ReverseProxyDispatcher.java

    class ReverseProxyDispatcher extends Dispatcher {
        private final OkHttpClient client;
        private final HttpUrl serverUrl;

        public ReverseProxyDispatcher(HttpUrl url) {
            serverUrl = url;
            client = new OkHttpClient.Builder().build();
        }

        @Override
        public MockResponse dispatch(final RecordedRequest request) throws InterruptedException {
            HttpUrl proxiedUri = HttpUrl.parse("http://example.com" + request.getPath())
                    .newBuilder()
                    .scheme(serverUrl.scheme())
                    .host(serverUrl.host())
                    .build();

            Request.Builder requestBuilder = new Request.Builder()
                    .url(proxiedUri)
                    .headers(request.getHeaders());

            if (request.getBodySize() != 0) {
                requestBuilder.method(request.getMethod(), new RequestBody() {
                    @Override
                    public MediaType contentType() {
                        return MediaType.parse(request.getHeader("Content-Type"));
                    }

                    @Override
                    public void writeTo(BufferedSink sink) throws IOException {
                        request.getBody().readAll(sink);
                    }
                });
            }

            Response response = null;
            try {
                response = client.newCall(requestBuilder.build()).execute();
            } catch (IOException e) {
                response = null;
            }

            if (response == null) {
                return new MockResponse()
                        .setStatus("Reverse proxy error")
                        .setResponseCode(500);
            }

            return new MockResponse()
                    .setHeaders(response.headers())
                    .setBody(response.body().source().buffer())
                    .setResponseCode(response.code());
        }
    }