Create Publisher¶

This page shows how to create a RabbitMQ publisher manually.

The concrete client is:

PublisherBound

It requires:

PublisherBoundDescriptor
IDataEncoder
RabbitMQ channel

Create Connection And Channel¶

var factory = new ConnectionFactory
{
    HostName = "localhost",
    UserName = "guest",
    Password = "guest",
    DispatchConsumersAsync = true
};

using var connection =
    factory.CreateConnection("publisher-demo");

using var channel =
    connection.CreateChannel();

For the RabbitMQ.Client v7 provider, CreateChannel() supports an optional delivery confirmation parameter used to enable publisher confirms during channel creation.

Create Formatter¶

This guide assumes that an IDataFormatter instance has already been created.

See:

Getting Started → Create Formatter

IDataFormatter formatter = ...;

Create Descriptor¶

var descriptor = new PublisherBoundDescriptor
{
    EnableChannelEvents = true,

    Exchanges =
    {
        new ExchangeBoundDescriptor
        {
            Name = "orders",
            Type = ExchangeTypes.Direct,
            Durable = true,
            AutoDelete = false,

            Queues =
            {
                new QueueBoundDescriptor
                {
                    Name = "orders.created",
                    Durable = true,
                    AutoDelete = false,

                    Binder = new BinderDescriptor
                    {
                        RoutingKey = "orders.created"
                    }
                }
            }
        }
    }
};

Create Publisher¶

await using var publisher =
    new PublisherBound(
        descriptor,
        formatter,
        channel);

Publish A Message¶

var message =
    new Message<OrderCreated>
    {
        Created = DateTime.UtcNow,
        Route = "orders.created",

        Data = new OrderCreated
        {
            OrderId = Guid.NewGuid(),
            CreatedAtUtc = DateTime.UtcNow
        }
    };

await publisher.SendAsync(message);

Complete Example¶

var factory = new ConnectionFactory
{
    HostName = "localhost",
    UserName = "guest",
    Password = "guest",
    DispatchConsumersAsync = true
};

using var connection =
    factory.CreateConnection("publisher-demo");

using var channel =
    connection.CreateChannel();

IDataFormatter formatter = ...;

var descriptor = new PublisherBoundDescriptor
{
    EnableChannelEvents = true,

    Exchanges =
    {
        new ExchangeBoundDescriptor
        {
            Name = "orders",
            Type = ExchangeTypes.Direct,
            Durable = true,

            Queues =
            {
                new QueueBoundDescriptor
                {
                    Name = "orders.created",
                    Durable = true,

                    Binder = new BinderDescriptor
                    {
                        RoutingKey = "orders.created"
                    }
                }
            }
        }
    }
};

await using var publisher =
    new PublisherBound(
        descriptor,
        formatter,
        channel);

await publisher.SendAsync(
    new Message<OrderCreated>
    {
        Created = DateTime.UtcNow,
        Route = "orders.created",

        Data = new OrderCreated
        {
            OrderId = Guid.NewGuid(),
            CreatedAtUtc = DateTime.UtcNow
        }
    });

Message Contract¶

public sealed class OrderCreated
{
    public Guid OrderId { get; init; }

    public DateTime CreatedAtUtc { get; init; }
}

Next Step¶

Continue with:

Create Subscriber, to consume messages from the queue.
Publishing, for advanced publishing scenarios.
Reference → PublisherBoundDescriptor, for a complete description of the publisher descriptor.