Proyectos de Subversion Moodle

<?php

namespace Aws;

use Aws\EndpointDiscovery\Configuration;

use Closure;

use Psr\Http\Message\RequestInterface;

/**

 * Builds and injects the user agent header values.

 * This middleware must be appended into step where all the

 * metrics to be gathered are already resolved. As of now it should be

 * after the signing step.

 */

class UserAgentMiddleware

{

    const AGENT_VERSION = 2.1;

    static $userAgentFnList = [

        'getSdkVersion',

        'getUserAgentVersion',

        'getHhvmVersion',

        'getOsName',

        'getLangVersion',

        'getExecEnv',

        'getEndpointDiscovery',

        'getAppId',

        'getMetrics'

    ];

    /** @var callable  */

    private $nextHandler;

    /** @var array */

    private $args;

    /** @var MetricsBuilder */

    private $metricsBuilder;

    /**

     * Returns a middleware wrapper function.

     *

     * @param array $args

     *

     * @return Closure

     */

    public static function wrap(

        array $args

    ) : Closure

    {

        return function (callable $handler) use ($args) {

            return new self($handler, $args);

        };

    }

    /**

     * @param callable $nextHandler

     * @param array $args

     */

    public function __construct(callable $nextHandler, array $args=[])

    {

        $this->nextHandler = $nextHandler;

        $this->args = $args;

    }

    /**

     * When invoked, its injects the user agent header into the

     * request headers.

     *

     * @param CommandInterface $command

     * @param RequestInterface $request

     *

     * @return mixed

     */

    public function __invoke(CommandInterface $command, RequestInterface $request)

    {

        $handler = $this->nextHandler;

        $this->metricsBuilder = MetricsBuilder::fromCommand($command);

        $request = $this->requestWithUserAgentHeader($request);

        return $handler($command, $request);

    }

    /**

     * Builds the user agent header value, and injects it into the request

     * headers. Then, it returns the mutated request.

     *

     * @param RequestInterface $request

     *

     * @return RequestInterface

     */

    private function requestWithUserAgentHeader(RequestInterface $request): RequestInterface

    {

        $uaAppend = $this->args['ua_append'] ?? [];

        $userAgentValue = array_merge(

            $this->buildUserAgentValue(),

            $uaAppend

        );

        // It includes the user agent values just for the User-Agent header.

        // The reason is that the SEP does not mention appending the

        // metrics into the X-Amz-User-Agent header.

        return $request->withHeader(

            'User-Agent',

            implode(' ', array_merge(

                $userAgentValue,

                $request->getHeader('User-Agent')

            ))

        );

    }

    /**

     * Builds the different user agent values.

     *

     * @return array

     */

    private function buildUserAgentValue(): array

    {

        $userAgentValue = [];

        foreach (self::$userAgentFnList as $fn) {

            $val = $this->{$fn}();

            if (!empty($val)) {

                $userAgentValue[] = $val;

            }

        }

        return $userAgentValue;

    }

    /**

     * Returns the user agent value for SDK version.

     *

     * @return string

     */

    private function getSdkVersion(): string

    {

        return 'aws-sdk-php/' . Sdk::VERSION;

    }

    /**

     * Returns the user agent value for the agent version.

     *

     * @return string

     */

    private function getUserAgentVersion(): string

    {

        return 'ua/' . self::AGENT_VERSION;

    }

    /**

     * Returns the user agent value for the hhvm version, but just

     * when it is defined.

     *

     * @return string

     */

    private function getHhvmVersion(): string

    {

        if (defined('HHVM_VERSION')) {

            return 'HHVM/' . HHVM_VERSION;

        }

        return "";

    }

    /**

     * Returns the user agent value for the os version.

     *

     * @return string

     */

    private function getOsName(): string

    {

        $disabledFunctions = explode(',', ini_get('disable_functions'));

        if (function_exists('php_uname')

            && !in_array('php_uname', $disabledFunctions, true)

        ) {

            $osName = "OS/" . php_uname('s') . '#' . php_uname('r');

            if (!empty($osName)) {

                return $osName;

            }

        }

        return "";

    }

    /**

     * Returns the user agent value for the php language used.

     *

     * @return string

     */

    private function getLangVersion(): string

    {

        return 'lang/php#' . phpversion();

    }

    /**

     * Returns the user agent value for the execution env.

     *

     * @return string

     */

    private function getExecEnv(): string

    {

        if ($executionEnvironment = getenv('AWS_EXECUTION_ENV')) {

            return $executionEnvironment;

        }

        return "";

    }

    /**

     * Returns the user agent value for endpoint discovery as cfg.

     * This feature is deprecated.

     *

     * @return string

     */

    private function getEndpointDiscovery(): string

    {

        $args = $this->args;

        if (isset($args['endpoint_discovery'])) {

            if (($args['endpoint_discovery'] instanceof Configuration

                && $args['endpoint_discovery']->isEnabled())

            ) {

                return 'cfg/endpoint-discovery';

            } elseif (is_array($args['endpoint_discovery'])

                && isset($args['endpoint_discovery']['enabled'])

                && $args['endpoint_discovery']['enabled']

            ) {

                return 'cfg/endpoint-discovery';

            }

        }

        return "";

    }

    /**

     * Returns the user agent value for app id, but just when an

     * app id was provided as a client argument.

     *

     * @return string

     */

    private function getAppId(): string

    {

        if (empty($this->args['app_id'])) {

            return "";

        }

        return 'app/' . $this->args['app_id'];

    }

    /**

     * Returns the user agent value for metrics.

     *

     * @return string

     */

    private function getMetrics(): string

    {

        // Resolve first metrics related to client arguments.

        $this->metricsBuilder->resolveAndAppendFromArgs($this->args);

        // Build the metrics.

        $metricsEncoded = $this->metricsBuilder->build();

        if (empty($metricsEncoded)) {

            return "";

        }

        return "m/" . $metricsEncoded;

    }

}