<Mule - DataWeave> Reference to variables where the variable name is dynamic - mule

Hi I would like to seek for assistance for a DataWeave usage scenario.
I need to check if a variable for a card name exists (the card name is dynamic and cannot forsee beforehand).
If the variable already exists, then append current payload to that card name variable;
Else create the variable with the current payload
The problem is I do not have idea on how to refer to a variable with dynamic name.
I can save the current card name to a variable say "cardName", but how can I refer to the variable in DataWeave code afterwards?
Pseudoly below is what I would like to achieve
May I seek for advice on the way to achieve it?

You can access the vars using below notation
vars[dynamic variable]
As I do not know how your flow looks like and assuming you have a payload,
{
"data": [
{
"cardName": "cardName1",
"dataToMap": "first data"
},
{
"cardName": "cardName2",
"dataToMap": "2nd data"
},
{
"cardName": "cardName1",
"dataToMap": "2nd data for card name 1"
}
]
}
You can loop through the payload.data (using for each) and you can map it as
%dw 2.0
output application/java
var varName = payload.cardName
---
if (vars[varName] != null)
vars[varName] ++ "** **" ++ payload.dataToMap
else
payload.dataToMap
and have a set variable with name set with #[****] to dynamically choose the variable.
End result of this will have two vars with name cardName1 and cardName2 and their corresponding value will be "first data** **2nd data for card name 1" and "2nd data", respectively.

Here is an example flow of dynamically naming variables using a Set Variable component inside a For-Each loop.
This is a good way to persist data after the For-Each loop exits, since the payload resets to the payload before the For-Each scope is called.
<mule xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd">
<flow name="dynamic-varsFlow" >
<scheduler doc:name="Scheduler" >
<scheduling-strategy >
<fixed-frequency frequency="10000"/>
</scheduling-strategy>
</scheduler>
<set-payload value='#[output application/json
var someInput = {
"data": [
{
"cardName": "cardName1",
"dataToMap": "first data"
},
{
"cardName": "cardName2",
"dataToMap": "2nd data"
},
{
"cardName": "cardName1",
"dataToMap": "2nd data for card name 1"
}
]
}
---
someInput.data]' doc:name="Set Payload" />
<foreach doc:name="For Each" >
<set-variable value='#[output application/json
var varName = payload.cardName as String
---
(if (vars[varName] != null)
vars[varName] ++ "** **" ++ payload.dataToMap
else
payload.dataToMap
)]' doc:name="Set Variable" variableName="#[payload.cardName]"/>
</foreach>
<foreach doc:name="Copy_of_For Each" >
<logger level="INFO" doc:name="Logger"
message="#[output application/json --- {varName: payload.cardName, varValue: vars[payload.cardName]}]"/>
</foreach>
</flow>
</mule>
`
Here are the log messages for each of the dynamically named vars inside the second For-Each loop. Notice there are two new vars dynamically named from the initial Set Payload data. In a more real-world flow, the payload would be read from the output of the Event Source, such as from an HTTP Connector or DB Connector:
Here is the payload and vars after the second For-Each scope is exited. The payload reverts back to it's initial value, but the changes made inside the first For-Each scope persist in the two vars:

You should use a Java map instead and use cardName as the key.

ok i might have not understood the ask 100% but i did a pretty simple flow to illustrate setting a variable dynamically if that variable doesnt exist. hope that helps you upto some extent. Here is how my complete flow looks like
in the set payload i am setting a dummy payload:
in the transform message next i declared a variable card which doesnt exists until then as you can see in the flow
and finally in the last set payload i am setting the payload with whatever vars.card hold
and i get the response back when i test my API
now if you want to dynamically declare the variable name with some value i believe that can be done too.

