在HTTP Request类中实现不同的请求方法

Question

I'm currently writing my own HTTP Request class and I hit a small problem. As you probably know, there are many request methods in PHP, like OPTIONS , GET , POST , PUT , HEAD , etc. but you cannot mix two or more of them in one request. And this is where my problems begins.

I have HTTPRequest class, which has two static methods, that creates it's instance - create() , to create custom HTTP Request and createFromGlobals() , to create instance of current request recieved by server.

So, what's the problem? The problem is, I want to find some way to separate request additional functions dependent on method (for example, I don't want to have getQueryString() function, when request method is PUT or POST) and I want the class to do it for me. Also, I want to keep classes dependencies loose, so whole system will stay flexible.

Do you know any design pattern that resolves problem like mine, or any way to do this?

Answer 1

Check out Symfony Components, it has a very nice Request class (among many other things), so you don't have to reinvent the wheel.

http://api.symfony.com/2.0/Symfony/Component/HttpFoundation/Request.html

Answer 2

I would probably implement what you want to achieve, similar to this (but keep in mind my comment about querystrings being valid with POST requests. At least, as far as I'm aware):

abstract class HTTPRequest
{
    public static function createFromGlobals()
    {
        $method = $_SERVER[ 'REQUEST_METHOD' ];

        /* initialize additional arguments from globals */

        return self::create( $method /*, additional arguments */ );
    }

    public static function create()
    {
        $arguments = func_get_args();
        $method = array_shift( $arguments );
        $method = ucfirst( strtolower( $method ) );

        $className = __CLASS__ . $method;
        if( !class_exists( $className ) )
        {
            throw new Exception( 'Implementation for method ' . $method . ' not found' );
        }

        $reflector = new ReflectionClass( $className );

        return $reflector->newInstanceArgs( $arguments );
    }

    /* implement common functionality */
}

class HTTPRequestGet
    extends HTTPRequest
{
    /* implement additional GET functionality */
}

class HTTPRequestPost
    extends HTTPRequest
{
    /* implement additional POST functionality */
}

/* etc... */

Usage:

$requestFromGlobals = HTTPRequest::createFromGlobals();
$customRequest = HTTPRequest::create( 'post', array( 'additional', 'arguments' ) );

Answer 3

I was considering something like this:

<?php

class HTTPRequest
{
    protected $method;
    public $parameters
    // ...

    public static function create(/* ... */)
    {
        // ...
        switch ($this->method)
        {
            case 'GET':
                $this->parameters = new Parameters($_GET);
                break;
            case 'POST':
                $this->parameters = array(
                    'post' => new Parameters($_POST),
                    'files' => new Parameters($_FILES)
                );
                break;
            // ...
        }
        // ...
    }
}

What do you think about it?