Question

WP_Http

Core class used for managing HTTP transports and making HTTP requests.

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description

This class is used to consistently make outgoing HTTP requests easy for developers while still being compatible with the many PHP configurations under which WordPress runs.

Debugging includes several actions, which pass different variables for debugging the HTTP API.

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源代码

File: wp-includes/class-http.php

class WP_Http {

	// Aliases for HTTP response codes.
	const HTTP_CONTINUE                   = 100;
	const SWITCHING_PROTOCOLS             = 101;
	const PROCESSING                      = 102;

	const OK                              = 200;
	const CREATED                         = 201;
	const ACCEPTED                        = 202;
	const NON_AUTHORITATIVE_INFORMATION   = 203;
	const NO_CONTENT                      = 204;
	const RESET_CONTENT                   = 205;
	const PARTIAL_CONTENT                 = 206;
	const MULTI_STATUS                    = 207;
	const IM_USED                         = 226;

	const MULTIPLE_CHOICES                = 300;
	const MOVED_PERMANENTLY               = 301;
	const FOUND                           = 302;
	const SEE_OTHER                       = 303;
	const NOT_MODIFIED                    = 304;
	const USE_PROXY                       = 305;
	const RESERVED                        = 306;
	const TEMPORARY_REDIRECT              = 307;
	const PERMANENT_REDIRECT              = 308;

	const BAD_REQUEST                     = 400;
	const UNAUTHORIZED                    = 401;
	const PAYMENT_REQUIRED                = 402;
	const FORBIDDEN                       = 403;
	const NOT_FOUND                       = 404;
	const METHOD_NOT_ALLOWED              = 405;
	const NOT_ACCEPTABLE                  = 406;
	const PROXY_AUTHENTICATION_REQUIRED   = 407;
	const REQUEST_TIMEOUT                 = 408;
	const CONFLICT                        = 409;
	const GONE                            = 410;
	const LENGTH_REQUIRED                 = 411;
	const PRECONDITION_FAILED             = 412;
	const REQUEST_ENTITY_TOO_LARGE        = 413;
	const REQUEST_URI_TOO_LONG            = 414;
	const UNSUPPORTED_MEDIA_TYPE          = 415;
	const REQUESTED_RANGE_NOT_SATISFIABLE = 416;
	const EXPECTATION_FAILED              = 417;
	const IM_A_TEAPOT                     = 418;
	const MISDIRECTED_REQUEST             = 421;
	const UNPROCESSABLE_ENTITY            = 422;
	const LOCKED                          = 423;
	const FAILED_DEPENDENCY               = 424;
	const UPGRADE_REQUIRED                = 426;
	const PRECONDITION_REQUIRED           = 428;
	const TOO_MANY_REQUESTS               = 429;
	const REQUEST_HEADER_FIELDS_TOO_LARGE = 431;
	const UNAVAILABLE_FOR_LEGAL_REASONS   = 451;

	const INTERNAL_SERVER_ERROR           = 500;
	const NOT_IMPLEMENTED                 = 501;
	const BAD_GATEWAY                     = 502;
	const SERVICE_UNAVAILABLE             = 503;
	const GATEWAY_TIMEOUT                 = 504;
	const HTTP_VERSION_NOT_SUPPORTED      = 505;
	const VARIANT_ALSO_NEGOTIATES         = 506;
	const INSUFFICIENT_STORAGE            = 507;
	const NOT_EXTENDED                    = 510;
	const NETWORK_AUTHENTICATION_REQUIRED = 511;

