Introduction to CodeIgniter Steve Webb Refresh OKC 17 Jun 2008

What is CodeIgniter? CodeIgniter is a lightweight web application framework written in PHP that adopts the model-view-controller approach to development

CodeIgniter is a lightweight web application framework written in PHP that adopts the model-view-controller approach to development

Why use a framework? Web application frameworks provide basic building blocks needed by most applications Database connections Business logic Form handling Separation of concerns Easier testing (unit tests)

Web application frameworks provide basic building blocks needed by most applications

Database connections

Business logic

Form handling

Separation of concerns

Easier testing (unit tests)

Why use CodeIgniter? Feature rich Lightweight Open source Well-supported by an active community Excellent “by example” documentation Easy to configure Supports multiple databases

Feature rich

Lightweight

Open source

Well-supported by an active community

Excellent “by example” documentation

Easy to configure

Supports multiple databases

Why use CodeIgniter? In short, CodeIgniter is nice because it does what it needs to do and then gets out of the way.

In short, CodeIgniter is nice because it does what it needs to do and then gets out of the way.

Model-View-Controller Model – representation of the data View – rendering of the data suitable for interaction with the user Controller – the “traffic cop” that passes model data to the views and vice versa This separation of concerns allows for greater flexibility, reuse of code, and overall preservation of the developer’s sanity

Model – representation of the data

View – rendering of the data suitable for interaction with the user

Controller – the “traffic cop” that passes model data to the views and vice versa

This separation of concerns allows for greater flexibility, reuse of code, and overall preservation of the developer’s sanity

Controller A class containing one or more related methods (custom PHP functions) Typical uses: Request a set of data from the model by sending arguments Send a payload of data to a view (web page) Receive a data payload from a view Apply business logic to make decisions Pass data to the model for inclusion in a database

A class containing one or more related methods (custom PHP functions)

Typical uses:

Request a set of data from the model by sending arguments

Send a payload of data to a view (web page)

Receive a data payload from a view

Apply business logic to make decisions

Pass data to the model for inclusion in a database

View Code that displays information to the user Views can be: Web pages with PHP code snippets inserted Web pages with forms to gather user input Other output (CSV, PDF, etc.)

Code that displays information to the user

Views can be:

Web pages with PHP code snippets inserted

Web pages with forms to gather user input

Other output (CSV, PDF, etc.)

Model A class containing one or more related methods (custom PHP functions) Typical uses: Create Read Update Delete

A class containing one or more related methods (custom PHP functions)

Typical uses:

Create

Read

Update

Delete

CodeIgniter Classes CI’s built-in classes contain the basic functionality that are frequently used by web applications The most-used classes are: Database Input Loader URI Validation

CI’s built-in classes contain the basic functionality that are frequently used by web applications

The most-used classes are:

Database

Input

Loader

URI

Validation

Database Class Generates queries using the Active Record Pattern Automatic escaping of input values Provides method “chaining” for easy query building $this->db->where(‘name’,$name);

Generates queries using the Active Record Pattern

Automatic escaping of input values

Provides method “chaining” for easy query building

$this->db->where(‘name’,$name);

Input Class Pre-processes user input (prevents common cross-site scripting techniques) Provides access to user input and other data: Form fields (POST) Cookies Server variables $this->input->post(‘fieldname’);

Pre-processes user input (prevents common cross-site scripting techniques)

Provides access to user input and other data:

Form fields (POST)

Cookies

Server variables

$this->input->post(‘fieldname’);

Loader Class Makes various resources available: Databases Views Helpers Plugins $this->load->view(‘viewname’);

Makes various resources available:

Databases

Views

Helpers

Plugins

$this->load->view(‘viewname’);

URI Class Provides access to specific parts of the URI string Useful for building RESTful URIs $this->uri->segment(n);

Provides access to specific parts of the URI string

Useful for building RESTful URIs

$this->uri->segment(n);

Validation Class Helps validate user form input Required fields Required string formatting (length, regexp) Enables success and failure messages on form submittal Enables re-population of form fields after form submittal

Helps validate user form input

Required fields

Required string formatting (length, regexp)

Enables success and failure messages on form submittal

Enables re-population of form fields after form submittal

Other Classes Benchmarking Calendaring Email Encryption File uploading FTP HTML Table Image Manipulation Language (internationalization) Output Pagination Session Trackback Unit testing XML-RPC Zip encoding

Benchmarking

Calendaring

Email

Encryption

File uploading

FTP

HTML Table

Image Manipulation

Language (internationalization)

Output

Pagination

Session

Trackback

Unit testing

XML-RPC

Zip encoding

Helpers and Plugins CodeIgniter comes with a wide array of “helper” functions that add convenience to applications and provide ease of reuse. $this->load->helper(‘helper_name’); CodeIgniter also allows for the use of custom add-on functions called “plugins”. $this->load->plugin(‘plugin_name’);

CodeIgniter comes with a wide array of “helper” functions that add convenience to applications and provide ease of reuse.

$this->load->helper(‘helper_name’);

CodeIgniter also allows for the use of custom add-on functions called “plugins”.

$this->load->plugin(‘plugin_name’);

My First CI Application Unzip CI zip file into application folder on web server [optional] For “pretty URLs”, add .htaccess file and enable mod_rewrite in Apache Configure database in CI’s <config.php> Write controller (or modify existing) Write view (or modify existing) Write model

Unzip CI zip file into application folder on web server

[optional] For “pretty URLs”, add .htaccess file and enable mod_rewrite in Apache

Configure database in CI’s <config.php>

Write controller (or modify existing)

Write view (or modify existing)

Write model

Demo