Interface IMessageListener
An interface for connecting to a message service, subscribing to a topic, and listening for messages. Used by the system in order for lemonedge to pass messages for synchronisation across services.
By default the MessageType config setting only allows Azure message bus configuration
Implementing this interface, and IMessenger, and marking them with the MessageManagerAttribute will expand the options from the config settings to enable using your custom message service.You can then configure the use of that by LemonEdge using MessageType, MessageConnectionString and MessageTopicForServerSync config settings
Inherited Members
Namespace: LemonEdge.API.Messages
Assembly: API.dll
Syntax
public interface IMessageListener : IMessengerBaseRemarks
When you have more than one web or task service, the system needs to synchronise the cache between them all. This can be done by either a shared cache server they all connect to, or by passing messages that invalidate local caches.
The performance between the two is a balance of the number of services being spun up and the general work load.
This message interface is a simple mechanism to enable the web and task services to communicate with each other to keep everything in sync. Expanding this implementation allows you to use messages using other technologies than the Azure message bus (the default lemonedge messaging option)Methods
AddExceptionHandler(Func<Exception, Task>)
Adds a handler for dealing with any exceptions for connections or message handling
Declaration
void AddExceptionHandler(Func<Exception, Task> exceptionHandler)Parameters
| Type | Name | Description |
|---|---|---|
| System.Func<System.Exception, System.Threading.Tasks.Task> | exceptionHandler | A function that deals with exceptions encountered while listening to messages |
AddMessageProcessor(Func<String, Task>)
Adds a handler to process any incoming messages for this connection
Declaration
void AddMessageProcessor(Func<string, Task> listener)Parameters
| Type | Name | Description |
|---|---|---|
| System.Func<System.String, System.Threading.Tasks.Task> | listener | The function that will be called to process any messages recieved from this connection |
Init(String, String, String)
Initializes a new MessageListener with the settings to connect to a message service and listen to a specific channel for messages
Declaration
Task Init(string connectionString, string topicName, string subscriberName)Parameters
| Type | Name | Description |
|---|---|---|
| System.String | connectionString | The connection string for the message service |
| System.String | topicName | The topic for messages |
| System.String | subscriberName | The name of the service subscribing to the messages |
Returns
| Type | Description |
|---|---|
| System.Threading.Tasks.Task | A task indicating the completion of the operation to connect to the message service |