http://

https://

http:// -- https://访问 HTTP(s) 网址

说明

允许通过 HTTP 1.0 的 GET方法,以只读访问文件或资源。 HTTP 请求会附带一个 Host: 头,用于兼容基于域名的虚拟主机。 如果在你的 php.ini 文件中或字节流上下文(context)配置了 user_agent 字符串,它也会被包含在请求之中。

数据流允许读取资源的 body,而 headers 则储存在了 $http_response_header 变量里。

如果需要知道文档资源来自哪个 URL(经过所有重定向的处理后), 需要处理数据流返回的系列响应报头(response headers)。

The from directive will be used for the From: header if set and not overwritten by the 上下文(Context)选项和参数.

用法

  • http://example.com
  • http://example.com/file.php?var1=val1&var2=val2
  • http://user:password@example.com
  • https://example.com
  • https://example.com/file.php?var1=val1&var2=val2
  • https://user:password@example.com

可选项

封装协议概要
属性 支持
allow_url_fopen 限制 Yes
允许读取 Yes
允许写入 No
允许添加 No
允许同时读和写 N/A
支持 stat() No
支持 unlink() No
支持 rename() No
支持 mkdir() No
支持 rmdir() No

更新日志

版本 说明
4.3.7 检测 IIS 服务器避免 "SSL: Fatal Protocol Error" 错误。
4.3.0 添加 https://
4.0.5 增加了对重定向的支持。

范例

Example #1 检测重定向后最终的 URL

<?php
$url 
'http://www.example.com/redirecting_page.php';

$fp fopen($url'r');

$meta_data stream_get_meta_data($fp);
foreach (
$meta_data['wrapper_data'] as $response) {

    
/* 我们是否被重定向了? */
    
if (strtolower(substr($response010)) == 'location: ') {

        
/* 更新我们被重定向后的 $url */
        
$url substr($response10);
    }

}

?>

注释

Note: openssl 扩展启用后才能够支持 HTTPS 协议。

HTTP 连接是只读的;还不支持对一个 HTTP 资源进行写数据或者复制文件。

比如发送 POSTPUT 请求, 可以在 HTTP Contexts 的支持下实现。

参见

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User Contributed Notes 4 notes

up
1
NEA at AraTaraBul dot com
7 years ago
HTTP post function;

<?php
function post_it($datastream, $url) {

$url = preg_replace("@^http://@i", "", $url);
$host = substr($url, 0, strpos($url, "/"));
$uri = strstr($url, "/");

     
$reqbody = "";
      foreach(
$datastream as $key=>$val) {
          if (!empty(
$reqbody)) $reqbody.= "&";
     
$reqbody.= $key."=".urlencode($val);
      }

$contentlength = strlen($reqbody);
    
$reqheader "POST $uri HTTP/1.1\r\n".
                  
"Host: $host\n". "User-Agent: PostIt\r\n".
    
"Content-Type: application/x-www-form-urlencoded\r\n".
    
"Content-Length: $contentlength\r\n\r\n".
    
"$reqbody\r\n";

$socket = fsockopen($host, 80, $errno, $errstr);

if (!
$socket) {
  
$result["errno"] = $errno;
  
$result["errstr"] = $errstr;
   return
$result;
}

fputs($socket, $reqheader);

while (!
feof($socket)) {
  
$result[] = fgets($socket, 4096);
}

fclose($socket);

return
$result;
}
?>
up
0
Sinured
7 years ago
If you want to send more than one custom header, just make header an array:

<?php
$default_opts
= array(
   
'http' => array(
       
'user_agent' => 'Foobar',
       
'header' => array(
           
'X-Foo: Bar',
           
'X-Bar: Baz'
       
)
    )
);
stream_context_get_default($default_opts);
readfile('http://www.xhaus.com/headers');
?>
up
0
dwalton at acm dot org
7 years ago
As it says on this page:

"The stream allows access to the body of the resource; the headers are stored in the $http_response_header variable. Since PHP 4.3.0, the headers are available using stream_get_meta_data()."

This one sentence is the only documentation I have found on the mysterious $http_response_header variable, and I'm afraid it's misleading.  It implies that from 4.3.0 onward, stream_get_meta_data() ought to be used in favor of $http_response_header. 

Don't be fooled!  stream_get_meta_data() requires a stream reference, which makes it ONLY useful with fopen() and related functions.  However, $http_response_header can be used to get the headers from the much simpler file_get_contents() and related functions, which makes it still very useful in 5.x.

Also note that even when file_get_contents() and friends fail due to a 4xx or 5xx error and return false, the headers are still available in $http_response_header.
up
-3
dfgfdg at adf dot com
1 month ago
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