Network loading framework OkHttp

Keywords: Android network http

1. What is OkHttp

github address: https://square.github.io/okhttp/

An open source project for processing network requests contributed by Square is the most widely used network framework for Android. Starting with Android 4.4
The underlying implementation of HttpURLConnection adopts OkHttp.

1. Support HTTP/2 and allow all requests to the same host to share a socket;
2. If it is not HTTP/2, the request delay is reduced through the connection pool;
3. Request GZip compressed data by default;
4. Response cache, avoiding the network of repeated requests;

Dependency:
implementation("com.squareup.okhttp3:okhttp:4.9.0")

Test (server used to test http requests):
URL:https://www.httpbin.org/

2. Basic usage of okhttp

OkHttpClient okHttpClient = new OkHttpClient();

Synchronization request:

Request request = new Request.Builder().url("https://www.httpbin.org/get?a=1&b=2").build();
                // Prepare the requested Call object
                Call call = okHttpClient.newCall(request);
                try {
                    Response response = call.execute();
                    Log.i(TAG, "getSync: " + response.body().string());
                } catch (IOException e) {
                    e.printStackTrace();
FormBody formBody = new FormBody.Builder()
                        .add("a", "1").add("b", "2").build();
Request request = new Request.Builder().url("https://www.httpbin.org/post")
                        .post(formBody).build();
                // Prepare the requested Call object
                Call call = okHttpClient.newCall(request);
                try {
                    Response response = call.execute();
                    Log.i(TAG, "postSync: " + response.body().string());
                } catch (IOException e) {
                    e.printStackTrace();
                }

Asynchronous request:

Request request = new Request.Builder().url("https://www.httpbin.org/get?a=1&b=2")
                .build();
        // Prepare the requested Call object
        Call call = okHttpClient.newCall(request);
        //Asynchronous request
        call.enqueue(new Callback() {
            @Override
            public void onFailure(@NotNull Call call, @NotNull IOException e) {

            }

            @Override
            public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
                if (response.isSuccessful()) {
                    Log.i(TAG, "getAsync: " + response.body().string());
                }
            }
FormBody formBody = new FormBody.Builder()
                .add("a", "1").add("b", "2").build();
        Request request = new Request.Builder().url("https://www.httpbin.org/post")
                .post(formBody).build();
        // Prepare the requested Call object
        Call call = okHttpClient.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(@NotNull Call call, @NotNull IOException e) {

            }

            @Override
            public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
                Log.i(TAG, "postAsync: " + response.body().string());
            }

3.POST request

The protocol stipulates that the data submitted by POST must be placed in the request body, but the protocol does not specify what encoding method the data must use. The common data coding methods are:
https://www.runoob.com/http/http-content-type.html

1. Content type: application/x-www-form-urlencoded data is encoded as a name / value pair, which is the default type;
2. Content type: multipart / form data data is encoded as a message, which is generally used for file upload;
3. Content type: binary data submitted by application / octet stream. If it is used for file upload, only one file can be uploaded;
4. Content type: submit json data for application/json
...
multipart upload file example (create test code and upload local desktop documents):

 @Test
    public void uploadFileTest() throws IOException {
        OkHttpClient okHttpClient = new OkHttpClient();
        File file1 = new File("C:\\Users\\Administrator\\Desktop\\1.txt");
        File file2 = new File("C:\\Users\\Administrator\\Desktop\\2.txt");
        MultipartBody multipartBody = new MultipartBody.Builder()
                .addFormDataPart("file1", file1.getName(), RequestBody.create(file1, MediaType.parse("text/plain")))
                .addFormDataPart("file2", file2.getName(), RequestBody.create(file2, MediaType.parse("text/plain")))
                .addFormDataPart("a", "1")
                .build();
        Request request = new Request.Builder().url("https://www.httpbin.org/post").post(multipartBody).build();
        Call call = okHttpClient.newCall(request);
        Response response = call.execute();
        System.out.println(response.body().string());
    }

