I have absolutely no problem in getting source code of the webpage in my local server with this:
$html = file_get_contents('https://opac.nlai.ir');
And I was also okay on my host using code below until just a few days ago:
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, 'http://opac.nlai.ir');
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_CONNECTTIMEOUT, 10);
$result = curl_exec($curl);
But today I figured out that now the site is using ssl and it is not working with http anymore and force redirect to https. So I did some search & found this as a fix:
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, 0);
curl_setopt($curl CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
The code above works just fine for sites like e.g. "https://google.com" (and any other https sites that I've tried! ) But not for that specific website ("https://opac.nlai.ir") In that case, page takes about a minute to load (!) and finally with var_dump($result) , I get "bool(false)" I don't know how that website can be different from other websites and I really want to know what cause the problem.
Sorry for my English.