CODEWITHSUNDEEP
phppreg-match
AM-
AM-

Reputation: 881

preg_match never passes

My account creation script's name input is validated with a preg_match as the field is only allowed to have either Latin or Cyrillic characters (in other words, it cannot have both), however, no matter what the name field contains, the preg_match condition is never satisfied. So far I've tried three possible variations of the code:

if (!(preg_match('/^[a-z]$/i',$_POST['name']) || preg_match('/^[а-я]$/i',$_POST['name']))) back('The message');

if (!preg_match('/^[a-z]$/i',$_POST['name']) &&  !preg_match('/^[а-я]$/i',$_POST['name'])) back('The message');

and one that attempts to stuff both the preg matches into one.

Could anyone please help me out in fixing this issue?

Upvotes: 1

Views: 324

Answers (4)

artragis
artragis

Reputation: 3713

With your condition, if the first "if" does not pass, the second won't either because they are equivalent !(A or B) <=> !A && !B what you want is a xor

Moreover, you just test only one character with your "preg match" here.

your condition should be

if( preg_match('/^[a-z]+$/iu',$_POST['name']) xor preg_match('/^[а-я]+$/iu',$_POST['name']){

   // do what you want

  }

Upvotes: 0

mario
mario

Reputation: 145482

You could also assert both in one regex:

if (!preg_match('/ ^[a-z]+$ | ^[\p{Cyrillic}]+$ /ixu',$_POST['name'])) {

Note the two | alternatives, bot constrained by ^ and $.

There is also \p{Latin}, not just \p{Cyrillic} for matching the complete character range.

Upvotes: 1

deceze
deceze

Reputation: 522155

Let's abstract those preg_match functions into the names is_latin and is_cyrillic for readability. You're then looking for the logic:

if is_latin xor is_cyrillic     -> OK
else                            -> not OK

Or, inverted:

if !(is_latin xor is_cyrillic)  -> not OK

xor is only true if one is true and the other false.

Additionally, your regexen match only a single character. You'll want /^[a-z]+$/i to match a whole word. Further, to match a non-latin word/regex, you need to use the u modifier like /^[а-я]+$/iu and make sure your source code and the subject are encoded in UTF-8. So:

if (!(preg_match('/^[a-z]+$/i', $_POST['name']) xor preg_match('/^[а-я]+$/iu', $_POST['name']))) {
    // error
}

You can even shorten this into one regex:

if (!preg_match('/^([a-z]+|[а-я]+)$/iu', $_POST['name'])) {
    // error
}

Upvotes: 1

jeroen
jeroen

Reputation: 91744

The problem is that you are limiting the name to exactly one character:

/^[a-z]$/i

Change it to:

/^[a-z]+$/i

and

/^[а-я]+$/i

Upvotes: 4

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