PHP reading lines from file and compare them - php

Question

I am trying to read all lines from a file and than see if a given string contains any of these lines.
My code
$mails = file('blacklist.txt');
$email = "hendrik#anonbox.net";
$fail = false;
foreach($mails as $mail) {
if(strpos($email, $mail) > 0) {
$fail = true;
}
}
if($fail) {
echo "Fail";
} else {
echo "you can use that";
}
The blacklist.txt can be found here http://pastebin.com/aJyVkcNx.
I would expect strpos return a position for at least one string in the blacklist, but it does not. I am guessing that somehow I am generating not the kind of values within the $mails as I am expecting.
EDIT this is print_r($mails) http://pastebin.com/83ZqVwHx
EDIT2 some clarification: I want to see if a domain is within an email, even if the mail contains subdomain.domain.tld. And I tried to use !== false instead of my > 0 which yielded the same result.

Answer 1

You need to parse the email well since you're checking the domain of the email address if its inside the blacklist. Example:
$email = "hendrik#foo.anonbox.net";
if(filter_var($email, FILTER_VALIDATE_EMAIL)) {
preg_match('/#.*?([^.]+[.]\w{3}|[^.])$/', $email, $matches);
if(!empty($matches) && isset($matches[1])) {
$domain = $matches[1];
} else {
// not good email
exit;
}
// THIS IS FOR SAMPLES SAKE, i know youre using file()
$blacklist = explode("\n", file_get_contents('http://pastebin.com/raw.php?i=aJyVkcNx'));
foreach($blacklist as $email) {
if(stripos($email, $domain) !== false) {
echo 'you are blacklisted';
exit;
}
}
}
// his/her email is ok continue

Answer 2

strpos returns FALSE if the string was not found.'
Simply use this :
$fail = false;
foreach($mails as $mail) {
if(strpos($email, $mail) === false) {
$fail = true;
}
}
Or even better use this:
$blacklist = file_get_contents('blacklist.txt');
$email = "hendrik#anonbox.net";
if(strpos($email, $blacklist) === false){
echo "fail";
} else {
echo "This email is not blacklisted";
}

Answer 3

You have found the common pitfall with the strpos function. The return value of the strpos function refers to the position at which it found the string. In this instance, if the string begins at the first character, it will return 0. Note that 0 !== false.
The correct way to use the function is:
if(strpos($email, $mail) !== false){
// the string was found, potentially at position 0
}
However, this function may not be necessary at all; if you are simply checking if $mail is the same as $email, instead of seeing if the string exists within a larger string, then just use:
if($mail == $email){
// they are the same
}

Answer 4

Though you might still use foreach, that’s array reduce pattern:
function check_against($carry, $mail, $blacklisted) {
return $carry ||= strpos($mail, $blacklisted) !== false;
};
var_dump(array_reduce($mails, "check_against", $email_to_check));
Hope it helps.

Answer 5

Yet another way to solve this. Works fine:
$blacklist = file_get_contents('blacklist.txt');
$email = "hendrik#x.ip6.li";
$domain = substr(trim($email), strpos($email, '#')+1);
if(strpos($blacklist, $domain)){
echo "Your email has been blacklisted!";
}else{
echo "You are all good to go! not blacklisted :-)";
}
Goodluck!