Handling events

Once an event is raised, it can be handled by a corresponding IConsumer to perform the desired action. The default consumer configuration can be customized by overriding the ConfigureConsumer method from the ConsumerDefinition interface. In the following example, an email is sent to the employee who has been assigned to an assignment:

Packages

Package	Link	Application in section
MassTransit		IConsumer

public class SendEmailToEmployeeOnEmployeeAssignedToAssignment
    : IConsumer<EmployeeAssignedToAssignment>
{
    private readonly IEmailSender emailSender;
    private readonly IRepository<Employee, EmployeeId> employees;
    private readonly IRepository<Assignment, AssignmentId> assignments;

    public SendEmailToEmployeeOnEmployeeAssignedToAssignment(
        IEmailSender emailSender,
        IRepository<Employee, EmployeeId> employees,
        IRepository<Assignment, AssignmentId> assignments)
    {
        this.emailSender = emailSender;
        this.employees = employees;
        this.assignments = assignments;
    }

    public async Task Consume(
        ConsumeContext<EmployeeAssignedToAssignment> context)
    {
        var msg = context.Message;

        var employee = await employees.FindAndEnsureExistsAsync(
            msg.EmployeeId,
            context.CancellationToken);

        var assignment = await assignments.FindAndEnsureExistsAsync(
            msg.AssignmentId,
            context.CancellationToken);

        await emailSender.SendEmployeeAssignedToAssignmentEmailAsync(
            employee,
            assignment,
            context.CancellationToken);
    }
}

Tip

More about consumers can be found here: MassTransit Consumers. To read how you can send this email using LeanCode CoreLibrary SendGrid integration visit here.