如何阻止cURL使用100继续？

Question

所以，长话短说，我有一个使用MVC Web API作为后端的AJAX应用程序。然而，客户端从不同的域调用并使用PHP代理文件来解决跨域请求问题。

但是，使用PHP代理，Web API会使用100 Continue HTTP标头响应某些请求，并且任何获取此请求的请求都需要花费过多的时间才能完成（我们谈论最多2分钟左右）并且还可以返回无效的回复。

此appears to be a known issue with cURL和解决方法通常被引用为插入以下行以删除cURL请求中的expect：100标头

不幸的是，解决方案对我来说似乎难以捉摸：

$headers = getallheaders();
$headers_new = "";
foreach($headers as $title => $body) {
    $headers_new[] = $title.": ".$body;
}
//$headers_new[] = 'Expect:';
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers_new);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Expect:') );

此代码有效但删除了所有其他标头（这对我来说是不可行的，因为我使用HTTP基本auth标头来通过API进行身份验证）。 您可能还注意到我尝试将Expect:添加到现有标头中，但这对我也没有帮助。

如何维护现有标头，还可以防止cURL期望100继续？

Answer 1

使用$headers_new[] = 'Expect:';确实有效，除非 $headers_new数组包含'Expect: 100-continue'的字符串。在这种情况下，您需要将其从数组中删除，否则它将期望100继续（逻辑上）。

因为在您的代码中使用了getallheaders()，并且您没有检查它是否已包含Expect: 100-continue标题，所以在您的情况下可能就是这种情况。

以下是一般情况（以及创建它的脚本）的摘要：

PHP Curl HTTP/1.1 100 Continue and CURLOPT_HTTPHEADER

GET request ..........................................: Continue: No
GET request with empty header ........................: Continue: No
POST request with empty header .......................: Continue: Yes
POST request with expect continue explicitly set .....: Continue: Yes
POST request with expect (set to nothing) as well ....: Continue: Yes
POST request with expect continue from earlier removed: Continue: No

代码：

<?php

$ch = curl_init('http://www.iana.org/domains/example/');

function curl_exec_continue($ch) {
    curl_setopt($ch, CURLOPT_HEADER, 1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $result   = curl_exec($ch);
    $continue = 0 === strpos($result, "HTTP/1.1 100 Continue\x0d\x0a\x0d\x0a");
    echo "Continue: ", $continue ? 'Yes' : 'No', "\n";

    return $result;
}

echo "GET request ..........................................: ", !curl_exec_continue($ch);

$header = array();
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "GET request with empty header ........................: ", !curl_exec_continue($ch);

curl_setopt($ch, CURLOPT_POST, TRUE);
curl_setopt($ch, CURLOPT_POSTFIELDS, array('hello'));
echo "POST request with empty header .......................: ", !curl_exec_continue($ch);

$header[] = 'Expect: 100-continue';
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "POST request with expect continue explicitly set .....: ", !curl_exec_continue($ch);

$header[] = 'Expect:';
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "POST request with expect (set to nothing) as well ....: ", !curl_exec_continue($ch);

unset($header[0]);
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "POST request with expect continue from earlier removed: ", !curl_exec_continue($ch);

Answer 2

感谢您的剧本，哈克。因为我需要这个用于HTTP PUT，所以我将其扩展了一下，结果如下：

GET request ..........................................: Continue: No
GET request with empty header ........................: Continue: No
POST request with empty header .......................: Continue: Yes
POST request with expect continue explicitly set .....: Continue: Yes
POST request with expect (set to nothing) as well ....: Continue: Yes
POST request with expect continue from earlier removed: Continue: No
PUT request with empty header ........................: Continue: Yes
PUT request with expect continue explicitly set ......: Continue: Yes
PUT request with expect (set to nothing) as well .....: Continue: Yes
PUT request with expect continue from earlier removed : Continue: No
DELETE request with empty header .....................: Continue: Yes
DELETE request with expect continue explicitly set ...: Continue: Yes
DELETE request with expect (set to nothing) as well ..: Continue: Yes
DELETE request with expect continue from earlier removed : Continue: No

这是脚本：

<?php 

$ch = curl_init('http://www.iana.org/domains/example/');

function curl_exec_continue($ch) {
    curl_setopt($ch, CURLOPT_HEADER, 1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $result   = curl_exec($ch);
    $continue = 0 === strpos($result, "HTTP/1.1 100 Continue\x0d\x0a\x0d\x0a");
    echo "Continue: ", $continue ? 'Yes' : 'No', "\n";

    return $result;
}

// --- GET

echo "GET request ..........................................: ", !curl_exec_continue($ch);

$header = array();
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "GET request with empty header ........................: ", !curl_exec_continue($ch);

// --- POST

curl_setopt($ch, CURLOPT_POST, TRUE);

curl_setopt($ch, CURLOPT_POSTFIELDS, array('hello'));
echo "POST request with empty header .......................: ", !curl_exec_continue($ch);

$header[] = 'Expect: 100-continue';
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "POST request with expect continue explicitly set .....: ", !curl_exec_continue($ch);

$header[] = 'Expect:';
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "POST request with expect (set to nothing) as well ....: ", !curl_exec_continue($ch);

unset($header[0]);
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "POST request with expect continue from earlier removed: ", !curl_exec_continue($ch);

// --- PUT

curl_setopt($ch, CURLOPT_PUT, TRUE);

$header = array();
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "PUT request with empty header ........................: ", !curl_exec_continue($ch);

$header[] = 'Expect: 100-continue';
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "PUT request with expect continue explicitly set ......: ", !curl_exec_continue($ch);

$header[] = 'Expect:';
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "PUT request with expect (set to nothing) as well .....: ", !curl_exec_continue($ch);

unset($header[0]);
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "PUT request with expect continue from earlier removed : ", !curl_exec_continue($ch);

// --- DELETE

curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "DELETE");

$header = array();
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "DELETE request with empty header .....................: ", !curl_exec_continue($ch);

$header[] = 'Expect: 100-continue';
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "DELETE request with expect continue explicitly set ...: ", !curl_exec_continue($ch);

$header[] = 'Expect:';
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "DELETE request with expect (set to nothing) as well ..: ", !curl_exec_continue($ch);

unset($header[0]);
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
echo "DELETE request with expect continue from earlier removed : ", !curl_exec_continue($ch);

?>

Answer 3

要移除标题101，请继续使用

curl_setopt($ch, CURLOPT_HTTPHEADER,array("Expect:"));