How to use the response from a ServiceCallout as the response for the Proxy?

[#1]

Hello,

I am implementing something on Edge Proxy. I am working only within "target endpoint". First request is assign message policy and whatever response comes, I parse particular value in response with help of Extract variable policy. Then I use 2 values from extract variable policy and pass it into service callout policy inside <Payload>. and I am changing <Path> here because my target url and service callout policy's path is different. I am providing correct url too in service call out policy in <Target> tag. Now my question is, I need final response is display from service callout policy not the first request sent from assign message policy.

Please guide me how can I use <response> tag of service callout policy too.

Thank you. 🙂

[anilsr]

Dear @Dhwani Trivedi ,

You need to use one more Assign Message policy after your service callout to override response send to client using variable collected in service callout response tag.

[#3]

Thank you @Anil Sagar .

Do you have any example on this either in documentation or http://stackoverflow.com/questions/tagged/apigee ?

Also, I am bit confuse in <Response> tag in service callout policy. Where and where it should helpful? I mean how I can use that and where I can use it? Please guid me.

Thank you.

[anilsr]

@Dhwani Trivedi

, Check examples and documentation here. Basically, Response from service callout is stored in variable mentioned in response tag.

<ServiceCallout name="GeoCodeClient">
    <Request clearPayload="false" variable="GeocodingRequest"/>
    <Response>GeocodingResponse</Response>
    <Timeout>30000</Timeout>
    <HTTPTargetConnection>
      <URL>http://maps.googleapis.com/maps/api/geocode/json</URL>
    </HTTPTargetConnection>
</ServiceCallout>

Response from Google API is stored in , GeocodingResponse variable that you can use in further policies after service callout policy.

One more example here that does mashup of policies.

[#5]

Thank you @Anil Sagar .

I used this in my project this and then after service callout policy I used Extract Variable Policy to display response but, I am getting "Paused" in trace before extract variable policy run. and get response of first request done through assign message policy.

As you suggested me in previous reply, I should use assign message policy after service call out policy right? what make a difference that tI can get final response display is from service call out policy? Could you help me out to understand please?

Thank you.

[DChiesa]

After the ServiceCallout, you have the response in a context variable. you then need to embed THAT response into the proxy response. Do that with another AssignMessage policy.

<AssignMessage name='AssignMessage-CalloutResponse'>
  <AssignTo createNew='false' transport='http' type='response'/>
  <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables>
  <Set>
    <Payload contentType='application/json' variablePrefix='%' variableSuffix='#'>%GeocodingResponse#</Payload>
    <StatusCode>200</StatusCode>
    <ReasonPhrase>OK</ReasonPhrase>
    <Headers>
      <Header name='xxx'>whatever you like</Header>
       ....
    </Headers>
    ...
  </Set>
</AssignMessage>

[#7]

Hello @Anil Sagar & @Dino

As you guided me, I added Assign message policy after service call out policy but, I am getting this below error in trace. This error come when service call out police comes in the picture.

Please see the attachment and guide me if you know.

Thank you.

[adas]

@Dhwani Trivedi

I didn't have access to your proxy source code, so I can't really tell what's going on there. Looks like there's an EOF exception in your service callout. Probably something is not configured correctly in your service callout policy.

I created a simple proxy with a service callout and javascript which does the same thing as above. You can use this for your use-case of populating the service callout response and proxy response. Please find the attachment.

[#9]

Thank you @arghya das. I saw your code. I did something like that but, in my service callout policy , I need to send<Request><Set> <Payload>""xyz"} </Payload></Set><Request> as a request json body. And I am providing <Response>newFinalResponse</Response>so, I can extract values using extract variable policy.

[adas]

@Dhwani Trivedi Best practices for service callouts would be to set the request payload, headers etc. in an AssignMessage. Once you have the response in a variable you can do extract variable or any other operations you want. Looking at your trace session, I was not sure if you were using any assign message policy to set the service callout request payload. Here's an example:

<AssignMessage name="AssignServiceCalloutPayload" enabled="true">
<AssignTo type="request">sc_request</AssignTo>
<IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables>
<Copy source="request">
    <Path>false</Path>
  </Copy>
<Remove>
</Remove>
<Add>
      <Headers>
        <Header name="verb">POST</Header>
    </Headers>
    <QueryParams>
        <QueryParam name="test">foobar</QueryParam>
    </QueryParams>
</Add>
<Set>
    <Payload>
        <![CDATA[<s:Envelope
         xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"
         xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"
         xmlns:xsd="http://www.w3.org/1999/XMLSchema">
        <s:Header>
         <m:transaction xmlns:m="soap-transaction" s:mustUnderstand="true">
          <transactionID>00511</transactionID>
         </m:transaction>
        </s:Header>
         <s:Body>
          <m:sayHello xmlns:m='urn:XML_module'>
          <!-- XML Data Structure begins -->
                <DATA_STRUCTURE>
                <DATA name="dataname" value="Hello World!"/>
                </DATA_STRUCTURE>
          <!-- XML Data Structure ends -->
          </m:sayHello>
         </s:Body>
        </s:Envelope>]]>
    </Payload>
    <Verb>GET</Verb>
</Set>
  <AssignVariable>
        <Name>target.copy.pathsuffix</Name>
    <Value>false</Value>
    </AssignVariable>
</AssignMessage>

[#11]

Thank you @arghya das. This is helpful but, I stuck, how can I change my uri path not whole url? and also, this policy comes in the picture at target endpoint response area as a new request and I am trying to display final response is the response that I get from this either Assign Message policy or service callout policy at response target endpoint side.

Please guide me.

[adas]

I am sorry, I don't think I understood your last comment. If I can take a look at your proxy, maybe I can give some guidance.

If I understood your requirement correctly, here's what you want:

- make a service callout with a POST body to a given URL

- get the response, extract certain elements of the response using a extract variable

- you also want to send the service callout response call to the caller as a proxy response

Have I captured your requirements, correctly. If yes, then the proxy that I attached earlier, does exactly that, except that it doesn't have an assign message policy to set the service callout request object (the policy I posted above). If there's anything that you are looking to do beyond this, it would be helpful if you can attach your proxy here so that I can take a look.

[#13]

@arghya das I have used the same javascript code which you attached in the proxy for copying service callout response to the caller as a proxy response but I am getting following javascript error related to the "content" variabale in context.proxyResponse.content = JSON.stringify(originalResponse);

{"fault":{"faultstring":"Execution of PopulateGeocodeResponse failed with error: Javascript runtime error: \"TypeError: Cannot set property \"content\" of undefined to \"{\n \"results\": [\n {\n \"address_components\": [\n {\n \"long_name\": \"123\",\n \"short_name\": \"123\",\n \"types\": [\n \"street_number\"\n ]\n },\n {\n \"long_name\": \"Main Street\",\n \"short_name\": \"Main St\",\n \"types\": [\n \"route\"\n ]\n },\n {\n \"long_name\": \"Rexford\",\n \"short_name\": \"Rexford\",\n \"types\": [\n \"locality\",\n \"political\"\n ]\n },\n {\n \"long_name\": \"Clifton Park\",\n \"short_name\": \"Clifton Park\",\n \"types\": [\n \"administrative_area_level_3\",\n \"political\"\n ]\n },\n {\n \"long_name\": \"Saratoga County\",\n \"short_name\": \"Saratoga County\",\n \"types\": [\n \"administrative_area_level_2\",\n \"political\"\n ]\n },\n {\n \"long_name\": \"New York\",\n \"short_name\": \"NY\",\n \"types\": [\n \"administrative_area_level_1\",\n \"political\"\n ]\n },\n {\n \"long_name\": \"United States\",\n \"short_name\": \"US\",\n \"types\": [\n \"country\",\n \"political\"\n ]\n },\n {\n \"long_name\": \"12148\",\n \"short_name\": \"12148\",\n \"types\": [\n \"postal_code\"\n ]\n },\n {\n \"long_name\": \"1132\",\n \"short_name\": \"1132\",\n \"types\": [\n \"postal_code_suffix\"\n ]\n }\n ],\n \"formatted_address\": \"123 Main St, Rexford, NY 12148, USA\",\n \"geometry\": {\n \"bounds\": {\n \"northeast\": {\n \"lat\": 42.8523593,\n \"lng\": -73.88743330000001\n },\n \"southwest\": {\n \"lat\": 42.8523465,\n \"lng\": -73.8874402\n }\n },\n \"location\": {\n \"lat\": 42.8523593,\n \"lng\": -73.88743330000001\n },\n \"location_type\": \"RANGE_INTERPOLATED\",\n \"viewport\": {\n \"northeast\": {\n \"lat\": 42.8537018802915,\n \"lng\": -73.8860877697085\n },\n \"southwest\": {\n \"lat\": 42.8510039197085,\n \"lng\": -73.88878573029152\n }\n }\n },\n \"partial_match\": true,\n \"place_id\": \"EiMxMjMgTWFpbiBTdCwgUmV4Zm9yZCwgTlkgMTIxNDgsIFVTQQ\",\n \"types\": [\n \"street_address\"\n ]\n }\n ],\n \"status\": \"OK\"\n}\" (geocoderesponse_js#2). at line 2 \"","detail":{"errorcode":"steps.javascript.ScriptExecutionFailed"}}}