	/**
	 * Send an HTTP request to a URI.
	 *
	 * Please note: The only URI that are supported in the HTTP Transport implementation
	 * are the HTTP and HTTPS protocols.
	 *
	 * @access public
	 * @since 2.7.0
	 *
	 * @param string       $url  The request URL.
	 * @param string|array $args {
	 *     Optional. Array or string of HTTP request arguments.
	 *
	 *     @type string       $method              Request method. Accepts 'GET', 'POST', 'HEAD', or 'PUT'.
	 *                                             Some transports technically allow others, but should not be
	 *                                             assumed. Default 'GET'.
	 *     @type int          $timeout             How long the connection should stay open in seconds. Default 5.
	 *     @type int          $redirection         Number of allowed redirects. Not supported by all transports
	 *                                             Default 5.
	 *     @type string       $httpversion         Version of the HTTP protocol to use. Accepts '1.0' and '1.1'.
	 *                                             Default '1.0'.
	 *     @type string       $user-agent          User-agent value sent.
	 *                                             Default WordPress/' . get_bloginfo( 'version' ) . '; ' . get_bloginfo( 'url' ).
	 *     @type bool         $reject_unsafe_urls  Whether to pass URLs through wp_http_validate_url().
	 *                                             Default false.
	 *     @type bool         $blocking            Whether the calling code requires the result of the request.
	 *                                             If set to false, the request will be sent to the remote server,
	 *                                             and processing returned to the calling code immediately, the caller
	 *                                             will know if the request succeeded or failed, but will not receive
	 *                                             any response from the remote server. Default true.
	 *     @type string|array $headers             Array or string of headers to send with the request.
	 *                                             Default empty array.
	 *     @type array        $cookies             List of cookies to send with the request. Default empty array.
	 *     @type string|array $body                Body to send with the request. Default null.
	 *     @type bool         $compress            Whether to compress the $body when sending the request.
	 *                                             Default false.
	 *     @type bool         $decompress          Whether to decompress a compressed response. If set to false and
	 *                                             compressed content is returned in the response anyway, it will
	 *                                             need to be separately decompressed. Default true.
	 *     @type bool         $sslverify           Whether to verify SSL for the request. Default true.
	 *     @type string       sslcertificates      Absolute path to an SSL certificate .crt file.
	 *                                             Default ABSPATH . WPINC . '/certificates/ca-bundle.crt'.
	 *     @type bool         $stream              Whether to stream to a file. If set to true and no filename was
	 *                                             given, it will be droped it in the WP temp dir and its name will
	 *                                             be set using the basename of the URL. Default false.
	 *     @type string       $filename            Filename of the file to write to when streaming. $stream must be
	 *                                             set to true. Default null.
	 *     @type int          $limit_response_size Size in bytes to limit the response to. Default null.
	 *
	 * }
	 * @return array|WP_Error Array containing 'headers', 'body', 'response', 'cookies', 'filename'.
	 *                        A WP_Error instance upon error.
	 */
	public function request( $url, $args = array() ) {
		$defaults = array(
			'method' => 'GET',
			/**
			 * Filters the timeout value for an HTTP request.
			 *
			 * @since 2.7.0
			 *
			 * @param int $timeout_value Time in seconds until a request times out.
			 *                           Default 5.
			 */
			'timeout' => apply_filters( 'http_request_timeout', 5 ),
			/**
			 * Filters the number of redirects allowed during an HTTP request.
			 *
			 * @since 2.7.0
			 *
			 * @param int $redirect_count Number of redirects allowed. Default 5.
			 */
			'redirection' => apply_filters( 'http_request_redirection_count', 5 ),
			/**
			 * Filters the version of the HTTP protocol used in a request.
			 *
			 * @since 2.7.0
			 *
			 * @param string $version Version of HTTP used. Accepts '1.0' and '1.1'.
			 *                        Default '1.0'.
			 */
			'httpversion' => apply_filters( 'http_request_version', '1.0' ),
			/**
			 * Filters the user agent value sent with an HTTP request.
			 *
			 * @since 2.7.0
			 *
			 * @param string $user_agent WordPress user agent string.
			 */
			'user-agent' => apply_filters( 'http_headers_useragent', 'WordPress/' . get_bloginfo( 'version' ) . '; ' . get_bloginfo( 'url' ) ),
			/**
			 * Filters whether to pass URLs through wp_http_validate_url() in an HTTP request.
			 *
			 * @since 3.6.0
			 *
			 * @param bool $pass_url Whether to pass URLs through wp_http_validate_url().
			 *                       Default false.
			 */
			'reject_unsafe_urls' => apply_filters( 'http_request_reject_unsafe_urls', false ),
			'blocking' => true,
			'headers' => array(),
			'cookies' => array(),
			'body' => null,
			'compress' => false,
			'decompress' => true,
			'sslverify' => true,
			'sslcertificates' => ABSPATH . WPINC . '/certificates/ca-bundle.crt',
			'stream' => false,
			'filename' => null,
			'limit_response_size' => null,
		);

		// Pre-parse for the HEAD checks.
		$args = wp_parse_args( $args );

		// By default, Head requests do not cause redirections.
		if ( isset($args['method']) && 'HEAD' == $args['method'] )
			$defaults['redirection'] = 0;

		$r = wp_parse_args( $args, $defaults );
		/**
		 * Filters the arguments used in an HTTP request.
		 *
		 * @since 2.7.0
		 *
		 * @param array  $r   An array of HTTP request arguments.
		 * @param string $url The request URL.
		 */
		$r = apply_filters( 'http_request_args', $r, $url );

		// The transports decrement this, store a copy of the original value for loop purposes.
		if ( ! isset( $r['_redirection'] ) )
			$r['_redirection'] = $r['redirection'];

