使用 Retrofit、okhttp 和 picasso 缓存图像和字符串

Posted 2023-03-22

【中文标题】使用 Retrofit、okhttp 和 picasso 缓存图像和字符串

【英文标题】：Caching Images and strings using Retrofit, okhttp and picasso

【发布时间】：2021-04-30 16:37:40

【问题描述】：

我正在尝试优化此代码以用于缓存目的。此代码仅在 1 天后重新连接到 Internet 以创建新缓存之前的缓存。我想在它再次访问网络之前让它保持 60 天 make new cache 。使用毕加索从缓存中获取的图像也会变慢 毕加索：2.5.2 改造2：改造：2.7.2 改造2：转换器-gson：2.7.2 okhttp3:okhttp:4.4.1 okhttp3:logging-interceptor:4.4.1

     if (retrofit==null) 
         OkHttpClient okHttpClient = new OkHttpClient().newBuilder()
                 .addInterceptor( provideHttpLoggingInterceptor() )
                 .addInterceptor( provideOfflineCacheInterceptor() )
                 .addNetworkInterceptor( provideCacheInterceptor() )
                 .cache( provideCache() )
                 .connectTimeout(60, TimeUnit.SECONDS)
                 .readTimeout(60, TimeUnit.SECONDS)
                 .writeTimeout(60, TimeUnit.SECONDS)
                 .build();

         OkHttp3Downloader okHttp3Downloader = new OkHttp3Downloader(okHttpClient);
         Picasso picasso = new Picasso.Builder(MyApplication.getInstance())
                 .downloader(okHttp3Downloader)
                 .build();


         Picasso.setSingletonInstance(picasso);

         retrofit = new Retrofit.Builder()
                 .baseUrl(Global.API_URL)
                 .client(okHttpClient)
                 .addConverterFactory(GsonConverterFactory.create())
                 .build();
     
     return retrofit;
 
 private static Cache provideCache ()
 
     Cache cache = null;
     try
     
         cache = new Cache( new File(MyApplication.getInstance().getCacheDir(), "wallpaper-cache" ),
                 100 * 1024 * 1024 ); // 100 MB
     
     catch (Exception e)
     
         Timber.e( e, "Could not create Cache!" );
     
     return cache;
 
 private static HttpLoggingInterceptor provideHttpLoggingInterceptor ()
 
     HttpLoggingInterceptor httpLoggingInterceptor =
             new HttpLoggingInterceptor( new HttpLoggingInterceptor.Logger()
             
                 @Override
                 public void log (String message)
                 
                     Timber.d( message );
                     Log.v("MYAPI",message);

                 
              );
     httpLoggingInterceptor.setLevel( BuildConfig.DEBUG ? HEADERS : NONE );
     return httpLoggingInterceptor;
 
 public static Interceptor provideCacheInterceptor ()
 
     return new Interceptor()
     
         @Override
         public Response intercept (Chain chain) throws IOException
         
             Response response = chain.proceed( chain.request() );
             int maxAge = 60  * 60; // read from cache
             return response.newBuilder()
                     .header( CACHE_CONTROL, "public, max-age=" + maxAge)
                     .removeHeader("Pragma")
                     .build();
         
     ;
 
 public static Interceptor provideOfflineCacheInterceptor ()
 
     return new Interceptor()
     

         @Override
         public Response intercept (Chain chain) throws IOException
         
             Request request = chain.request();
             if ( !MyApplication.hasNetwork() )
             
                 int maxStale = 60 * 60 * 24 * 28; // tolerate 4-weeks stale
                 request = request.newBuilder()
                         .header( CACHE_CONTROL,  "public, only-if-cached, max-stale=" + maxStale)
                         .removeHeader("Pragma")
                         .build();
             
             return chain.proceed( request );
         
     ;
 

 ```



 

【参考方案1】：

你可以像这个例子How to cache okHTTP response from Web server那样在拦截器中重写缓存头

public class CacheInterceptor implements Interceptor 
    @Override
    public Response intercept(Chain chain) throws IOException 
        Response response = chain.proceed(chain.request());

        CacheControl cacheControl = new CacheControl.Builder()
                .maxAge(15, TimeUnit.MINUTES) // 15 minutes cache
                .build();

        return response.newBuilder()
                .removeHeader("Pragma")
                .removeHeader("Cache-Control")
                .header("Cache-Control", cacheControl.toString())
                .build();
    

【讨论】：

你能用完整的代码更新我吗，因为我不知道我是否会更改缓存拦截器或离线缓存拦截器或 HttpLoggingInterceptor

请提供一个可运行的复制品，我可以在 Intellij 中将其作为项目打开。也许作为一个github项目，我会看看。