In this blog post, we’ll explore into why cancellation tokens are indispensable in the context of ASP.NET Core and EF Core, and how they contribute to the overall performance and user experience of our applications.

Cancellation tokens are a powerful tool for managing asynchronous operations. At their core, they provide a mechanism to signal the cancellation of ongoing tasks, enabling developers to gracefully handle scenarios where responsiveness and performance are critical.

In the context of ASP.NET Core, cancellation tokens ensure that the web application remains responsive. When a user decides to navigate away from a page or cancel an ongoing request, cancellation tokens step in to gracefully halt any running processes. Consider a scenario where a user clicks a button to fetch data from the server. Without cancellation tokens, the application might continue waiting for the data, oblivious to the fact that the user has moved on. With cancellation tokens, the ongoing operation can be intelligently halted, freeing up resources and providing a smoother user experience. In case of Entity Framework (EF) Core, when dealing with database operations, some queries or updates can take a significant amount of time. Cancellation tokens come to the rescue here as well. They enable us to cancel a database operation if it’s taking too long, preventing the application from feeling sluggish or unresponsive.

As we start working with cancellation tokens, here are some best practices to keep in mind

• Integrate Cancellation Tokens Early: Incorporate cancellation tokens into code from the beginning to reap the benefits across the application.
• Graceful Degradation: Implement graceful degradation by handling cancellations appropriately. Provide users with feedback or alternative actions when they decide to cancel an operation.
• Error Handling: Be prepared to handle errors that might occur when a cancellation is requested. This ensures a smooth and error-free user experience.

Here is an example of Cancellation token implementation in Minimal API.

app.MapGet("/persons", async (BookstoreDbContext dbContext, CancellationToken cancellationToken) =>
{
    var persons = await dbContext.Persons.AsNoTracking()
        .ToListAsync(cancellationToken);
    return Results.Ok(persons);
});

In a nutshell, cancellation tokens are the unsung heroes of responsive and user-friendly ASP.NET Core and EF Core applications. By implementing them, we can empower the application to handle interruptions seamlessly, making for a smoother user experience.

Happy Programming.