		/**
		 * Filters whether to preempt an HTTP request's return value.
		 *
		 * Returning a non-false value from the filter will short-circuit the HTTP request and return
		 * early with that value. A filter should return either:
		 *
		 *  - An array containing 'headers', 'body', 'response', 'cookies', and 'filename' elements
		 *  - A WP_Error instance
		 *  - boolean false (to avoid short-circuiting the response)
		 *
		 * Returning any other value may result in unexpected behaviour.
		 *
		 * @since 2.9.0
		 *
		 * @param false|array|WP_Error $preempt Whether to preempt an HTTP request's return value. Default false.
		 * @param array               $r        HTTP request arguments.
		 * @param string              $url      The request URL.
		 */
		$pre = apply_filters( 'pre_http_request', false, $r, $url );

		if ( false !== $pre )
			return $pre;

		if ( function_exists( 'wp_kses_bad_protocol' ) ) {
			if ( $r['reject_unsafe_urls'] ) {
				$url = wp_http_validate_url( $url );
			}
			if ( $url ) {
				$url = wp_kses_bad_protocol( $url, array( 'http', 'https', 'ssl' ) );
			}
		}

		$arrURL = @parse_url( $url );

		if ( empty( $url ) || empty( $arrURL['scheme'] ) ) {
			return new WP_Error('http_request_failed', __('A valid URL was not provided.'));
		}

		if ( $this->block_request( $url ) ) {
			return new WP_Error( 'http_request_failed', __( 'User has blocked requests through HTTP.' ) );
		}

		// If we are streaming to a file but no filename was given drop it in the WP temp dir
		// and pick its name using the basename of the $url
		if ( $r['stream'] ) {
			if ( empty( $r['filename'] ) ) {
				$r['filename'] = get_temp_dir() . basename( $url );
			}

			// Force some settings if we are streaming to a file and check for existence and perms of destination directory
			$r['blocking'] = true;
			if ( ! wp_is_writable( dirname( $r['filename'] ) ) ) {
				return new WP_Error( 'http_request_failed', __( 'Destination directory for file streaming does not exist or is not writable.' ) );
			}
		}

		if ( is_null( $r['headers'] ) ) {
			$r['headers'] = array();
		}

		// WP allows passing in headers as a string, weirdly.
		if ( ! is_array( $r['headers'] ) ) {
			$processedHeaders = WP_Http::processHeaders( $r['headers'] );
			$r['headers'] = $processedHeaders['headers'];
		}

		// Setup arguments
		$headers = $r['headers'];
		$data = $r['body'];
		$type = $r['method'];
		$options = array(
			'timeout' => $r['timeout'],
			'useragent' => $r['user-agent'],
			'blocking' => $r['blocking'],
			'hooks' => new WP_HTTP_Requests_Hooks( $url, $r ),
		);

		// Ensure redirects follow browser behaviour.
		$options['hooks']->register( 'requests.before_redirect', array( get_class(), 'browser_redirect_compatibility' ) );

		// Validate redirected URLs.
		if ( function_exists( 'wp_kses_bad_protocol' ) && $r['reject_unsafe_urls'] ) {
			$options['hooks']->register( 'requests.before_redirect', array( get_class(), 'validate_redirects' ) );
		}

		if ( $r['stream'] ) {
			$options['filename'] = $r['filename'];
		}
		if ( empty( $r['redirection'] ) ) {
			$options['follow_redirects'] = false;
		} else {
			$options['redirects'] = $r['redirection'];
		}

		// Use byte limit, if we can
		if ( isset( $r['limit_response_size'] ) ) {
			$options['max_bytes'] = $r['limit_response_size'];
		}

		// If we've got cookies, use and convert them to Requests_Cookie.
		if ( ! empty( $r['cookies'] ) ) {
			$options['cookies'] = WP_Http::normalize_cookies( $r['cookies'] );
		}

		// SSL certificate handling
		if ( ! $r['sslverify'] ) {
			$options['verify'] = false;
			$options['verifyname'] = false;
		} else {
			$options['verify'] = $r['sslcertificates'];
		}

		// All non-GET/HEAD requests should put the arguments in the form body.
		if ( 'HEAD' !== $type && 'GET' !== $type ) {
			$options['data_format'] = 'body';
		}

		/**
		 * Filters whether SSL should be verified for non-local requests.
		 *
		 * @since 2.8.0
		 *
		 * @param bool $ssl_verify Whether to verify the SSL connection. Default true.
		 */
		$options['verify'] = apply_filters( 'https_ssl_verify', $options['verify'] );

		// Check for proxies.
		$proxy = new WP_HTTP_Proxy();
		if ( $proxy->is_enabled() && $proxy->send_through_proxy( $url ) ) {
			$options['proxy'] = new Requests_Proxy_HTTP( $proxy->host() . ':' . $proxy->port() );

			if ( $proxy->use_authentication() ) {
				$options['proxy']->use_authentication = true;
				$options['proxy']->user = $proxy->username();
				$options['proxy']->pass = $proxy->password();
			}
		}

		// Avoid issues where mbstring.func_overload is enabled
		mbstring_binary_safe_encoding();

		try {
			$requests_response = Requests::request( $url, $headers, $data, $type, $options );

