FilterChain class abstract interface

Represents a chain of filters through which an HTTP request and response pass before reaching the final handler.

Each filter in the chain can:

• Inspect or modify the request and response
• Perform cross-cutting concerns (logging, authentication, validation, etc.)
• Short-circuit the request by not calling the next element in the chain

Calling next passes control to the next filter in the chain. If no filters remain, the request proceeds to the target handler.

Example

class LoggingFilter implements Filter {
  @override
  Future<void> doFilter(ServerHttpRequest request, ServerHttpResponse response, FilterChain chain) async {
    print("Request URI: ${request.getRequestURI()}");
    await chain.next(request, response); // continue the chain
    print("Response status: ${response.getStatus()}");
  }
}

class SecurityFilter extends OncePerRequestFilter {
  @override
  Future<void> doFilterInternal(ServerHttpRequest request, ServerHttpResponse response, FilterChain chain) async {
    if (!request.hasValidToken()) {
      response.setStatus(HttpStatus.UNAUTHORIZED);
      return; // short-circuit
    }
    await chain.next(request, response);
  }
}

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

next(ServerHttpRequest request, ServerHttpResponse response) → Future<void>

Passes control to the next filter in the chain.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited