API Management Policy - pass x-www-form-urlencoded body

Question

I have an old asmx web service that can be invoked using postman like so

I want to expose this via API Management as a JSON endpoint and then have a policy to transform XML but I'm unsure how to set the request details in the policy

I have tried to do this below (and variations of it) but I always get the message error 'requestXML is missing'

<set-body template="liquid">
            <soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
                <soap:Body>
                    requestXml: "<Request Caller="Harness"><GetEmployerOfferings><EmployerCode>CHCA</EmployerCode></GetEmployerOfferings></Request>"
                </soap:Body>
            </soap:Envelope>
        </set-body>
        <set-header name="Content-Type" exists-action="override">
            <value>application/x-www-form-urlencoded</value>
        </set-header>

How do I pass this to the backend service via an APIM policy?

I'm just trying to hard code passing the requestXml to the backend for now but my json request would look something like this...{ "getEmployerOfferings": { "requestXml": "sample" } } — David
Do you mean the "sample" in the json your provided above refer to <Request Caller="Harness"><GetEmployerOfferings><EmployerCode>CHCA</EmployerCode></GetEmployerOfferings></Request> ? You want to request the apim with a request body in json, but the property requestXml of the json is still a xml ? — Hury Shen

Hury Shen Hury Shen · Accepted Answer · 2020-09-04T06:52:57

For your requirement, I'm a little confused about your json sample as I asked in comment. But I can also provide some information for your reference.

1. If you want to test hard code passing the requestXml to the backend, the correct format should be requestXml=xxxx but not requestXml:xxxx because you use "x-www-form-urlencoded" as content-type (in postman we can use requestXml:xxxx). So the policy in apim should be:

<set-body>requestXml=<Request Caller="Harness"><GetEmployerOfferings><EmployerCode>CHCA</EmployerCode></GetEmployerOfferings></Request></set-body>

But as your body contains xml <>, so it will remove <Request Caller="Harness"><GetEmployerOfferings><EmployerCode>CHCA</EmployerCode></GetEmployerOfferings></Request> automatically after save the policy. Only leave <set-body>requestXml=</set-body>, so test with hard code may not success.

2. And to my understanding, if you want to request the APIM with the json data like below:

{
    "getEmployerOfferings": {
        "requestXml": "<Request Caller=\"Harness\"><GetEmployerOfferings><EmployerCode>CHCA</EmployerCode></GetEmployerOfferings></Request>"
    }
}

If your request json like the sample above, you can refer to the policy below:

<inbound>
    <base />
    <set-body>@{
        var request = context.Request.Body.As<JObject>();
        var xmlstring = request["getEmployerOfferings"]["requestXml"].ToString();
        var result = "requestXml=" + xmlstring;
        return result;
    }</set-body>
    <set-header name="Content-Type" exists-action="override">
        <value>application/x-www-form-urlencoded</value>
    </set-header>
</inbound>

Test the apim, we can find the final request body after operation, it shows:

API Management Policy - pass x-www-form-urlencoded body

1 Answers