Video cache support for Android

Table of Content

• Why AndroidVideoCache?
• Features
• Get started
• Recipes
  • Disk cache limit
  • Listen caching progress
  • Providing names for cached files
  • Adding custom http headers
  • Using exoPlayer
  • Sample
• Known problems
• Whats new
• Code contributions
• Where published?
• Questions?
• License

Why AndroidVideoCache?

Because there is no sense to download video a lot of times while streaming! AndroidVideoCache allows to add caching support to your VideoView/MediaPlayer, ExoPlayer or any another player with help of single line!

Features

• caching to disk during streaming;
• offline work with cached resources;
• partial loading;
• cache limits (max cache size, max files count);
• multiple clients for same url.

Note AndroidVideoCache works only with direct urls to media file, it doesn't support any streaming technology like DASH, SmoothStreaming, HLS.

Get started

Just add dependency (AndroidVideoCache is available in jcenter):

dependencies {
    compile 'com.danikula:videocache:2.7.1'
}

and use url from proxy instead of original url for adding caching:

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

    HttpProxyCacheServer proxy = getProxy();
    String proxyUrl = proxy.getProxyUrl(VIDEO_URL);
    videoView.setVideoPath(proxyUrl);
}

private HttpProxyCacheServer getProxy() {
    // should return single instance of HttpProxyCacheServer shared for whole app.
}

To guarantee normal work you should use single instance of HttpProxyCacheServer for whole app. For example you can store shared proxy in your Application:

public class App extends Application {

    private HttpProxyCacheServer proxy;

    public static HttpProxyCacheServer getProxy(Context context) {
        App app = (App) context.getApplicationContext();
        return app.proxy == null ? (app.proxy = app.newProxy()) : app.proxy;
    }

    private HttpProxyCacheServer newProxy() {
        return new HttpProxyCacheServer(this);
    }
}

or use simple factory. More preferable way is use some dependency injector like Dagger.

Recipes

Disk cache limit

By default HttpProxyCacheServer uses 512Mb for caching files. You can change this value:

private HttpProxyCacheServer newProxy() {
    return new HttpProxyCacheServer.Builder(this)
            .maxCacheSize(1024 * 1024 * 1024)       // 1 Gb for cache
            .build();
}

or can limit total count of files in cache:

private HttpProxyCacheServer newProxy() {
    return new HttpProxyCacheServer.Builder(this)
            .maxCacheFilesCount(20)
            .build();
}

or even implement your own DiskUsage strategy:

private HttpProxyCacheServer newProxy() {
    return new HttpProxyCacheServer.Builder(this)
            .diskUsage(new MyCoolDiskUsageStrategy())
            .build();
}

Listen caching progress

Use HttpProxyCacheServer.registerCacheListener(CacheListener listener) method to set listener with callback onCacheAvailable(File cacheFile, String url, int percentsAvailable) to be aware of caching progress. Do not forget to to unsubscribe listener with help of HttpProxyCacheServer.unregisterCacheListener(CacheListener listener) method to avoid memory leaks.

Use HttpProxyCacheServer.isCached(String url) method to check was url's content fully cached to file or not.

See sample app for more details.

Providing names for cached files

By default AndroidVideoCache uses MD5 of video url as file name. But in some cases url is not stable and it can contain some generated parts (e.g. session token). In this case caching mechanism will be broken. To fix it you have to provide own FileNameGenerator:

public class MyFileNameGenerator implements FileNameGenerator {

    // Urls contain mutable parts (parameter 'sessionToken') and stable video's id (parameter 'videoId').
    // e. g. http://example.com?videoId=abcqaz&sessionToken=xyz987
    public String generate(String url) {
        Uri uri = Uri.parse(url);
        String videoId = uri.getQueryParameter("videoId");
        return videoId + ".mp4";
    }
}

...
HttpProxyCacheServer proxy = new HttpProxyCacheServer.Builder(context)
    .fileNameGenerator(new MyFileNameGenerator())
    .build()

Adding custom http headers

You can add custom headers to requests with help of HeadersInjector:

public class UserAgentHeadersInjector implements HeaderInjector {

    @Override
    public Map<String, String> addHeaders(String url) {
        return Maps.newHashMap("User-Agent", "Cool app v1.1");
    }
}

private HttpProxyCacheServer newProxy() {
    return new HttpProxyCacheServer.Builder(this)
            .headerInjector(new UserAgentHeadersInjector())
            .build();
}

Using exoPlayer

You can use exoPlayer with AndroidVideoCache. See sample app in exoPlayer branch. Note exoPlayer supports cache as well.

Sample

See sample app.

Known problems

• In some cases clients can't connect to local proxy server ('Error pinging server' error). May be it is result of previous error. Note in this case video will be played, but without caching.

Whats new

See Release Notes here

Code contributions

If it's a feature that you think would need to be discussed please open an issue first, otherwise, you can follow this process:

1. Fork the project
2. Create a feature branch (git checkout -b my_branch)
3. Fix a problem. Your code must contain test for reproducing problem. Your tests must be passed with help of your fix
4. Push your changes to your new branch (git push origin my_branch)
5. Initiate a pull request on github
6. Rebase master branch if your local branch is not actual. Merging is not acceptable, only rebase
7. Your pull request will be reviewed and hopefully merged :)

Where published?

Here

Questions?

danikula@gmail.com

License

Copyright 2014-2017 Alexey Danilov

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.