Using wiremock, can I return a body that is dependent on the post request

Question

I am trying to test an openid provider class. The openid consumer class is making an http request. I am mocking the response to this request using wiremock. I am trying to mock a valid openid response. However, the valid response depends on the request parameters. Using wiremock, can I set up a mock request where the body of the response is dependent on the request parameters?

Answer 1

This is possible, you just have to make use of a ResponseTansformer. In the below example code the responseDefinition is determined by the stubbing given below. Here I mock an encoding service by simply returning the body bytes back to the caller. Although in the transformer I am free to return whatever I like based on the contents of the request.

int port = 8080;
WireMockServer wireMockServer = new WireMockServer(new WireMockConfiguration().port(port).extensions(new ResponseTransformer() {
    @Override
    public ResponseDefinition transform(Request request, ResponseDefinition responseDefinition, FileSource files) {
        return new ResponseDefinitionBuilder().like(responseDefinition)
                .withBody(request.getBodyAsString().getBytes())
                .build();
    }

    @Override
    public String name() {
        return "request body returning request transformer";
    }
}));
wireMockServer.start();
WireMock.configureFor("localhost", port);

stubFor(post(urlEqualTo("/encode"))
        .willReturn(aResponse()
                .withHeader("Content-Type", "application/octet-stream")
                .withStatus(200)));

stubFor(post(urlEqualTo("/decode"))
        .willReturn(aResponse()
                .withHeader("Content-Type", "application/octet-stream")
                .withStatus(200)));

Answer 2

Wiremock supports extensions that you can write yourself that act as a middleware used to intercept the request and response bodies so you can format it however you like. It's very flexible and allows you to make up new response bodies dynamically or even no response at all.

As an example, we wrote an extension for this at Opentable and open sourced it on Maven Central. It allows you treat the json attributes as variables and interpolate them into your response body. Check it out. Let us know how it goes or if you have any questions. https://github.com/opentable/wiremock-body-transformer