Middleware, Validation, Dependency Injection, oh my!

[eandre]

We're excited to announce Encore now supports three of the most highly requested features: Middleware, Validation support, and Dependency Injection! Each one is large enough to warrant its own release but here's a three-for-one!

This means you can now:

• Define service-specific or global middleware to implement cross-cutting concerns spanning several endpoints
• Automatically validate incoming requests before invoking handlers
• Simplify testing of Encore APIs and services
• Hook into the service initialization and graceful shutdown process for custom logic

🥐 Run encore version update to grab the latest version, or read on for more information.

Encore Middleware

Middleware has been one of the most highly requested Encore features, and it's finally here! Unlike typical Go HTTP middleware, Encore's middleware operates on fully unmarshalled types which enables some incredible workflows. Here's how you define a middleware:

import (
    "encore.dev/middleware"
    "encore.dev/rlog"
)

//encore:middleware target=all
func MyMiddleware(req middleware.Request, next middleware.Next) middleware.Response {
    resp := next(req)
    rlog.Info("returning response", "payload", resp.Payload)
    return resp
}

See the middleware docs for more information!

Validation support

Encore now supports request validation out of the box! To use it, simplify define a Validate() error method on your request types. For example:

//encore:api public
func MyEndpoint(ctx context.Context, p *Params) error {
    // ...
}

type Params struct {
    Worry bool
}

func (p *Params) Validate() error {
    if p.Worry {
        return errors.New("don't worry, be happy")
    }
    return nil
}

See the validation docs for more information!

Dependency Injection

You can now define Encore APIs as methods on a Service Struct, which allows you to use dependency injection for easier testing of your Encore API endpoints. It introduces the new //encore:service directive that you can use to define a struct type as a Service Struct. It looks like this:

//encore:service
type Service struct { /* dependencies go here */ }

//encore:api public
func (s *Service) MyAPI(ctx context.Context) error { /* ... */ }

The new Service Struct approach also comes with several other features, like service initialization and graceful shutdown hooks!
Read the docs on Service Structs and
Dependency Injection for more information.

Bug fixes and other improvements

• Fixed a case where the runtime was not fully initialized for test-only packages using sqldb.Named (compiler: fix runtime init #335)
• Fixed trace viewer tooltip being difficult to hover into (Fix top offset for trace tooltip #332)
• Fixed encore.dev/docs keyboard shortcuts

Thanks to our contributors

We rely on the community to improve Encore, and we're overwhelmed by your support and encouragement. Thanks to @Willyham, @melkstam, @bjaanes, @Minivera, @davidmytton, @maxd and others for your feedback and contributions!

Join the most pioneering developer community

Developers building with Encore are forward-thinkers working on exciting and innovative products. Join the conversation on Slack to see what's going on, learn from others, and share what you're working on.

What's next

Over the coming weeks we'll be adding support for configuration, Azure Pub/Sub, caching, and more. Vote on your favorite feature on the roadmap!

If you like what we're up to, why not star Encore here on GitHub?

As always, if you have questions or feedback, tell us on Slack or just reply to this email.

We're excited to hear your feedback! ❤️

Catch you in the cloud,

The Encore Team

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