MockWebServer: customize response based on the request

By default MockWebServer use a queue to specify a series of responses. These responses will be delivered to the client in sequential order.

 

How to customize the responses?

Using a dispatcher we can customize these responses.

 

Step 1: Define Dispatcher.

 

Dispatcher dispatcher = new Dispatcher() {

	@Override
	public MockResponse dispatch(RecordedRequest request) throws InterruptedException {

		switch (request.getPath()) {
		case "/v1/welcome1":
			return new MockResponse().setResponseCode(200).setBody("Good Morning");
		case "/v1/app-details":
			return new MockResponse().setResponseCode(200).setBody("version=9");
		case "/v1/owner":
			return new MockResponse().setResponseCode(200).setBody(json);
		}
		return new MockResponse().setResponseCode(404);
	}
};

Step 2: Set the dispatcher to MockWebServer.

mockWebServer.setDispatcher(dispatcher);

Find the below working application.

 

SimpleRestClient.java

package com.sample.app;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.Consts;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;

public class SimpleRestClient {

	private String url;

	public SimpleRestClient(String url) {
		this.url = url;
	}

	public String getRequest() throws ClientProtocolException, IOException {
		CloseableHttpClient httpclient = HttpClients.createDefault();

		HttpGet httpget = new HttpGet(url);
		return getResponseAsString(httpclient.execute(httpget));

	}

	public CloseableHttpResponse getClosebaleResponse() throws ClientProtocolException, IOException {

		HttpRequestBase httpget = new HttpGet(url);

		CloseableHttpClient httpclient = HttpClients.createDefault();
		return httpclient.execute(httpget);

	}

	public String maxConnTimeOut(int noOfSeconds) throws ClientProtocolException, IOException {
		RequestConfig.Builder requestConfigBuilder = RequestConfig.custom();
		requestConfigBuilder.setConnectTimeout(noOfSeconds * 1000);
		requestConfigBuilder.setConnectionRequestTimeout(noOfSeconds * 1000);
		requestConfigBuilder.setSocketTimeout(noOfSeconds * 1000);
		RequestConfig requestConfig = requestConfigBuilder.build();

		HttpRequestBase httpget = new HttpGet(url);
		httpget.setConfig(requestConfig);

		CloseableHttpClient httpclient = HttpClients.createDefault();
		CloseableHttpResponse httpResponse = httpclient.execute(httpget);

		return getResponseAsString(httpResponse);

	}

	public void postAndIgnore() throws ClientProtocolException, IOException {
		List<NameValuePair> formparams = new ArrayList<NameValuePair>();
		formparams.add(new BasicNameValuePair("name", "Krishna"));
		formparams.add(new BasicNameValuePair("password", "password"));
		formparams.add(new BasicNameValuePair("mailId", "abcdef@abcdef.com"));
		UrlEncodedFormEntity requestBody = new UrlEncodedFormEntity(formparams, Consts.UTF_8);

		HttpPost httppost = new HttpPost(url + "?appName=chatserver");
		httppost.setEntity(requestBody);

		try (CloseableHttpClient httpclient = HttpClientBuilder.create().build();) {
			httpclient.execute(httppost);
		}

	}


	public static String getResponseAsString(InputStream is) throws IOException {
		try (InputStreamReader isReader = new InputStreamReader(is)) {
			BufferedReader reader = new BufferedReader(isReader);
			StringBuffer sb = new StringBuffer();
			String str;
			while ((str = reader.readLine()) != null) {
				sb.append(str);
			}

			return sb.toString();
		}

	}

	public static String getResponseAsString(CloseableHttpResponse closeableHttpResponse)
			throws UnsupportedOperationException, IOException {

		HttpEntity httpEntity = closeableHttpResponse.getEntity();
		return getResponseAsString(httpEntity.getContent());

	}

}

HelloWorldTest.java

package mockwebserver;

import static org.junit.Assert.assertThrows;
import static org.junit.jupiter.api.Assertions.assertEquals;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.SocketTimeoutException;
import java.util.concurrent.TimeUnit;

import org.apache.http.client.methods.CloseableHttpResponse;
import org.junit.jupiter.api.Test;

import com.sample.app.SimpleRestClient;

import okhttp3.HttpUrl;
import okhttp3.mockwebserver.Dispatcher;
import okhttp3.mockwebserver.MockResponse;
import okhttp3.mockwebserver.MockWebServer;
import okhttp3.mockwebserver.RecordedRequest;

public class HelloWorldTest {

	@Test
	public void hello() throws IOException {
		try (MockWebServer mockWebServer = new MockWebServer();) {
			String msg1 = "Good Morning";
			String msg2 = "Good Afternoon";
			String msg3 = "Good Evening";

			mockWebServer.enqueue(new MockResponse().setBody(msg1));
			mockWebServer.enqueue(new MockResponse().setBody(msg2));
			mockWebServer.enqueue(new MockResponse().setBody(msg3));

			mockWebServer.start(1234);

