/**
* Fetch a public key and check the capability of the threemaId
*
* @param string $threemaId
* @param \Closure $capabilityCheck
* @return string Public key as binary
* @throws Exception
*/
private final function fetchPublicKeyAndCheckCapability($threemaId, \Closure $capabilityCheck = null)
{
//fetch the public key
$receiverPublicKey = $this->connection->fetchPublicKey($threemaId);
if (null === $receiverPublicKey || !$receiverPublicKey->isSuccess()) {
throw new Exception('Invalid threema id');
}
if (null !== $capabilityCheck) {
//check capability
$capability = $this->connection->keyCapability($threemaId);
if (null === $capability || false === $capabilityCheck->__invoke($capability)) {
throw new Exception('threema id does not have the capability');
}
}
return $this->cryptTool->hex2bin($receiverPublicKey->getPublicKey());
}
