Mr. Justin “JET” Turner CSCI 3000 – Fall 2015 CRN Section A – TR 9:30-10:45 CRN – Section B – TR 5:30-6:45

CI - Helpers Helper files are used to provide access to a few stand- alone functions The functions could be used to help with any components of the MVC structure Note: These functions are not tied into the parent object, so the $this variable is not defined If we need access to the CI object, we get it using: $CI =& get_instance(); =& is the PHP pass-by-reference, so instead of copying the object, we are pointing at the same object

CI - Helpers We can define multiple functions in the same helper file, but we should only do this if they are strongly related We need to create the helper file at: /application/helpers/filename_helper.php Then we can load the helper using: $this->load->helper(“filename”); Finally, we can all the helper functions directly function_name();

CI - Helpers if ( ! defined('BASEPATH')) exit('No direct script access allowed'); if ( ! function_exists(‘function_name')) { function function_name() { $CI =& get_instance(); }

CI - Libraries Building a custom library can be done entirely from scratch, or extending from a CI library for added functionality For CI to properly load the library, it is important the class name and file name match

CI - Libraries Library file location: /application/libraries/My_library.php Load the library: $this->load->library(“My_library”); Finally, accessing the library: $this->My_library->libraryFunction(); Our constructor will also assign the CI object reference to some instance data to better enforce our OOP

CI - Libraries if ( ! defined('BASEPATH')) exit('No direct script access allowed'); class myLibrary { public function __construct() { $this->ci =& get_instance(); }

CI - Libraries If you want to extend a CI library, or fully replace a default one, then you just need to have it in the libraries folder, named exactly the same .php class CI_ {} Many of the CI libraries are prefixed with CI_ The load/autoload functions will check for a local library before moving to the framework/system for library

CI - Sessions Session data is a way for your web application to maintain data with a given user You can store variables in the session, and use those values on every page visited by a specific user afterwards Maintaining authentication is almost always at least partially done through storing session data We might load some profile data from a database into a session for easier access on future pages, such as which theme to use in the application

CI - Sessions CI has a full session library writing data into session variables and getting it back out $this->session->set_userdata(“name”, “value”); //can also take an associative array $this->session->userdata(“name”); $this->session->has_userdata(“name”); $this->session->unset_userdata(“name”);

CI - Sessions CI also has a concept called “flash data” which is session data that is not kept after the very next page load This can be useful for error messages you want to display on the next page, but don’t need after that $this->session->set_flashdata(“name”, “value”); $this->session->flashdata(“name”); $this->session->keep_flashdata(“name”);

CI – Encryption/Hashing There are two terms we need to define: Hashing A one-way process of converting data from an arbitrary size into data of a fixed size Encryption / Decryption A two-way process converting data into an unrecognizable form and then back into the original form When working with passwords, we want to perform a hash function When they try to log in, we hash the password entered and compare the two hash values

CI – Encryption/Hashing Encryption can be used for data we want to protect, but need to be able to get the original formatted data back at some point CI used to provide a method for hashing, but with changes to recent versions of PHP, the built in hash() function suites that need without a custom function We can use hash_algos() to get a list of available hashing algorithms

CI - Encryption The CI library has extensive information on available encryption methods One item you need is a key, which is often produced using a hash method You could use something about your logged in user, such as their username, to create the key, then their data is better tied to their account

Project 2 - CodeIgniter Create a CodeIgniter application that uses the following: Create a form to collect data from the user Use the Form Helper, Form Validation Library, File Upload Library, and Image Manipulation Library Manipulate the uploaded image by resizing it Use the Output library to help you render the image using CI (not a direct link to the image) Something like: application/files/image/2 would render the image from the row with ID = 2

Project 2 - CodeIgniter This project should be on a separate sub-domain project2.yourdomain.com For 10% bonus (2pts) Set up a log in page, and use the Session Library to help you ensure that no page loads unless the user is logged in Provide a Username/Password in the dropbox comments

Reminders Project 1 – Responsive Site – Due Oct 8 th The Midterm project will be an in-class assignment

Next Time Instructions for configuring Sessions in GoDaddy A quick review of what you can expect the mid term to be like Time to work on Project 1 and 2, and ask questions if you are running into any issues