Creating a Bloggin Tool with CodeIgniter.pdf

Thomas Myer

a Blogging

Tool with

Codeigniter ®

Wiley Publishing, Inc.

Updates, source code, and Wrox technical support at www.wrox.com

Creating

Contents

Introducing CodeIgniter

What’s Model-View-Controller?

Why Bother with MVC?

Installing and Configuring CodeIgniter

The Root Folder

The system/Folder

The system/application Folder

Tweaking the Configuration

Getting Started

The Public-Facing Site

Creating the Template View

Creating the Home Page View

Creating the Category View

Creating the Blog Details View

Creating the Login Form

Verifying Logins

Creating the MAdmins Model

Creating the verifyUser() Function

A Small Note about Creating Your First User

Creating the Admin Dashboard

Creating the Dashboard Controller

Building the Admin Area

Creating the Rest of the Admin Functions

Summary

About Thomas Myer

Wrox Blox0 Creating a Blogging Tool with CodeIgniter By Myer - ISBN0 97804704133881 Prepared for CHRISTOPHER RINGWALD/ email0

with the WroxBlox Terms of Service. No part of it may be reproduced or transmitted in any form by any means without prior written

permission from the publisher. Redistribution or other use that violates the Wrox Blox Terms of Service or otherwise violates the U.S.

Creating a Blogging Tool

with Codeigniter

Let’s imagine for a second that you’re working on a team of marketers, writers, and designers, and

that the marketing manager requests that you create a blogging tool from scratch. It doesn’t have

to be complex, but it can’t be any of the off-the-shelf applications available for free on the Web (like

WordPress). It has to be small, efficient, and very fast. Most important, it needs to integrate seam-

lessly with an existing web site.

Oh, and one more thing: “Could we have a working prototype up and running by 5 p . m . today?”

You look at your watch and notice that it is 11:25 a . m . You do a quick calculation — you have just

enough time to grab lunch and start cracking away at the project with CodeIgniter. No problem,

you think. A blog is pretty simple. You’ve seen hundreds (if not thousands) of them in action, and

you’ve integrated all kinds of code with various models. With CodeIgniter by your side, you

should be able to kick out most of what you need in just a few hours.

You say yes, you’ll build it, as long as everyone understands that it’s a working prototype. With

that, you run off to get some lunch and sketch out some basic requirements.

Sound impossible? With CodeIgniter, it isn’t. In this Wrox Blox, you’ll see how to put together a

very simple blogging application in an afternoon. The key here is “simple.” At the end of the

process, you won’t have some kind of WordPress competitor. But you will have a very useful,

portable, and slick little blogging tool that you can add to any existing site (CodeIgniter or not).

Here’s a quick run down of what you’ll end up with:

q A public-facing home page that shows the last 10 blog posts

q A way to show posts by category

q A way to display a single post with comments (and a way for others to comment

on a post)

Wrox Blox0 Creating a Blogging Tool with CodeIgniter By Myer - ISBN0 97804704133881 Prepared for CHRISTOPHER RINGWALD/ email0

with the WroxBlox Terms of Service. No part of it may be reproduced or transmitted in any form by any means without prior written

permission from the publisher. Redistribution or other use that violates the Wrox Blox Terms of Service or otherwise violates the U.S.

Creating a Blogging Tool with Codeigniter®

An administrative area that requires a username and password for access

An administrative area to manage users, posts, and categories

Now that you know what to build, it’s time to download CodeIgniter and get the general overview.

Introducing CodeIgniter

CodeIgniter was created by the good folks over at EllisLab, Inc. It is a Model-View-Controller (MVC)

framework with a very small footprint. In form and function, it is very similar to other MVC

frameworks, like Ruby on Rails. Like Ruby on Rails, it requires very little configuration to get started.

I’ve been able to create prototype applications within hours of talking to a client, and then refined the

prototypes over the course of a few days.

It’s this kind of prototyping power and flexibility, by the way, that will transform the way you work

with clients. It allows you to be responsive and collaborative in ways that you’re probably not used to.

Unlike Ruby on Rails, CodeIgniter doesn’t require you to adhere to a strict set of coding rules.

For example, you don’t have to name your database tables a certain way, and your models another.

You don’t even have to have strictly formatted table fields — which makes CodeIgniter an excellent

platform for recoding legacy applications.

Below are a few more great things about CodeIgniter:

There is a growing toolbox of helpers and libraries that help you do your job quickly.

You don’t have to learn a complex templating language.

You don’t need to work with large-scale monolithic libraries.

You can run your applications in PHP 4 or PHP 5 without too much hassle.

CodeIgniter applications run with exceptional performance.

This section doesn’t get into too many more details right now. You’ll start seeing the difference once you

start coding. For now, it might be useful to talk a little bit about MVC and why it’s important. Then

you’ll get to work.

What’s Model-View-Controller?

Model-View-Controller is a design pattern that allows developers to separate their code cleanly into

three categories:

Models — help you maintain data.

Views — display data from the model and user interface elements.

Controllers — handle user events that interact with models and views.

Wrox Blox0 Creating a Blogging Tool with CodeIgniter By Myer - ISBN0 97804704133881 Prepared for CHRISTOPHER RINGWALD/ email0

with the WroxBlox Terms of Service. No part of it may be reproduced or transmitted in any form by any means without prior written

permission from the publisher. Redistribution or other use that violates the Wrox Blox Terms of Service or otherwise violates the U.S.

Creating a Blogging Tool with Codeigniter®

The important thing to remember is that MVC takes the user into account — it begins with them. It’s the

user who clicks a link, moves the mouse, or submits a form. It’s the controller that monitors this activity

and takes the appropriate action (such as manipulating the model and updating the view).

Because of MVC’s three-part separation, developers can create multiple views and controllers for any

given model without forcing changes in the model design. Similarly, multiple controllers can make use

of any model. This separation allows for easily maintained, portable, and organized applications.

For example, think about an MVC application that allows us to track eCommerce items in an online

store. You would have the following:

A model for product information

Multiple views to show single products, products in a list, products in search results, and so on

At least one controller that would organize those views into destinations, such as index()

(for home page), product_detail(), and search_results()

Drilling down further, an MVC eCommerce application might involve the following flow of events:

1. The user visits the store’s home page.

. This simple event requires a controller action for the home page, which makes a quick call to the

model to retrieve the 10 most popular products based on recent sales.

. The model’s data are then transmitted to the view for the home page.

4. The view (including the data retrieved by the model) is what the user sees in the browser.

5. The user clicks a link to see details on a particular product.

6. The underlying controller captures this user input (clicking the link), uses the model to retrieve

the product in question from the database, and then loads the appropriate view.

7. The cycle begins anew when the user takes another action, such as running a search or clicking a

link.

Another way of thinking about this breakdown of roles is to map it out as follows (see Figure 1 ):

User Input and Traffic Control = Controller

Data Interaction and Processing = Model

Output = View

Wrox Blox0 Creating a Blogging Tool with CodeIgniter By Myer - ISBN0 97804704133881 Prepared for CHRISTOPHER RINGWALD/ email0

with the WroxBlox Terms of Service. No part of it may be reproduced or transmitted in any form by any means without prior written

permission from the publisher. Redistribution or other use that violates the Wrox Blox Terms of Service or otherwise violates the U.S.

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