Can not get header from request->getHeader(), but from getallheaders() is normal. I use Apache 2.4.12, PHP 5.6.7
What exactly is your question?
$clientId = $app->request->getHeader('API_ID'); $clientId = NULL
but with $serverHeader = getallheaders(); $clientId = $serverHeader['API_ID']; This get the data.
Which Headers do you get if you call getHeaders() ?
$allHeaders = $app->request->getHeaders(); var_dump($allHeaders);
Is your Header "API_ID" in this array list?
It's return NULL for get by getHeaders(). And yes, API_ID is in headers if get by getallheaders().
Are you using \Phalcon\DI::FactoryDefault() for your depenency injection?
If not, try
$app->getShared('request')->getHeaders();