Month: November 2011

CodeIgniter Slug Library

ProgrammingNovember 21, 2011

I am happy to announce a simple CodeIgniter library to help you generate slugs for your urls. This is something I use on almost every project and it has been invaluable to me. Hopefully you will find it useful as well.

For those that are not familiar with the term slug WordPress defines it as:

A slug is a few words that describe a post or a page. Slugs are usually a URL friendly version of the title.

Description

What this library does is allow you to pass a string such as a titile and then generate a url friendly string from it. Also and most importantly it checks against fields in your db so that you will not have any duplicates. For example:

"This is my title"

Would become:

"this-is-my-title"

If a duplicate is found then it appends a number. Example:

"this-is-my-title-1"

Example

First load the library with an array of config items:

$config = array(
    'table' => 'mytable,
    'id' => 'id',
    'field' => 'uri',
    'title' => 'title',
    'replacement' => 'dash' // Either dash or underscore
);
$this->load->library('slug', $config);

When creating a uri for a new record in your db you can do it like this:

$data = array(
    'title' => 'My Test',
);
$data['uri'] = $this->slug->create_uri($data);
$this->db->insert('mytable, $data);

Then for when you are editing an existing record: (Notice the create_uri uses the second param to compare against other fields).

$data = array(
    'title' => 'My Test',
);
$data['uri'] = $this->slug->create_uri($data, $id);
$this->db->where('id', $id);
$this->db->update('mytable', $data);

Download

You can clone the repo by running the code below:

$ git clone git://github.com/ericbarnes/CodeIgniter-Slug-Library

Or visit the GitHub Repo.

CodeIgniter Optimizations

ProgrammingNovember 9, 2011

I am currently building a pretty large CMS system on top of CodeIgniter and I wanted to share some of the best performance optimizations I have found. Although CodeIgniter is optimized out of the box, when you start building large scale applications with large controllers, it is easy to miss things that can add up to your overall performance.

Do Not Save Queries

$this->db->save_queries = FALSE;

By default CodeIgniter keeps an array of all the queries¹ ran so that they can be used in the profiler for debugging. This is great during development but in most production cases that is not needed and just wasted memory. I recommend disabling this in production mode and can be conditionally setup with a simple if statement:

if (ENVIRONMENT == 'production')
{
    $this->db->save_queries = FALSE;
}

Output Cache

CodeIgniter supports several levels of caching and the most extreme is caching is the entire output. That is designed to cache the entire parsed page then just display it the html for the amount of minutes you designate.

By default CodeIgniter writes this cache to files which increases your i/o and it might suit you better to use apc² (example) or memcache for the storage.

The downside to this is if you are needing some form of dynamic data like user information. Then it will not work. If that is a requirement for you then consider caching queries or other areas where your site is slow. Or you can do like getsparks and use ajax calls to dynamically populate the user information.

Consider Nginx + php-fpm + apc

I know everybody uses Apache and it has tons of tutorials and an all around good server. But in my tests straight out of the box Nginx out performs Apache and I am not the only one

I had a standard AWS medium instance running about 25 sites that was averaging 30% CPU usage during the day with Apache + APC. After just switching to Nginx and php-fpm it is now averaging around 10%. That is a huge difference!

Autoloading Can Be Dangerous

CodeIgniter comes with an “Auto-load” feature that permits libraries, helpers, and models to be initialized automatically every time the system runs.

Lets face it autoloading is awesome, but does come with some drawbacks. The biggest is that everything autoloaded is loaded on every request. This means for every page and every ajax call all those items are being loaded. So unless you are, in fact, going to need it for everything then I wouldn’t recommend auto loading. Instead consider base controllers or loading only when needed.

Only Load What You Need

Touching on autoloading is another common issue I have seen. Loading when you don’t need too. Ideally you do not want to load anything unless you are going to use it in the code that is running.

class Welcome extends CI_Controller {
    public function __construct()
    {
        $this->load->library('email');
        $this->load->library('ftp');
    }
    public function index()
    {
        $this->load->view('home_page');
    }
}

As you can see in the example above we are loading two libraries that will never be used when viewing the home page so by including them you are just wasting resources.

Nginx PHP Gotchas

ProgrammingNovember 3, 2011

Here are some changes I needed to make to my Nginx conf that didn’t seem obvious to me and will hopefully be of help to others:

Random 502 gateway errors

fastcgi_buffers 8 16k;
fastcgi_buffer_size 32k;

413 Request Entity Too Large

This is caused because by default file uploads are limited to 1mb.

server {
    client_max_body_size 20M;

Resources:

• nginx error – 413 Request Entity Too Large
• Fixed the upstream sent too big header error

CodeIgniter Nginx Virtual Host

ProgrammingNovember 1, 2011

Currently I am in the process of switching a server from Apache to Nginx and here is a quick tip for those using CodeIgniter or who want to host a bunch of very similar domains. For each server line I do this: 

server {
    server_name .mysite.com;
    root /sites/mysite/www;
    include /sites/nginx/ci_vhost;
}
server {
    server_name .mysecondsite.com;
    root /sites/secondpath/www;
    include /sites/nginx/ci_vhost;
}

Then the ci_vhost includes the common settings: 

index index.html index.php index.htm;

# set expiration of assets to MAX for caching
location ~* .(ico|css|js|gif|jpe?g|png)(?[0-9]+)?$ {
    expires max;
    log_not_found off;
}

location / {
    # Check if a file exists, or route it to index.php.
    try_files $uri $uri/ /index.php;
}

location ~* .php$ {
    fastcgi_pass 127.0.0.1:9000;
    fastcgi_index index.php;
    fastcgi_split_path_info ^(.+.php)(.*)$;
    include fastcgi_params;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
}

This allows you to have all the shared settings in one location and will make future changes much easier. Also this works perfectly for me with CodeIgniter’s default setup. Removing index.php and leaving uri_protocol to AUTO.