PHP cURL不返回Content-Encoding头

Question

当我在我的终端上运行curl -I http://api.stackoverflow.com/1.1/badges时，它显示了以下标头：

HTTP/1.1 200 OK
Cache-Control: private
Content-Length: 42804
Content-Type: application/json; charset=utf-8
Content-Encoding: gzip
X-AspNetMvc-Version: 4.0
X-RateLimit-Max: 300
X-RateLimit-Current: 297
X-AspNet-Version: 4.0.30319
Set-Cookie: .ASPXBrowserOverride=; expires=Mon, 08-Oct-2012 04:29:28 GMT; path=/
Date: Tue, 09 Oct 2012 04:29:27 GMT

然而，当我通过PHP运行相同的cURL请求时，我得到如下结果：

Array
(
    [url] => http://api.stackoverflow.com/1.1/badges?10102
    [content_type] => application/json; charset=utf-8
    [http_code] => 200
    [header_size] => 277
    [request_size] => 85
    [filetime] => -1
    [ssl_verify_result] => 0
    [redirect_count] => 0
    [total_time] => 0.168343
    [namelookup_time] => 0.023417
    [connect_time] => 0.046293
    [pretransfer_time] => 0.046365
    [size_upload] => 0
    [size_download] => 42804
    [speed_download] => 254266
    [speed_upload] => 0
    [download_content_length] => 42804
    [upload_content_length] => 0
    [starttransfer_time] => 0.097563
    [redirect_time] => 0
    [certinfo] => Array
        (
        )

    [redirect_url] => 
)

对我来说最重要的区别是，当通过PHP运行时，我不会得到Content-Encoding头，如果没有它，我不知道内容是否需要进行gzip膨胀。

有没有一种方法可以获得Content-Encoding头文件，或者用其他方法检查gzip压缩？

Answer 1

返回的getinfo数组中既没有header_response也没有accept-encoding。我以为getinfo上的CURLINFO_HEADER_OUT会给出响应报头，但只给出了请求报头。

但是您可以使用设置为true的CURLOPT_HEADER选项来获取原始标头。所以我建议你做一些不那么自然的事情：

$curl = curl_init();

$opts = array (
        CURLOPT_URL => 'http://api.stackoverflow.com/1.1/badges',
        CURLOPT_TIMEOUT => 120,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_ENCODING => 'gzip',
        CURLOPT_HEADER => true,
);
curl_setopt_array($curl, $opts);

$return = curl_exec($curl);

list($rawHeader, $response) = explode("\r\n\r\n", $return, 2);

$cutHeaders = explode("\r\n", $rawHeader);
$headers = array();
foreach ($cutHeaders as $row)
{
    $cutRow = explode(":", $row, 2);
    $headers[$cutRow[0]] = trim($cutRow[1]);
}

echo $headers['Content-Encoding']; // gzip

Answer 2

如果将CURLOPT_HEADER设置为true，curl将返回正文旁边的头部。如果只对头部感兴趣，可以将CURLOPT_NOBODY设置为true，并且不返回正文(这模拟命令行上的-I标志)。

此示例仅设置CURLOPT_HEADER，读取Content-Encoding标头(如果已设置)并解压缩正文：

$curl = curl_init();

curl_setopt($curl, CURLOPT_URL, "http://api.stackoverflow.com/1.1/badges");
curl_setopt($curl, CURLOPT_HEADER, 1);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);

$response = curl_exec($curl);
curl_close($curl);

list($header, $body) = explode("\r\n\r\n", $response, 2);
if(preg_match('@Content-Encoding:\s+(\w+)@i', $header, $match)) {
    switch (strtolower($match[1])) {
        case 'gzip':
            $body = gzdecode($body);
        break;

        case 'compress':
            $body = gzuncompress($body);
        break;

        case 'deflate':
            $body = gzdeflate($body);
        break;
    }
}
echo $header;
echo $body;

免责声明：gzdecode可能在您的PHP版本中不可用。我用PHP 5.4.4对它进行了测试，它可以正常工作。

您还可以安装HTTP_Request2-PEAR包，它将为您完成此操作(另外，您无需解析HTTP头即可轻松访问头文件)：

include 'HTTP/Request2.php';
$request  = new HTTP_Request2('http://api.stackoverflow.com/1.1/badges',
    HTTP_Request2::METHOD_GET);

$response = $request->send();

echo $response->getBody();