CodeIgniter is an MVC framework that allows developers to build applications in a logical manner. It provides features like clean URLs, form validation, security protections, and image manipulation tools out of the box. While CodeIgniter does not enforce rigid structures, it enables organization of applications into models, views, and controllers. It aims to help developers write code faster without forcing atypical approaches. The framework has good documentation and an active community for support.

1. 5 Reasons To Love CodeIgniter

2. Everyone Loves Their Framework

3. What Is CodeIgniter?It’s an MVC framework.MVC stands for Model View Controller and it’s a logical way of organizing an application. Models interact with the databaseControllers take care of the logicViews present the outputCodeIgniter doesn’t force you to do things this way, it enables you to do so.

4. Why CodeIgniter?According To MeMost frameworks will help you write better code faster. CodeIgniter will help you do that without forcing you into some intricate, and weird way of doing things.According To EllisLab (creators of CI)“…helps you write kick-ass PHP programs”

5. Submit URIs To Your WillOne of the foundations of CI is “clean URLs”. Nice looking, well organized URLs, without any of the ugliness of query strings.Uglyatlantaphp.org/presenters.php?action=display&name=nicPrettyatlantaphp.org/presenters/display/nic

6. How Does it Work?It’s a thing of beauty, really.class Presenters extends Controller{ function display($var){ echo $var; }}//Echoes “nic”

7. Need More Control?Why yes, there’s a class for thatatlantaphp.org/archives/show/picture/1234$this->uri->segment(3); //picture$this->uri->segment(99,0); //Returns 0 instead of FALSE$this->uri->uri_to_assoc(); //[array](‘picture’ => ‘1234’)$this->uri->uri_string(); // /archives/show/picture/1234$this->uri->total_segments(); //4There are several more functions to play around with.

8. Form and Data ValidationThe Form view<?php echo validation_errors(); ?><form action="form_test" method="post”> <label for="username">Username</label> <input type="text" name="username" value="<?php echo set_value('username'); ?>"/> <input type="submit" value="Submit" /></form>

9. The controllerclass Form_test extends Controller { function index(){ //Index is always the default for the controller $this->load->library('form_validation'); $this->form_validation->set_rules('username', 'Username', 'required|min_length[5]'); if ($this->form_validation->run() == FALSE) { $this->load->view('form_view’); } else { $this->load->view('form_ok'); } }}

11. Other Cool Stuff$this->form_validation->set_rules('username', 'Username', 'trim|required|min_length[5]’);$this->form_validation->set_rules('username', 'Username', ‘check_duplicate');$this->form_validation->set_error_delimiters(’<span class="error">', '</span>');<?php echo form_error('username'); ?>set_select() set_checkbox() and set_radio()

12. Security and XSS FilteringCodeIgniter does a few things right off the bat.Destroys $_GET.Destroys all global variables (although register_globals is off by default since 4.2.0)Filters $_POST and $_COOKIE array keys, allowing only alphanumeric characters plus “~%.:_\-”XSS filtering can be enabled globally or called by a function.

13. XSS FilteringCan be enabled two waysLocally: $data = $this->input->xss_clean($data);$img_file = this->input->xss_clean($file, TRUE) //Checks image files for XSS attacks$name = $this->input->post(‘name’, TRUE) //$_POST[‘name’]Globally (in the config file):config['global_xss_filtering'] = TRUE;

14. Database SecurityThere are many ways to sanitize your queries, CodeIgniter offers a few.Bindings$sql = “SELECT FROM members WHERE name = ?”;$this->db->query($sql, array(‘nic’));Using the Active Record class takes care of security aspects$this->db->where(’name', $name);$this->db->update(’users', $data);Other Functions$this->db->protect_identifiers('table_name');$this->db->escape($data);$this->db->escape_str($data);$this->db->escape_like_str($data);

15. PaginationIt’s always an issue to display large data sets in an orderly manner. CodeIgniter provides a way to set up proper pagination in a few lines of code.In the controller$this->load->library('pagination');$config['base_url'] = 'http://atlantaphp.org/pager/index/';$config['total_rows'] = 200;$config['per_page'] = 10; $this->pagination->initialize($config);In the viewecho $this->pagination->create_links();

17. Image ManipulationCodeIgniter does four image processing types very easily: crop*, resize, rotate, watermark.Create a thumbnail$config['image_library'] = 'gd2';$config['source_image'] = 'assets/images/elephpant.jpg';$config['create_thumb'] = TRUE;$config['maintain_ratio'] = TRUE; //Saved from a P.I.T.A$config['width'] = 75;$config['height’] = 50;$this->load->library('image_lib', $config); $this->image_lib->resize();*Never got crop to work 

18. Rotate$config['image_library'] = 'gd2';$config['source_image'] = 'assets/images/elephpant.jpg';$config['new_image'] = 'assets/images/elephpant_rotate.jpg'; $config['rotation_angle'] = '180';$config['rotation_angle'] = 'hor';$this->load->library('image_lib', $config); $this->image_lib->rotate;

19. Watermark$config['source_image'] = 'assets/images/elephpant.jpg';$config['new_image'] = 'assets/images/elephpant_wm.jpg'; $config['wm_text'] = 'ATLANTAPHP ROCKS!';$config['wm_type'] = 'text';$config['wm_font_path'] = 'assets/images/tesox.ttf';$config['wm_font_size'] = '25';$config['wm_font_color'] = 'ffffff';$config['wm_vrt_alignment'] = 'top';$config['wm_hor_alignment'] = 'center';$config['wm_padding'] = '10';$this->load->library('image_lib', $config); $this->image_lib->watermark();

20. Errors and Cleaning HouseThe image manipulation functions return boolean values, so you can display errors on FALSEif( ! $this->image_lib->watermark()){ echo $this->image_lib->display_errors(); } Clean up after yourself!$this->image_lib->clear(); //Clears the config values

22. More To LoveExtremely easy to set up.Intuitive (i.e. short learning curve.)It’s open source and has a permissive license.Extend existing libraries and add your own.Load only what you use.The community is outstanding. It has a Smiley helper!

23. ResourcesCodeIgniter User Guidehttp://codeigniter.com/user_guide/CodeIgniter Forumshttp://codeigniter.com/forums/CodeIgniter From Scratch (Nettuts video series)http://net.tutsplus.com/articles/news/codeigniter-from-scratch-day-1/Forrst – Not a CI dedicated site, but many CI users belong to the community, and the service itself is built on CI.http://forrst.com/