curl_setopt在浏览器中工作正常但在cron选项卡中没有

Cron command - wget --spider 'url'

php file-

function getHTML($url,$timeout)
{

$ch = curl_init($url); // initialize curl with given url

       curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER["HTTP_USER_AGENT"]); //set  useragent

       curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); // write the response to a variable

       curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); // follow redirects if any

       curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout); // max. seconds to execute

       curl_setopt($ch, CURLOPT_FAILONERROR, 1); // stop when it encounters an error

       return @curl_exec($ch);

}

error- Remote file exists and could contain further links, but recursion is disabled -- not retrieving.

not getting where I am going wrong.

The problem is that you are referencing '$_SERVER["HTTP_USER_AGENT"]' on line 6, but when executing from a crontab, $_SERVER['HTTP_USER_AGENT'] is not defined. Use isset() to check if an array item exists.

<?php
function getHTML($url,$timeout)
{

       $ch = curl_init($url); // initialize curl with given url

       curl_setopt($ch, CURLOPT_USERAGENT, (isset($_SERVER["HTTP_USER_AGENT"]) ? $_SERVER["HTTP_USER_AGENT"] : "PHP/5.5")); //set  useragent

       curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); // write the response to a variable

       curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); // follow redirects if any

       curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout); // max. seconds to execute

       curl_setopt($ch, CURLOPT_FAILONERROR, 1); // stop when it encounters an error

       return @curl_exec($ch);

}