Supported Protocols and Wrappers
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http://

https://

http:// -- https:// — Accessing HTTP(s) URLs

说明

Allows read-only access to files/resources via HTTP 1.0, using the HTTP GET method. A Host: header is sent with the request to handle name-based virtual hosts. If you have configured a user_agent string using your php.ini file or the stream context, it will also be included in the request.

The stream allows access to the body of the resource; the headers are stored in the $http_response_header variable.

If it's important to know the URL of the resource where your document came from (after all redirects have been processed), you'll need to process the series of response headers returned by the stream.

The from directive will be used for the From: header if set and not overwritten by the Context options and parameters.

可选项

可选项

Wrapper Summary
Attribute Supported
Restricted by allow_url_fopen Yes
Allows Reading Yes
Allows Writing No
Allows Appending No
Allows Simultaneous Reading and Writing N/A
Supports stat() No
Supports unlink() No
Supports rename() No
Supports mkdir() No
Supports rmdir() No

更新日志

版本 说明
4.3.7 Detect buggy IIS servers to avoid "SSL: Fatal Protocol Error" errors.
4.3.0 Added https://.
4.0.5 Added support for redirects.

范例

Example #1 Detecting which URL we ended up on after redirects

<?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) {

    /* Were we redirected? */
    if (strtolower(substr($response, 0, 10)) == 'location: ') {

        /* update $url with where we were redirected to */
        $url = substr($response, 10);
    }

}

?>

Example #2 Sending custom headers with an HTTP request

Custom headers may be sent using context options. It is also possible to use this hack: Custom headers may be sent with an HTTP request by taking advantage of a side-effect in the handling of the user_agent INI setting. Set user_agent to any valid string (such as the default PHP/version setting) followed by a carriage-return/line-feed pair and any additional headers.

<?php
ini_set('user_agent', "PHP\r\nX-MyCustomHeader: Foo");

$fp = fopen('http://www.example.com/index.php', 'r');
?>

Results in the following request being sent:

GET /index.php HTTP/1.0
Host: www.example.com
User-Agent: PHP
X-MyCustomHeader: Foo

注释

Note: HTTPS is only supported when the openssl extension is enabled.

HTTP connections are read-only; writing data or copying files to an HTTP resource is not supported.

Sending POST and PUT requests, for example, can be done with the help of HTTP Contexts.

参见

Supported Protocols and Wrappers
在线手册：中文 英文
PHP手册
PHP手册 - N: Accessing HTTP(s) URLs

用户评论:

Nick Lewis (26-Jun-2008 12:17)

A note on how to deal with Cookies

To receive a cookie:

$httphandle = fopen($url,"r");
$meta = stream_get_meta_data($httphandle);
for ($j = 0; isset($meta['wrapper_data'][$j]); $j++) {
   $httpline = $meta['wrapper_data'][$j];
   @list($header,$parameters) = explode(";",$httpline,2);
   @list($attr,$value) = explode(":",$header,2);
   if (strtolower(trim($attr)) == "set-cookie") {
      $cookie = trim($value);
      break;
   }
}
fclose($httphandle);
echo $cookie;

To send a cookie:

$user_agent = ini_get("user_agent");
ini_set("user_agent",$user_agent . "\r\nCookie: " . $cookie);
$httphandle = fopen($url,"r");
fclose($httphandle);
ini_set("user_agent",$user_agent);

spazdaq (24-Oct-2007 11:27)

just an FYI about digest authentication.

While one of the above http examples has the username and password info supplied with the url, this must only be for basic authentication. it does not appear to work for digest authentication. you have to handle the digest followup request on your own.

NEA at AraTaraBul dot com (30-Jul-2007 12:06)

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;
}
?>

Sinured (28-Jun-2007 11:24)

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');
?>

dwalton at acm dot org (17-Nov-2006 08:18)

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.