How to remove the protocol and domain from a url string?

Question

I am running the following code in PHP. My intention is to get "contact.html" in the response, but what I actually get in the output is ntact.html

$str = 'http://localhost/contact.html';
echo $str . "<br>";
echo ltrim($str,'http://localhost');

Any thoughts why PHP is behaving this way and what can I do to fix this?

Answer 1

ltrim doesn't do what you think it does. It uses a character collection, so all characters within are deleted. You should delete the substring using str_replace.

http://php.net/manual/en/function.str-replace.php

$str = 'http://localhost/contact.html';
echo $str . "<br>";
echo str_replace('http://localhost/', '', $str);

Output:

http://localhost/contact.html
contact.html

I do realize that you're trying to only replace a string that's at the beginning of your string, but if you have an http://localhost later in your string, you might have bigger problems.

Documentation on ltrim: http://php.net/manual/en/function.ltrim.php (The Hello World example should be enlightening on explaining exactly what ltrim is doing)

Another example of ltrim misuse: PHP ltrim behavior with character list

Answer 2

As far as I know ltrim() is used for stripping whitespaces from the beginning of a string. See documentation.

If you want to take the string after http://localhost/ you can use substr():

$str = 'http://localhost/contact.html';
echo $str . "<br>";
echo substr($str,18); // 18 is the length + 1 of http://localhost/

Answer 3

From the manual on ltrim() (emphasis mine):

You can also specify the characters you want to strip, by means of the character_mask parameter. Simply list all characters that you want to be stripped. With .. you can specify a range of characters.

That means that you list a set of characters to be removed, not a word/string. Here's an example.

$str = "foo";
echo ltrim($str, "for"); // Removes everything, because it encounters an F, then two O, outputs ""
echo ltrim($str, "f"); // Removes F only, outputs "oo"
echo ltrim($str, "o"); // Removes nothing, outputs "foo"

That means that any character listed in the character mask would be removed. Instead, you can remove the beginning of the string by str_replace(), by replacing http://localhost with an empty string.

$str = 'http://localhost/contact.html';
echo $str . "<br>";
echo str_replace('http://localhost', '', $str);

• Live demo
• http://php.net/manual/en/function.ltrim.php
• http://php.net/manual/en/function.str-replace.php

Answer 4

ltrim works up there is no match in your character_mask which in your case http://localhost .

The output will be like this ntact.html why ?

It will match http://localhost and after that there is / it will remove it because it is in character mask and so on.

why stopped at n because it is not in your charter mask.

So , ltrim will continue remove unless there is no match in character mask

$str = 'http://localhost/contact.html';
echo  ltrim($str, 'http');// output ://localhost/contact.html

and here i will add only one in mask / and it will remove both //

$str = 'http://localhost/contact.html';
echo  ltrim($str, 'http:/');// output localhost/contact.html

Answer 5

Other answers explain why ltrim isn't doing what you thought it would, but there's probably a better tool for this job.

Your string is a URL. PHP has a built-in function to handle those neatly.

echo parse_url($str, PHP_URL_PATH);

(parse_url does return the path with a leading slash. If you need to remove that, then ltrim will work just fine since you'll only trimming one character.)