OkHttp.java

package moe.kurumi.moegallery.utils;

import java.io.IOException;

import okhttp3.HttpUrl;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.logging.HttpLoggingInterceptor;

public class OkHttp {

    public final static String USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36";

    private OkHttpClient.Builder mOkHttpBuilder;

    private OkHttp() {
        HttpLoggingInterceptor loggingInterceptor = new HttpLoggingInterceptor();
        loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);

        Interceptor interceptor = new Interceptor() {
            @Override
            public Response intercept(Chain chain) throws IOException {
                Request request = chain.request();
                HttpUrl url = request.url()
                        .newBuilder()
                        .build();
                request = request.newBuilder()
                        .header("User-Agent", OkHttp.USER_AGENT)
                        .url(url).build();
                return chain.proceed(request);
            }
        };

        mOkHttpBuilder = new OkHttpClient.Builder()
                .addInterceptor(loggingInterceptor)
                .addInterceptor(interceptor);
    }

    public static OkHttp getInstance() {
        return SingletonHelper.INSTANCE;
    }

    public void addNetworkInterceptor(Interceptor interceptor) {
        mOkHttpBuilder.addNetworkInterceptor(interceptor);
    }

    public OkHttpClient client() {
        return mOkHttpBuilder.build();
    }

    private static class SingletonHelper {
        private final static OkHttp INSTANCE = new OkHttp();
    }
}