			HttpUrl baseUrl = mockWebServer.url("/v1/welcome");

			SimpleRestClient simpleRestClient = new SimpleRestClient(baseUrl.toString());

			String body1 = simpleRestClient.getRequest();
			assertEquals(msg1, body1);

			String body2 = simpleRestClient.getRequest();
			assertEquals(msg2, body2);

			String body3 = simpleRestClient.getRequest();
			assertEquals(msg3, body3);

			mockWebServer.shutdown();
		}

	}

	@Test
	public void urlRedirection() throws IOException {
		try (MockWebServer mockWebServer = new MockWebServer();) {
			mockWebServer.start(1234);

			mockWebServer.enqueue(new MockResponse().setResponseCode(HttpURLConnection.HTTP_MOVED_TEMP)
					.addHeader("Location: " + mockWebServer.url("/new-path")).setBody("This page has moved!"));

			mockWebServer.enqueue(new MockResponse().setBody("This is the new location!"));

			HttpUrl baseUrl = mockWebServer.url("/v1/welcome");

			SimpleRestClient simpleRestClient = new SimpleRestClient(baseUrl.toString());

			CloseableHttpResponse httpResponse = simpleRestClient.getClosebaleResponse();

			int statusCode = httpResponse.getStatusLine().getStatusCode();
			String body = SimpleRestClient.getResponseAsString(httpResponse);

			assertEquals(200, statusCode);
			assertEquals("This is the new location!", body);

			mockWebServer.shutdown();
		}

	}

	@Test
	public void delayResponseTime() throws IOException {
		try (MockWebServer mockWebServer = new MockWebServer();) {
			mockWebServer.start(1234);

			mockWebServer.enqueue(new MockResponse().setBody("Hello World").setBodyDelay(5, TimeUnit.SECONDS));

			HttpUrl baseUrl = mockWebServer.url("/v1/welcome");

			SimpleRestClient simpleRestClient = new SimpleRestClient(baseUrl.toString());

			Throwable exception = assertThrows(SocketTimeoutException.class, () -> {
				String response = simpleRestClient.maxConnTimeOut(2);

				assertEquals("Hello World", response);
			});

			assertEquals("Read timed out", exception.getMessage());

			mockWebServer.shutdown();
		}
	}

	@Test
	public void validateRequestBody() throws IOException, InterruptedException {
		try (MockWebServer mockWebServer = new MockWebServer();) {
			mockWebServer.start(1234);

			mockWebServer.enqueue(new MockResponse().setBody("Hello World"));

			HttpUrl baseUrl = mockWebServer.url("/v1/welcome");

			SimpleRestClient simpleRestClient = new SimpleRestClient(baseUrl.toString());
			simpleRestClient.postAndIgnore();

			RecordedRequest recordedRequest = mockWebServer.takeRequest();
			assertEquals("POST", recordedRequest.getMethod());
			assertEquals("name=Krishna&password=password&mailId=abcdef%40abcdef.com",
					recordedRequest.getBody().readUtf8());
			assertEquals("application/x-www-form-urlencoded; charset=UTF-8", recordedRequest.getHeader("Content-Type"));

			HttpUrl httpUrl = recordedRequest.getRequestUrl();
			assertEquals("http://localhost:1234/v1/welcome?appName=chatserver", httpUrl.toString());

			mockWebServer.shutdown();
		}
	}

	@Test
	public void customizeResponses() throws IOException, InterruptedException {
		String json = "{\"org\": \"abc_org\", \"location\": \"India\"}";

		try (MockWebServer mockWebServer = new MockWebServer();) {
			mockWebServer.start(1234);

			Dispatcher dispatcher = new Dispatcher() {

				@Override
				public MockResponse dispatch(RecordedRequest request) throws InterruptedException {

					switch (request.getPath()) {
					case "/v1/welcome1":
						return new MockResponse().setResponseCode(200).setBody("Good Morning");
					case "/v1/app-details":
						return new MockResponse().setResponseCode(200).setBody("version=9");
					case "/v1/owner":
						return new MockResponse().setResponseCode(200).setBody(json);
					}
					return new MockResponse().setResponseCode(404);
				}
			};
			mockWebServer.setDispatcher(dispatcher);

			SimpleRestClient simpleRestClient = new SimpleRestClient("http://localhost:1234/v1/app-details");
			String resp = simpleRestClient.getRequest();

			assertEquals("version=9", resp);

			mockWebServer.shutdown();
		}
	}

}

junit output

You can download the complete working application from below link.

https://github.com/harikrishna553/java-libs/tree/master/okhttp3/mockwebserver/mockwebserver-demo

 

 

 

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