Middleware class abstract

Runs before a route's controller.

There are two ways to write one.

Override handle when the middleware only inspects or augments the request, and rejects by throwing. This is the common case:

class RequireApiKey extends Middleware {
  @override
  Future<void> handle(Request req) async {
    if (req.header('x-api-key') != expected) {
      throw Unauthenticated(message: 'Bad key');
    }
  }
}

Override process when the middleware needs to do something after the rest of the chain runs — timing, logging, adding a header that depends on the response — or to skip the chain entirely:

class Timing extends Middleware {
  @override
  Future<void> process(Request req, Next next) async {
    final started = DateTime.now();
    await next();
    final ms = DateTime.now().difference(started).inMilliseconds;
    req.response.headers.add('X-Duration-Ms', '$ms');
  }
}

Not calling next() stops the chain: no later middleware runs and the controller is not invoked. The middleware is then responsible for the response.

Overriding both is a mistake — process wins and handle is ignored.

Implementers

• SecurityHeaders
• Throttle

Constructors

Middleware()

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

handle(Request req) → Future<void>

Inspect or reject the request. Throw to abort the chain.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

process(Request req, Next next) → Future<void>

Wraps the rest of the chain.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited