Determining URL or String PHP - php

Question

I'm making a link and text service, but I have a problem, which is: there is only 1 input text form, and the user could paste something like this:
http:// asdf .com - which would register as a link, or 'asdf http:// test .com' because of the http://, it would register as a url, or
asdf - which would register as a string, because it doesn't contain http://
BUT my problem arises when the user writes something like:
asdf http://asdf.com, which in my current program outputs a "url" value. I've been experimenting for about an hour now, and I've got 3 bits of code (they were all in the same document being commented, so forgive me if they give errors!)
<?
$str = $_POST['paste'];
if(stristr($str, "http://")) {
$type = "url";
}
if(stristr($str, "https://")) {
$type = "url";
}
if($type!="url") {
$type = "string";
}
?>
Next:
<?
$type = "url";
if($type=="url"){
$t = substr($str, 8);
if(stristr($t, "https://")==$t){
$type = "url";}
if(stristr($t, "https://")==$t){
$type = "url";}
if(stristr($t, "http://")!=$t){
$type = "string";}
if(stristr($t, "https://")!=$t){
$type = "string";}
}
echo $type;
?>
Next:
<?
$url = "hasttp://cake.com";
if(stristr($url, "http://")=="") {
$type = "string"; } else {
$type = "url";
$sus = 1;}
if(stristr($url, "http://")==$url) {
$type = "url"; }
if($sus==1) {
$r = substr($url, 7);
if(stristr($r,"http://")!="http://") {
$type = "url"; }
if($r=="") {
$type = "string";
}
}
echo $type;
?>
I have no clue how I could go about classifying a string like 'asdf http://asdf.com' as a string, whilst classifying 'asdf' as a string, and classifying 'http://asdf.com' as a url.. Another idea I haven't tried yet is strpos, but that's what I'm working on now.
Any ideas?
Thanks alot! :)
Some parts of this question are getting cut off for some reason, apologies!

Answer 1

$type = '';
if (preg_match('%^https?://[^\s]+$%', $url)) {
$type = 'url';
} else {
$type = 'string';
}
This will match any value which starts with http:// or https://, and does not contain any space in it as type url. If the value does not start with http:// or https://, or it contains a space in it, it will be type string.

Answer 2

PHP parse_url is your function:
On seriously malformed URLs, parse_url() may return FALSE.
If the component parameter is omitted, an associative array is returned. At least one element will be present within the array. Potential keys within this array are:
scheme - e.g. http
host
port
user
pass
path
query - after the question mark ?
fragment - after the hashmark #
If the component parameter is specified, parse_url() returns a string (or an integer, in the case of PHP_URL_PORT) instead of an array. If the requested component doesn't exist within the given URL, NULL will be returned.

Answer 3

If I'm understanding the problem correctly you want to detect when the user inputs both a string and a url and parse each of them correspondingly.
Try using explode(" ", $userInput);, this will return an array containing all strings separated by a space. Than you can check that for each element in the array and set the type.

Answer 4

$type = strpos($str, 'http') === 0 ? 'url' : 'string':
The strpos function returns the position of a match within a string or FALSE if no match. The tripple equals checks that the result does not only translates to 0 (as FALSE would have done), but that it is in fact integer as well (i.e., the string begins with http).
You could also use something like
switch (true) {
case strpos(trim($str), 'http://') === 0:
case strpos(trim($str), 'https://') === 0:
$type = 'url';
break;
default:
$type = 'string';
break; // I know this is not needed, but it is pretty :-)
}

Answer 5

You should use a regular expression to check if the string starts with http
if(preg_match('/^http/',$string_to_check)){
//this is a url
}