intro to mvc development in php

Intro to MVC Development in PHPEd Finkler • http://funkatron.com • @funkatron#tekmvc • php|tek 2009

Thee AgendaAll About MVC

Why CodeIgniter?

The CI MVC Model

CI Basics

Running CI out of the box

Making a basic web app

Making a web api

Libraries, components, logging and caching

All About MVChttp://www.flickr.com/photos/airship/118352487/

What is MVC?

What is MVC?

1979, Norwegian, Xerox Parc

Give user the impression of interacting directly with data

Used in GUI apps first

http://short.ie/g95zua

A Diagram

Controller

ModelView

The Model

"Represent knowledge"

The data/business functionality

The View

Visual representation of the model

The screens and widgets of app

Gets data from model & updates model

The Controller

Link between user and system

Responsible for intercepting user input

Passes user input to view via messages

Why Does MVC Help?

Separation of concerns

Don't mix your chocolate with my peanut butter

"Swappability"

Avoid tight coupling

MVC is not magic fairy dust

But understanding it and using itcan make you a better developer

Variations on MVC

http://short.ie/k2f9rk

http://www.flickr.com/photos/stevem78/2975614995/

MVPModel-View-Presenter (Dolphin Smalltalk variant)

Presenter primarily updates model

Presenter

ModelView

PAC

Presentation-Abstraction-Controller

Presentation ModelControl

Presentation ModelControl

Presentation ModelControl

Presentation ModelControlPresentation ModelControl

Light vs Heavy

Where does the logic go?

Event-driven vs direct calls

Observer pattern

Why CodeIgniter?http://www.flickr.com/photos/alternatewords/2332580309/

Why not CakePHP or Zend Framework or Limonade or Symfony or Solar or Kohana or Zoop or Yii or Akelos or PHP on Trax or Prado or Seagull?

Because you've gotta pick one, dammit

All of them have value*

* except Zend Framework

That being said, CI is…Easy to understand

Simple

doesn't require advanced OOP

Doesn't force lots of conventions

Plays well with others

Quick to get up and running

Good docs and great community

Backed by invested entity (http://ellislab.com)

CodeIgniter MVC Implementation

More of a Passive View Pattern

http://short.ie/5o7eg4

Controller

ModelView

CI application flow

Stolen from CI user guide

App components

Front controller

Routing

Security

Controller

Model

Library

Helper

Plugin

Scripts

View

Caching

Front controller

index.php

Routing

class Search extends Controller {

public function single($id) { // [...] }}

http://domain.com/index.php/controller/method/param

Security

Filtering or blocking unsafe input

ControllerThe core of everything

"Heavy": you could do everything in controller

public methods are available as actions from URL

private methods prefixed with “_”

<?phpclass Site extends Controller {

function Site() { parent::Controller(); $this->load->library('session'); } function index() { // mletters model is auto-loaded $rows = $this->mletters->getMany(10); $data['rows'] = $this->_prepData($rows); $this->load->view('index', $data); } function _prepData($rows) { // do some cleanup on the data… }?>

Model

ActiveRecord pattern available, not required

Query binding

Don't like the DB layer? Use something else

Zend_DB, Doctrine, DataMapper (http://bit.ly/datamapper), IgniteRecord (http://bit.ly/igrec) …

$sql = "SELECT * FROM some_table WHERE id = ? AND status = ? AND author = ?";$this->db->query($sql, array(3, 'live', 'Rick'));

Library

A class designed to work on related tasks

Helper

Procedural funcs, grouped by file

Mostly for views; available in controllers

/** * Plural * * Takes a singular word and makes it plural * * @access public * @param string * @param bool * @return str */ function plural($str, $force = FALSE){ // [...]}

Plugin

Single procedural function

More extensive functionality than helper

$vals = array( 'word' => 'Random word', 'img_path' => './captcha/', 'img_url' => 'http://example.com/captcha/', 'font_path' => './system/fonts/texb.ttf', 'img_width' => '150', 'img_height' => 30, 'expiration' => 7200 );

$cap = create_captcha($vals);echo $cap['image'];

Script

Other scripts the CI app might use

ViewBuild response to clientCI Views are limitedUses plain PHP as templating lang

<?php foreach ($rows as $row): ?> <li class="letter"> <div class="body"> <h3>Dear Zend,</h3> <p><?=$row->body?></p> </div> <div class="meta"> <div class="posted"> <a href="<?=site_url('/site/single/'.$row->id)?>">Posted <?=$row->posted?></a> </div> <div class="favorite">Liked by <?=$row->favorite_count?> person(s). <a href="<?=site_url('/site/favorite/'.$row->id)?>">I like this</a> </div> </div> </li><?php endforeach ?>

View

Optional template markup

Want a heavier template lang? Use one.

<html><head><title>{blog_title}</title></head><body>

<h3>{blog_heading}</h3>

{blog_entries} <h5>{title}</h5> <p>{body}</p> {/blog_entries}</body></html>

$this->load->library('parser');$this->parser->parse('blog_template', $data);

Caching

Saves response to file

Serves up file contents if cache not expired

CI Basics

http://www.flickr.com/photos/canoafurada/395304306/

CI Structure

index.php

system application

base classes &built-in functionality

app-specific classes& functionality

front controllerpoints to system andapplication folders

CI Structure

default layout

CI Structure

custom layout

only index.php is under document root

The CI Object

$this inside controllers

The loader

$this->load->{view|library|model|helper|etc}('name');

CI Out of the box

The Welcome App

Put CI on the server

Load it in the browser

Why does Welcome load?

How URLs map

Trace with Xdebug/MacGDBp

Making a web application

Population estimates DB

Get our data from Numbrary: http://short.ie/w3f6h3)

Make a new controller

Change the default route

Config DB settings

Make a model

Make a view

Make fancier views

Make a web APIhttp://www.flickr.com/photos/dunechaser/2429621774/

Web API for pop. est. DB

Let users query our DB via HTTP

Return results on JSON or serialized PHP

Libraries, Components, Logging and Caching

http://www.flickr.com/photos/metaphorge/515054465/

Autoloading

Make certain libs, models, helpers, etc available automatically

Libraries

Extending core libs

application/libraries/MY_Library.php

Replacing core libs

application/libraries/CI_Library.php

Creating your own libs

application/libraries/Library.php

Constructor: Library();

Helpers

Make your own

application/helpers/name_helper.php

Add to existing

application/helpers/MY_name_helper.php

Example: PHP lang helper

Using non-CI components

The CI Way

Examples: Simplepie, Markdown

The dirty, bad way

require() that jazz

Caching

set cache path in config

make dir writable

enable caching in controller methods

Logging

set path in config

make dir writable

manual logging: log_message(level, msg)

Error handling

CI uses it's own error handler

Can block expected behavior

Example

Questions?@funkatron/#tekmvccoj@funkatron.com

http://www.flickr.com/photos/deadhorse/508559841/