Node for Not HTTP

The talk gave an overview of some of the cool things you can do with node.js that are not related to websites. To do this, I cobbled together an actionhero project that would take input form HTTP, WebSockets, Telnet, and twitter which allowed us to turn a desk lamp on and off. I taught a room about the DMX lighting protocol and how to build an actionhero server in 20 minutes!

- Slides: https://docs.google.com/presentation/d/1jijGOARfeMDSqZnl52uv3N9zL8K4Eiu4g6wGTtUIll4
- Github Project: https://github.com/evantahler/nodefornot_http
- Video: http://strongloop.com/node-js/videos/#An-Introduction-to-Non-HTTP-Clients-for-Node.js

Transcript

1. Node.js for !(HTTP)
   @evantahler
   https://github.com/evantahler/node_for_not_http
   

   View Slide

2. Node is great at HTTP
   var http = require('http');
   http.createServer(function (req, res) {
   res.writeHead(200, {'Content-Type': 'text/plain'});
   res.end('Hello World\n');
   }).listen(1337, '127.0.0.1');
   

   View Slide

3. What else can node do well?
   ● WebSockets
   ● TCP (socket)
   ● UDP (socket)
   ● Driver Communication
   ● Incoming Streams via all of the above
   The event loop is great for handling any connection
   type, not just HTTP (just don’t block the CPU).
   

   View Slide

4. What are we going to do?
   Lets turn this light on and off…
   … via telnet
   … via websockets
   … via twitter
   … via the temperature in the room
   … via joysticks
   This talk will be a quick survey of some of using node.js for things other
   than HTTP
   

   View Slide

5. {{ BioPage }}
   @evantahler
   evantahler.com
   ● Director of Technology @ TaskRabbit
   ● Creator of the actionhero.js framework
   We are hiring! Talk to me later!
   

   View Slide

6. When we last saw our hero...
   www.actionherojs.com
   actionhero.js is a multi-transport API Server with integrated
   cluster capabilities and delayed tasks.
   

   View Slide

7. View Slide

8. 0: Lights
   

   View Slide

9. 0) How do we talk to this light?
   

   View Slide

10. 0) How do we talk to this light?
    

    View Slide

11. DMX is pretty cool
    ● DMX is EASY
    It was the 1980’s...
    1. send null (0v)
    2. send a buffer of integer values (8 bits)
    3. sleep 20ms.
    4. goto 1
    

    View Slide

12. Unix is pretty cool
    ● Everything is a file!
    ○ COM port -> /dev/usb..
    var ftdi = require('ftdi');
    

    View Slide

13. 0) How do we talk to DMX?
    var ftdi = require('ftdi');
    ...
    ftdi.find(function(err, devices){
    api.dmx.device = new ftdi.FtdiDevice(devices[0]);
    api.dmx.device.on('error', function(e){ … });
    api.dmx.device.open(api.config.dmx, function(){ … });
    })
    ...
    api.dmx.universe = Buffer(513);
    setInterval(function(){
    api.dmx.device.write(api.dmx.universe);
    }, 20);
    Demo Time!
    

    View Slide

14. 0) A DMX action
    actionhero generateAction --name=dmx
    …
    exports.action = {
    name: 'dmx',
    description: 'dmx',
    ...
    inputs: {required: ['channel', 'power'], optional: []},
    run: function(api, connection, next){
    var channel = parseInt(connection.params.channel);
    var power = parseInt(connection.params.power);
    try{
    api.dmx.set(channel, power);
    }catch(err){
    connection.error = err;
    }
    next(connection, true);
    }
    };
    Demo Time!
    

    View Slide

15. 1: Telnet
    

    View Slide

16. 1) How do we talk to Telnet?
    server.server = net.createServer(...);
    …
    > telnet localhost 5000
    Trying 127.0.0.1...
    Connected to localhost.
    Escape character is '^]'.
    {"welcome":"Hello! Welcome to the actionhero api","room":"defaultRoom","context":"api"}
    > detailsView
    {"status":"OK","context":"response","data":{"id":"2d68c389-521d-4dc6-b4f1-8292cd6cbde6","remoteIP":"127.0.0.1","remotePort":
    57393,"params":{},"connectedAt":1368918901456,"room":"defaultRoom","totalActions":0,"pendingActions":0},"messageCount":1}
    > randomNumber
    {"randomNumber":0.4977603426668793,"context":"response","messageCount":2}
    Demo Time!
    

    View Slide

17. 1) How do we talk to Telnet?
    Telnet API Considerations:
    ● Simultaneous Actions / Parallelism for a
    single connection
    ● Line Terminators
    ● Data Transports
    

    View Slide

18. 2: Websockets
    

    View Slide

19. 2) How do we talk to websockets?
    ● The same design considerations apply as
    telnet!
    ○ … and now you need to worry about fall-back
    protocols and http handshakes
    

    View Slide

20. 2) How do we talk to websockets?
    client = new ActionheroClient;
    client.on('connected', function(){ console.log('connected!') })
    client.on('disconnected', function(){ console.log('disconnected :(') })
    client.on('alert', function(message){ alert(message) })
    client.on('api', function(message){ alert(message) })
    client.on('welcome', function(message){ appendMessage(message); })
    client.on('say', function(message){ appendMessage(message); })
    client.connect(function(err, details){
    if(err){
    console.log(err);
    }else{
    client.action('someAction', {key: 'k', value: 'v'}, function(error data){
    // do stuff
    });
    }
    });
    Demo Time!
    

    View Slide

21. 3: Twitter
    

    View Slide

22. 3) How do we Twitter?
    ● Servers vs. Connections, a philosophical
    aside.
    ○ We could write another initializer for twitter, and
    handle the data as it streams in.
    ○ But isn’t each tweet kind of like a connection?
    ■ data, client_id, message…
    

    View Slide

23. 3) How do we Twitter?
    actionhero generateServer \
    --name=twitter
    

    View Slide

24. 3) How do we Twitter?
    server.addTweet = function(tweet){
    var twitterUser;
    try{
    twitterUser = tweet.user.screen_name;
    }catch(e){
    var twitterUser = "unknown";
    }
    server.buildConnection({
    id: tweet.id,
    rawConnection : {
    hashtag: api.config.servers.twitter.hashtag,
    clientId: tweet.id,
    message: tweet.text,
    twitterUser: twitterUser,
    },
    remoteAddress : 0,
    remotePort : 0 ,
    }); // will emit "connection"
    Demo Time!
    

    View Slide

25. All together now...
    [[ I just used twitter to control the #nodelights ]]
    

    View Slide

26. Thanks!
    

    View Slide

27. References
    Me: http://evantahler.com
    Actionhero: http://actionherojs.com
    ● Docs: http://actionherojs.com/docs/
    About DMX: http://playground.arduino.cc/Learning/DMX
    Hardware:
    ● Dimmer Pack: http://www.amazon.com/gp/product/B000FVZUMM/
    ● DMX Driver: http://www.enttec.com/index.php?main_menu=Products&pn=70303
    This Project: https://github.com/evantahler/node_for_not_http
    

    View Slide