What Headers to use when using HttpResponseCache.get

Question

I'm trying to use httpResponseCache to cache some of my requests. Problem is, I'd like to know if the request is cached before making the request.

I saw in the source for HttpResponseCache that there is a get method that takes in (URI, requestMethod, Map< String, List< String > >) and returns a cachedResponse. I've tried a couple different sets of (URI, "GET", Headers), but I can't seem to figure out what the headers would be, and every time I request a cachedResponse using get, I get back null, even though there is a response cached.

Has anyone been successful in using the get method to determine if a request is cached before making the request / alternatively is there a different way to check if something is cached before making the request? I understand I can use hitCount to figure out if the response was taken from cache, and I can use the "Cache-Control","only-if-cached" to force a cached response. I would just like to be able to check if it is cached.

Here's some code I've used to try to accomplish this. In the onCreate of the Activity, I do initialize the cache this way:

try {
               File httpCacheDir = new File(this.getCacheDir(), "http");
               long httpCacheSize = 10 * 1024 * 1024; // 10 MiB
               Class.forName("android.net.http.HttpResponseCache")
                       .getMethod("install", File.class, long.class)
                       .invoke(null, httpCacheDir, httpCacheSize);
        }
            catch (Exception httpResponseCacheNotAvailable) {
                Log.d(TAG,"HttpResponseCache not available.");
           }

And then try to use it this way:

   HttpResponseCache cache = HttpResponseCache.getInstalled();
            try {
                HashMap map = new HashMap<String, List<String>>();
                CacheResponse response = cache.get(URI.create(base_url), "GET", map);
                //response is always null
                Log.d(TAG," Response is!:"+response);
            } catch (IOException e) {
                e.printStackTrace();
            }

Sorry/thanks/ Any help is super appreciated!

My **cache.get** always returns null here. Did you find a solution? — IgorGanapolsky, Feb 15 '18 at 15:36

score -1 · Answer 1 · answered Nov 19 '14 at 09:01

HttpURLConnection connection = (HttpURLConnection)url.openConnection();
HttpResponseCache cache = HttpResponseCache.getInstalled();
cache.get(new URI(url.toString()), "GET", connection.getHeaderFields());

That is how it should be done, but I haven't tried it yet.

What Headers to use when using HttpResponseCache.get

1 Answers1