CURL解析超時的解決方案

背景：項目中需要在抓取紛享銷客CRM圖片上傳到OSS,調用OssClient.php時，容易發生解析超時(多重試幾次就ok)。

錯誤提示：

[2019-04-08 19:41:01] lumen.DEBUG: 出錯文件：/home/zrj/www/admin/yundou-admin/vendor/aliyuncs/oss-sdk-php/src/OSS/OssClient.php  
[2019-04-08 19:41:01] lumen.DEBUG: 出錯編碼：0  
[2019-04-08 19:41:01] lumen.DEBUG: 出錯行號：2187  
[2019-04-08 19:41:01] lumen.DEBUG: 出錯信息：RequestCoreException: cURL resource: Resource id #371; cURL error: Resolving timed out after 10521 milliseconds (28) 

Resolving timed out after 10521 milliseconds (28)
解析超時

源碼分析:

try {
            $ossClient = new OssClient(self::$accessKeyId, self::$accessKeySecret, self::$endpoint);
            $ossClient->uploadFile(self::$bucket, $ossFileName, $localhostFileName);//上傳文件
            $ossClient->putBucketAcl(self::$bucket, OssClient::OSS_ACL_TYPE_PUBLIC_READ);
        } catch (OssException $e) {
            self::debugException($e);
            throw new \Exception("上傳oss失敗:" . $e->getMessage(), $e->getCode());
        }

1.實例化OssClient客戶端後，調用uploadFile方法。
2.uploadFile調用了auth,驗證並且執行請求，按照OSS Api協議，執行操作。

    /**
     * 上傳本地文件
     *
     * @param string $bucket bucket名稱
     * @param string $object object名稱
     * @param string $file 本地文件路徑
     * @param array $options
     * @return null
     * @throws OssException
     */
    public function uploadFile($bucket, $object, $file, $options = NULL)
    {
        ......
        $response = $this->auth($options);
        $result = new PutSetDeleteResult($response);
        return $result->getData();
    }

3.auth中調用RequestCore類創建請求

    /**
     * 驗證並且執行請求，按照OSS Api協議，執行操作
     *
     * @param array $options
     * @return ResponseCore
     * @throws OssException
     * @throws RequestCore_Exception
     */
    private function auth($options)
    {
            ......
        //創建請求
        $request = new RequestCore($this->requestUrl, $this->requestProxy);
        $request->set_useragent($this->generateUserAgent());
                ......
                try {
            $request->send_request();
        } catch (RequestCore_Exception $e) {
            throw(new OssException('RequestCoreException: ' . $e->getMessage()));
        }
    }

4.OSS\Http\RequestCore類中send_request方法通過CURL發送請求(調用了prep_request準備請求方法)

 /**
     * Sends the request, calling necessary utility functions to update built-in properties.
     *
     * @param boolean $parse (Optional) Whether to parse the response with ResponseCore or not.
     * @return string The resulting unparsed data from the request.
     */
    public function send_request($parse = false)
    {
        set_time_limit(0);

        $curl_handle = $this->prep_request();
        $this->response = curl_exec($curl_handle);

        if ($this->response === false) {
            throw new RequestCore_Exception('cURL resource: ' . (string)$curl_handle . '; cURL error: ' . curl_error($curl_handle) . ' (' . curl_errno($curl_handle) . ')');
        }

        $parsed_response = $this->process_response($curl_handle, $this->response);

        curl_close($curl_handle);

        if ($parse) {
            return $parsed_response;
        }

        return $this->response;
    }

5.最終可以推導出問題出在RequestCore中的CURL。

解決方案：
curl有一個CURLOPT_IPRESOLVE選項，作用是指定使用那種IP協議(IPV4/IPV6)。

CURLOPT_IPRESOLVE - specify which IP protocol version to use

選項：
CURL_IPRESOLVE_WHATEVER

Default, resolves addresses to all IP versions that your system allows.

CURL_IPRESOLVE_V4

Resolve to IPv4 addresses.

CURL_IPRESOLVE_V6

Resolve to IPv6 addresses.

這裏要注意：默認值（curl沒有主動設置CURLOPT_IPRESOLVE選項時，則系統會使用默認值）。

Default, resolves addresses to all IP versions that your system allows.

含義爲：默認使用服務器系統允許的所有IP版本來解析地址。
而服務器系統可能存在同時支持IPV4/IPV6,CURL會挨個去試。當本地網絡不支持其中任何一種IP版本協議時，會出現超時。

所以，最終的解決方案爲顯式指定CURL的CURLOPT_IPRESOLVE選項。

curl_setopt($ch, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4);

參考官方CURLOPT_IPRESOLVE