PHP cURL doesn't work with - in subdomains

Question

I have a PHP script that I'm trying to get the contents of a page. The code im using is below

$url = "http://test.tumblr.com";

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
$txt = curl_exec($ch);
curl_close($ch);

echo "$txt";

It works fine for me as it is now. The problem I'm having is, if I change the string URL to

$url = "http://-test.tumblr.com"; or $url = "http://test-.tumblr.com";

It will not work. I understand that -test.example.com or test-.example.com is not a valid hostnames but with Tumblr they do exists. Is there a work around for this?

I even tried creating a header redirect on another php file so cURL would be first getting a valid hostname but works the same way.

Thank you

You can try file_get_contents if you just have to grab contents — Hanky Panky, Jan 24 '13 at 10:24
@HankyPankyㇱ I have already tried that also, same results. :) — chillers, Jan 24 '13 at 10:24
@PeterKelly when you visit them they do exists. You're experiencing the same problem I'm having. — chillers, Jan 24 '13 at 10:26
@PeterKelly I'm using chrome. Here is another URL `http://-racing-heart-.tumblr.com` example only I have no affiliations to that URL. — chillers, Jan 24 '13 at 10:29
@njzk2 That's strange, they do work for me fine. Must be a issue with Tumblr. — chillers, Jan 24 '13 at 10:32
Probably Tumblr catches this with a wildcard DNS entry [SO Question: Create Subdomains on the fly with .htaccess (PHP)](http://stackoverflow.com/questions/586129/create-subdomains-on-the-fly-with-htaccess-php). — Deep Frozen, Jan 24 '13 at 10:35

score 0 · Answer 1 · edited Jun 20 '20 at 09:12

Domain Names with hyphens

As you can see in a previous question about the allowed characters in a subdomain, - is not a valid character to start or end a subdomain with. So this is actually correct behavior. The same problem was reported over the curl mailing list some time ago but since curl follows the standard, there is actually nothing to change on their site.

Most likely tumblr knows about this and therefore offers some alternative address leading to the same site.

Possible workaround

However you could try using nslookup to manually lookup the IP and then send your request directly to this IP (and manually setting the hostname to the correct value). I didn't try this out, but it seems as if nslookup is capable to resolve malformatted domain names that start or end in a hyphen.

curl

Additionally you should know, that the php curl function should be a direct interface to the curl command line tool and therefore, if you would encounter special behavior it would most likely be due to the logic in the curl command line tool and not the php function.

They do not offer any work around except to see if the blog exists. I'm trying to find a work around. :) — chillers, Jan 24 '13 at 10:30
I've updated the answer with a possible workaround. I didn't try it out but I think it could work. — s1lence, Jan 24 '13 at 16:09

PHP cURL doesn't work with - in subdomains

1 Answers1

Domain Names with hyphens

Possible workaround

curl