json format upload example:

```java
 @Test
    public void jsonTest() throws IOException {
        OkHttpClient okHttpClient = new OkHttpClient();
        RequestBody requestBody =
                RequestBody.create("{\"a\":1,\"b\":2}", MediaType.parse("application/json"));
        Request request = new Request.Builder().url("https://www.httpbin.org/post").post(requestBody).build();
        Call call = okHttpClient.newCall(request);
        Response response = call.execute();
        System.out.println(response.body().string());

   }

4.Builder builder

OkHttpClient okHttpClient = new OkHttpClient.Builder().build();

5. Interceptor

Concept and detailed use

OkHttpClientokHttpClient=newOkHttpClient.Builder().addInterceptor(newXXX).build();
OkHttpClientokHttpClient=newOkHttpClient.Builder().addNetworkInterceptor(newXXX).build();

6. Caching and cookies

OkHttp implements cache processing according to the Http protocol rules. For example, after we initiate the first request, if we need to enter it later
Line the same request. At this time, if the caching rules are met, the network communication with the server can be reduced and the response can be read directly from the local file cache
Return to requester. However, by default, OkHttp's cache is off and needs to be turned on.


Interceptor and cache code example:

 @Test
    public void interceptorTest() {
        OkHttpClient okHttpClient = new OkHttpClient.Builder()
                .cache(new Cache(new File("C:\\Users\\Administrator\\Desktop"),
                        1024 * 1024)).addNetworkInterceptor(new Interceptor() {
                    @NotNull
                    @Override
                    public Response intercept(@NotNull Chain chain) throws IOException {
                        System.out.println("version:" + chain.request().header("version"));
                        return chain.proceed(chain.request());
                    }
                }).addInterceptor(new Interceptor() {
                    @NotNull
                    @Override
                    public Response intercept(@NotNull Chain chain) throws IOException {
                        //Preprocessing
                        Request request = chain.request().newBuilder().addHeader("os", "android")
                                .addHeader("version", "1.0").build();
                        Response response = chain.proceed(request);
                        //Post processing
                        return response;
                    }
                }).build();

        Request request = new Request.Builder().url("https://www.httpbin.org/get?a=1&b=2").build();
        // Prepare the requested Call object
        Call call = okHttpClient.newCall(request);
        try {
            Response response = call.execute();
            System.out.println(response.body().string());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

Cookie is the data (usually encrypted) stored on the user's local terminal by some websites in order to identify the user's identity and track the session (such as determining the login status), which is temporarily or permanently saved by the user's client computer

About the use of cookie s:

public class CookieUnitTest {
    Map<String, List<Cookie>> cookies = new HashMap<>();

    @Test
    public void cookieTest() {
        OkHttpClient okHttpClient = new OkHttpClient.Builder()
                .cookieJar(new CookieJar() {
                    @Override
                    public void saveFromResponse(@NotNull HttpUrl httpUrl, @NotNull List<Cookie> list) {
                        cookies.put(httpUrl.host(), list);
                    }

                    @NotNull
                    @Override
                    public List<Cookie> loadForRequest(@NotNull HttpUrl httpUrl) {
                        List<Cookie> cookies = CookieUnitTest.this.cookies.get(httpUrl.host());
                        return cookies == null ? new ArrayList<>() : cookies;
                    }
                })
                .build();
        FormBody formBody = new FormBody.Builder().add("username", "lanceedu")
                .add("password", "123123").build();
        Request request = new Request.Builder().url("https://www.wanandroid.com/user/login")
                .post(formBody).build();
        // Prepare the requested Call object
        Call call = okHttpClient.newCall(request);
        try {
            Response response = call.execute();
            System.out.println(response.body().string());
        } catch (IOException e) {
            e.printStackTrace();
        }


        request = new Request.Builder().url("https://www.wanandroid.com/lg/collect/list/0/json")
                .build();
        // Prepare the requested Call object
        call = okHttpClient.newCall(request);
        try {
            Response response = call.execute();
            System.out.println(response.body().string());
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

Returned data:

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PS: the API for playing Android is used here (you can access the favorite articles only after you stay logged in): https://www.wanandroid.com/blog/show/2



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This article demo: https://github.com/gujunhe/NetworkDemo.git

Posted by dprichard on Sat, 30 Oct 2021 12:08:34 -0700