121 lines
3.6 KiB
PHP
121 lines
3.6 KiB
PHP
<?php
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/**
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* Slim Framework (http://slimframework.com)
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*
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* @link https://github.com/slimphp/Slim
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* @copyright Copyright (c) 2011-2016 Josh Lockhart
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* @license https://github.com/slimphp/Slim/blob/3.x/LICENSE.md (MIT License)
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*/
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namespace Slim;
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use RuntimeException;
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use SplStack;
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use SplDoublyLinkedList;
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use Psr\Http\Message\ServerRequestInterface;
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use Psr\Http\Message\ResponseInterface;
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use UnexpectedValueException;
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/**
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* Middleware
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*
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* This is an internal class that enables concentric middleware layers. This
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* class is an implementation detail and is used only inside of the Slim
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* application; it is not visible to—and should not be used by—end users.
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*/
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trait MiddlewareAwareTrait
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{
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/**
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* Middleware call stack
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*
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* @var \SplStack
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* @link http://php.net/manual/class.splstack.php
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*/
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protected $stack;
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/**
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* Middleware stack lock
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*
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* @var bool
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*/
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protected $middlewareLock = false;
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/**
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* Add middleware
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*
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* This method prepends new middleware to the application middleware stack.
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*
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* @param callable $callable Any callable that accepts three arguments:
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* 1. A Request object
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* 2. A Response object
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* 3. A "next" middleware callable
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* @return static
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*
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* @throws RuntimeException If middleware is added while the stack is dequeuing
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* @throws UnexpectedValueException If the middleware doesn't return a Psr\Http\Message\ResponseInterface
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*/
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protected function addMiddleware(callable $callable)
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{
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if ($this->middlewareLock) {
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throw new RuntimeException('Middleware can’t be added once the stack is dequeuing');
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}
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if (is_null($this->stack)) {
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$this->seedMiddlewareStack();
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}
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$next = $this->stack->top();
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$this->stack[] = function (ServerRequestInterface $req, ResponseInterface $res) use ($callable, $next) {
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$result = call_user_func($callable, $req, $res, $next);
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if ($result instanceof ResponseInterface === false) {
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throw new UnexpectedValueException(
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'Middleware must return instance of \Psr\Http\Message\ResponseInterface'
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);
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}
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return $result;
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};
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return $this;
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}
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/**
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* Seed middleware stack with first callable
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*
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* @param callable $kernel The last item to run as middleware
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*
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* @throws RuntimeException if the stack is seeded more than once
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*/
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protected function seedMiddlewareStack(callable $kernel = null)
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{
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if (!is_null($this->stack)) {
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throw new RuntimeException('MiddlewareStack can only be seeded once.');
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}
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if ($kernel === null) {
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$kernel = $this;
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}
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$this->stack = new SplStack;
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$this->stack->setIteratorMode(SplDoublyLinkedList::IT_MODE_LIFO | SplDoublyLinkedList::IT_MODE_KEEP);
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$this->stack[] = $kernel;
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}
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/**
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* Call middleware stack
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*
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* @param ServerRequestInterface $req A request object
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* @param ResponseInterface $res A response object
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*
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* @return ResponseInterface
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*/
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public function callMiddlewareStack(ServerRequestInterface $req, ResponseInterface $res)
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{
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if (is_null($this->stack)) {
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$this->seedMiddlewareStack();
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}
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/** @var callable $start */
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$start = $this->stack->top();
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$this->middlewareLock = true;
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$resp = $start($req, $res);
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$this->middlewareLock = false;
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return $resp;
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}
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}
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