Compare data from a text file

[matt6805]

I'm trying to compare email addresses a user provides me with one previously written to a txt file. The idea here is, the user fills out a form and their address is written to a text file separated by commas. Then, they're taken back to a page a later date with a single input field. The user is asked to enter the email address they originally registered with. Then, this script is called:

<?php
//Post the email address
$strEmailAddress	=	$_POST["email"];

//Open and Read the file
$myFile = "registration.txt";
$fh = fopen($myFile, 'r');
$theData = fread($fh, filesize($myFile));

//Just Here to see what comes out. An email address is printed as expected
print $theData;

//compare posted email address to the contents of the registration.txt file
if (preg_match($strEmailAddress, $theData)) {
    echo "A match was found.";
} else {
    echo "A match was not found.";
}
?>

When I run this, I never get a match. I've made sure to test the fact that the email address is indeed being posted to this php page. Right now for simplicity sake, I've only added one email address to the text file. I'm sure my code is not right but I'm new to PHP and can't find the right code to make this work in my research online. Does anyone know what the snag here is? Thanks.

Regards,
Matt

[sneakyimp]

A few things.

You might want to watch out for magic quotes. If user for some reason puts any kind of quote mark or other escapable character in their email address, it will have a backslash added if your server is configured to use magic_quotes.

Are you sure the file is getting opened? You might consider checking for errors.

$myFile = "registration.txt";
if (!file_exists($myFile)) {
  die('the data file was not found');
}
$fh = fopen($myFile, 'r')
  or die('could not open ' . $myFile);
$theData = fread($fh, filesize($myFile));
if(!$theData) {
  die('no data was returned from ' . $myFile);
}

Lastly, [man]preg_match[/man] expects the first parameter to be a regular expression. I'm not certain but things like periods and @ might be meaningful in a regular expression. You might want to try a different matching function like [man]stristr[/man].

[matt6805]

Ok so using a bit of what you pasted here, this what I have:

//Post the email address
$strEmailAddress	=	$_POST["email"];

$myFile = "registration.txt";
if (!file_exists($myFile)) {
  die('the data file was not found');
}
$fh = fopen($myFile, 'r')
  or die('could not open ' . $myFile);
$theData = fread($fh, filesize($myFile));
if(!$theData) {
  die('no data was returned from ' . $myFile);
} 
//just testing to see if the file is being read
echo $theData;


if(stristr($theData, '[e-mail]') === TRUE) {
    echo 'I found your address in registration.txt';
  }else {
	echo 'I did not find your address in registration.txt';
  }

Note I echoed the contents of $theData just to be sure the file is being read. I get the email addresses printing out one after another with a space in between them(email1 email2 email3). The way they are written to the text file is as such:

//Write the email address to a text file for later checking
$myFile = "registration.txt";
$fh = fopen($myFile, 'a') or die("can't open file");
$break = "\n";
fwrite($fh, $strEmailAddress);
fwrite($fh, $break);
fclose($fh);
die();

Not sure that's necessary to show, but that's how i'm doing it. This produces a text file with one address per line.

The function stristr should be looking in the variable $theData for the email address "[e-mail]". I don't think it's doing that. Also, that wouldn't help the situation. I would need the appropriate synatax to dump the value of $_POST["email"] between those quotes as a string because that's the email address that it's checking against the list keeps changing based on user input.

I really appreciate the help 🙂

Regards,
Matt

[sneakyimp]

You should read the docs on [man]stristr[/man]. It's NEVER going to === true. You should get in the habit of checking the phpdocs for any functions you are not familiar with -- like preg_match or stristr.