robrighter's Node.js presentation for DevChatt

Current @robrighter

What is Node.js? _ non-blocking _ evented _ javascript @robrighter

Why is node useful? @robrighter

Why is node useful? It can handle a ton of concurrent connections @robrighter

A Gross Oversimpliﬁcation of HTTP Give me a page Sure Connection Closed @robrighter

AJAX Polling Got any updates? No Connection Closed Got any updates? No Connection Closed @robrighter

Comet Got any updates? ...wait Yes Connection Closed @robrighter

Websocket asyncronous updates @robrighter

Evented Programming @robrighter

Non-Evented Example mysql_select_db("example", $con); $result = mysql_query("SELECT * FROM user WHERE fname='Bill'"); while($row = mysql_fetch_array($result)){ echo $row['fname']; } @robrighter

Evented Example fs.readFile("./file", function (err, data) { if (err) throw err; sys.puts(data); }); @robrighter

An Example @robrighter

Server Side @robrighter

Setup the Data Source var rb = new lpb.LongPollingBuffer(70); var dump = process.createChildProcess("tcpdump",["-i","en1","-A","-n","port", "80"]); var ignorelist = ['localhost','foxnews.com']; //Setup the listener to handle the flow of data from the dump dump.addListener("output", function (data) { var hosts = data.match(/Host: (.*)/g); if(hosts){ _.each(hosts, function(item){ var out = item.slice(6); sys.puts(out); if(!_.detect(ignorelist, function(s){ return (item.indexOf(s) > -1); })){ rb.push(out); } }); } }); @robrighter

LongPollingBuffer DATA ARRAY DATA: 1 1 1 0 1 0 0 1 1 0 OFFSET: 0 2 3 4 5 6 7 8 9 10 CLIENT ONE CLIENT TWO @robrighter

Setup the Updater fu.get("/update", function (req, res) { //Send the HTTP Headers res.sendHeader(200,{"Content-Type": "text/html"}); //Parse out the since from the query string var thesince; if(url.parse(req.url,true).hasOwnProperty('query') && url.parse(req.url,true).query.hasOwnProperty('since')){ thesince = parseInt(url.parse(req.url,true)['query']['since']); } else { thesince = -1; } //Setup the datalistener (note why this works so well with JS scoping) rb.addListenerForUpdateSince(thesince, function(data){ var body = '['+_.map(data,JSON.stringify).join(',n')+']'; res.write( body ); res.close(); }); }); @robrighter

Client Side @robrighter

Long Polling Request var url = “/update?since=” + lastrecieved; $.getJSON(url, function(data){ var itemstoadd = _.map(data.reverse(),function(item){ lastrecieved = item["offset"]; return domainmarkup(item['value']); }); var uc = $("#updatedcontent"); _.map(itemstoadd, function(item){ if(!interrupt){ uc.prepend(item); } }); setTimeout('getupdate(lastrecieved)', 1000); }); @robrighter

Questions? github.com/robrighter twitter.com/robrighter @robrighter

robrighter's Node.js presentation for DevChatt

by robrighter on Mar 23, 2010

Accessibility

Tags

Upload Details

Usage Rights

1 Embed 2

Statistics

robrighter’s Node.js presentation for DevChatt — Presentation Transcript