Related

how to reuse the xpr file in Mule 4

In my case, I'm doing a migration from Mule 3 to Mule 4.
This flow, which includes transformers like DOM to XML, XML to DOM, and an expression component, needs to be migrated.
In Mule 4, I want to reuse the xrp file.
My flow for XML payload transform uses an XPR file by the expression component in Mule 3.
<flow name="rate-dtostepFlow">
<http:listener config-ref="HTTP_Listener_Configuration" path="/dtostep" allowedMethods="POST" doc:name="HTTP"/>
<mulexml:xml-to-dom-transformer returnClass="org.dom4j.Document" doc:name="XML to DOM"/>
<set-variable variableName="domPayload" value="#[payload]" doc:name="set domPayload "/>
<expression-component file="xpr/responseStubCannasure.xpr" doc:name="Expression"/>
<mulexml:dom-to-xml-transformer doc:name="DOM to XML"/>
</flow>
Input XML: https://github.com/Manikandan99/rate-dtostep/blob/master/request.xml
Output XML: https://github.com/Manikandan99/rate-dtostep/blob/master/response.xml
my MULE 3 application : https://github.com/Manikandan99/rate-dtostep/tree/master/rate-dtostep
ResponseStubcannsure xpr file:
import org.dom4j.*;
import java.util.*;
import java.util.logging.Logger;
Logger logger = Logger.getLogger("");
dtoCoverageStepsNodes = flowVars.domPayload.selectNodes("//DTOCoverage[#Status=\'Active\']/DTOSteps");
for (Node node : dtoCoverageStepsNodes){
//logger.info("inside: detach");
node.detach();
}
dtoCoverageNodes = flowVars.domPayload.selectNodes("//DTOCoverage[#Status=\'Active\']");
int i = 500;
for (Node node : dtoCoverageNodes){
//node.detach();
//logger.info("inside: assign prem");
node.addAttribute("FullTermAmt", Integer.toString(i));
node.addElement("DTOSteps");
stepNode = node.selectSingleNode("DTOSteps");
stepNode.addElement("DTOStep")
.addAttribute("Order","1")
.addAttribute("Name","Final Premium")
.addAttribute("Desc","Final Premium Desc")
.addAttribute("Operation","=")
.addAttribute("Factor",Integer.toString(i))
.addAttribute("Value",Integer.toString(i));
i+=1;
}
The xpr file transform the xml payload in the following ways:
updated the value of the DTOStep node.
The attribute value of DTOStep is autoincremented from 500 each time.
Please assist me.
You need to migrate the complete flow to Mule 4. The file responseStubCannasure.xpr is just a script in MEL (Mule 3 expression language). The extension is irrelevant, it could have been anything. MEL is very similar to Java so you could reuse the logic by encapsulating it into a Java class. You will need to add to the Java code the conversion to DOM4J from the input XML because Mule 4 doesn't support it. Probably is slightly easier to migrate the MEL script to a Groovy script because the basic syntax is very similar and both support scripts. Migrating to Java is just taking the additional steps of encapsulating the script into a method of a class and defining explicitly the types for variables.
Alternatively you could just delete the last 4 operations of the flow and replace them with a DataWeave transformation. Using a recursive function to navigate the keys and value recursively, using a condition to check if we are in the element DTOCoverage, with attribute Status == "Active" and then replace the nested element with the DTOSteps/DTOStep combination. Which is what your script does.
Example:
%dw 2.0
output application/xml
var startingValue=500
fun transformSteps(x, index)=
x filterObject ($$ as String != "DTOSteps") ++
{
DTOSteps: DTOStep #(Order:1, Factor: index + startingValue, Value: index + startingValue, Name:"Final Premiun", Operation:"=", Desc: "Final Premium Desc"): null
}
fun transformCoverage(x, index)=
{
val: x match {
case is Object -> x mapObject
if ($$ as String == "DTOCoverage" and $$.#Status == "Active")
{
DTOCoverage #(( $$.# - "FullTermAmt" ), FullTermAmt: $$$ + startingValue):
transformSteps($, index)
}
else
(($$): transformCoverage($, index+1))
else -> $
},
index: index
}
---
transformCoverage(payload,1).val
This solution doesn't completely resolve the Value and Factor (why two attributes with the same value?) sequential increase. You may need to do an additional transformation, or use Groovy or Java code to renumber them.

Convert the values in .csv file to json format in a data weave based on the parameter in lookup function which is calling from another data weave

How to use the lookup function in data weave(1.0) which calls a flow with some parameters. Flow functionality is to convert the values in the .csv file to JSON based on the parameter in the lookup function.
The lookup fucntion docs are here:
https://docs.mulesoft.com/mule-runtime/3.9/dataweave-language-introduction
You pass in the payload as the second parameter as a Map (object):
%dw 1.0 %output application/json
---
{ a: lookup("mySecondFlow",{b:"Hello"}) }
Here is a Mule flow that can accept this object with the 'b' key:
<flow name="mySecondFlow">
<set-payload doc:name="Set Payload" value="#[payload.b + ' world!' ]"/>
</flow>
This example will produce this output:
{
"a": "Hello world!"
}