[#14]

@raghavendra: Hi Arghya Das I have replicated the code given in 'service-callout-rev2-2015-09-10.zip' ,but I am getting null response.I have created everything as suggested in the example.

Here are the details .

Proxy.xml:ServiceCalloutwithJavascript

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <APIProxy revision="1" name="ServiceCalloutwithJavascript"> <Basepaths>/servicecalloutwithjavascript</Basepaths> <ConfigurationVersion majorVersion="4" minorVersion="0"/> <CreatedAt>1477461021716</CreatedAt> <CreatedBy>nvraghavendra254@gmail.com</CreatedBy> <Description/> <DisplayName>ServiceCalloutwithJavascript</DisplayName> <LastModifiedAt>1477467445649</LastModifiedAt> <LastModifiedBy>nvraghavendra254@gmail.com</LastModifiedBy> <Policies> <Policy>Assign-Message-1</Policy> <Policy>GeoCodeClient</Policy> <Policy>PopulateResponse</Policy> </Policies> <ProxyEndpoints> <ProxyEndpoint>default</ProxyEndpoint> </ProxyEndpoints> <Resources> <Resource>jsc://PopulateResponse.js</Resource> </Resources> <Spec/> <TargetServers/> <TargetEndpoints/> <validate>false</validate> </APIProxy>

Assign message-1:Assign-Message-1

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <AssignMessage async="false" continueOnError="false" enabled="true" name="Assign-Message-1"> <DisplayName>Assign Message-1</DisplayName> <Properties/> <Copy source="response"> <Headers/> <QueryParams/> <FormParams/> <Payload/> <Verb/> <StatusCode/> <ReasonPhrase/> <Path/> </Copy> <Set> <Headers/> <QueryParams/> <FormParams/> <!-- <Verb>GET</Verb> --> <Path/> <Payload contentType="application/json"/> </Set> <AssignVariable> <Name>name</Name> <Value/> <Ref/> </AssignVariable> <IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables> <AssignTo createNew="false" transport="http" type="request"/> </AssignMessage>

Service callout:GeoCodeClient

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <ServiceCallout name="GeoCodeClient"> <DisplayName>GeoCodeClient</DisplayName> <Properties/> <Request clearPayload="true" variable="GeocodingRequest"> <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables> </Request> <Response>>GeocodingResponse</Response> <Timeout>30000</Timeout> <HTTPTargetConnection> <Properties/> <URL>http://services.groupkt.com/country/get/iso2code/IN</URL> </HTTPTargetConnection> </ServiceCallout>

Javascript: PopulateResponse

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <Javascript async="false" continueOnError="false" enabled="true" timeLimit="200" name="PopulateResponse"> <DisplayName>PopulateResponse</DisplayName> <Properties/> <ResourceURL>jsc://PopulateResponse.js</ResourceURL> </Javascript>

javascript:

var originalResponse = JSON.parse(context.getVariable('GeocodingResponse.content')); context.proxyResponse.content = JSON.stringify(originalResponse);

Note: I have used no endpoint proxypoint ,where I dont define any target endpoint.

Please help me on this .