How to write an Apple Push Notification Provider in C#?

Question

Apple really had bad documentation about how the provider connects and communicates to their service (at the time of writing - 2009). I am confused about the protocol. How i

Answer 1

I hope this is relevant (slightly), but I have just successfully created one for Java, so conceptually quite similar to C# (except perhaps the SSL stuff, but that shouldn't be too hard to modify. Below is a sample message payload and crypto setup:

    int port = 2195;
    String hostname = "gateway.sandbox.push.apple.com";


    char []passwKey = "".toCharArray();
    KeyStore ts = KeyStore.getInstance("PKCS12");
    ts.load(new FileInputStream("/path/to/apn_keystore/cert.p12"), passwKey);

    KeyManagerFactory tmf = KeyManagerFactory.getInstance("SunX509");
    tmf.init(ts,passwKey);
    SSLContext sslContext = SSLContext.getInstance("TLS");
    sslContext.init(tmf.getKeyManagers(), null, null);
    SSLSocketFactory factory =sslContext.getSocketFactory();
    SSLSocket socket = (SSLSocket) factory.createSocket(hostname,port); // Create the ServerSocket
    String[] suites = socket.getSupportedCipherSuites();
    socket.setEnabledCipherSuites(suites);
    //start handshake

    socket.startHandshake();


    // Create streams to securely send and receive data to the server
    InputStream in = socket.getInputStream();
    OutputStream out = socket.getOutputStream();



    // Read from in and write to out...
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    baos.write(0); //The command
    System.out.println("First byte Current size: " + baos.size());

    baos.write(0); //The first byte of the deviceId length    
    baos.write(32); //The deviceId length

    System.out.println("Second byte Current size: " + baos.size());

    String deviceId = "

}

Once again, not C#, but at least closer than the poor ObjC sample that Apple provides.