HttpsURLConnectionとHttpResponseCacheをAndroidで強制的にキャッシュする方法は？

Question

私はwiktionary.orgからページをリクエストする方法を持っていますが、問題はサーバがヘッダにCache-control => private, must-revalidate, max-age=0を返すことで、HttpsURLConnectionは要求を格納できません。

強制的にページをキャッシュする方法はありますか？

protected static synchronized String getUrlContent(String url) throws ApiException { 
    if (sUserAgent == null) { 
     throw new ApiException("User-Agent string must be prepared"); 
    } 

    try { 
     URL obj = new URL(url); 
     HttpsURLConnection connection = (HttpsURLConnection) obj.openConnection(); 

     connection.setRequestMethod("GET"); 
     connection.setRequestProperty("User-Agent", sUserAgent); 
     //connection.addRequestProperty("Cache-Control", "max-stale"); 
     //connection.addRequestProperty("Cache-Control", "public, max-age=3600"); 
     //connection.addRequestProperty("Cache-Control", "only-if-cached"); 

     int responseCode = connection.getResponseCode(); 
     if (responseCode != HttpURLConnection.HTTP_OK) { // success 
      throw new ApiException("Invalid response from server: " + responseCode); 
     } 

     InputStream inputStream = connection.getInputStream(); 
     ByteArrayOutputStream content = new ByteArrayOutputStream(); 

     // Read response into a buffered stream 
     int readBytes = 0; 
     while ((readBytes = inputStream.read(sBuffer)) != -1) { 
      content.write(sBuffer, 0, readBytes); 
     } 

     HttpResponseCache cache = HttpResponseCache.getInstalled(); 
     if (cache != null) { 
      Log.w("!!!", "Cache hit count: " + cache.getHitCount()); 
      //connection.addRequestProperty("Cache-Control", "public, max-age=3600"); 
      Log.w("!!!", "Cache-Control: " + connection.getHeaderField("Cache-Control")); 
      //cache.put(new URI(url), connection); 
     } 

     // Return result from buffered stream 
     return new String(content.toByteArray()); 

    } catch (Exception e) { 
     throw new ApiException("Problem communicating with API", e); 
    } 
} 

アップデート：まだ

ないokhttp interceptors

static private OkHttpClient client; 
static private Cache cache; 

public static OkHttpClient getClient() { 
    if (client == null) { 
     File cacheDirectory = new File(App.getInstance().getCacheDir().getAbsolutePath(), "HttpCache"); 
     cache = new Cache(cacheDirectory, 1024 * 1024); 
     client = new OkHttpClient.Builder() 
       .cache(cache) 
       .addInterceptor(REWRITE_CACHE_CONTROL_INTERCEPTOR).build(); 
    } 
    return client; 
} 

/** Dangerous interceptor that rewrites the server's cache-control header. */ 
private static final Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() { 
    @Override public Response intercept(Interceptor.Chain chain) throws IOException { 
     Response originalResponse = chain.proceed(chain.request()); 
     return originalResponse.newBuilder() 
       .header("Cache-Control", "max-age=60") 
       .build(); 
    } 
}; 

protected static synchronized String getUrlContent(String url) throws ApiException { 
    try { 

     OkHttpClient httpClient = getClient(); 

     Request request = new Request.Builder() 
       .url(url) 
       .build(); 

     Response response = httpClient.newCall(request).execute(); 

     Log.w("!!!", "hitCount: " + cache.hitCount()); 

     return response.body().string(); 

    } catch (Exception e) { 
     throw new ApiException("Problem communicating with API", e); 
    } 
} 

Answer 1

でキャッシュヒットを取得することができ、あなたのOKHttpClientを初期化するとき、キャッシュ制御を書き換えるaddNetworkInterceptorの代わりaddInterceptorを使用してください。