			// Convert the response into an array
			$http_response = new WP_HTTP_Requests_Response( $requests_response, $r['filename'] );
			$response = $http_response->to_array();

			// Add the original object to the array.
			$response['http_response'] = $http_response;
		}
		catch ( Requests_Exception $e ) {
			$response = new WP_Error( 'http_request_failed', $e->getMessage() );
		}

		reset_mbstring_encoding();

		/**
		 * Fires after an HTTP API response is received and before the response is returned.
		 *
		 * @since 2.8.0
		 *
		 * @param array|WP_Error $response HTTP response or WP_Error object.
		 * @param string         $context  Context under which the hook is fired.
		 * @param string         $class    HTTP transport used.
		 * @param array          $args     HTTP request arguments.
		 * @param string         $url      The request URL.
		 */
		do_action( 'http_api_debug', $response, 'response', 'Requests', $r, $url );
		if ( is_wp_error( $response ) ) {
			return $response;
		}

		if ( ! $r['blocking'] ) {
			return array(
				'headers' => array(),
				'body' => '',
				'response' => array(
					'code' => false,
					'message' => false,
				),
				'cookies' => array(),
				'http_response' => null,
			);
		}

		/**
		 * Filters the HTTP API response immediately before the response is returned.
		 *
		 * @since 2.9.0
		 *
		 * @param array  $response HTTP response.
		 * @param array  $r        HTTP request arguments.
		 * @param string $url      The request URL.
		 */
		return apply_filters( 'http_response', $response, $r, $url );
	}

	/**
	 * Normalizes cookies for using in Requests.
	 *
	 * @since 4.6.0
	 * @access public
	 * @static
	 *
	 * @param array $cookies List of cookies to send with the request.
	 * @return Requests_Cookie_Jar Cookie holder object.
	 */
	public static function normalize_cookies( $cookies ) {
		$cookie_jar = new Requests_Cookie_Jar();

		foreach ( $cookies as $name => $value ) {
			if ( $value instanceof WP_Http_Cookie ) {
				$cookie_jar[ $value->name ] = new Requests_Cookie( $value->name, $value->value, $value->get_attributes() );
			} elseif ( is_scalar( $value ) ) {
				$cookie_jar[ $name ] = new Requests_Cookie( $name, $value );
			}
		}

		return $cookie_jar;
	}

	/**
	 * Match redirect behaviour to browser handling.
	 *
	 * Changes 302 redirects from POST to GET to match browser handling. Per
	 * RFC 7231, user agents can deviate from the strict reading of the
	 * specification for compatibility purposes.
	 *
	 * @since 4.6.0
	 * @access public
	 * @static
	 *
	 * @param string            $location URL to redirect to.
	 * @param array             $headers  Headers for the redirect.
	 * @param array             $options  Redirect request options.
	 * @param Requests_Response $original Response object.
	 */
	public static function browser_redirect_compatibility( $location, $headers, $data, &$options, $original ) {
		// Browser compat
		if ( $original->status_code === 302 ) {
			$options['type'] = Requests::GET;
		}
	}

	/**
	 * Validate redirected URLs.
	 *
	 * @since 4.7.5
	 *
	 * @throws Requests_Exception On unsuccessful URL validation
	 * @param string $location URL to redirect to.
	 */
	public static function validate_redirects( $location ) {
		if ( ! wp_http_validate_url( $location ) ) {
			throw new Requests_Exception( __('A valid URL was not provided.'), 'wp_http.redirect_failed_validation' );
		}
	}

	/**
	 * Tests which transports are capable of supporting the request.
	 *
	 * @since 3.2.0
	 * @access public
	 *
	 * @param array $args Request arguments
	 * @param string $url URL to Request
	 *
	 * @return string|false Class name for the first transport that claims to support the request. False if no transport claims to support the request.
	 */
	public function _get_first_available_transport( $args, $url = null ) {
		$transports = array( 'curl', 'streams' );

		/**
		 * Filters which HTTP transports are available and in what order.
		 *
		 * @since 3.7.0
		 *
		 * @param array  $transports Array of HTTP transports to check. Default array contains
		 *                           'curl', and 'streams', in that order.
		 * @param array  $args       HTTP request arguments.
		 * @param string $url        The URL to request.
		 */
		$request_order = apply_filters( 'http_api_transports', $transports, $args, $url );

		// Loop over each transport on each HTTP request looking for one which will serve this request's needs.
		foreach ( $request_order as $transport ) {
			if ( in_array( $transport, $transports ) ) {
				$transport = ucfirst( $transport );
			}
			$class = 'WP_Http_' . $transport;

