pkgs/shelf_packages_handler/lib/shelf_packages_handler.dart

// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:shelf/shelf.dart';

import 'src/dir_handler.dart';
import 'src/package_config_handler.dart';

/// A handler that serves the contents of a virtual packages directory.
///
/// This effectively serves `package:${request.url}`. It locates packages using
/// the mapping defined by [packageMap]. If [packageMap] isn't passed, it
/// defaults to the current isolate's package resolution logic.
///
/// The [packageMap] maps package names to the base uri for resolving
/// `package:` uris for that package.
///
/// This can only serve assets from `file:` URIs.
Handler packagesHandler({Map<String, Uri>? packageMap}) =>
    PackageConfigHandler(packageMap: packageMap).handleRequest;

/// A handler that serves virtual `packages/` directories wherever they're
/// requested.
///
/// This serves the same assets as [packagesHandler] for every URL that contains
/// `/packages/`. Otherwise, it returns 404s for all requests.
///
/// This is useful for ensuring that `package:` imports work for all entrypoints
/// in Dartium.
Handler packagesDirHandler({Map<String, Uri>? packageMap}) =>
    DirHandler('packages', packagesHandler(packageMap: packageMap)).call;