# Flight

Flight is an extensible micro-framework for PHP.
It allows you to quickly build RESTful web applications with minimal effort:

    require 'flight/Flight.php';

    Flight::route('/', function(){
        echo 'hello world!';
    });

    Flight::start();


## Installation

1\. Download and extract the Flight framework files to your web directory.

2\. Configure your webserver.

For **Apache**, edit your `.htaccess` file with the following:

    RewriteEngine On
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ index.php [QSA,L]

For **Nginx**, add the following to your _server_ declaration:

    server {
        location / {
            try_files $uri $uri/ /index.php;
        }
    }

3\. Create your `index.php` file.

First include the framework.

    require 'flight/Flight.php';

Then define a route and assign a function to handle the request.

    Flight::route('/', function(){
        echo 'hello world!';
    });

Finally, start the framework.

    Flight::start();


## Routing

### The Basics

Routing in Flight is done by matching a URL pattern with a callback function.
Routes are matched in the order they are defined. The first route to match a request is invoked.

    Flight::route('/', function(){
        echo 'hello world!';
    });

The callback can be any object that is callable. So you can use a regular function:

    function hello(){
        echo 'hello world!';
    }
    Flight::route('/', 'hello');

Or a class method:

    class Greeting {
        public static function hello() {
            echo 'hello world!';
        }
    }
    Flight::route('/', array('Greeting','hello'));

### Method Routing

By default, route patterns are matched against all request methods. You can respond to specific
methods by placing an identifier before the URL.

    Flight::route('GET /', function(){
        echo 'I received a GET request.';
    });
    Flight::route('POST /', function(){
        echo 'I received a POST request.';
    });

You can also map multiple methods to a single callback by using a `|` delimiter:

    Flight::route('GET|POST /', function(){
        echo 'I received either a GET or a POST request.';
    });

Method specific routes have precedence over global routes.

### Regular Expressions

You can use regular expressions in your routes:

    Flight::route('/user/[0-9]+', function(){
        // This will match /user/1234
    });

You can also user the wildcard character `*` for matching:

    Flight::route('/blog/*', function(){
        // This will match /blog/2000/02/01
    });

### Named Parameters

You can specify named parameters in routes which will be passed along to your callback function.

    // For the URL /bob/123, this will display
    //    name = bob
    //    id = 123
    Flight::route('/@name/@id', function($params){
        foreach ($params as $key => $value) {
            echo "$key = $value\n";
        }
    });

You can also include regular expressions with your named parameters:

    // This will match /bob/123
    // But will not match /bob/12345
    Flight::route('/@name/@id:[0-9]{3}', function($params){
        echo 'hello, '.$params['name'];
    });

Note that named parameters only match URL segments. If you want to match multiple segments use the `*` wildcard.


## Extending

Flight is extensible. You can map your own methods, register your own classes, or even override existing classes and methods.

### Mapping Methods

To map your own custom method, you use the `map` function:

    // Map your method
    Flight::map('hello', function($name){
        echo "hello {$name}!";
    });

    // Call your custom method
    Flight::hello('Bob');

### Registering Classes

To register your own class, you use the `register` function:

    // Register your class
    Flight::register('user', 'User');

    // Get an instance of your class
    $user = Flight::user();

If the `User` class is not defined, Flight will look in it's local folder for a file called `User.php` and autoload it.
This is how Flight loads its default classes like Response, Request, and Router.

You can define the constructor parameters for your class by passing in an additional array:

    // Register class with constructor parameters
    Flight::register('db', 'Database', array('localhost','mydb','user','pass'));

    // Get an instance of your class
    // This will create an object with the defined parameters
    //
    //     new Database('localhost', 'test', 'user', 'pass');
    //
    $db = Flight::db();

You can also define a callback that will be executed immediately after class construction.

    // The callback will be passed the object that was constructed
    Flight::register('db', 'Database', array('localhost', 'mydb', 'user', 'pass'), function($db){
        $db->connect();
    });

By default, every time you load your class you will get a shared instance.
To get a new instance of a class, simply pass in *false* as a parameter:

    // Shared instance of User
    $shared = Flight::user();

    // New instance of User
    $new = Flight::user(false);

Keep in mind that mapped methods have precedence over registered classes. If you declare both
for the same method name, only the mapped method will be invoked.

## Overriding

Flight ships with lots of default functionality to help you get your started.
However, you can override these features to suit your needs without having to modify any code.

