<?php
/*
 * Copyright 2013 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/**
 * Http Streams based implementation of Google_IO.
 *
 * @author Stuart Langley <slangley@google.com>
 */
require_once realpath(dirname(__FILE__) . '/../../../autoload.php');

class Google_IO_Stream extends Google_IO_Abstract
{

    const TIMEOUT = "timeout";

    const ZLIB = "compress.zlib://";

    private $options = array();

    private $trappedErrorNumber;

    private $trappedErrorString;

    private static $DEFAULT_HTTP_CONTEXT = array(
        "follow_location" => 0,
        "ignore_errors" => 1
    );

    private static $DEFAULT_SSL_CONTEXT = array(
        "verify_peer" => true
    );

    /**
     * Execute an HTTP Request
     *
     * @param Google_HttpRequest $request
     *            the http request to be executed
     * @return Google_HttpRequest http request with the response http code,
     *         response headers and response body filled in
     * @throws Google_IO_Exception on curl or IO error
     */
    public function executeRequest(Google_Http_Request $request)
    {
        $default_options = stream_context_get_options(stream_context_get_default());
        $requestHttpContext = array_key_exists('http', $default_options) ? $default_options['http'] : array();
        if ($request->getPostBody()) {
            $requestHttpContext["content"] = $request->getPostBody();
        }
        $requestHeaders = $request->getRequestHeaders();
        if ($requestHeaders && is_array($requestHeaders)) {
            $headers = "";
            foreach ($requestHeaders as $k => $v) {
                $headers .= "$k: $v\r\n";
            }
            $requestHttpContext["header"] = $headers;
        }
        $requestHttpContext["method"] = $request->getRequestMethod();
        $requestHttpContext["user_agent"] = $request->getUserAgent();
        $requestSslContext = array_key_exists('ssl', $default_options) ? $default_options['ssl'] : array();
        if (! array_key_exists("cafile", $requestSslContext)) {
            $requestSslContext["cafile"] = dirname(__FILE__) . '/cacerts.pem';
        }
        $options = array(
            "http" => array_merge(self::$DEFAULT_HTTP_CONTEXT, $requestHttpContext),
            "ssl" => array_merge(self::$DEFAULT_SSL_CONTEXT, $requestSslContext)
        );
        $context = stream_context_create($options);
        $url = $request->getUrl();
        if ($request->canGzip()) {
            $url = self::ZLIB . $url;
        }
        $this->client->getLogger()->debug('Stream request', array(
            'url' => $url,
            'method' => $request->getRequestMethod(),
            'headers' => $requestHeaders,
            'body' => $request->getPostBody()
        ));
        // We are trapping any thrown errors in this method only and
        // throwing an exception.
        $this->trappedErrorNumber = null;
        $this->trappedErrorString = null;
        // START - error trap.
        set_error_handler(array(
            $this,
            'trapError'
        ));
        $fh = fopen($url, 'r', false, $context);
        restore_error_handler();
        // END - error trap.
        if ($this->trappedErrorNumber) {
            $error = sprintf("HTTP Error: Unable to connect: '%s'", $this->trappedErrorString);
            $this->client->getLogger()->error('Stream ' . $error);
            throw new Google_IO_Exception($error, $this->trappedErrorNumber);
        }
        $response_data = false;
        $respHttpCode = self::UNKNOWN_CODE;
        if ($fh) {
            if (isset($this->options[self::TIMEOUT])) {
                stream_set_timeout($fh, $this->options[self::TIMEOUT]);
            }
            $response_data = stream_get_contents($fh);
            fclose($fh);
            $respHttpCode = $this->getHttpResponseCode($http_response_header);
        }
        if (false === $response_data) {
            $error = sprintf("HTTP Error: Unable to connect: '%s'", $respHttpCode);
            $this->client->getLogger()->error('Stream ' . $error);
            throw new Google_IO_Exception($error, $respHttpCode);
        }
        $responseHeaders = $this->getHttpResponseHeaders($http_response_header);
        $this->client->getLogger()->debug('Stream response', array(
            'code' => $respHttpCode,
            'headers' => $responseHeaders,
            'body' => $response_data
        ));
        return array(
            $response_data,
            $responseHeaders,
            $respHttpCode
        );
    }

    /**
     * Set options that update the transport implementation's behavior.
     *
     * @param
     *            $options
     */
    public function setOptions($options)
    {
        $this->options = $options + $this->options;
    }

    /**
     * Method to handle errors, used for error handling around
     * stream connection methods.
     */
    public function trapError($errno, $errstr)
    {
        $this->trappedErrorNumber = $errno;
        $this->trappedErrorString = $errstr;
    }

    /**
     * Set the maximum request time in seconds.
     *
     * @param $timeout in
     *            seconds
     */
    public function setTimeout($timeout)
    {
        $this->options[self::TIMEOUT] = $timeout;
    }

    /**
     * Get the maximum request time in seconds.
     *
     * @return timeout in seconds
     */
    public function getTimeout()
    {
        return $this->options[self::TIMEOUT];
    }

    /**
     * Test for the presence of a cURL header processing bug
     *
     * {@inheritDoc}
     *
     * @return boolean
     */
    protected function needsQuirk()
    {
        return false;
    }

    protected function getHttpResponseCode($response_headers)
    {
        $header_count = count($response_headers);
        for ($i = 0; $i < $header_count; $i ++) {
            $header = $response_headers[$i];
            if (strncasecmp("HTTP", $header, strlen("HTTP")) == 0) {
                $response = explode(' ', $header);
                return $response[1];
            }
        }
        return self::UNKNOWN_CODE;
    }
}
