Multiple Applications via Symlinks

Without trying to replace the other great wiki article here: Multiple Applications, I thought this might be another unique way of addressing the problem. The article comes from a post I made in the forums here: multiple sites, 1 codebase, using symlinks (with smarty)

Now onto the meat ...

MY REQUIREMENTS

My project called for a specific configuration of sites and applications:

site #1: one application
site #2: has both frontend and backend applications
     (will also operate on wildcard sub-domains)
site #3: uses ssl with one application
site #4: one application (internal access)

All 4 sites are heavily related ... and will often want to use the same models, libraries, helpers, views etc. Unfortunately CI doesn't give me a place to store these resources cross-application, and I really didn't feel comfortable editing or extending the core CI classes. That might have made upgrading the framework painful with later releases. I like the idea of just 'dropping in' a new system folder without worry.

MY HOMEWORK (B-)

So as I was looking into CI initially, I found a lot of posts about running multiple-application sites. Overall, I got the impression that this was something CI 'could' do with tweaking (depending on your specific sites/applications) but wasn't particularly great at out of the box. Thankfully, CI is so easy to work with that there are a number of solutions to consider.

Option 1:

One alternative was to run all my apps out of the same application folder, and just give them unique controllers ... I considered this but thought it might be difficult to keep site #1 from calling site #2's controllers by editing the urls. My sites needed to be fairly secure in this regard.

Option 2:

Another alternative was to modify the loader of the CI core classes to include a new search path, essentially adding a Library level where cross-application code goes. This would have been the most attractive option if I felt more comfortable editing core files. But I don't ... ick! Hopefully CI adopts a similar solution officially in a later release.

Some related links on that method:

[url=http://www.jaaulde.com/test_bed/CodeIgniter/modLoader/]http://www.jaaulde.com/test_bed/CodeIgniter/modLoader/[/url] [url=http://codeigniter.com/forums/viewthread/49157/]http://codeigniter.com/forums/viewthread/49157/[/url]

And other options I won't get into right now ...

MY BACKGROUND INFO

My situation is unique to me perhaps. I happen to own the box my sites are being hosted on, so all configuration options are available. My sites use the traditional php5, mysql5, apache2 on Free(as in beer)BSD. I can edit httpd.conf freely and create .htaccess files as needed.

MY SOLUTION

I found I was able to share a (parent) application folder (located outside each site's root) with a specific site's (local) application folder ... I did this by creating a series of symbolic links in each (local) application folder to represent the corresponding folders in my (parent) application folder ...

I literally matched symbolic links to parent folders exactly ... EXCEPT for the (local) application's 'controllers' folder, which was really the meat of each website.

It might be easier to show you the following folder hierarchy I used:

application/
    my global application folder, where most the code goes
CodeIgniter_1.5.4/
    my CI installs system folder and other files, I leave the version 
    number so that I can link to a new system in the index.php if 
    needed for testing
common/
    an apache directory alias called common lets me link to subfolders here
    called img, js, css, file, etc. Having one folder with all my includes makes
    it easy to specify in an .htaccess file that CI should leave links alone with
    the word common in it.
Smarty_2.6.18/
    my smarty install, contains the actual libraries
www_site1/
    the site root for site #1
www_site2/
    the site root for site #2
www_site3/
    the site root for site #3
www_site4/
    the site root for site #4

A closer look at my (GLOBAL) application folder:

cache
    SMARTY SPECIFIC FOLDER with write access
config
    standard codeigniter
configs
    SMARTY SPECIFIC FOLDER
controllers
    NOT USED GLOBALLY - EACH SITE HAS ITS LOCAL CONTROLLERS FOLDER
    FOLDER IS ACTUALLY EMPTY
errors
    standard codeigniter
helpers
    standard codeigniter
hooks
    standard codeigniter
libraries
    contains a wrapper class called MySmarty.php for smarty useage
models
    standard codeigniter
templates
    SMARTY SPECIFIC FOLDER
templates_c
    SMARTY SPECIFIC FOLDER with write access
views
    standard codeigniter

A closer look at my (LOCAL) application folders (EACH SITE HAS ITS OWN):

cache
    symbolic link to parent
config
    symbolic link to parent
configs
    symbolic link to parent
controllers
    ALL LOCAL SITE SPECIFIC CONTROLLERS GO HERE
    default controller is index.php as set in CI's global config
errors
    symbolic link to parent
helpers
    symbolic link to parent
hooks
    symbolic link to parent
libraries
    symbolic link to parent
models
    symbolic link to parent
templates
    symbolic link to parent
templates_c
    symbolic link to parent
views
    symbolic link to parent

A closer look at my individual site's ROOT folders

    
.htaccess
    (see below)
index.php
    links to (local) application folder and global system folder
    system folder can be changed in one place to reference a new CI install
applications
    mostly contains symbolic links, but has a legit controllers folder

A closer look at my sites individual .htaccess files:

Options +SymLinksIfOwnerMatch
    
<IfModule mod_rewrite.c>
    RewriteEngine on
    RewriteCond $1 !^(index\.php|common|robots\.txt)
    RewriteRule ^(.*)$ /index.php/$1 [L]
</IfModule>

TWEAKAGE:

A few small edits I made along the way.

**For SSL. **

Since I have a single CI config file for multiple applications/sites I had to make a small change to the way the $config[base_url] was captured. It now prefixes the URL with the proper protocol if SSL is in use on that site.

$config['base_url']    = (isset($_SERVER['HTTPS']) ? 'https://' : 'http://').$_SERVER['HTTP_HOST']."/";

instead of

$config['base_url']    = "http://".$_SERVER['HTTP_HOST']."/";

For Smarty.

In my (global) applications autoload.php file, I add the following:

$autoload['libraries'] = array('mySmarty');

Then I create a class file in my (global) application/libraries folder (remember to edit the smarty path)

Found on the CI forums, thx to the author whoever you are!

if (!defined('APPPATH')) exit('No direct script access allowed');

require_once(APPPATH . "../../Smarty_2.6.18/libs/Smarty.class.php");

/*
|==========================================================
| Code Igniter - by pMachine
|----------------------------------------------------------
| www.codeignitor.com
|----------------------------------------------------------
| Copyright (c) 2006, pMachine, Inc.
|----------------------------------------------------------
| This library is licensed under an open source agreement:
| www.codeignitor.com/docs/license.html
|----------------------------------------------------------
| File: libraries/Smarty.php
|----------------------------------------------------------
| Purpose: Wrapper for Smarty Templates
|==========================================================
*/

class MySmarty extends Smarty{

    var $smarty;
    
    function MySmarty()
    {
        $this->smarty = new Smarty();
        $this->smarty->template_dir = APPPATH . "templates";
        $this->smarty->compile_dir = APPPATH . "templates_c";
        $this->smarty->cache_dir = APPPATH . "cache";
        $this->smarty->config_dir = APPPATH . "configs";
        $this->smarty->compile_check = true;
        $this->smarty->debugging = true;
        log_message('debug', "Smarty Class Initialized");
    }
    
    function assign($key,$value)
    {
        $this->smarty->assign($key,$value);
    }
    
    function display($template)
    {
        $this->smarty->display($template);
    }

}

I hope this is helpful for some, I appreciated having the forums as a resource to gather information from. CodeIgniter has a great community here.

Peace. :)