What I'm going to post here is a php function that will create a standard url from a user-inputted url so that any string will be converted to a functioning url.
First it will convert all characters to lowercase:
$url = strtolower($url);
Now add http:// if it is not at the beggining:
if(strncasecmp('http://',$url,7) !== 0){
//There is no http:// at the beginning:
$url = 'http://'.$url;
}
What strncasecmp does is it takes a string, and then a number. It then checks to see if that string is contained within the first (That second parameter) characters contain it. It returns 0 if it is found.
So in the example it checks to see if http:// is there, and if it is not, it adds it.
Now strip all folders (This is optional, but here I will show how to make sure only the main domain is left
$parts = explode('/',$url);
if(sizeof($parts) !== 1){
//no / in the string: (No http, no ending /)
$url = $parts[2];
}
So now we've got something like "http://{user_input}/".
Let's make sure it has (or not) www. And if not, let's add it (Just for consistency)
if(strncasecmp('www.',$url,4) !== 0){
//There is no www.
return 'http://www.'.$url.'/';
}else{
return 'http://'.$url.'/';
}
Now we have "http://www.{user input}/" , we are basically done!
If you really want to this this correctly you could check if the URL exists, but this is just a waste of bandwidth and opens a door for attacks from my point of view…
So if you want to do this, create the following function:
function url_exists($strURL) {
$resURL = curl_init();
curl_setopt($resURL, CURLOPT_URL, $strURL);
curl_setopt($resURL, CURLOPT_BINARYTRANSFER, 1);
curl_setopt($resURL, CURLOPT_HEADERFUNCTION, 'curlHeaderCallback');
curl_setopt($resURL, CURLOPT_FAILONERROR, 1);
curl_exec ($resURL);
$intReturnCode = curl_getinfo($resURL, CURLINFO_HTTP_CODE);
curl_close ($resURL);
if ($intReturnCode != 200 && $intReturnCode != 302 && $intReturnCode != 304) {
return false;
}Else{
return true ;
}
}
And call it from our previous script:
if(url_exists($url)) {
return true;
}else{
return false;
}
Full code now:
So the whole thing would be something like this:
//Function to make main domain from url:
function url_exists($strURL) {
$resURL = curl_init();
curl_setopt($resURL, CURLOPT_URL, $strURL);
curl_setopt($resURL, CURLOPT_BINARYTRANSFER, 1);
curl_setopt($resURL, CURLOPT_HEADERFUNCTION, 'curlHeaderCallback');
curl_setopt($resURL, CURLOPT_FAILONERROR, 1);
curl_exec ($resURL);
$intReturnCode = curl_getinfo($resURL, CURLINFO_HTTP_CODE);
curl_close ($resURL);
if ($intReturnCode != 200 && $intReturnCode != 302 && $intReturnCode != 304) {
return false;
}Else{
return true ;
}
}
//And now the function
function domain($url,$checkIfExists=0){
//This function creates a url in the form http://www.domain.com/
$url = strtolower($url);
if(strncasecmp('http://',$url,7) !== 0){
//There is no http:// at the beginning:
$url = 'http://'.$url;
}
$parts = explode('/',$url);
if(sizeof($parts) !== 1){
//no / in the string: (No http, no ending /)
$url = $parts[2];
}
//Now check if the url has or not www. in it:
if(strncasecmp('www.',$url,4) !== 0){
//There is no www.
return 'http://www.'.$url.'/';
}else{
return 'http://'.$url.'/';
}
if($checkIfExists !== 0){
//User wanted to check if exists:
If(url_exists($url)) {
return $url;
}else{
return false;
}
}
}