Azure APIM - Outbound Policy - Set Outbound Body

Question

Hi,

I have an API Operation calling a service that returns only 204.
I need to return in the response to the client a variable that was generated in APIM inbound policy and used on the request to the backend

I need to return to the client the value of that variable.
I'm able to set in the in the response header but not in the Body (the response body continues to be empty).

How can I return the variable in the outbound body?

I have it working for the header like this:

<outbound>
<base />
<set-header name="myHeaderName" exists-action="override">
<value>@((String)context.Variables["MyVariableName"])</value>
</set-header>
</outbound>

Many thanks,
JD

Answer 1

Hi @juni dev Thanks for reaching out. Please refer the sample policy below

<policies>  
    <inbound>  
        <set-variable name="FirstName" value="@(context.User.FirstName)" />  
    </inbound>  
    <backend>  
    </backend>  
    <outbound>  
        <return-response>  
            <set-status code="200" reason="OK" />  
            <set-body>@((string)context.Variables.GetValueOrDefault("FirstName"))</set-body>  
        </return-response>  
    </outbound>  
    <on-error>  
    </on-error>  
</policies>  

But this will not work if the backend returns 204 response code because as per the standards 204 (No Content) MUST NOT include a message-body.
reference: https://www.rfc-editor.org/rfc/rfc2616#section-10.1

Do let me know if you have any queries.

Please 'Accept as answer' and ‘Upvote’ if it helped so that it can help others in the community looking for help on similar topics.