Retrofit how to log in?

Question

Java

There is a rest service, authorization works like this:
restservice.ru/api/login?username=abc&password=12345
further it is supported through cookies:
JSESSIONID = "BLABLABLA",
Question:
How to log in using Retrofit,
and then substitute cookies received during authorization , in further requests to the service ?
PS Thanks in advance!

Answer 1

The documentation tells us this:
A request Header can be updated dynamically using the @Header annotation. A corresponding parameter must be provided to the @Header. If the value is null, the header will be omitted. Otherwise, toString will be called on the value, and the result used.

@GET("/user")
Call<User> getUser(@Header("Authorization") String authorization)

In general, we take the case when there is no api as such, and you need to log in to the site by sending a request, as if we were a web client.
Experimental kotomatrix.ru.
When parsing requests, it turned out that authorization occurs through submitting a form.

public interface KotomatrixService {
    @FormUrlEncoded
    @POST("http://kotomatrix.ru")
    Call<String> login(@Field("login") String login, @Field("password") String pass, @Field("act") String act, @Field("remember") String remember);
}

public class ApiFactory {
    private static final int CONNECT_TIMEOUT = 15;
    private static final int WRITE_TIMEOUT = 60;
    private static final int TIMEOUT = 60;
    private static final OkHttpClient CLIENT = new OkHttpClient();

    static {
        CLIENT.setConnectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS);
        CLIENT.setWriteTimeout(WRITE_TIMEOUT, TimeUnit.SECONDS);
        CLIENT.setReadTimeout(TIMEOUT, TimeUnit.SECONDS);
    }

    @NonNull
    public static KotomatrixService getKotomatrixService() {
        return getRetrofit().create(KotomatrixService.class);
    }

    @NonNull
    private static Retrofit getRetrofit() {
        return new Retrofit.Builder()
                .baseUrl("http://kotomatrix.ru")
                .addConverter(String.class, new StringConverter())
                .client(CLIENT)
                .build();
    }
}

public final class StringConverter implements Converter<String> {
    @Override
    public String fromBody(ResponseBody body) throws IOException {
        return body.string();
    }

    @Override
    public RequestBody toBody(String value) {
        return RequestBody.create(MediaType.parse("text/plain"), value);
    }
}

public class MainActivity extends AppCompatActivity implements Callback<String> {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        KotomatrixService service = ApiFactory.getKotomatrixService();
        Call<String> call = service.login("testUser", "testUser", "login", "true");
        call.enqueue(MainActivity.this);
    }

    @Override
    public void onResponse(Response<String> response) {
        if (response.isSuccess()) {
            // ищем куку и сохраняем
        }
    }

    @Override
    public void onFailure(Throwable t) {
    }
}

In this example, upon successful authorization, the server will return kotomatrixCOOK, look for the value here response.rawResponse.headers and save it in SharedPreferences .