File_get_contents返回与直接url调用不同的结果比较

Hi i am try to get linkedin count for share with php .

code is

$url_social = 'https://www.linkedin.com/countserv/count/share?url=' . urlencode(trim($url)) . '&format=json';
$res = file_get_contents($url_social, false, $context);

out put of above code i got it

Array
(
    [count] => 0
    [fCnt] => 0
    [fCntPlusOne] => 1
    [url] => https://www.botoa.com/contest/detail/40/77/20160428_2
)

but sam url i try to direct url in browser with url : https://www.linkedin.com/countserv/count/share?url=https%3A%2F%2Fwww.botoa.com%2Fcontest%2Fdetail%2F40%2F77%2F20160428_2&format=json

its return result

{
count: 8,
fCnt: "8",
fCntPlusOne: "9",
url: "https://www.botoa.com/contest/detail/40/77/20160428_2"
}

so different is you can see count in first result 0 and second 8 why ? and what is possible solution