPayloadID] #[json:ResponseStatusCd]" level="DEBUG" doc:name="Logger"/>
<smtp:outbound-endpoint host="${mail.host}" to="${mail.to}" from="${mail.from}" subject="Error Response for PayloadID #[json:RequestPayloadID], Status #[json:ResponseStatusCd]" responseTimeout="10000" doc:name="SMTP />
I am not sure why in the subject #[json:RequestPayloadID] and #[json:ResponseStatusCd] evaluation fail though I get the data back in the logger . Thanks.
Expressions are not supported everywhere in Mule (alas): this is one place where it isn't.
You have to use message properties to set the subject dynamically:
<set-property propertyName="subject"
value="Error Response for PayloadID #[json:RequestPayloadID], Status #[json:ResponseStatusCd]" />
FTR json: is the old expression style, nowadays you should be using MEL instead: http://www.mulesoft.org/documentation/display/current/Mule+Expression+Language+Tips#MuleExpressionLanguageTips-JSONProcessing
I am trying to use a choice router to handle HTTP messages based on their path. This works well until I hit the case where the message is being submitted with a PUT method and the trailing part of the path is the customerID. So I have a path similar to this: services/v1/customer/{custNo}. In the choice router I have:
<choice doc:name="Route Message By Path">
<when expression="message.inboundProperties['http.relative.path'] == 'services/v1/users'">
<flow-ref name="NewUser" doc:name="New User"/>
</when>
<when expression="message.inboundProperties['http.relative.path'] == 'services/v1/users/{userID}'">
<flow-ref name="UpdateUser" doc:name="Update User"/>
</when>
<when expression="message.inboundProperties['http.relative.path'] == 'services/v1/emails'">
<flow-ref name="CaptureEmail" doc:name="Capture Email"/>
</when>
<when expression="message.inboundProperties['http.relative.path'] == 'services/v1/taxes'">
<flow-ref name="Taxes" doc:name="Taxes"/>
</when>
<otherwise>
<logger message="The path submitted is unknown. Submitted path is: #[message.inboundProperties['http.relative.path']]" level="INFO" doc:name="Unknown path"/>
<set-payload value="The path submitted is unknown. Submitted path is: #[message.inboundProperties['http.relative.path']]" doc:name="Set Payload"/>
<http:response-builder status="500" contentType="text/plain" doc:name="HTTP Response Builder"/>
</otherwise>
</choice>
I have this working using rest and annotated java classes but I would rather keep it simple and in mule components if I can. Is there a way to wildcard the path in the MEL for the router? Also, if keeping with using the choice router, is there a good/simple way of extracting the customer number from the path?
For the wildcard, you could use the regex function in your MEL expressions: http://www.mulesoft.org/documentation/display/current/Mule+Expression+Language+Reference
Something like:
<when expression="#[regex('services/v1/users/.*', message.inboundProperties['http.relative.path'])]">
However, I think the apikit and the apikit router might be better suited to your needs as it handles path and method routing and variable templating automatically: http://www.mulesoft.org/documentation/display/current/APIkit+Basic+Anatomy
Or for older versions of Mule maybe the Rest router: http://mulesoft.github.io/mule-module-rest-router/mule/rest-router-config.html