为什么php的file_get_contents错误地从xkcd中检索json文件？

Question

In writing a PHP script to download xkcd comics, i incurred errors when trying to get specific comics (as opposed to the latest one). Specifically, pointing file_get_contents at the following url:

xkcd.com/$COMIC_NUM/info.0.json

inexplicably retrieved the xhtml version of the comic's page on xkcd.com, and not a JSON file. However, if i request the exact same url in my browser, the correct JSON file is downloaded. I'm not sure why this is happening, but i suspect it has something to do with the request headers being sent.

Please help! :S

Answer 1

Whilst I it personally works perfectly with file_get_contents for me, you could try using cURL as follows (if you have it available) as this would be a more robust solution:

<?php
    $COMIC_NUM = 849;

    $curlSession = curl_init();
    curl_setopt($curlSession, CURLOPT_URL, '"http://xkcd.com/'.$COMIC_NUM.'/info.0.json');
    curl_setopt($curlSession, CURLOPT_BINARYTRANSFER, true);
    curl_setopt($curlSession, CURLOPT_RETURNTRANSFER, true);
    $jsonData = curl_exec($curlSession);
    curl_close($curlSession);

    echo($jsonData);
?>