Igniting your web-service
Using CodeIgniter and REST to share information between
applications, servers and services.
Phil Sturgeon
email@philsturgeon.co.uk http://twitter.com/philsturgeon
http://philsturgeon.co.uk http://github.com/philsturgeon

What the hell is REST?
An easy way to transfer data between client(s) & server
Provides data in XML, JSON, HTML, CSV... pretty much anything
depending on what HTTP Accept header you send.
Works over HTTP GET, POST, PUT and DELETE
Not a technology, more of a convention

That sounds just like...
XML-RPC

That sounds just like...
XML-RPC
SOAP

That sounds just like...
XML-RPC
JSON-RPC
SOAP

That sounds just like...
XML-RPC Request
SOAP
Response
JSON-RPC

That sounds just like...
XML-RPC Request
SOAP
Response
JSON-RPC

That sounds just like...
XML-RPC Request
{ “method": "sayHelloTo", "params": "to" : ["my little friend"], "id": 1}
SOAP
Response
{ "result": "Say hello to: my little friend!", "id": 1}
JSON-RPC

So how does REST do it?
Request
http://twitter.com/users/show/philsturgeon
HTTP Accept: application/json
Responce
{
"verified":false,
"profile_background_tile":false,
"description":"I work as a developer for @HargLansdown and use my spare time to
develop, write articles about programming and create slightly intoxicated
screencasts.",
"profile_background_color":"024d68",
...etc
}

What’s this got to do with CodeIgniter?
CodeIgniter is the perfect match for creating
and ingesting REST
Strong OOP architecture
Use existing models and libraries
Use ActiveRecord and ORM
Validate POST requests with Form_validation

Average CodeIgniter architectures
One (or two) servers
Database
CodeIgniter frontend models run
database queries
Models need to know if they are looking
at MySQL, MSSQL, Oracle, etc. Frontend
Makes scalability tricky

API based architecture
Flexible server architecture
Database
Use it for desktop apps or Mobile Apps
mobile applications
Public API already created
(optional) CodeIgniter
Desktop Apps
REST API
Business logic central
Frontend no longer
database dependant
Performance - Implement Frontend Third-party sites
basic caching on API layer

Case study
HargreavesLansdown
http://h-l.co.uk/

Objects and data access for constructing web pages
Case study
Author: James Tyrrell
Last updated: 03/04/07
Database Broker Focus MySQL MS SQL
servers
HargreavesLansdown Data
abstraction
TCF
components
creole
Creole: Provides a unified set
of methods for interacting with
databases
Middleware
Remote
Remote Object
servers
functions Models
Remote SOAP REST
Data server class Classes Classes
transport
HTTP POST SOAP Call RESTful GET
Posts requests to the middleware
Remote
SOAP and unserializes the results it gets
client class
Client back.
Contain the application logic for the
Business Front-end CMS, Smarty, error logging,
logic classes business processes, email, user
security, etc.
Web server
Other
Page Systems
Atlas
constructor
(default.php)
Presentation
layer
Page processors: Contain code
required to build the content of a
module (e.g. fund data, news
headlines) and output to Smarty
Page processors templates. Contains module-
level logic (e.g. to switch
between steps in a process).
Stored in the section directories.
http://h-l.co.uk/
Subscripts & templates: Stored
Subscripts and templates in the /inc & /tpl sub-folders of
each section

Objects and data access for constructing web pages
Case study
Author: James Tyrrell
Last updated: 03/04/07
Database Broker Focus MySQL MS SQL
servers
HargreavesLansdown Data
abstraction
TCF
components
creole
Creole: Provides a unified set
of methods for interacting with
databases
Middleware
Remote
Remote Object
servers
functions Models
Remote SOAP REST
Data server class Classes Classes
transport
HTTP POST SOAP Call RESTful GET
Posts requests to the middleware
Remote
SOAP and unserializes the results it gets
client class
Client back.
Contain the application logic for the
Business Front-end CMS, Smarty, error logging,
logic classes business processes, email, user
security, etc.
Web server
Other
Page Systems
Atlas
constructor
(default.php)
Presentation
layer
Page processors: Contain code
required to build the content of a
module (e.g. fund data, news
headlines) and output to Smarty
Page processors templates. Contains module-
level logic (e.g. to switch
between steps in a process).
Stored in the section directories.
http://h-l.co.uk/
Subscripts & templates: Stored
Subscripts and templates in the /inc & /tpl sub-folders of
each section

Objects and data access for constructing web pages
Case study
Author: James Tyrrell
Last updated: 03/04/07
Database Broker Focus MySQL MS SQL
servers
HargreavesLansdown Data
abstraction
TCF
components
creole
Creole: Provides a unified set
of methods for interacting with
databases
Middleware
Remote
Remote Object
servers
functions Models
Data
transport
CodeIgniter
Remote
server class
SOAP
Classes
REST
Classes
REST API
HTTP POST SOAP Call RESTful GET
Posts requests to the middleware
Remote
SOAP and unserializes the results it gets
client class
Client back.
Contain the application logic for the
Business Front-end CMS, Smarty, error logging,
logic classes business processes, email, user
security, etc.
Web server
Other
Page Systems
Atlas
constructor
(default.php)
Presentation
layer
Page processors: Contain code
required to build the content of a
module (e.g. fund data, news
headlines) and output to Smarty
Page processors templates. Contains module-
level logic (e.g. to switch
between steps in a process).
Stored in the section directories.
http://h-l.co.uk/
Subscripts & templates: Stored
Subscripts and templates in the /inc & /tpl sub-folders of
each section

Serving REST content in CodeIgniter
http://github.com/philsturgeon/codeigniter-restserver

How does it work?
<?php
require(APPPATH.'/libraries/REST_Controller.php');
1x REST_Controller.php class Example_api extends REST_Controller {
function user_get()
{
1x (or more) API controllers $user = $this->user_model->get_user( $this->get('id') );
if(!empty($user))
{
HTTP method based methods
$this->response($user, 200); // 200 being the HTTP response code
}
else
{
Normal CodeIgniter stuff }
$this->response(NULL, 404);
}
$this->response($data)
function user_post()
{
$result = $this->user_model->update( $this->post('id'), $_POST );
$this->response($result, 200); // 200 being the HTTP response code
}
?>

Quick CodeIgniter REST API recap
Building an API can be useful for small and big sites alike
Build your data interaction code once, use it everywhere
Use ActiveRecord and ORM over standalone abstraction layers
Keep your application independent of the data source via the API.

Who else is doing it?

Making REST requests in CodeIgniter
http://github.com/philsturgeon/codeigniter-restclient

Integration with “2.0” services you say?
VERY Basic Example
$this->load->library('rest', array(
'server' => 'http://twitter.com/'
));
$result = $this->rest->get('users/show/philsturgeon');
This GET’s all data from http://twitter.com/users/show/philsturgeon
and detects what format it is being returned in. It spots it is XML
and parses it accordingly.

Integration with “2.0” services you say?
More complicated example
$this->load->library('rest', array(
'server' => 'http://twitter.com/',
'http_user' => 'philsturgeon',
'http_pass' => 'password'
));
$params = array(
'status'=> 'Run, @dallard’s robots are attacking!'
);
$result = $this->rest->post('statuses/update.xml', $params);
Posts a new message as the user provided.

Summary
REST API’s mean you can run actions on other services,
websites and applications.
i.e: Do almost anything on Twitter, Flickr and Facebook
that you can do on the site.
Can replace your models with REST requests, or implement
to libraries.