[PHP] CURL 跟隨301、302轉址實現 Google 雲端硬碟檔案下載

這個題目在寫爬蟲的時候算滿常見會要解決的問題。

正好這次因為要爬的對象把資料改放到 Google 雲端硬碟上，所以就來紀錄一下這段程式吧！

是說指令版的 curl 實在是超好物，一跨到程式上就麻煩不少了ＸＤ

<?php
//Ref: http://php.net/manual/en/ref.curl.php#93163
function get_final_url($url, $cookie = "", $timeout = 5) {
    $url = str_replace("&amp;", "&", urldecode(trim($url)));
    //保留餅乾資訊
    if ($cookie == "") {
        $cookie = tempnam(sys_get_temp_dir(), "mxp_");
    }
    //假一下瀏覽器請求
    $user_agent = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36";
    //CURL 初始化
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_COOKIEJAR, $cookie);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_ENCODING, "");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_AUTOREFERER, true);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
    curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
    curl_setopt($ch, CURLOPT_MAXREDIRS, 10);
    $content = curl_exec($ch);
    $response = curl_getinfo($ch);
    curl_close($ch);
    //設定根層級的假請求
    ini_set("user_agent", $user_agent);
    //請求標頭
    $headers = get_headers($response['url']);
    //判斷是否有 301, 302 轉址
    if ($response['http_code'] == 301 || $response['http_code'] == 302) {
        $location = "";
        foreach ($headers as $value) {
            if (substr(strtolower($value), 0, 9) == "location:") {
                //取得轉址的連結，遞迴請求
                return get_final_url(trim(substr($value, 9, strlen($value))), $cookie);
            }
        }
    }
    $filename = "";
    foreach ($headers as $value) {
        if (substr(strtolower($value), 0, 20) == "content-disposition:") {
            //如果有檔案名稱資訊，就存下來等等下載用
            $filename = urldecode(trim(substr($value, 20, strlen($value))));
        }
    }
    //如果不是使用 301, 302 轉址，可能網頁內容會有 JavaScript 或提示轉址資訊，可以在這裡分析
    // if (preg_match("/window.location.replace('(.*)')/i", $content, $value) ||
    //  preg_match("/window.location="(.*)"/i", $content, $value)
    // ) {
    //  return get_final_url($value[1]);
    // }
    //把最後的連結檔案下載回去
    $filename = explode("''", $filename);
    $fp = fopen($filename[1], 'w');
    $ch = curl_init($response['url']);
    curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);
    curl_setopt($ch, CURLOPT_FILE, $fp);
    $data = curl_exec($ch);
    curl_close($ch);
    fclose($fp);
    return array("filename" => $filename[1], "url" => $response['url']);
}
print_r(get_final_url('https://drive.google.com/uc?export=download&id=0B21MNCxxxxxxxxxxxxxxxxxxx1xdVk'));

Gist: Link

範例既然是針對 Google 雲端硬碟，就在最後解析出最終檔案位置時一併把他下載回來。