curl_multi_exec：下载的某些图像缺少一些数据/流不完整

时间：2018-07-16 00:14:46

标签： php curl php-curl curl-multi

我已经实现了一个PHP函数，该函数使用PHP curl_multi_init()方法检查并下载大量图像（> 1'000）（通过数组传递给它）。

已经对它进行了几次重做，因为我得到了0字节文件之类的东西，所以我现在有一个解决方案，可以下载所有图像-但是下载的所有其他图像文件都不完整。

在我看来，我好像使用file_put_contents()太早了，这意味着在使用curl_multi_exec()完全接收了某些图像数据之前。

很不幸，我没有遇到任何类似的问题，也没有任何Google结果，在这种情况下，我需要使用curl_multi_exec，但不想使用curl-opt-header“ CURLOPT_FILE来检索和保存图像“。

希望有人能够帮助我解决我所缺少的内容以及为什么我在本地保存一些损坏的图像。

以下是一些检索到的损坏图像的示例：

example image 1 example image 2

这是一个示例数组，我将其传递给我的Multi-CURL-Function：

$curl_httpresources = [
        [ 'http://www.gravatar.com/avatar/example?d=mm&r=x&s=427'
        ,'/srv/www/data/images/1_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=identicon&r=x&s=427'
        ,'/srv/www/data/images/2_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=monsterid&r=x&s=427'
        ,'/srv/www/data/images/3_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=wavatar&r=x&s=427'
        ,'/srv/www/data/images/4_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=retro&r=x&s=427'
        ,'/srv/www/data/images/5_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=mm&r=x&s=427'
        ,'/srv/www/data/images/6_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=identicon&r=x&s=427'
        ,'/srv/www/data/images/7_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=monsterid&r=x&s=427'
        ,'/srv/www/data/images/8_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=wavatar&r=x&s=427'
        ,'/srv/www/data/images/9_unsplash.jpg' ],
        [ 'http://www.gravatar.com/avatar/example?d=retro&r=x&s=427'
        ,'/srv/www/data/images/10_unsplash.jpg' ],
];

我的多卷曲PHP函数

现在我正在使用的功能-以及某种“作品”，除了一些部分下载的文件-这是代码：

function cURLfetch(array $resources)
{
    /** Disable PHP timelimit, because this could take a while... */
    set_time_limit(0);

    /** Validate the $resources Array (not empty, null, or alike) */
    $resources_num = count($resources);
    if ( empty($resources) || $resources_num <= 0 ) return false;

    /** Callback-Function for writing data to file */
    $callback = function($resource, $filepath)
    {
        file_put_contents($filepath, $resource);
        /** For Debug only: output <img>-Tag with saved $resource */
        printf('<img src="%s"><br>', str_replace('/srv/www', '', $filepath));
    };

    /**
     * Initialize CURL process for handling multiple parallel requests 
     */
    $curl_instance = curl_multi_init();
    $curl_multi_exec_active = null;
    $curl_request_options = [
                                CURLOPT_USERAGENT => 'PHP-Script/1.0 (+https://website.com/)',
                                CURLOPT_TIMEOUT => 10,
                                CURLOPT_FOLLOWLOCATION => true,
                                CURLOPT_VERBOSE => false,
                                CURLOPT_RETURNTRANSFER => true,
                            ];

    /**
     * Looping through all $resources
     *   $resources[$i][0] = HTTP resource
     *   $resources[$i][1] = Target Filepath
     */
    for ($i = 0; $i < $resources_num; $i++)
    {
        $curl_requests[$i] = curl_init($resources[$i][0]);
        curl_setopt_array($curl_requests[$i], $curl_request_options);
        curl_multi_add_handle($curl_instance, $curl_requests[$i]);
    }

    do {
        try {
            $curl_execute = curl_multi_exec($curl_instance, $curl_multi_exec_active);
        } catch (Exception $e) {
            error_log($e->getMessage());
        }
    } while ($curl_execute == CURLM_CALL_MULTI_PERFORM);


