CODEWITHSUNDEEP
phpregex
Gao Lin
Gao Lin

Reputation: 59

PHP Regex - Minimum of 8 characters, 1 letter, 1 number

So I thought I had this right?

        if(!preg_match('^(?=.*[a-z])(?=.*[A-Z])(?=.*\d).+.{7,}$', $passOne)) {
            $msg = "Password does not contain at least 1 number/letter, 8 character minimum requirement.";
        }

I test it over at https://regex101.com/ and put ^(?=.*[a-z])(?=.*[A-Z])(?=.*\d).+.{7,}$ to work and things like RubyGlue12 pass and is a match and other things that aren't.

But no matter what, I cannot make any match in the actual PHP code. Even if the POST is a variable manually.

edit: $_POST['password'] is $passOne

Help?

Upvotes: 2

Views: 8184

Answers (2)

seane
seane

Reputation: 599

Here's a regex that tests for what the password should not be, instead of what it should be.

/^(.{0,7}|[^a-z]*|[^\d]*)$/i

Example:

if (preg_match('/^(.{0,7}|[^a-z]*|[^\d]*)$/i', $passOne)) {
  echo "Validation failed.\n";
}

Explanation:

There are essentially 3 separate tests within the regex (each separated by a |, and each are case-insensitive due to the i option at the end). If it passes any of the tests, then the entire validation fails.

  • Test 1: Does the entire string only contain 0-7 characters? Fail.
  • Test 2: Does the entire string contain no alpha characters? Fail.
  • Test 3: Does the entire string contain no digits? Fail.

Upvotes: 1

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626870

You have .+.{7,} that does not make much sense since it means match any characters 1 or more times, and then any characters 7 or more times.

1 letter, 1 digit and min 8 characters regex will look like

(?i)^(?=.*[a-z])(?=.*\d).{8,}$

Regex explanation:

  • (?i) - Turning case sensitivity off (unless you need to check for 1 uppercase and 1 lowercase letters - then, remove the i flag and replace (?=.*[a-z]) with (?=.*[a-z])(?=.*[A-Z]))
  • ^ - Start of string
  • (?=.*[a-z]) - Positive look-ahead requirement to have at least 1 letter
  • (?=.*\d) - Positive look-ahead requirement to have at least 1 digit
  • .{8,} - At least 8 characters
  • $ - End of string.

And PHP code is:

$re = "/^(?=.*[a-z])(?=.*\\d).{8,}$/i"; 
$passOne = "RubyGlue12";
//$passOne = "eee"; // uncomment to echo the error message
if(!preg_match($re, $passOne)) {
  echo "Password does not contain at least 1 number/letter, 8 character minimum requirement.";
}

And yes, with preg_match function, you must use some regex delimiters. I am using / here.

Upvotes: 6

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