			// Check to see if this transport is a possibility, calls the transport statically.
			if ( !call_user_func( array( $class, 'test' ), $args, $url ) )
				continue;

			return $class;
		}

		return false;
	}

	/**
	 * Dispatches a HTTP request to a supporting transport.
	 *
	 * Tests each transport in order to find a transport which matches the request arguments.
	 * Also caches the transport instance to be used later.
	 *
	 * The order for requests is cURL, and then PHP Streams.
	 *
	 * @since 3.2.0
	 *
	 * @static
	 * @access private
	 *
	 * @param string $url URL to Request
	 * @param array $args Request arguments
	 * @return array|WP_Error Array containing 'headers', 'body', 'response', 'cookies', 'filename'. A WP_Error instance upon error
	 */
	private function _dispatch_request( $url, $args ) {
		static $transports = array();

		$class = $this->_get_first_available_transport( $args, $url );
		if ( !$class )
			return new WP_Error( 'http_failure', __( 'There are no HTTP transports available which can complete the requested request.' ) );

		// Transport claims to support request, instantiate it and give it a whirl.
		if ( empty( $transports[$class] ) )
			$transports[$class] = new $class;

		$response = $transports[$class]->request( $url, $args );

		/** This action is documented in wp-includes/class-http.php */
		do_action( 'http_api_debug', $response, 'response', $class, $args, $url );

		if ( is_wp_error( $response ) )
			return $response;

		/**
		 * Filters the HTTP API response immediately before the response is returned.
		 *
		 * @since 2.9.0
		 *
		 * @param array  $response HTTP response.
		 * @param array  $args     HTTP request arguments.
		 * @param string $url      The request URL.
		 */
		return apply_filters( 'http_response', $response, $args, $url );
	}

	/**
	 * Uses the POST HTTP method.
	 *
	 * Used for sending data that is expected to be in the body.
	 *
	 * @access public
	 * @since 2.7.0
	 *
	 * @param string       $url  The request URL.
	 * @param string|array $args Optional. Override the defaults.
	 * @return array|WP_Error Array containing 'headers', 'body', 'response', 'cookies', 'filename'. A WP_Error instance upon error
	 */
	public function post($url, $args = array()) {
		$defaults = array('method' => 'POST');
		$r = wp_parse_args( $args, $defaults );
		return $this->request($url, $r);
	}

	/**
	 * Uses the GET HTTP method.
	 *
	 * Used for sending data that is expected to be in the body.
	 *
	 * @access public
	 * @since 2.7.0
	 *
	 * @param string $url The request URL.
	 * @param string|array $args Optional. Override the defaults.
	 * @return array|WP_Error Array containing 'headers', 'body', 'response', 'cookies', 'filename'. A WP_Error instance upon error
	 */
	public function get($url, $args = array()) {
		$defaults = array('method' => 'GET');
		$r = wp_parse_args( $args, $defaults );
		return $this->request($url, $r);
	}

	/**
	 * Uses the HEAD HTTP method.
	 *
	 * Used for sending data that is expected to be in the body.
	 *
	 * @access public
	 * @since 2.7.0
	 *
	 * @param string $url The request URL.
	 * @param string|array $args Optional. Override the defaults.
	 * @return array|WP_Error Array containing 'headers', 'body', 'response', 'cookies', 'filename'. A WP_Error instance upon error
	 */
	public function head($url, $args = array()) {
		$defaults = array('method' => 'HEAD');
		$r = wp_parse_args( $args, $defaults );
		return $this->request($url, $r);
	}

	/**
	 * Parses the responses and splits the parts into headers and body.
	 *
	 * @access public
	 * @static
	 * @since 2.7.0
	 *
	 * @param string $strResponse The full response string
	 * @return array Array with 'headers' and 'body' keys.
	 */
	public static function processResponse($strResponse) {
		$res = explode("\r\n\r\n", $strResponse, 2);

		return array('headers' => $res[0], 'body' => isset($res[1]) ? $res[1] : '');
	}

	/**
	 * Transform header string into an array.
	 *
	 * If an array is given then it is assumed to be raw header data with numeric keys with the
	 * headers as the values. No headers must be passed that were already processed.
	 *
	 * @access public
	 * @static
	 * @since 2.7.0
	 *
	 * @param string|array $headers
	 * @param string $url The URL that was requested
	 * @return array Processed string headers. If duplicate headers are encountered,
	 * 					Then a numbered array is returned as the value of that header-key.
	 */
	public static function processHeaders( $headers, $url = '' ) {
		// Split headers, one per array element.
		if ( is_string($headers) ) {
			// Tolerate line terminator: CRLF = LF (RFC 2616 19.3).
			$headers = str_replace("\r\n", "\n", $headers);
			/*
			 * Unfold folded header fields. LWS = [CRLF] 1*( SP | HT ) <US-ASCII SP, space (32)>,
			 * <US-ASCII HT, horizontal-tab (9)> (RFC 2616 2.2).
			 */
			$headers = preg_replace('/\n[ \t]/', ' ', $headers);
			// Create the headers array.
			$headers = explode("\n", $headers);
		}

		$response = array('code' => 0, 'message' => '');

