IRequestHandlers vs INotificationHandler

[cecilphillip]

Please excuse my trivial question, but I'm a little unsure about the major differences between IRequestHandler<T> and INotificationHandler<T>.

The interface methods looks fairly similar.

• INotificationHandler<T> - void Handle(TNotification notification);
• IRequestHandler<T> - void Handle(TRequest message);

They also both seem applicable for fire & forget scenarios. When exactly would you use notifications over void returning requests? I'm probably missing something very blatant here.

[jbogard]

Requests are for: 1 request to 1 handler. Handler may or may not return a value Notifications are for: 1 notification to n handlers. Handler may not return a value. In practical terms, requests are "commands", notifications are "events". Command would be directing MediatR to do something like "ApproveInvoiceCommand -> ApproveInvoiceHandler". Event would be notifications, like "InvoiceApprovedEvent -> SendThankYouEmailToCustomerHandler" HTH

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On Thu, Apr 27, 2017 at 2:27 PM, Cecil Phillip ***@***.***> wrote: Please excuse my trivial question, but I'm a little unsure about the major differences between IRequestHandler<T> and INotificationHandler<T>. The interface methods looks fairly similar. - INotificationHandler<T> - void Handle(TNotification notification); - IRequestHandler<T> - void Handle(TRequest message); <https://github.com/jbogard/MediatR/blob/master/src/MediatR/INotificationHandler.cs#L14> (https://github.com/jbogard/MediatR/blob/master/ src/MediatR/IRequestHandler.cs#L30 <https://github.com/jbogard/MediatR/blob/master/src/MediatR/IRequestHandler.cs#L30> ) They also both seem applicable for fire & forget scenarios. When exactly would you use notifications over void returning requests? I'm probably missing something very blatant here. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#163>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAGYMiD48W1u2NTwltpqvnwmP_YneIWaks5r0OwGgaJpZM4NKqcy> .

[cecilphillip]

Gotcha. Thanks!