# MessageHandler
The MessageHandler is used to handle messages from the enterprise WeChat dialogue window.
The SDK has all the basic functionality needed for the developer, the developer just needs to create a custom subclass to supplement the business logic that needs to be customised.
# Custom MessageHandler
In the current example, we named our custom MessageHandler WorkCustomMessageHandler.
WorkCustomMessageHandler.cs Reference file for this project:
/MessageHandlers/ directory WorkCustomMessageHandler.cs MessageHandler main file, responsible for general message handling. WorkCustomMessageContext.cs Custom rewrite of DefaultMpMessageContext context (optional)
Of all the demonstrated override methods in WorkCustomMessageHandler.cs, only the DefaultResponseMessage() method is required to be overridden, and all the other OnXxxRequest() methods are optional, so that when the user sends a message, and the corresponding override method cannot be found, then the message will be handled by the DefaultMpMessageContext.cs. When the user sends a message and can't find a corresponding overridden method, the DefaultResponseMessage() method will be called.
The MessageHandler has two ways of carrying the message so that it can be accessed externally (by the WeChat server) via a URL. These are the Middleware method (recommended) and the Controller method. The WorkCustomMessageHandler used in both ways is common, so it can be switched and coexisted at any time.
# Middleware approach to hosting MessageHandler
The middleware approach is the recommended and most simplified way, there is no need to create any new files, just introduce the middleware in the Program.cs file underneath all the Senparc.Weixin registration code after it has been executed:
app.UseMessageHandlerForWork("/WorkAsync", WorkCustomMessageHandler.GenerateMessageHandler, options =>
{
options.AccountSettingFunc = context => Senparc.Weixin.Config.SenparcWeixinSetting;
});
Once done, the MessageHandler can be accessed via Url Domain/WorkAsync, set to the message URL of the public backend.
test /WorkAsync (opens new window)
Reference document for this project:
/Program.cs
For more middleware approaches, please refer to (the same way as public use): "Using MessageHandler Middleware in .NET Core 2.0/3.0" (opens new window) (also for .NET 6.0 and above).
# Controller approach to hosting MessageHandler
When the middleware approach is not enough, you can use a Controller to "expand" the execution process and control or intervene more precisely at each step.
To use Controller, you need to create 2 Actions, which correspond to WeChat background authentication (Get request) and real message push (Post request). The project example is located in WorkController.cs.
WorkController.cs Reference file for this project:
/Controllers/WorkController.cs
Once done, you can access the MessageHandler via Url Domain/Work, set to the message URL of the public backend.
For more Controller methods, please refer to Understanding MessageHandler (opens new window) (recommended to use the full set of asynchronous methods).