Zend AMF and exception handling

Question

I have created an Zend AMF service using the FlashBuilder tools. What I wanted to try was to change one of those automatically created methods to throw an exception in order to see the behaviour. Instead of the exception being serialized back to my Flex app it gives me the following:

[RPC Fault faultString="Channel disconnected" faultCode="Client.Error.DeliveryInDoubt" faultDetail="Channel disconnected before an acknowledgement was received"] at mx.rpc::AbstractInvoker/http://www.adobe.com/2006/flex/mx/internal::faultHandler()[E:\dev\4.0.0\frameworks\projects\rpc\src\mx\rpc\AbstractInvoker.as:345] at mx.rpc::Responder/fault()[E:\dev\4.0.0\frameworks\projects\rpc\src\mx\rpc\Responder.as:68] at mx.rpc::AsyncRequest/fault()[E:\dev\4.0.0\frameworks\projects\rpc\src\mx\rpc\AsyncRequest.as:113] at NetConnectionMessageResponder/channelDisconnectHandler()[E:\dev\4.0.0\frameworks\projects\rpc\src\mx\messaging\channels\NetConnectionChannel.as:684] at flash.events::EventDispatcher/dispatchEventFunction() at flash.events::EventDispatcher/dispatchEvent() at mx.messaging::Channel/disconnectSuccess()[E:\dev\4.0.0\frameworks\projects\rpc\src\mx\messaging\Channel.as:1214] at mx.messaging.channels::NetConnectionChannel/internalDisconnect()[E:\dev\4.0.0\frameworks\projects\rpc\src\mx\messaging\channels\NetConnectionChannel.as:175] at mx.messaging.channels::AMFChannel/internalDisconnect()[E:\dev\4.0.0\frameworks\projects\rpc\src\mx\messaging\channels\AMFChannel.as:355] at mx.messaging.channels::AMFChannel/statusHandler()[E:\dev\4.0.0\frameworks\projects\rpc\src\mx\messaging\channels\AMFChannel.as:445]

The channel disconnects...

[RPC Fault faultString="Channel disconnected" faultCode="Client.Error.DeliveryInDoubt" faultDetail="Channel disconnected before an acknowledgement was received"]

This is the code:

public function getAllUser() {

$stmt = mysqli_prepare($this->connection, "SELECT * FROM $this->tablename");
$this->throwExceptionOnError();

mysqli_stmt_execute($stmt);
$this->throwExceptionOnError();

$rows = array();

mysqli_stmt_bind_result($stmt, $row->id, $row->user_group_id, $row->username, $row->password, $row->active, $row->activation_key, $row->timezone, $row->created_on, $row->modified_on);

while (mysqli_stmt_fetch($stmt)) {
 $row->created_on = new DateTime($row->created_on);
 $row->modified_on = new DateTime($row->modified_on);
 $rows[] = $row;
 $row = new stdClass();
 mysqli_stmt_bind_result($stmt, $row->id, $row->user_group_id, $row->username, $row->password, $row->active, $row->activation_key, $row->timezone, $row->created_on, $row->modified_on);
}

mysqli_stmt_free_result($stmt);
mysqli_close($this->connection);

$errorCode = 1;

            throw(new Exception('the error message you want', $errorCode));

return $rows;

}

Notice the throw statement:

throw(new Exception('the error message you want', $errorCode));

I really didn't expect this. How can I make it work?

Thank you in advanced!!!

Answer 1

Well it does serialize the exception message and code which does the job for us. Partially but does it. I didn't notice that the service component I copied the code from in my question contained an exception handler which would suppress the exception and just disconnect the channel. I removed the exception handler letting the exception bubble up to Zend which in turn send the exception message and message code to the client.

I would like to have the actual exception sent as an AS3 object but what can I say. In this way I would have the properties of the exception serialized also. Unfortunately the same goes for custom exceptions.

Answer 2

Zend Amf is just a serialization protocol of response types to cast them into the AMF format. No error messages are sent back as they normally have sensitive security information in them. Most other PHP amf serialization do not work this way. If you have an exception you need to catch it and convert it to a standard support response type. Also in any of your code every Try needs a Catch as it is not a control structure even if PHP allows you to get away with it.

If you have configured your endpoint to not be production and just need it for debugging.

require_once 'Zend/Amf/Exception.php'; throw new Zend_Amf_Exception('the error message you want', $errorCode);