Exploding the internet

With jQuery and Couch DB

http://gul.ly/h6

http://htmlten.com/slides

Boaz Sender

• @BoazSender On Twitter
• boaz on freenode (/msg boaz)
• boazsender.com on the www
• JavaScript Programmer at Bocoup

What is CouchDB?

• Key value document store
• HTTP REST interface
• JavaScript Views
• Highly available and scalable

What are we going to talk about?

• Why CouchDB?
• Eventual consistency
• Setting up couch on the server
• Interacting with CouchDB using JavaScript in the client
• Writing views
• Use cases

Why CouchDB?

• HTTP interface
• Flexible views
• Built in validation
• Turnkey replication

Eventual consistency

• High availability over consistency
• Revision system
• Replication

Setting up couch on the server

• # sudo aptitude install couchdb
• # /etc/init.d/couchdb start
• visit: http://yourdomain:5984
• Relax

Interacting with CouchDB

Using JavaScript in the client

• Make a database
• Get the database
• Write a record
• Get a record

Make a database

  $.ajax({
    url: 'http://htmlten.com/db/couchdemo/', 
    type: 'PUT',
    success: function(response){
    	console.log(response);
    }
  });

• All the dbs: _all_dbs
• All the documents in a db: _all_docs
  • descending=true
  • startkey="doc2"
  • endkey="doc3"

Get the database

  $.ajax({
    url: 'http://htmlten.com/db/couchdemo/', 
    type: 'GET',
    success: function(response){
      console.log(response);
    }
  });

• All the dbs: _all_dbs
• All the documents in a db: _all_docs
  • descending=true
  • startkey="doc2"
  • endkey="doc3"

Write a record

  var newRecordId = '1',
  newRecord   = {
    //'_id': '1',
    'firstname' : 'boaz',
    'lastname'  : 'sender',
    'twitterhandle' : '@boazsender',
    'height'        : '72'
  };
  
  $.ajax({
    url: 'http://htmlten.com/db/couchdemo/' + newRecordId, 
    type: 'PUT',
    data: JSON.stringify(newRecord),
    dataType: 'JSON',
    success: function(response){
      console.log(response)
    }
  });

Get a record

	var recordId = '1';
	$.ajax({
      url: 'http://htmlten.com/db/couchdemo/' + recordId, 
  	  type: 'GET',
      success: function(response){
	      console.log(response)
      }
	});

• _all_docs

Writing views

• MapReduce
  • First you run your map function on each document
  • Then you reduce that set with a reduce function
  • That's pretty awesome

Getting your view data

  $.ajax({
    url: 'http://htmlten.com/db/couchdemo/_design/heights/_view/users_by_height', 
    type: 'GET',
    success: function(response){
    	console.log(response)
    }
  });

Use Cases

• Static data
• More reads than writes
• Unpredictable data models
• One user(s)
• Offline applications

Questions

Thank You

• @BoazSender On Twitter
• boaz on freenode
• boazsender.com on the www
• JavaScript Programmer at Bocoup