Lagom Send custom header

Question

I'm working on Lagom POC on sending POST request to Non lagom service with custom Header. In my case I'm trying to hit postman-echo to test the custom header. However, it looks the headers are not set though I made code changes accordingly:

public CompletionStage<DsapAuthorizationResponse> hitAPI(AuthorizationRequest request) {
            DsapWSRequest dsapWSRequest = new DsapWSRequest();
            dsapWSRequest.username = request.username;
            dsapWSRequest.password = request.password;
            CompletionStage<DsapAuthorizationResponse> dsapresponse = dsapExternalService
                    .authenticate()
                    .handleRequestHeader(requestHeader -> {
                        requestHeader.withHeader("Authorization","Basic mncndsjna");
                        System.out.println("My Headers>>>>>>>> " + requestHeader);
                        return requestHeader;
                    })
                    .handleResponseHeader((responseHeader,b) -> {
                        System.out.println("RESPonse Header >>>>>>> : "+responseHeader);
                        return b;
                    })
                    .invoke(dsapWSRequest);
            return dsapresponse;

        }

In the above code header authorization is not set in the request. I am not getting this header in the echo which is mapped correctly in my POJO.

here is the complete code from my GitHub https://github.com/sourabhsar/Lagom-Unmanaged-Service-Demo/tree/poc/lagom-request-response

I followed the steps mentioned here: https://groups.google.com/forum/#!topic/lagom-framework/yvKmqvtZWFs

and also followed few other blogs/articles. However so far I haven't found any blog which they are sending request to unmanaged external service with custom header. I'm not sure whats wrong in my code.

Answer 1

requestHeader.withHeader returns a new object with the added header, but the code you have written returns the original requestHeader object. In general, many Lagom APIs follow a principle of using immutable objects, with methods that return a new, modified instance, rather than changing the instance the method is called on.

Try this:

.handleRequestHeader(requestHeader -> {
    RequestHeader modifiedRequestHeader =
        requestHeader.withHeader("Authorization","Basic mncndsjna");
    System.out.println("My Headers>>>>>>>> " + modifiedRequestHeader);
    return modifiedRequestHeader;
})