XML Feed - Valid HTTP Header User Agent?

问题

I am trying to load an external feed using the script below, but the file that is generated is always empty. The service who offers the XML doesn't offer any support, but claims that I should send 'a valid HTTP Header User Agent', not explaining what a valid HTTP Header User Agent should be.

<?php
$feed = "[FEEDURL]"; //Hey Stackoverflow, I removed the URL on purpose
$content = file_get_contents($feed);
$dir = dirname($_SERVER['SCRIPT_FILENAME']);
$fp = fopen($dir.'/feedcopy.txt', 'w');
fwrite($fp, $content);
fclose($fp);
?>

Anyone got a clue? This script works with other XML feeds, so that shouldn't be the problem. Many thanks in advance.

回答1:

You need to use a valid context resource with stream_context_create() like so:

<?php
$feed = "[FEEDURL]"; //Hey Stackoverflow, I removed the URL on purpose

$options = array(
  'http' => array(
    'method' => "GET",
    'header' => "User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.57 Safari/537.17\r\n" // Chrome v24
  )
);
$context = stream_context_create($options);

$content = file_get_contents($feed, false, $context);

$dir = dirname($_SERVER['SCRIPT_FILENAME']);
$fp = fopen($dir.'/feedcopy.txt', 'w');
fwrite($fp, $content);
fclose($fp);
?>

来源：https://stackoverflow.com/questions/14844919/xml-feed-valid-http-header-user-agent