CODEWITHSUNDEEP
azureazure-api-management
ards
ards

Reputation: 13

Change response body in azure api management service

I am testing out a GET request with APIm using json placeholder api and cannot replace my response body. Any help is appreciated!

JSON response:

{
    "userId": 1,
    "id": 1,
    "title": "delectus aut autem",
    "completed": false
}

Here is my policy:

<policies>
    <inbound>
        <base />
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
 <base />
<choose>
  <when condition="@(context.Response.StatusCode == 200)">
    <set-body>@{
        var response = context.Response.Body.As<JObject>();
        response["id"] = "Hello World!";
        return response.ToString();
      }
    </set-body>
  </when>
</choose>
    </outbound>
    <on-error>
        <base />
    </on-error>
</policies>

I end up with this error:

set-body (7.739 ms) { "messages": [ { "message": "Expression evaluation failed.", "expression": "\n var response = context.Response.Body.As();\n response["id"] = 2;\n return response.ToString();\n ", "details": "The message body is not a valid JSON. Unexpected character encountered while parsing value: �. Path '', line 0, position 0.\r\n at Newtonsoft.Json.JsonTextReader.ParseValue()\r\n at Newtonsoft.Json.Linq.JObject.Load(JsonReader reader, JsonLoadSettings settings)\r\n at Microsoft.WindowsAzure.ApiManagement.Proxy.Gateway.MessageBody.AsJObject(Stream stream, Encoding encoding, JsonSerializerSettings settings)\r\n at Microsoft.WindowsAzure.ApiManagement.Proxy.Gateway.MessageBody.As[T](Boolean preserveContent)" }, "Expression evaluation failed. The message body is not a valid JSON. Unexpected character encountered while parsing value: �. Path '', line 0, position 0.\r\n at Newtonsoft.Json.JsonTextReader.ParseValue()\r\n at Newtonsoft.Json.Linq.JObject.Load(JsonReader reader, JsonLoadSettings settings)\r\n at Microsoft.WindowsAzure.ApiManagement.Proxy.Gateway.MessageBody.AsJObject(Stream stream, Encoding encoding, JsonSerializerSettings settings)\r\n at Microsoft.WindowsAzure.ApiManagement.Proxy.Gateway.MessageBody.As[T](Boolean preserveContent)", "Unexpected character encountered while parsing value: �. Path '', line 0, position 0." ] }

update 1:

Executing this policy and shows that the body is null. Is there a way to wait for the response body? When I debug it within vscode and step through it, I'm getting the response successfully. Here's my new outbound policy:

<policies>
    <inbound>
        <base />
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <base />
        <return-response>
            <set-header name="Content-Type">
                <value>application/json</value>
            </set-header>
            <set-header name="Accept">
                <value>application/json</value>
            </set-header>
            <set-body>@{
            JObject body = null;
        try {
            body = context.Response.Body.As<JObject>(preserveContent: true);
            return  "{\"id\":"+ @body["type"] + "}";

        } catch (Exception e) {
            return JsonConvert.SerializeObject(context.Response.Body);
        }
        }
        </set-body>
        </return-response>
    </outbound>
    <on-error>
        <base />
    </on-error>
</policies>

Update 2

Added a trace:

<trace source="test">
    <message>@{
        return context.Response.Body.As<string>(preserveContent: true);
    }</message>
</trace>

result of the trace:

test (0.006 ms)
"��\u0002\u0000 ���%\u001d�WV\rm%\n:\u0018�˫�y�ȁ[�P۝߁��>�\u0000�w9\u0015s\b�èS7���˻\u0013�\u0005늇>qs*��\f�\u0001"

Upvotes: 0

Views: 2804

Answers (2)

Martin
Martin

Reputation: 1

I had the same issue, for me, the header needed to be set in the request. Here's a link https://github.com/MicrosoftDocs/azure-docs/issues/95956

Upvotes: 0

ards
ards

Reputation: 13

Setting the header to Accept-Encoding: * gave me a successful response. I thought Content-Type: application/json; charset=utf-8 was enough for encoding. I need to do a deeper dive Accept-Encoding but when I saw the error in the trace, it looked like an encoding issue and that's how I arrived with my solution.

Upvotes: 1

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