Substitute values in payload

I have an XML Message with two parameters in it which I use to call a REST service endpoint. However, if any of them are a certain value I would like to change them before my call, for example
<Interface Server="ABC" Server2="DEF"/>
If any of those have the value "ABC" it should always be replaced with "BC" and in my call to the REST service I would send param1="BC" and param2="DEF" in the above example.
I was thinking of a Choice router and check if Server is "ABC" then set a flow-variable param1="BC" but then I realized I would have to do the same again for Server2 if that one is "ABC" ...and that feels like.. it must be an easier way to achieve this?
Am I right? Could I use some clever MEL or XPATH3 expression to always substitue the values to "BC" if any of them are "ABC"?
Regards
You can try the following configuration:
<enricher doc:name="Message Enricher">
<dw:transform-message doc:name="Transform Message">
<dw:set-payload><![CDATA[%dw 1.0
%output application/java
%var evaluation = "ABC"
%var substitution = "BC"
%function substitute(serverVal)(
serverVal when serverVal != evaluation otherwise substitution
)
---
payload.Interface.# mapObject {
($$): substitute($)
}
]]></dw:set-payload>
</dw:transform-message>
<enrich source="#[payload.Server]" target="#[variable:param1]"/>
<enrich source="#[payload.Server2]" target="#[variable:param2]"/>
</enricher>
Regardless how many attribute in your XML source, you just need to add the enricher element accordingly.
For example, you have a new XML source: <Interface Server="ABC" Server2="DEF" Server3="ABC"/>
Then you only need to add: <enrich source="#[payload.Server3]" target="#[variable:param3]"/> to set the new variable.
Notes: DataWeave is one of the EE features. For CE, you can replace it with other transformer, for example: Groovy. In the example below, the payload is in form of String. The original application/xml format is transformed to String using byte-array-to-string-transformer.
<scripting:component doc:name="Groovy">
<scripting:script engine="Groovy"><![CDATA[def attributeMap = new XmlSlurper().parseText(payload).attributes()
attributeMap.each() {
it.value = it.value == "ABC" ? "BC" : it.value
}
payload = attributeMap]]></scripting:script>
</scripting:component>

If else condition checking in Mule Expression component not storing out session Variable?

I'm trying to do simple if else condition in expression component. After expression component I have logger. My query here is I'm not able to see the test1 but can able to view temp value in logger component. Why?
Same time, if I print test1 value in system.out.println. Getting the value, but why not in logger?.
<quartz:inbound-endpoint responseTimeout="10000" doc:name="Quartz" connector-ref="Quartz" jobName="Feedjob" repeatInterval="36000000" >
<quartz:event-generator-job groupName="Feedjob" jobGroupName="Feedjob"/>
</quartz:inbound-endpoint>
<s3:list-objects config-ref="Amazon_S3" doc:name="Amazon S3" bucketName="${amazon.BucketName}" prefix="master"/>
<foreach doc:name="For Each">
<set-variable variableName="TestValue" value="#[payload.getKey()]" doc:name="Variable"/>
<expression-component doc:name="Expression"><![CDATA[
sessionVars.temp = message.outboundProperties['MULE_CORRELATION_SEQUENCE'] ;
if ( sessionVars.temp == "2"){
sessionVars.test1 = sessionVars.temp ;
System.out.println(sessionVars.test1);
return message.payload;
}
else{
System.out.println(" No test");
return message.payload;
}
]]></expression-component>
<logger message="Payload**********temp:#[sessionVars.temp] test1: #[sessionVars.test1]" level="INFO" doc:name="Logger"/>
</foreach>
<logger message="Outside For each logger**********temp:#[sessionVars.temp] test1: #[sessionVars.test1]" level="INFO" doc:name="Logger"/>
It seems to be once after payload returning from expression component sessionVars.temp is set, but sessionVars.test1 diaappears. It is strange. Where I'm wrong?
Two ways to fix this:
use #[sessionVars['test1']] instead of #[sessionVars.test1] while accessing session variables.
declare the session variable sessionVars.test1=""; before the if block
The issue seems to be with the way variables are accessed with . operator. It only happens when the variable is declared in a component which doesn't create those variables the first time (in your case, the test1 variable is created only in the second foreach iteration and not in the first). If your condition had been if ( sessionVars.temp == "1"), you wouldn't face this issue.
Apparently mule had already fixed this in latest versions, 3.7 seems to be working as expected. I had the same issue in 3.5.
I tried to recreate your scenario in following way :-
<set-property propertyName="MULE_CORRELATION_SEQUENCE" value="2" doc:name="Property"/>
<expression-component doc:name="Expression"><![CDATA[
sessionVars.temp = message.outboundProperties['MULE_CORRELATION_SEQUENCE'] ;
if ( sessionVars.temp == "2"){
sessionVars.test1 = sessionVars.temp ;
System.out.println(sessionVars.test1);
return message.payload;
}
else{
System.out.println(" No test");
return message.payload;
}
]]></expression-component>
and I am able to get the value in logger :- INFO 2015-08-06 09:19:48,556 [[testcon].HTTP_Listener_Configuration1.worker.01] org.mule.api.processor.LoggerMessageProcessor: Payload**********temp:2 test1: 2
Make sure your outbound property MULE_CORRELATION_SEQUENCE is not null or contains value

