如何遍历php中的文本文件以查找特定的文本行

Question

I have made a program that lets you enter the username and password then it stores it in a text file and when i want to login i want to make it so it loops through the text file that has the usr/pass in to find if you entered your credentials in correctly. I'm not sure how to do this. please can somebody help

Answer 1

Example text.txt file:

$ cat text.txt

text1|answer1
text2|answer2
text3|answer3

Example code:

cat test2.php

 <?php $text="text1"; $file="text.txt"; $f = fopen($file, 'r'); while($data = fgets($f)) { $ar_data=explode('|',$data); if($ar_data[0]==$text) { echo "looking for: ".$ar_data[1]."\\n"; } }

Example usage: $ php test2.php looking for: answer1

The text fileis not a good way for verify user credentials. You should try sql database. sqlite3 for example.

Answer 2

You can just hard code them in an array:

 $passwords = ['someuser' => 'password'];

If you really want to store them in a file, so you can change them (for example) without editing the code, One way is to use something like this:

 $passwords = ['someuser' => 'password'];
 file_put_contents('passwords.php', '<?php return '.var_export($passwords,true).';');

This will create a file with something this in it (white space not withstanding):

 <?php return array('someuser' => 'password');

Then when you need to import it into code you can simply use

 $passwords = require 'passwords.php';

Which will put the contents of that file into that variable. Then you can check them really easily like so:

$passwords = require 'passwords.php';
if(isset($passwords[$user]) && $passwords[$user] == $password){
    //do something when logged in
}

You can also modify the array and then save it:

$passwords = require 'passwords.php';

$passwords['someuser'] = $new_password;

file_put_contents('passwords.php', '<?php return '.var_export($passwords,true).';');

Of course you can even edit the passwords manually in the file. Sort of like a config file.

As I mentioned in the comments, it's better to use the DB, encryption and what not but as you said

this is only for me and someone else

As long as you don't have any third party data, and your ok with the security implications of this, then you can probably squeak by with the above.

To explain it:

Var Export converts arrays to valid PHP code, but in a string format. Then if we add the PHP open tag <?php , the return call return and the ending ; to it and save it in a PHP file, we now have a valid PHP file with dynamic passwords saved in it as an array.

When you have such a file that returns an array, you can inject that into a variable just by setting it like I showed above. Then it's a simple matter of checking to see if everything matches up.

Performance wise your offloading most of the penalty of this to saving the file, importing an array like this is very fast as is the key lookup. Much faster then iterating though a file and trying to parse the data from it.

You'll have to get the paths and filenames right and all that Jazz, but it should be pretty strait forward.