		/*
		 * If a redirection has taken place, The headers for each page request may have been passed.
		 * In this case, determine the final HTTP header and parse from there.
		 */
		for ( $i = count($headers)-1; $i >= 0; $i-- ) {
			if ( !empty($headers[$i]) && false === strpos($headers[$i], ':') ) {
				$headers = array_splice($headers, $i);
				break;
			}
		}

		$cookies = array();
		$newheaders = array();
		foreach ( (array) $headers as $tempheader ) {
			if ( empty($tempheader) )
				continue;

			if ( false === strpos($tempheader, ':') ) {
				$stack = explode(' ', $tempheader, 3);
				$stack[] = '';
				list( , $response['code'], $response['message']) = $stack;
				continue;
			}

			list($key, $value) = explode(':', $tempheader, 2);

			$key = strtolower( $key );
			$value = trim( $value );

			if ( isset( $newheaders[ $key ] ) ) {
				if ( ! is_array( $newheaders[ $key ] ) )
					$newheaders[$key] = array( $newheaders[ $key ] );
				$newheaders[ $key ][] = $value;
			} else {
				$newheaders[ $key ] = $value;
			}
			if ( 'set-cookie' == $key )
				$cookies[] = new WP_Http_Cookie( $value, $url );
		}

		// Cast the Response Code to an int
		$response['code'] = intval( $response['code'] );

		return array('response' => $response, 'headers' => $newheaders, 'cookies' => $cookies);
	}

	/**
	 * Takes the arguments for a ::request() and checks for the cookie array.
	 *
	 * If it's found, then it upgrades any basic name => value pairs to WP_Http_Cookie instances,
	 * which are each parsed into strings and added to the Cookie: header (within the arguments array).
	 * Edits the array by reference.
	 *
	 * @access public
	 * @version 2.8.0
	 * @static
	 *
	 * @param array $r Full array of args passed into ::request()
	 */
	public static function buildCookieHeader( &$r ) {
		if ( ! empty($r['cookies']) ) {
			// Upgrade any name => value cookie pairs to WP_HTTP_Cookie instances.
			foreach ( $r['cookies'] as $name => $value ) {
				if ( ! is_object( $value ) )
					$r['cookies'][ $name ] = new WP_Http_Cookie( array( 'name' => $name, 'value' => $value ) );
			}

			$cookies_header = '';
			foreach ( (array) $r['cookies'] as $cookie ) {
				$cookies_header .= $cookie->getHeaderValue() . '; ';
			}

			$cookies_header = substr( $cookies_header, 0, -2 );
			$r['headers']['cookie'] = $cookies_header;
		}
	}

	/**
	 * Decodes chunk transfer-encoding, based off the HTTP 1.1 specification.
	 *
	 * Based off the HTTP http_encoding_dechunk function.
	 *
	 * @link https://tools.ietf.org/html/rfc2616#section-19.4.6 Process for chunked decoding.
	 *
	 * @access public
	 * @since 2.7.0
	 * @static
	 *
	 * @param string $body Body content
	 * @return string Chunked decoded body on success or raw body on failure.
	 */
	public static function chunkTransferDecode( $body ) {
		// The body is not chunked encoded or is malformed.
		if ( ! preg_match( '/^([0-9a-f]+)[^\r\n]*\r\n/i', trim( $body ) ) )
			return $body;

		$parsed_body = '';

		// We'll be altering $body, so need a backup in case of error.
		$body_original = $body;

		while ( true ) {
			$has_chunk = (bool) preg_match( '/^([0-9a-f]+)[^\r\n]*\r\n/i', $body, $match );
			if ( ! $has_chunk || empty( $match[1] ) )
				return $body_original;

			$length = hexdec( $match[1] );
			$chunk_length = strlen( $match[0] );

			// Parse out the chunk of data.
			$parsed_body .= substr( $body, $chunk_length, $length );

			// Remove the chunk from the raw data.
			$body = substr( $body, $length + $chunk_length );

			// End of the document.
			if ( '0' === trim( $body ) )
				return $parsed_body;
		}
	}

	/**
	 * Block requests through the proxy.
	 *
	 * Those who are behind a proxy and want to prevent access to certain hosts may do so. This will
	 * prevent plugins from working and core functionality, if you don't include api.wordpress.org.
	 *
	 * You block external URL requests by defining WP_HTTP_BLOCK_EXTERNAL as true in your wp-config.php
	 * file and this will only allow localhost and your site to make requests. The constant
	 * WP_ACCESSIBLE_HOSTS will allow additional hosts to go through for requests. The format of the
	 * WP_ACCESSIBLE_HOSTS constant is a comma separated list of hostnames to allow, wildcard domains
	 * are supported, eg *.wordpress.org will allow for all subdomains of wordpress.org to be contacted.
	 *
	 * @since 2.8.0
	 * @link https://core.trac.wordpress.org/ticket/8927 Allow preventing external requests.
	 * @link https://core.trac.wordpress.org/ticket/14636 Allow wildcard domains in WP_ACCESSIBLE_HOSTS
	 *
	 * @staticvar array|null $accessible_hosts
	 * @staticvar array      $wildcard_regex
	 *
	 * @param string $uri URI of url.
	 * @return bool True to block, false to allow.
	 */
	public function block_request($uri) {
		// We don't need to block requests, because nothing is blocked.
		if ( ! defined( 'WP_HTTP_BLOCK_EXTERNAL' ) || ! WP_HTTP_BLOCK_EXTERNAL )
			return false;