For example, when Flight cannot match a URL to a route, it invokes the `notFound` method which sends a generic HTTP 404 response.
You can override this method to handle 404 errors however you like by mapping over it:

    Flight::map('notFound', function(){
        // Display custom 404 page
        include 'errors/404.html';
    });

Flight also has custom error handling which you can override:

    Flight::map('error', function($e){
        // Log error somewhere
        log_error($e);
    });

Flight also allows you to replace core components if you want.
For example you can replace the default Router class with your own custom class:

    // Register your custom class
    Flight::register('router', 'MyRouter');

    // When Flight loads the Router instance, it will load your class
    $myrouter = Flight::router();

You can replace any of the default Flight components:

    Flight::request();
    Flight::response();
    Flight::router();
    Flight::view();

However, core framework methods like `map` and `register` cannot be overridden.


## Method Filtering

Flight allows you to filter methods before and after they are called. There are no predefined hooks
you need to memorize. You can simply filter any method Flight invokes, including custom methods that
you've mapped.

You can have a filter run before a method by doing:

    Flight::before('start', function(&$params){
        // Do something
    });

You can have a filter run after a method by doing:

    Flight::after('start', function(&$output){
        // Do something
    });

You can add as many filters as you want to any method. They will be called in the order
that they are declared.

Notice that the filter callbacks have arguments passed to them. All *before* filters
are passed an array of the method parameters. All *after* filters are passed the output of
the method being filtered. The arguments are passed by reference so your filter simply needs
to modify the contents.

    // Map a custom method
    Flight::map('hello', function($name){
        return "Hello, {$name}!";
    });

    // Add a before filter
    Flight::before('hello', function(&$params){
        // Manipulate the parameter
        $params[0] = strtoupper($params[0]);
    });

    // Add an after filter
    Flight::after('hello', function(&$output){
        // Manipulate the output
        $output .= " Have a nice day!";
    }

    // Invoke the custom method
    echo Flight::hello('bob');

This should display:

    Hello BOB! Have a nice day! 

Note that core framework methods like `map` and `register` cannot be filtered because they are called
directly and not invoked dynamically.


## Variables

Flight allows you to save variables so that they can be used anywhere in your application.

    // Save your variable
    Flight::set('id', 123);

    // Elsewhere in your application
    $id = Flight::get('id');

To see if a variable has been set you can do:

    if (Flight::exists('id')) {
        // Do something
    }

You can clear a variable by doing:

    // Clears the id variable
    Flight::clear('id');

    // Clears all variables
    Flight::clear();

Flight also uses variables for configuration purposes.

    Flight::set('flight.lib.path', '/path/to/library');


## Views

Flight provides you with some basic templating functionality. To display a view call the `render` method with the
name of the template file and the optional template data:

    Flight::render('hello.php', array('name', 'Bob'));

The template data you pass in is automatically injected into the template and can be accessed using the `$this` variable. Template files
are simply PHP files. If the template file has the following content:

    Hello, <?php echo $this->name; ?>!

The output would be:

    Hello, Bob!

By default Flight will look in the current working directory for template files. You can set an alternate path for view templates
by setting the following config:

    Flight::set('flight.view.path', '/path/to/views');

### Custom Views

Flight allows you to swap out the default view engine simply by registering your own view class.
Here's how you would use Smarty for your templates:

    // Load Smarty library
    require_once './Smarty/libs/Smarty.class.php';

    // Register Smarty as the view class
    // Also pass a callback function to configure Smarty on startup
    Flight::register('view', 'Smarty', array(), function($smarty){
        $smarty->template_dir = './templates/';
        $smarty->compile_dir = './templates_c/';
        $smarty->config_dir = './config/';
        $smarty->cache_dir = './cache/';
    });

    // Assign template data
    Flight::view()->assign('name', 'Bob');

    // Display the template
    Flight::view()->display('hello.tpl');

For completeness, you should also override Flight's default render method:

    Flight::map('render', function($template, $data){
        Flight::view()->assign($data);
        Flight::view()->display($template);
    });


## Error Handling

### Errors and Exceptions

All errors and exceptions are caught Flight and passed to the `error` method. The default behavior is to send an HTTP 500
response with some the error information. You can override this for your own needs.

### Not Found

When a URL can't be found, Flight calls the `notFound` method. The default behavior is to
send an HTTP 404 response with a simple message. You can override this for your own needs.


## Redirects

You can redirect the current request by using the `redirect` method and passing in a new URL:

    Flight::redirect('/new/location');


## Stopping

You can stop the framework at any point by calling the `halt` method:

    Flight::halt();

You can also specify an optional HTTP status code and message:

    Flight::halt(200, 'Be right back...');

Calling `halt` will discard any response content up to that point.
If you want to stop the framework and output the current response, use the `stop` method:

    Flight::stop();


## Requirements

Flight requires PHP 5.3 or later.


## License

Flight licensed under the [MIT](http://www.opensource.org/licenses/mit-license.php) license.