Facing issue while convering json data into xml : mule esb

I tried to convert my json data into xml format. But Only half of data is convert into xml.
My payload is
{"orders":[{"orderName":"Laptop","price":34000,"Date":"2014/01/12","Type":"DELL","stock":52,"code":"152666AS"},
{"orderName":"Chip","price":345,"Date":"2014/02/20","Type":"DELL","stock":50,"code":"152666AW"},
{"orderName":"Laptop1","price":35000,"Date":"2015/02/13","Type":"DELL1","stock":51,"code":"152666AX"}]}
But in output I got only one json item
<?xml version='1.0'?>
<orders>
<orderName>Laptop</orderName>
<price>34000</price>
<Date>2014/01/12</Date>
<Type>DELL</Type>
<stock>52</stock>
<code>152666AW</code>
</orders>
My flow is as follow
<flow name="testFlow">
<http:listener config-ref="HTTP_Quickbook" path="/" doc:name="HTTP"/>
<connector-test:my-processor config-ref="ConnectorTest__Configuration_type_strategy" content="APP" doc:name="ConnectorTest"/>
<json:json-to-xml-transformer mimeType="application/json" doc:name="JSON to XML"/>
<logger message="#[payload]" level="INFO" doc:name="Logger"/>
</flow>
I need whole json string in xml format . What I have to change?
I tested with creating custom transformer.. My custom transformer is as follow
InputStream input = new FileInputStream(new File("test.json"));
OutputStream output = System.out;
XMLInputFactory inputFactory = XMLInputFactory.newInstance();
inputFactory.setProperty(XMLInputFactory.IS_COALESCING, true);
XMLEventReader reader = inputFactory.createXMLEventReader(input);
XMLOutputFactory outputFactory = new JsonXMLOutputFactory();
outputFactory.setProperty(JsonXMLOutputFactory.PROP_PRETTY_PRINT, true);
XMLEventWriter writer = outputFactory.createXMLEventWriter(output);
writer = new XMLMultipleEventWriter(writer, false,"/orders");
writer.add(reader);
reader.close();
writer.close();
Now I got following error
com.ctc.wstx.exc.WstxUnexpectedCharException: Unexpected character '{' (code 123) in prolog; expected '<'
at [row,col {unknown-source}]: [1,1]
How to solve this?
i can suggest you one thing to make your requirement to work.
if you are want to generate the xml from json.
do the below
add set-payload component to you flow explicitly specify the value as
{"root":#[payload]}
it will work and i could able to generate the xml data out of the sample data you pasted.
please do try and post your status
Your issue comes from the transformation of the array of orders that fails and returns only one entry.
Behind the scene, the json:json-to-xml-transformer uses Staxon for XML to JSON transformation. Here is the doc on array transformation in Staxon: https://github.com/beckchr/staxon/wiki/Mastering-Arrays
We can see in the Mule source that PROP_MULTIPLE_PI is false and PROP_AUTO_ARRAY is not set to true, therefore only one item of the array is considered, the others are dropped.
So the best is for you to write your own transformer either using Staxon too, configured with the array handling settings you want, or using Groovy XML Markup builder to generate the XML in a nice and easy way.
For what you're looking for json
{
"ocs:price": {
"#exponent": "-1",
"#text": "2"
}
}
That's the format to convert for example that from JSON to XML like this :
<ocs:price exponent="-1">2</ocs:price>
In java/groovy script I used something like this to convert it
import net.sf.json.JSON
import net.sf.json.JSONSerializer
import net.sf.json.xml.XMLSerializer
String str = '''{
"ocs:price": {
"#exponent": "-1",
"#text": "2"
}
}'''
JSON json = JSONSerializer.toJSON( str )
XMLSerializer xmlSerializer = new XMLSerializer()
xmlSerializer.setTypeHintsCompatibility( false )
String xml = xmlSerializer.write( json )
System.out.println(xml)