		$check = parse_url($uri);
		if ( ! $check )
			return true;

		$home = parse_url( get_option('siteurl') );

		// Don't block requests back to ourselves by default.
		if ( 'localhost' == $check['host'] || ( isset( $home['host'] ) && $home['host'] == $check['host'] ) ) {
			/**
			 * Filters whether to block local requests through the proxy.
			 *
			 * @since 2.8.0
			 *
			 * @param bool $block Whether to block local requests through proxy.
			 *                    Default false.
			 */
			return apply_filters( 'block_local_requests', false );
		}

		if ( !defined('WP_ACCESSIBLE_HOSTS') )
			return true;

		static $accessible_hosts = null;
		static $wildcard_regex = array();
		if ( null === $accessible_hosts ) {
			$accessible_hosts = preg_split('|,\s*|', WP_ACCESSIBLE_HOSTS);

			if ( false !== strpos(WP_ACCESSIBLE_HOSTS, '*') ) {
				$wildcard_regex = array();
				foreach ( $accessible_hosts as $host )
					$wildcard_regex[] = str_replace( '\*', '.+', preg_quote( $host, '/' ) );
				$wildcard_regex = '/^(' . implode('|', $wildcard_regex) . ')$/i';
			}
		}

		if ( !empty($wildcard_regex) )
			return !preg_match($wildcard_regex, $check['host']);
		else
			return !in_array( $check['host'], $accessible_hosts ); //Inverse logic, If it's in the array, then we can't access it.

	}

	/**
	 * Used as a wrapper for PHP's parse_url() function that handles edgecases in < PHP 5.4.7.
	 *
	 * @access protected
	 * @deprecated 4.4.0 Use wp_parse_url()
	 * @see wp_parse_url()
	 *
	 * @param string $url The URL to parse.
	 * @return bool|array False on failure; Array of URL components on success;
	 *                    See parse_url()'s return values.
	 */
	protected static function parse_url( $url ) {
		_deprecated_function( __METHOD__, '4.4.0', 'wp_parse_url()' );
		return wp_parse_url( $url );
	}

	/**
	 * Converts a relative URL to an absolute URL relative to a given URL.
	 *
	 * If an Absolute URL is provided, no processing of that URL is done.
	 *
	 * @since 3.4.0
	 *
	 * @static
	 * @access public
	 *
	 * @param string $maybe_relative_path The URL which might be relative
	 * @param string $url                 The URL which $maybe_relative_path is relative to
	 * @return string An Absolute URL, in a failure condition where the URL cannot be parsed, the relative URL will be returned.
	 */
	public static function make_absolute_url( $maybe_relative_path, $url ) {
		if ( empty( $url ) )
			return $maybe_relative_path;

		if ( ! $url_parts = wp_parse_url( $url ) ) {
			return $maybe_relative_path;
		}

		if ( ! $relative_url_parts = wp_parse_url( $maybe_relative_path ) ) {
			return $maybe_relative_path;
		}

		// Check for a scheme on the 'relative' url
		if ( ! empty( $relative_url_parts['scheme'] ) ) {
			return $maybe_relative_path;
		}

		$absolute_path = $url_parts['scheme'] . '://';

		// Schemeless URL's will make it this far, so we check for a host in the relative url and convert it to a protocol-url
		if ( isset( $relative_url_parts['host'] ) ) {
			$absolute_path .= $relative_url_parts['host'];
			if ( isset( $relative_url_parts['port'] ) )
				$absolute_path .= ':' . $relative_url_parts['port'];
		} else {
			$absolute_path .= $url_parts['host'];
			if ( isset( $url_parts['port'] ) )
				$absolute_path .= ':' . $url_parts['port'];
		}

		// Start off with the Absolute URL path.
		$path = ! empty( $url_parts['path'] ) ? $url_parts['path'] : '/';

		// If it's a root-relative path, then great.
		if ( ! empty( $relative_url_parts['path'] ) && '/' == $relative_url_parts['path'][0] ) {
			$path = $relative_url_parts['path'];

		// Else it's a relative path.
		} elseif ( ! empty( $relative_url_parts['path'] ) ) {
			// Strip off any file components from the absolute path.
			$path = substr( $path, 0, strrpos( $path, '/' ) + 1 );

