Per the WAMP v1 specification, a "CALLERROR" message must include an error URI describing the error in its payload. The BabDev\WebSocket\Server\WAMP\ErrorUriResolver interface describes a service that can be used to accomplish this.

The specification, however, does not specify any error identifiers that must be supported. Therefore, it is up to the application to decide whether they will use this resolver in their message handlers or message middleware when handling RPC messages. Because this library emits "CALLERROR" messages if the BabDev\WebSocket\Server\WAMP\Middleware\DispatchMessageToHandler middleware cannot locate a message handler for the given request, the error URI resolver is provided in part to allow applications to customize the URI used for these errors. The default BabDev\WebSocket\Server\WAMP\DefaultErrorUriResolver implementation only supports the not-found error type and will return a generic URI for all other error types.