CODEWITHSUNDEEP
wso2
Mewster
Mewster

Reputation: 1063

WSO2 API config, query param to payload factory to json to data service

I'm having a few problems in understanding how to pass a query param to a payload factory that creates a json, and then passing its data to a data service. What I thought would be the correct config is

<payloadFactory media-type="json">
    <format>{"cod_uo" : "$1"}</format>
    <args>
        <arg evaluator="xml" expression="get-property('query.param.id')"/>
    </args>
</payloadFactory>
<log>
    <property expression="json-eval($.cod_uo)" name="string"/>
</log>
<dataServiceCall description="GET operation" serviceName="MyService">
    <operations type="single">
        <operation name="MyOperationName">
            ---> <param evaluator="xml" expression="json-eval('$.cod_uo')" name="cod_uo"/> <-- This Line
        </operation>
    </operations>
    <source type="inline"/>
    <target type="body"/>
</dataServiceCall>

but the system doesn't recognize the json-eval function here. I tried also a direct json evaluation with

<param evaluator="json" name="id" expression="$.cod_uo"/>

but i get a DataServiceCallMediator

Current Request Name: MyOperationName
Current Params: {cod_uo=}
Nested Exception:-
java.lang.NumberFormatException: For input string: ""

What is the correct method to use the 'cod_uo' property of the payload factory payload in a subsequent data service call?

I'm using the latest Integration Studio (8.0.0.202104161647)

The log ALWAYS returns

{api:MyApi:v1.0.0} To: /my/path?id=123, MessageID: urn:uuid:[uuid], correlation_id: [correlation_id], Direction: request, string = 123

All combinations + errors:

<param evaluator="xml" expression="json-eval('$.cod_uo')" name="cod_uo"/>

[2021-07-30 08:50:41,179] ERROR {SynapseXPath} - Evaluation of the XPath expression json-eval('$.cod_uo') resulted in an error org.jaxen.UnresolvableException: No Such Function json-eval

<param evaluator="xml" expression="json-eval($.cod_uo)" name="cod_uo"/>

(doesn't compile: "Invalid XPath expression for attribute expression : json-eval($.cod_uo)"

<param evaluator="json" expression="json-eval('$.cod_uo')" name="cod_uo"/>
<param evaluator="json" expression="json-eval($.cod_uo)" name="cod_uo"/>
<param evaluator="json" expression="$.cod_uo" name="cod_uo"/>


Current Request Name: MyOperationName
Current Params: {cod_uo=}
Nested Exception:-
org.postgresql.util.PSQLException: ERROR: invalid input syntax for integer: ""

<param evaluator="xml" expression="$.cod_uo" name="cod_uo"/>

(doesn't compile: Invalid XPath expression for attribute expression : $.cod_uo)

Upvotes: 0

Views: 700

Answers (1)

Athiththan
Athiththan

Reputation: 2218

Since both Payload Factory mediator and the Data Service Call mediator is in the same sequence, you can make use of the get-property() function to retrieve the value and assign it.

For example,

<param evaluator="json" name="id" expression="get-property('query.param.id')"/>

Furthermore, if you wanted to access the property through json-eval(), I think there has been a typo that is causing the empty value behavior. Please remove the quotes around the key and try the scenario

Update Note: The json-eval() approach didn't solve the problem. But, keeping the following segment as a reference. Look at the Update section to access the payload using XPath expression.

<!-- without single quotes around the $.myId -->
<param evaluator="json" name="id" expression="json-eval($.myId)"/>

Update

You can also try accessing the Payload using XPath expression as following

<param evaluator="xml" name="id" expression="$body//myId"/>

Upvotes: 2

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