			// Build the new path.
			$path .= $relative_url_parts['path'];

			// Strip all /path/../ out of the path.
			while ( strpos( $path, '../' ) > 1 ) {
				$path = preg_replace( '![^/]+/\.\./!', '', $path );
			}

			// Strip any final leading ../ from the path.
			$path = preg_replace( '!^/(\.\./)+!', '', $path );
		}

		// Add the Query string.
		if ( ! empty( $relative_url_parts['query'] ) )
			$path .= '?' . $relative_url_parts['query'];

		return $absolute_path . '/' . ltrim( $path, '/' );
	}

	/**
	 * Handles HTTP Redirects and follows them if appropriate.
	 *
	 * @since 3.7.0
	 *
	 * @static
	 *
	 * @param string $url The URL which was requested.
	 * @param array $args The Arguments which were used to make the request.
	 * @param array $response The Response of the HTTP request.
	 * @return false|object False if no redirect is present, a WP_HTTP or WP_Error result otherwise.
	 */
	public static function handle_redirects( $url, $args, $response ) {
		// If no redirects are present, or, redirects were not requested, perform no action.
		if ( ! isset( $response['headers']['location'] ) || 0 === $args['_redirection'] )
			return false;

		// Only perform redirections on redirection http codes.
		if ( $response['response']['code'] > 399 || $response['response']['code'] < 300 )
			return false;

		// Don't redirect if we've run out of redirects.
		if ( $args['redirection']-- <= 0 )
			return new WP_Error( 'http_request_failed', __('Too many redirects.') );

		$redirect_location = $response['headers']['location'];

		// If there were multiple Location headers, use the last header specified.
		if ( is_array( $redirect_location ) )
			$redirect_location = array_pop( $redirect_location );

		$redirect_location = WP_Http::make_absolute_url( $redirect_location, $url );

		// POST requests should not POST to a redirected location.
		if ( 'POST' == $args['method'] ) {
			if ( in_array( $response['response']['code'], array( 302, 303 ) ) )
				$args['method'] = 'GET';
		}

		// Include valid cookies in the redirect process.
		if ( ! empty( $response['cookies'] ) ) {
			foreach ( $response['cookies'] as $cookie ) {
				if ( $cookie->test( $redirect_location ) )
					$args['cookies'][] = $cookie;
			}
		}

		return wp_remote_request( $redirect_location, $args );
	}

	/**
	 * Determines if a specified string represents an IP address or not.
	 *
	 * This function also detects the type of the IP address, returning either
	 * '4' or '6' to represent a IPv4 and IPv6 address respectively.
	 * This does not verify if the IP is a valid IP, only that it appears to be
	 * an IP address.
	 *
	 * @link http://home.deds.nl/~aeron/regex/ for IPv6 regex
	 *
	 * @since 3.7.0
	 * @static
	 *
	 * @param string $maybe_ip A suspected IP address
	 * @return integer|bool Upon success, '4' or '6' to represent a IPv4 or IPv6 address, false upon failure
	 */
	public static function is_ip_address( $maybe_ip ) {
		if ( preg_match( '/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/', $maybe_ip ) )
			return 4;

		if ( false !== strpos( $maybe_ip, ':' ) && preg_match( '/^(((?=.*(::))(?!.*\3.+\3))\3?|([\dA-F]{1,4}(\3|:\b|$)|\2))(?4){5}((?4){2}|(((2[0-4]|1\d|[1-9])?\d|25[0-5])\.?\b){4})$/i', trim( $maybe_ip, ' []' ) ) )
			return 6;

		return false;
	}

}

---

更新日志

Version	description
2.7.0	Introduced.

---

Methods

• _dispatch_request Dispatches a HTTP request to a supporting transport.
• _get_first_available_transport Tests which transports are capable of supporting the request.
• block_request Block requests through the proxy.
• browser_redirect_compatibility Match redirect behaviour to browser handling.
• buildCookieHeader Takes the arguments for a ::request() and checks for the cookie array.
• chunkTransferDecode Decodes chunk transfer-encoding, based off the HTTP 1.1 specification.
• get Uses the GET HTTP method.
• handle_redirects Handles HTTP Redirects and follows them if appropriate.
• head Uses the HEAD HTTP method.
• is_ip_address Determines if a specified string represents an IP address or not.
• make_absolute_url Converts a relative URL to an absolute URL relative to a given URL.
• normalize_cookies Normalizes cookies for using in Requests.
• parse_url Used as a wrapper for PHP's parse_url() function that handles edgecases in < PHP 5.4.7. deprecated
• post Uses the POST HTTP method.
• processHeaders Transform header string into an array.
• processResponse Parses the responses and splits the parts into headers and body.
• request Send an HTTP request to a URI.
• validate_redirects Validate redirected URLs.

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User Contributed Notes