PHP获取http请求的头信息实现步骤

php手册提供了现成的函数：
getallheaders
(php 4, php 5)
getallheaders — fetch all http request headers
说明
array getallheaders ( void )
fetches all http headers from the current request.
this function is an alias for apache_request_headers(). please read theapache_request_headers() documentation for more information on how this function works.
返回值
an associative array of all the http headers in the current request, orfalse on failure.
example #1 getallheaders() example

<?php
foreach (getallheaders() as $name => $value) {
echo "$name: $value\n";
}
?>

不过这个函数只能在apache环境下使用，iis或者nginx并不支持，可以通过自定义函数实现

<?php
<span class=html>if (!function_exists('getallheaders'))
{
    function getallheaders()
    {
       foreach ($_server as $name => $value)
       {
           if (substr($name, 0, 5) == 'http_')
           {
               $headers[str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5)))))] = $value;
           }
       }
       return $headers;
    }
}</span>
?>

好了，看看都打印出了啥吧

<?php
print_r(getallheaders());

获得结果：

array
(
[accept] => */*
[accept-language] => zh-cn
[accept-encoding] => gzip, deflate
[user-agent] => mozilla/4.0 (compatible; msie 7.0; windows nt 5.1; trident/4.0; .net clr 2.0.50727)
[host] => localhost
[connection] => keep-alive
)