<?php 
namespace GuzzleHttp; 
 
use GuzzleHttp\Cookie\CookieJarInterface; 
use GuzzleHttp\Exception\RequestException; 
use GuzzleHttp\Promise\RejectedPromise; 
use GuzzleHttp\Psr7; 
use Psr\Http\Message\ResponseInterface; 
use Psr\Log\LoggerInterface; 
use Psr\Log\LogLevel; 
 
/** 
 * Functions used to create and wrap handlers with handler middleware. 
 */ 
final class Middleware 
{ 
    /** 
     * Middleware that adds cookies to requests. 
     * 
     * The options array must be set to a CookieJarInterface in order to use 
     * cookies. This is typically handled for you by a client. 
     * 
     * @return callable Returns a function that accepts the next handler. 
     */ 
    public static function cookies() 
    { 
        return function (callable $handler) { 
            return function ($request, array $options) use ($handler) { 
                if (empty($options['cookies'])) { 
                    return $handler($request, $options); 
                } elseif (!($options['cookies'] instanceof CookieJarInterface)) { 
                    throw new \InvalidArgumentException('cookies must be an instance of GuzzleHttp\Cookie\CookieJarInterface'); 
                } 
                $cookieJar = $options['cookies']; 
                $request = $cookieJar->withCookieHeader($request); 
                return $handler($request, $options) 
                    ->then(function ($response) use ($cookieJar, $request) { 
                        $cookieJar->extractCookies($request, $response); 
                        return $response; 
                    } 
                ); 
            }; 
        }; 
    } 
 
    /** 
     * Middleware that throws exceptions for 4xx or 5xx responses when the 
     * "http_error" request option is set to true. 
     * 
     * @return callable Returns a function that accepts the next handler. 
     */ 
    public static function httpErrors() 
    { 
        return function (callable $handler) { 
            return function ($request, array $options) use ($handler) { 
                if (empty($options['http_errors'])) { 
                    return $handler($request, $options); 
                } 
                return $handler($request, $options)->then( 
                    function (ResponseInterface $response) use ($request, $handler) { 
                        $code = $response->getStatusCode(); 
                        if ($code < 400) { 
                            return $response; 
                        } 
                        throw RequestException::create($request, $response); 
                    } 
                ); 
            }; 
        }; 
    } 
 
    /** 
     * Middleware that pushes history data to an ArrayAccess container. 
     * 
     * @param array $container Container to hold the history (by reference). 
     * 
     * @return callable Returns a function that accepts the next handler. 
     */ 
    public static function history(array &$container) 
    { 
        return function (callable $handler) use (&$container) { 
            return function ($request, array $options) use ($handler, &$container) { 
                return $handler($request, $options)->then( 
                    function ($value) use ($request, &$container, $options) { 
                        $container[] = [ 
                            'request'  => $request, 
                            'response' => $value, 
                            'error'    => null, 
                            'options'  => $options 
                        ]; 
                        return $value; 
                    }, 
                    function ($reason) use ($request, &$container, $options) { 
                        $container[] = [ 
                            'request'  => $request, 
                            'response' => null, 
                            'error'    => $reason, 
                            'options'  => $options 
                        ]; 
                        return new RejectedPromise($reason); 
                    } 
                ); 
            }; 
        }; 
    } 
 
    /** 
     * Middleware that invokes a callback before and after sending a request. 
     * 
     * The provided listener cannot modify or alter the response. It simply 
     * "taps" into the chain to be notified before returning the promise. The 
     * before listener accepts a request and options array, and the after 
     * listener accepts a request, options array, and response promise. 
     * 
     * @param callable $before Function to invoke before forwarding the request. 
     * @param callable $after  Function invoked after forwarding. 
     * 
     * @return callable Returns a function that accepts the next handler. 
     */ 
    public static function tap(callable $before = null, callable $after = null) 
    { 
        return function (callable $handler) use ($before, $after) { 
            return function ($request, array $options) use ($handler, $before, $after) { 
                if ($before) { 
                    $before($request, $options); 
                } 
                $response = $handler($request, $options); 
                if ($after) { 
                    $after($request, $options, $response); 
                } 
                return $response; 
            }; 
        }; 
    } 
 
