<?php namespace GuzzleHttp; use GuzzleHttp\Promise\PromiseInterface; use Psr\Http\Message\RequestInterface; use Psr\Http\Message\ResponseInterface; /** * Creates a composed Guzzle handler function by stacking middlewares on top of * an HTTP handler function. * * @final */ class HandlerStack { /** * @var (callable(RequestInterface, array): PromiseInterface)|null */ private $handler; /** * @var array{(callable(callable(RequestInterface, array): PromiseInterface): callable), (string|null)}[] */ private $stack = []; /** * @var (callable(RequestInterface, array): PromiseInterface)|null */ private $cached; /** * Creates a default handler stack that can be used by clients. * * The returned handler will wrap the provided handler or use the most * appropriate default handler for your system. The returned HandlerStack has * support for cookies, redirects, HTTP error exceptions, and preparing a body * before sending. * * The returned handler stack can be passed to a client in the "handler" * option. * * @param (callable(RequestInterface, array): PromiseInterface)|null $handler HTTP handler function to use with the stack. If no * handler is provided, the best handler for your * system will be utilized. */ public static function create(callable $handler = null): self { $stack = new self($handler ?: Utils::chooseHandler()); $stack->push(Middleware::httpErrors(), 'http_errors'); $stack->push(Middleware::redirect(), 'allow_redirects'); $stack->push(Middleware::cookies(), 'cookies'); $stack->push(Middleware::prepareBody(), 'prepare_body'); return $stack; } /** * @param (callable(RequestInterface, array): PromiseInterface)|null $handler Underlying HTTP handler. */ public function __construct(callable $handler = null) { $this->handler = $handler; } /** * Invokes the handler stack as a composed handler * * @return ResponseInterface|PromiseInterface */ public function __invoke(RequestInterface $request, array $options) { $handler = $this->resolve(); return $handler($request, $options); } /** * Dumps a string representation of the stack. * * @return string */ public function __toString() { $depth = 0; $stack = []; if ($this->handler !== null) { $stack[] = '0) Handler: '.$this->debugCallable($this->handler); } $result = ''; foreach (\array_reverse($this->stack) as $tuple) { ++$depth; $str = "{$depth}) Name: '{$tuple[1]}', "; $str .= 'Function: '.$this->debugCallable($tuple[0]); $result = "> {$str}\n{$result}"; $stack[] = $str; } foreach (\array_keys($stack) as $k) { $result .= "< {$stack[$k]}\n"; } return $result; } /** * Set the HTTP handler that actually returns a promise. * * @param callable(RequestInterface, array): PromiseInterface $handler Accepts a request and array of options and * returns a Promise. */ public function setHandler(callable $handler): void { $this->handler = $handler; $this->cached = null; } /** * Returns true if the builder has a handler. */ public function hasHandler(): bool { return $this->handler !== null; } /** * Unshift a middleware to the bottom of the stack. * * @param callable(callable): callable $middleware Middleware function * @param string $name Name to register for this middleware. */ public function unshift(callable $middleware, string $name = null): void { \array_unshift($this->stack, [$middleware, $name]); $this->cached = null; } /** * Push a middleware to the top of the stack. * * @param callable(callable): callable $middleware Middleware function * @param string $name Name to register for this middleware. */ public function push(callable $middleware, string $name = ''): void { $this->stack[] = [$middleware, $name]; $this->cached = null; } /** * Add a middleware before another middleware by name. * * @param string $findName Middleware to find * @param callable(callable): callable $middleware Middleware function * @param string $withName Name to register for this middleware. */ public function before(string $findName, callable $middleware, string $withName = ''): void { $this->splice($findName, $withName, $middleware, true); } /** * Add a middleware after another middleware by name. * * @param string $findName Middleware to find * @param callable(callable): callable $middleware Middleware function * @param string $withName Name to register for this middleware. */ public function after(string $findName, callable $middleware, string $withName = ''): void { $this->splice($findName, $withName, $middleware, false); } /** * Remove a middleware by instance or name from the stack. * * @param callable|string $remove Middleware to remove by instance or name. */ public function remove($remove): void { if (!is_string($remove) && !is_callable($remove)) { trigger_deprecation('guzzlehttp/guzzle', '7.4', 'Not passing a callable or string to %s::%s() is deprecated and will cause an error in 8.0.', __CLASS__, __FUNCTION__); } $this->cached = null; $idx = \is_callable($remove) ? 0 : 1; $this->stack = \array_values(\array_filter( $this->stack, static function ($tuple) use ($idx, $remove) { return $tuple[$idx] !== $remove; } )); } /** * Compose the middleware and handler into a single callable function. * * @return callable(RequestInterface, array): PromiseInterface */ public function resolve(): callable { if ($this->cached === null) { if (($prev = $this->handler) === null) { throw new \LogicException('No handler has been specified'); } foreach (\array_reverse($this->stack) as $fn) { /** @var callable(RequestInterface, array): PromiseInterface $prev */ $prev = $fn[0]($prev); } $this->cached = $prev; } return $this->cached; } private function findByName(string $name): int { foreach ($this->stack as $k => $v) { if ($v[1] === $name) { return $k; } } throw new \InvalidArgumentException("Middleware not found: $name"); } /** * Splices a function into the middleware list at a specific position. */ private function splice(string $findName, string $withName, callable $middleware, bool $before): void { $this->cached = null; $idx = $this->findByName($findName); $tuple = [$middleware, $withName]; if ($before) { if ($idx === 0) { \array_unshift($this->stack, $tuple); } else { $replacement = [$tuple, $this->stack[$idx]]; \array_splice($this->stack, $idx, 1, $replacement); } } elseif ($idx === \count($this->stack) - 1) { $this->stack[] = $tuple; } else { $replacement = [$this->stack[$idx], $tuple]; \array_splice($this->stack, $idx, 1, $replacement); } } /** * Provides a debug string for a given callable. * * @param callable|string $fn Function to write as a string. */ private function debugCallable($fn): string { if (\is_string($fn)) { return "callable({$fn})"; } if (\is_array($fn)) { return \is_string($fn[0]) ? "callable({$fn[0]}::{$fn[1]})" : "callable(['".\get_class($fn[0])."', '{$fn[1]}'])"; } /** @var object $fn */ return 'callable('.\spl_object_hash($fn).')'; } }