奇怪的PDO行为

Question

After some hours I have to post this question even if the answer maybe obvious to someone else.

The problem is that I want to test for the tokens, but even when I hardcode this, I still get INVALID. And I know it has to be right, because I tested it in PHPADMIN directly. What's odd is that it always passes the first time (without being hardcoded), but after that it is useless? The tokens are retrieved from a cookie.

public function findTriplet($credential, $token, $persistentToken) {

    $token = "459078a3b05ce938ed58f9678ac78f1agcgfsewe4";
    $persistentToken = "24d317b742da89ddf5b8ed50993d0f3cgcgfsewe4";
    $credential ="34";
    $q = "SELECT IF(SHA1(?) = {$this->tokenColumn}, 1, -1) AS token_match " .
         "FROM {$this->tableName} WHERE {$this->credentialColumn} = ? " .
         "AND {$this->persistentTokenColumn} = SHA1(?) LIMIT 1 ";
    $query = $this->db->prepare($q);
    $query->execute(array($token, $credential, $persistentToken));
    $result = $query->fetchColumn();

    if (!$result) {
        return self::TRIPLET_NOT_FOUND;
    } else if ($result == 1) {
        return self::TRIPLET_FOUND;
    } else {
        return self::TRIPLET_INVALID; }
    }

EDIT

The limit clause always catches the first row it finds, therefore I always get a mismatch Now I have to fix this.

The solution was simple. Delete the entry that was just validated before inserting a new row with the newly generated token. The new row should contain the SAME persistenceToken you just validated against. REMEMBER, this will still be UNSECURE, so set a FLAG on the serverside that this was a cookielogin, and require a REAL LOGIN for handling important data.

Answer 1

I think your if checks are in the wrong order:

    if(!$result) {  return self::TRIPLET_NOT_FOUND;}
    elseif ($result == 1) {     return self::TRIPLET_FOUND;}
    else {  return self::TRIPLET_INVALID;}

In the SQL, 1 means found, -1 means not found, and anything else would be invalid. But in the PHP, a -1 would fall into the else clause, and return self::TRIPLET_INVALID, whereas an invalid result would fall into if(!$result) and return self::TRIPLET_NOT_FOUND.