    /** 
     * Middleware that handles request redirects. 
     * 
     * @return callable Returns a function that accepts the next handler. 
     */ 
    public static function redirect() 
    { 
        return function (callable $handler) { 
            return new RedirectMiddleware($handler); 
        }; 
    } 
 
    /** 
     * Middleware that retries requests based on the boolean result of 
     * invoking the provided "decider" function. 
     * 
     * If no delay function is provided, a simple implementation of exponential 
     * backoff will be utilized. 
     * 
     * @param callable $decider Function that accepts the number of retries, 
     *                          a request, [response], and [exception] and 
     *                          returns true if the request is to be retried. 
     * @param callable $delay   Function that accepts the number of retries and 
     *                          returns the number of milliseconds to delay. 
     * 
     * @return callable Returns a function that accepts the next handler. 
     */ 
    public static function retry(callable $decider, callable $delay = null) 
    { 
        return function (callable $handler) use ($decider, $delay) { 
            return new RetryMiddleware($decider, $handler, $delay); 
        }; 
    } 
 
    /** 
     * Middleware that logs requests, responses, and errors using a message 
     * formatter. 
     * 
     * @param LoggerInterface  $logger Logs messages. 
     * @param MessageFormatter $formatter Formatter used to create message strings. 
     * @param string           $logLevel Level at which to log requests. 
     * 
     * @return callable Returns a function that accepts the next handler. 
     */ 
    public static function log(LoggerInterface $logger, MessageFormatter $formatter, $logLevel = LogLevel::INFO) 
    { 
        return function (callable $handler) use ($logger, $formatter, $logLevel) { 
            return function ($request, array $options) use ($handler, $logger, $formatter, $logLevel) { 
                return $handler($request, $options)->then( 
                    function ($response) use ($logger, $request, $formatter, $logLevel) { 
                        $message = $formatter->format($request, $response); 
                        $logger->log($logLevel, $message); 
                        return $response; 
                    }, 
                    function ($reason) use ($logger, $request, $formatter) { 
                        $response = $reason instanceof RequestException 
                            ? $reason->getResponse() 
                            : null; 
                        $message = $formatter->format($request, $response, $reason); 
                        $logger->notice($message); 
                        return \GuzzleHttp\Promise\rejection_for($reason); 
                    } 
                ); 
            }; 
        }; 
    } 
 
    /** 
     * This middleware adds a default content-type if possible, a default 
     * content-length or transfer-encoding header, and the expect header. 
     * 
     * @return callable 
     */ 
    public static function prepareBody() 
    { 
        return function (callable $handler) { 
            return new PrepareBodyMiddleware($handler); 
        }; 
    } 
 
    /** 
     * Middleware that applies a map function to the request before passing to 
     * the next handler. 
     * 
     * @param callable $fn Function that accepts a RequestInterface and returns 
     *                     a RequestInterface. 
     * @return callable 
     */ 
    public static function mapRequest(callable $fn) 
    { 
        return function (callable $handler) use ($fn) { 
            return function ($request, array $options) use ($handler, $fn) { 
                return $handler($fn($request), $options); 
            }; 
        }; 
    } 
 
    /** 
     * Middleware that applies a map function to the resolved promise's 
     * response. 
     * 
     * @param callable $fn Function that accepts a ResponseInterface and 
     *                     returns a ResponseInterface. 
     * @return callable 
     */ 
    public static function mapResponse(callable $fn) 
    { 
        return function (callable $handler) use ($fn) { 
            return function ($request, array $options) use ($handler, $fn) { 
                return $handler($request, $options)->then($fn); 
            }; 
        }; 
    } 
} 
 
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