How to check line in file (php) - php

Question

I'm new to php and wanted to make a simple php script to check a form of my html site.
To answer the questions:
I have a file, that's the Name of the User and I want to check if the password that is in there (line 1) is the same as the one in the "password" field on my site. And when it's like this it should open a site.
Maybe a check if the file exists would be nice :D
This is my php-file, it's named "check.php":
<?php
$f = fopen($_POST["name"], "r");
$theData = fgets($f);
if ($_POST["pw"] == $theData) {
$ch = curl_init("site.com");
curl_exec($ch);
}
fclose($f);
?>
This is my html-file:
<h2>Check</h2>
<form action="check.php" method='post'>
<b>Name: </b><input name="name" type="text" value="Name"> <br>
<b>Password: </b><input name="pw" type="text" value="Passwort"> <br>
<input type="submit" value="Check">
<input type="reset" value="Reset">
</form>
I hope one can help me ^^
I've tried a lot of things now, nothing really worked.

Answer 1

To process a form fields you should do like this in your check.php file(simplest one)
if(isset($_POST['submit']))
{
$name = $_PSOT['name'];
$password = $_POST['password'];
if($name == 'admin' && $password == 'admin')
{
header('Location:admin.php');exit;
}else{
echo 'Wrong user name or password';
}
}
may be you are asking to do like this
if(isset($_POST['submit']))
{
$name = $_PSOT['name'];
$password = $_POST['password'];
$file_type = '.txt';
$path = 'path to folder/'.$name.$file_type;
if(file_exists($path))
{
$user_pass = fopen($path, "r");
$flag = 0;
while(!feof($user_pass))
{
$p = fgets($user_pass);
if($password == $p)
{
$flag = 1;
}
}
fclose($user_pass);
if($flag == 1)
{
header('Location:to your page link/weblink');exit;
}else{
echo 'Wrong password';
}
}else{
echo 'User does not exists';
}
}