Question

我想通过打开套接字连接并发送原始HTTP请求来发出HTTP请求而不依赖于cURL和allow_url_fopen = 1：

/**
 * Make HTTP GET request
 *
 * @param   string   the URL
 * @param   int      will be filled with HTTP response status code
 * @param   string   will be filled with HTTP response header
 * @return  string   HTTP response body
 */
function http_get_request($url, &$http_code = '', &$res_head = '') 
{
  $scheme = $host = $user = $pass = $query = $fragment = '';
  $path = '/';
  $port = substr($url, 0, 5) == 'https' ? 443 : 80;

  extract(parse_url($url)); 

  $path .= ($query ? "?$query" : '').($fragment ? "#$fragment" : '');

  $head = "GET $path HTTP/1.1\r\n"
        . "Host: $host\r\n"
        . "Authorization: Basic ".base64_encode("$user:$pass")."\r\n"
        . "Connection: close\r\n\r\n";

  $fp = fsockopen($scheme == 'https' ? "ssl://$host" : $host, $port) or 
    die('Cannot connect!');

  fputs($fp, $head);
  while(!feof($fp)) {
    $res .= fgets($fp, 4096);
  }
  fclose($fp);

  list($res_head, $res_body) = explode("\r\n\r\n", $res, 2);
  list(, $http_code, ) = explode(' ', $res_head, 3);

  return $res_body;
}

该函数运行正常，但由于我使用的是HTTP / 1.1，因此响应主体通常以Chunked-encoded字符串返回。例如（来自维基百科）：

25
This is the data in the first chunk

1C
and this is the second one

3
con
8
sequence
0

我不想使用http_chunked_decode()，因为它具有PECL依赖性，我想要一个高度可移植的代码。

如何轻松解码HTTP-chunked编码字符串，以便我的函数可以返回原始HTML？我还必须确保解码字符串的长度与Content-Length:标头匹配。

任何帮助将不胜感激。感谢。

Answer 1

由于函数返回HTTP响应头，您应检查'Transfer-Encoding'是否为'chunked'，然后解码分块编码的字符串。在伪代码中：

CALL parse_http_header
IF 'Transfer-Encoding' IS 'chunked'
  CALL decode_chunked

解析HTTP响应标头：

下面是将HTTP响应头解析为关联数组的函数。

function parse_http_header($str) 
{
  $lines = explode("\r\n", $str);
  $head  = array(array_shift($lines));
  foreach ($lines as $line) {
    list($key, $val) = explode(':', $line, 2);
    if ($key == 'Set-Cookie') {
      $head['Set-Cookie'][] = trim($val);
    } else {
      $head[$key] = trim($val);
    }
  }
  return $head;
}

该函数将返回如下数组：

Array
(
    [0] => HTTP/1.1 200 OK
    [Expires] => Tue, 31 Mar 1981 05:00:00 GMT
    [Content-Type] => text/html; charset=utf-8
    [Transfer-Encoding] => chunked
    [Set-Cookie] => Array
        (
            [0] => k=10.34; path=/; expires=Sat, 09-Jun-12 01:58:23 GMT; domain=.example.com
            [1] => guest_id=v1%3A13; domain=.example.com; path=/; expires=Mon, 02-Jun-2014 13:58:23 GMT
        )
    [Content-Length] => 43560
)

注意Set-Cookie标头如何解析为数组。您需要稍后解析cookie以将URL与需要发送的cookie相关联。

解码分块编码的字符串

下面的函数将chunked编码的字符串作为参数，然后返回解码后的字符串。

function decode_chunked($str) {
  for ($res = ''; !empty($str); $str = trim($str)) {
    $pos = strpos($str, "\r\n");
    $len = hexdec(substr($str, 0, $pos));
    $res.= substr($str, $pos + 2, $len);
    $str = substr($str, $pos + 2 + $len);
  }
  return $res;
}

// Given the string in the question, the function above will returns:
//
// This is the data in the first chunk
// and this is the second one
// consequence

Answer 2

我不知道你最不需要做什么，但是如果你指定HTTP/1.0而不是HTTP/1.1，你就不会得到一个分块响应。

Answer 3

此功能在Wordpress中使用。

function decode_chunked($data) {
    if (!preg_match('/^([0-9a-f]+)(?:;(?:[\w-]*)(?:=(?:(?:[\w-]*)*|"(?:[^\r\n])*"))?)*\r\n/i', trim($data))) {
        return $data;
    }



    $decoded = '';
    $encoded = $data;

    while (true) {
        $is_chunked = (bool) preg_match('/^([0-9a-f]+)(?:;(?:[\w-]*)(?:=(?:(?:[\w-]*)*|"(?:[^\r\n])*"))?)*\r\n/i', $encoded, $matches);
        if (!$is_chunked) {
            // Looks like it's not chunked after all
            return $data;
        }

        $length = hexdec(trim($matches[1]));
        if ($length === 0) {
            // Ignore trailer headers
            return $decoded;
        }

        $chunk_length = strlen($matches[0]);
        $decoded .= substr($encoded, $chunk_length, $length);
        $encoded = substr($encoded, $chunk_length + $length + 2);

        if (trim($encoded) === '0' || empty($encoded)) {
            return $decoded;
        }
    }

    // We'll never actually get down here
    // @codeCoverageIgnoreStart
}

如何在进行原始HTTP请求时轻松解码HTTP-chunked编码的字符串？

3 个答案: