Custom unique identifier generator

[Aurélien Pillevesse]

Currently, the unique identifier generator is a function available here that cannot be easily modified:

oauth2-server/src/Grant/AbstractGrant.php

Line 569 in eb91b41

 protected function generateUniqueIdentifier($length = 40) 

Would it be possible to customize the generation of the unique identifier?
In my case, I'd like to use the UUID, for example, to make sure that the identifier is unique.
In someone else's case, he'd like to use the auto-incremented ID.

What do you think of this improvement to make unique ID generation more easily modifiable?

An idea could be :

public function enableGrantType(GrantTypeInterface $grantType, DateInterval $accessTokenTTL = null, UniqueIdGeneratorInterface $uniqueIdGenerator = null)
{
    if ($accessTokenTTL === null) {
        $accessTokenTTL = new DateInterval('PT1H');
    }

    --> if ($uniqueIdGenerator === null) {
    -->     $uniqueIdGenerator = /*a class which represents the current unique id generator behavior */;
    --> }

    $grantType->setAccessTokenRepository($this->accessTokenRepository);
    $grantType->setClientRepository($this->clientRepository);
    $grantType->setScopeRepository($this->scopeRepository);
    $grantType->setDefaultScope($this->defaultScope);
    $grantType->setPrivateKey($this->privateKey);
    $grantType->setEmitter($this->getEmitter());
    $grantType->setEncryptionKey($this->encryptionKey);
    $grantType->revokeRefreshTokens($this->revokeRefreshTokens);
    --> $grantType->setUniqueIdGenerator($uniqueIdGenerator);

    $this->enabledGrantTypes[$grantType->getIdentifier()] = $grantType;
    $this->grantTypeAccessTokenTTL[$grantType->getIdentifier()] = $accessTokenTTL;
}

Or another idea :

(instead of this)

while ($maxGenerationAttempts-- > 0) {
    $accessToken->setIdentifier($this->generateUniqueIdentifier());
    try {
        $this->accessTokenRepository->persistNewAccessToken($accessToken);
        return $accessToken;
    } catch (UniqueTokenIdentifierConstraintViolationException $e) {
        if ($maxGenerationAttempts === 0) {
            throw $e;
        }
    }
}


(doing this)        

$accessToken->setIdentifier($this->accessTokenRepository->getUniqueIdentifier());
$this->accessTokenRepository->persistNewAccessToken($accessToken);
return $accessToken;