AndroidAsync

AndroidAsync is a low level network protocol library. If you are looking for an easy to use, higher level, Android aware, http request library, check out Ion (it is built on top of AndroidAsync). The typical Android app developer would probably be more interested in Ion.

But if you're looking for a raw Socket, HTTP client/server, WebSocket, and Socket.IO library for Android, AndroidAsync is it.

Features

• Based on NIO. One thread, driven by callbacks. Highly efficient.
• All operations return a Future that can be cancelled
• Socket client + socket server
• HTTP client + server
• WebSocket client + server
• Socket.IO client

Download

Download the latest JAR or grab via Maven:

<dependency>
    <groupId>com.koushikdutta.async</groupId>
    <artifactId>androidasync</artifactId>
    <version>(insert latest version)</version>
</dependency>

Download a url to a String

// url is the URL to download.
AsyncHttpClient.getDefaultInstance().getString(url, new AsyncHttpClient.StringCallback() {
    // Callback is invoked with any exceptions/errors, and the result, if available.
    @Override
    public void onCompleted(Exception e, AsyncHttpResponse response, String result) {
        if (e != null) {
            e.printStackTrace();
            return;
        }
        System.out.println("I got a string: " + result);
    }
});

Download JSON from a url

// url is the URL to download.
AsyncHttpClient.getDefaultInstance().getJSONObject(url, new AsyncHttpClient.JSONObjectCallback() {
    // Callback is invoked with any exceptions/errors, and the result, if available.
    @Override
    public void onCompleted(Exception e, AsyncHttpResponse response, JSONObject result) {
        if (e != null) {
            e.printStackTrace();
            return;
        }
        System.out.println("I got a JSONObject: " + result);
    }
});

Or for JSONArrays...

// url is the URL to download.
AsyncHttpClient.getDefaultInstance().getJSONArray(url, new AsyncHttpClient.JSONArrayCallback() {
    // Callback is invoked with any exceptions/errors, and the result, if available.
    @Override
    public void onCompleted(Exception e, AsyncHttpResponse response, JSONArray result) {
        if (e != null) {
            e.printStackTrace();
            return;
        }
        System.out.println("I got a JSONArray: " + result);
    }
});

Download a url to a file

AsyncHttpClient.getDefaultInstance().getFile(url, filename, new AsyncHttpClient.FileCallback() {
    @Override
    public void onCompleted(Exception e, AsyncHttpResponse response, File result) {
        if (e != null) {
            e.printStackTrace();
            return;
        }
        System.out.println("my file is available at: " + result.getAbsolutePath());
    }
});

Caching is supported too

// arguments are the http client, the directory to store cache files, and the size of the cache in bytes
ResponseCacheMiddleware.addCache(AsyncHttpClient.getDefaultInstance(),
                                  getFileStreamPath("asynccache"),
                                  1024 * 1024 * 10);

Can also create web sockets:

AsyncHttpClient.getDefaultInstance().websocket(get, "my-protocol", new WebSocketConnectCallback() {
    @Override
    public void onCompleted(Exception ex, WebSocket webSocket) {
        if (ex != null) {
            ex.printStackTrace();
            return;
        }
        webSocket.send("a string");
        webSocket.send(new byte[10]);
        webSocket.setStringCallback(new StringCallback() {
            public void onStringAvailable(String s) {
                System.out.println("I got a string: " + s);
            }
        });
        webSocket.setDataCallback(new DataCallback() {
            public void onDataAvailable(ByteBufferList byteBufferList) {
                System.out.println("I got some bytes!");
                // note that this data has been read
                byteBufferList.recycle();
            }
        });
    }
});

AndroidAsync also supports socket.io (version 0.9.x)

SocketIOClient.connect(AsyncHttpClient.getDefaultInstance(), "http://192.168.1.2:3000", new ConnectCallback() {
    @Override
    public void onConnectCompleted(Exception ex, SocketIOClient client) {
        if (ex != null) {
            ex.printStackTrace();
            return;
        }
        client.setStringCallback(new StringCallback() {
            @Override
            public void onString(String string) {
                System.out.println(string);
            }
        });
        client.on("someEvent", new EventCallback() {
            @Override
            public void onEvent(JSONArray argument, Acknowledge acknowledge) {
                System.out.println("args: " + arguments.toString());
            }
        });
        client.setJSONCallback(new JSONCallback() {
            @Override
            public void onJSON(JSONObject json) {
                System.out.println("json: " + json.toString());
            }
        });
    }
});

Need to do multipart/form-data uploads? That works too.

AsyncHttpPost post = new AsyncHttpPost("http://myservercom/postform.html");
MultipartFormDataBody body = new MultipartFormDataBody();
body.addFilePart("my-file", new File("/path/to/file.txt");
body.addStringPart("foo", "bar");
post.setBody(body);
AsyncHttpClient.getDefaultInstance().execute(post, new StringCallback() {
    @Override
    public void onCompleted(Exception e, AsyncHttpResponse source, String result) {
        if (e != null) {
            ex.printStackTrace();
            return;
        }
        System.out.println("Server says: " + result);
    }
});

AndroidAsync also let's you create simple HTTP servers:

AsyncHttpServer server = new AsyncHttpServer();

List<WebSocket> _sockets = new ArrayList<WebSocket>();

server.get("/", new HttpServerRequestCallback() {
    @Override
    public void onRequest(AsyncHttpServerRequest request, AsyncHttpServerResponse response) {
        response.send("Hello!!!");
    }
});

// listen on port 5000
server.listen(5000);
// browsing http://localhost:5000 will return Hello!!!

And WebSocket Servers:

server.websocket("/live", new WebSocketRequestCallback() {
    @Override
    public void onConnected(final WebSocket webSocket, AsyncHttpServerRequest request) {
        _sockets.add(webSocket);
        
        //Use this to clean up any references to your websocket
        websocket.setClosedCallback(new CompletedCallback() {
            @Override
            public void onCompleted(Exception ex) {
                try {
                    if (ex != null)
                        Log.e("WebSocket", "Error");
                } finally {
                    _sockets.remove(webSocket);
                }
            }
        });
        
        webSocket.setStringCallback(new StringCallback() {
            @Override
            public void onStringAvailable(String s) {
                if ("Hello Server".equals(s))
                    webSocket.send("Welcome Client!");
            }
        });
    
    }
});

//..Sometime later, broadcast!
for (WebSocket socket : _sockets)
    socket.send("Fireball!");

Futures

All the API calls return Futures.

Future<String> string = client.getString("http://foo.com/hello.txt");
// this will block, and may also throw if there was an error!
String value = string.get();

Futures can also have callbacks...

Future<String> string = client.getString("http://foo.com/hello.txt");
string.setCallback(new FutureCallback<String>() {
    @Override
    public void onCompleted(Exception e, String result) {
        System.out.println(result);
    }
});

For brevity...

client.getString("http://foo.com/hello.txt")
.setCallback(new FutureCallback<String>() {
    @Override
    public void onCompleted(Exception e, String result) {
        System.out.println(result);
    }
});