What is codeigniter :
CodeIgniter is PHP MVC framework for developing applications. CodeIgniter provides out of the box libraries for connecting to the database and also performing various operations. Like sending emails, uploading files, etc.
Features in and of themselves are a very poor way to judge an application since they tell you nothing about the user experience, or how intuitively or intelligently it is designed. Features don’t reveal anything about the quality of the code, or the performance, or the attention to detail, or security practices. The only way to really judge an app is to try it and get to know the code. Installing CodeIgniter is child’s play so we encourage you to do just that. In the mean time here’s a list of CodeIgniter’s main features.
The entire source code of CodeIgniter framework is close to 2MB. That will makes it easy to master CodeIgniter and how it works. It also simplifies deploying and updating to it.
codeigniter framework uses the Model-View-Controller architectural design. It is industry standard practices when working with web applications. MVC separates the data, business logic, and presentation.
It is fully light-weighted. Core system of CodeIgniter requires very small library and other libraries may be added upon dynamic request based upon your needs. That’s why it is quite fast and light weighted.
Short learning curve:
CodeIgniter framework is very easy to master for anyone who is already familiar with PHP. Within a very short time, the student can start developing professional applications using CodeIgniter framework.
Model-View-Controller Based System
Extremely Light Weight
Full Featured database classes with support for several platforms.
Query Builder Database Support
Form and Data Validation
Security and XSS Filtering
Email Sending Class. Supports Attachments, HTML/Text email, multiple protocols (sendmail, SMTP, and Mail) and more.
Image Manipulation Library (cropping, resizing, rotating, etc.). Supports GD, ImageMagick, and NetPBM
File Uploading Class
Full Page Caching
User Agent Class
Zip Encoding Class
Template Engine Class
Unit Testing Class
Search-engine Friendly URLs
Flexible URI Routing
Support for Hooks and Class Extensions
Large library of “helper” functions
How CodeIgniter Works?
CodeIgniter is an MVC framework. MVC stands for Model View Controller. When user requests a resource, the controller responds first. The controller understands the user request then request the necessary data if necessary.
For example, if you want to retrieve a customer with the id= 3, the controller will receive your request, then request the model to retrieve the record with the id of 3. The model returns the record to the controller. The controller then forwards the result to the view which formats it into a human-readable format. Then the results are returned to the user in the browser.