在文本文件中搜索字符串

Question

I get a user.txt file. There are all the users saved in this format:

Vorname: Michael | Nachname : Schmidt | Username: DarkDecipio | Passwort: 3609e297fb0b6fb1105cba71d5c024b3
Vorname: John | Nachname : Doe | Username: Dummy | Passwort: d78c03d72e72b44a131d255aec3c8a11

Now when a new User send a register form to the php file, i want to look, if the username is already taken. So i must search all Username's, if there the sended username. But i can't do it with strstr() or something like that, because the Prename (Vorname) or Surname (Nachname) can be the same like the Username. Or the username can include a part of the sended username...

Hope you understand it.
Note: I know it's a ugly solution to save users in a text file, but this is a project in my school and we MUST use textfiles...

Answer 1

Off the top of my head, I can think of two options. Assume $line is the current line in your file and you are looking for 'DarkDecipio':

First, use regular expressions to ensure you are picking up the section you want:

if ( preg_match('/Username:\s*DarkDecipio/', $line) ) {
    echo 'Match';
}

Second, split the lines by | and then use strstr on the third item in each array:

$items = explode('|', $line);
if ( strstr($items[2], 'DarkDecipio') ) {
    echo 'Match';
}