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Topics

topic.subscribe()

Subscribe a handler to a topic and receive new events for processing.

using Nitric.Sdk;

var updates = Nitric.Topic("updates");

updates.Subscribe(context => {
  Console.WriteLine(context.Req.Payload);

  return context;
});

Nitric.Run();

Parameters


middleware required Func<EventContext, EventContext> or Middleware<EventContext>[]

The middleware (code) to be triggered by the topic.


Examples

Subscribe to a topic

using Nitric.Sdk;

var updates = Nitric.Topic("updates");

updates.Subscribe(context => {
  Console.WriteLine(context.Req.Payload);

  return context;
});

Nitric.Run();

Subscibe to a topic with chained middleware

using Nitric.Sdk;

var updates = Nitric.Topic("updates");

updates.Subscribe((context, next) =>
  {
    // Validate request

    return next(context);
  }, (context, next) => {
    Console.WriteLine(context.Req.Payload);

    return next(context);
  }
);

Nitric.Run();

Notes

  • A function may only subscribe to a topic once, if multiple subscribers are required, create them in different functions.
  • A function may subscribe to OR publish to a topic but not both
Previous
topic.publish()