Creating a log in page sourcing from a CSV - php

Question

I am attempting to create a login page for my website. I have it set up so the user can create an account and these credentials are saved to a csv, saved on my ftp. (All the HTML and CSS is functional) I would like the system to work as follows:
1. From login page the user enters their credentials.
2. The CSV is searched, when the email is found the inputted password is compared with the corresponding password in the CSV.
3. If they match then another page is opened/If they don't match an error is displayed.
Here is the CSV:
Test#gmail.com,password1
Test2#gmail.com.password2
Here is the php which writes to the CSV:
<?php
$filename = $_POST['filename'];
foreach($_POST as $name => $value)
{
IF ($value != "Submit" and $value !=$filename)
{
$messagedisplay = $messagedisplay . $name. ": " . $value . "<BR>";
$filedata = $filedata . $value . ",";
}
}
$filedata = rtrim($filedata,",");
$filedata = $filedata . PHP_EOL;
$fs = fopen($filename,a);
fwrite($fs,$filedata);
fclose($fs);
$messagedisplay = "Your account has been created, please return to the main website and login.";
print $messagedisplay;
?>
Any ideas on how I would check the CSV to see if a) the email exists in the CSV and b) check the passwords match, subsequently redirecting to another page. Thanks.

Answer 1

In your case you could slurp the csv into an array. Then it's as simple as iterating through the array until you find a match.
<?php
$credentials = [
['foo', 'jubblies'],
['bar', 'jangles']
];
$check_credentials = function($username, $password) use ($credentials) {
foreach($credentials as $credential)
if($credential[0] == $username && $credential[1] == $password)
return true;
return false;
};
var_dump($check_credentials('foo', 'jiblets'));
var_dump($check_credentials('foo', 'jubblies'));
var_dump($check_credentials('ace', 'detective'));
Output
boolean false
boolean true
boolean false
Reading your credentials from a csv file into an array (similar format as above) could be accomplished something like this:
function get_credentials_from_file($path) {
$fp = fopen($path, 'r');
while ($line = fgetcsv($fp)) {
$lines[] = $line;
}
fclose($fp);
return $lines;
}
$credentials = get_credentials_from_file('/tmp/file.csv');
See also fputcsv, for csv writing.
Take care when storing user data.
If you end up reading and writing from/to a csv or text file, you'll have to manage file locks etc. It could well be easier to use a database.
See: Php's password_hash and password_verify to avoid storing plain text passwords.