    /** Wait until data arrives on all sockets */
    $h = 0; // initialise a counter
    while ($curl_multi_exec_active && $curl_execute == CURLM_OK)
    {
        if (curl_multi_select($curl_instance) != -1)
        {
            do {
              $curl_data = curl_multi_exec($curl_instance, $curl_multi_exec_active);
              $curl_done = curl_multi_info_read($curl_instance);
              /** Check if there is data... */
              if ($curl_done['handle'] !== NULL)
              {
                  /** Continue ONLY if HTTP statuscode was OK (200) */
                  $info = curl_getinfo($curl_done['handle']);
                  if ($info['http_code'] == 200)
                  {
                      if (!empty(curl_multi_getcontent($curl_requests[$h]))) {
                          /** Curl request successful. Process data using the callback function. */
                          $callback(curl_multi_getcontent($curl_requests[$h]), $resources[$h][1]);
                      }
                      $h++; // count up
                   }
               }
            } while ($curl_data == CURLM_CALL_MULTI_PERFORM);
        }
    }

    /** Close all $curl_requests */
    foreach($curl_requests as $request) {
        curl_multi_remove_handle($curl_instance, $request);
    }
    curl_multi_close($curl_instance);

    return true;
}

/** Start fetching images from an Array */
cURLfetch($curl_httpresources);

非常感谢您的帮助，非常感谢！

1 个答案:

答案 0 :(得分：0)

我最终在经典循环中仅使用常规的cURL请求，以查询所有> 1'000张图像并下载带有“ HTTP 200 OK”响应的图像。我最初担心的是，由于可能会错误识别DDoS，服务器可能会切断连接没有效果，为什么这种方法在我的情况下效果很好。

这是我正在使用的常规cURL请求的最终功能：

function cURLfetchUrl($url, $save_as_file)
{
    /** Validate $url & $save_as_file (not empty, null, or alike) */
    if ( empty($url) || is_numeric($url) ) return false;
    if ( empty($save_as_file) || is_numeric($save_as_file) ) return false;

    /** Disable PHP timelimit, because this could take a while... */
    set_time_limit(0);

    try {
        /**
         * Set cURL options to be passed to a single request
         */
        $curl_request_options = [
                                    CURLOPT_USERAGENT => 'PHP-Script/1.0 (+https://website.com/)',
                                    CURLOPT_TIMEOUT => 5,
                                    CURLOPT_FOLLOWLOCATION => true,
                                    CURLOPT_RETURNTRANSFER => true,
                                ];

        /** Initialize & execute cURL-Request */
        $curl_instance = curl_init($url);
        curl_setopt_array($curl_instance, $curl_request_options);
        $curl_data = curl_exec($curl_instance);
        $curl_done = curl_getinfo($curl_instance);

        /** cURL request successful */
        if ($curl_done['http_code'] == 200)
        {
            /** Open a new file handle, write the file & close the file handle */
            if (file_put_contents($save_as_file, $curl_data) !== false) {
                // logging if file_put_contents was OK
            } else {
                // logging if file_put_contents FAILED
            }
        }

        /** Close the $curl_instance */
        curl_close($curl_instance);

        return true;

    } catch (Exception $e) {
        error_log($e->getMessage());
        return false;
    }
}

并执行它：

$curl_httpresources = [
    [ 'http://www.gravatar.com/avatar/example?d=mm&r=x&s=427'
    ,'/srv/www/data/images/1_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=identicon&r=x&s=427'
    ,'/srv/www/data/images/2_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=monsterid&r=x&s=427'
    ,'/srv/www/data/images/3_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=wavatar&r=x&s=427'
    ,'/srv/www/data/images/4_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=retro&r=x&s=427'
    ,'/srv/www/data/images/5_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=mm&r=x&s=427'
    ,'/srv/www/data/images/6_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=identicon&r=x&s=427'
    ,'/srv/www/data/images/7_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=monsterid&r=x&s=427'
    ,'/srv/www/data/images/8_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=wavatar&r=x&s=427'
    ,'/srv/www/data/images/9_unsplash.jpg' ],
    [ 'http://www.gravatar.com/avatar/example?d=retro&r=x&s=427'
    ,'/srv/www/data/images/10_unsplash.jpg' ],
];

/** cURL all request from the $curl_httpresources Array */
if (count($curl_httpresources) > 0)
{
    foreach ($curl_httpresources as $resource)
    {
        cURLfetchUrl($resource[0], $resource[1]);
    }
}

仍然，如果有人有想法，如何使用curl_multi正确地检索文件数据流，那将是很棒的，因为我对初始问题的回答只是一种不同的方法，而不是解决初始方法。

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