| // Copyright (c) 2014, 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. |
| |
| library shelf.message; |
| |
| import 'dart:async'; |
| import 'dart:collection'; |
| import 'dart:convert'; |
| |
| // TODO(kevmoo): use UnmodifiableMapView from SDK once 1.4 ships |
| import 'package:collection/wrappers.dart' as pc; |
| import 'package:http_parser/http_parser.dart'; |
| import 'package:stack_trace/stack_trace.dart'; |
| |
| /// Represents logic shared between [Request] and [Response]. |
| abstract class Message { |
| /// The HTTP headers. |
| /// |
| /// The value is immutable. |
| final Map<String, String> headers; |
| |
| /// The streaming body of the message. |
| /// |
| /// This can be read via [read] or [readAsString]. |
| final Stream<List<int>> _body; |
| |
| /// Creates a new [Message]. |
| /// |
| /// If [headers] is `null`, it is treated as empty. |
| Message(this._body, {Map<String, String> headers}) |
| : this.headers = _getIgnoreCaseMapView(headers); |
| |
| /// The contents of the content-length field in [headers]. |
| /// |
| /// If not set, `null`. |
| int get contentLength { |
| if (_contentLengthCache != null) return _contentLengthCache; |
| if (!headers.containsKey('content-length')) return null; |
| _contentLengthCache = int.parse(headers['content-length']); |
| return _contentLengthCache; |
| } |
| int _contentLengthCache; |
| |
| /// The MIME type of the message. |
| /// |
| /// This is parsed from the Content-Type header in [headers]. It contains only |
| /// the MIME type, without any Content-Type parameters. |
| /// |
| /// If [headers] doesn't have a Content-Type header, this will be `null`. |
| String get mimeType { |
| var contentType = _contentType; |
| if (contentType == null) return null; |
| return contentType.mimeType; |
| } |
| |
| /// The encoding of the message body. |
| /// |
| /// This is parsed from the "charset" paramater of the Content-Type header in |
| /// [headers]. |
| /// |
| /// If [headers] doesn't have a Content-Type header or it specifies an |
| /// encoding that [dart:convert] doesn't support, this will be `null`. |
| Encoding get encoding { |
| var contentType = _contentType; |
| if (contentType == null) return null; |
| if (!contentType.parameters.containsKey('charset')) return null; |
| return Encoding.getByName(contentType.parameters['charset']); |
| } |
| |
| /// The parsed version of the Content-Type header in [headers]. |
| /// |
| /// This is cached for efficient access. |
| MediaType get _contentType { |
| if (_contentTypeCache != null) return _contentTypeCache; |
| if (!headers.containsKey('content-type')) return null; |
| _contentTypeCache = new MediaType.parse(headers['content-type']); |
| return _contentTypeCache; |
| } |
| MediaType _contentTypeCache; |
| |
| /// Returns a [Stream] representing the body. |
| /// |
| /// Can only be called once. |
| Stream<List<int>> read() => _body; |
| |
| /// Returns a [Future] containing the body as a String. |
| /// |
| /// If [encoding] is passed, that's used to decode the body. |
| /// Otherwise the encoding is taken from the Content-Type header. If that |
| /// doesn't exist or doesn't have a "charset" parameter, UTF-8 is used. |
| /// |
| /// This calls [read] internally, which can only be called once. |
| Future<String> readAsString([Encoding encoding]) { |
| if (encoding == null) encoding = this.encoding; |
| if (encoding == null) encoding = UTF8; |
| return Chain.track(encoding.decodeStream(read())); |
| } |
| } |
| |
| /// Creates on an unmodifiable map of [headers] with case-insensitive access. |
| Map<String, String> _getIgnoreCaseMapView(Map<String, String> headers) { |
| if (headers == null) return const {}; |
| // TODO(kevmoo) generalize this model with a 'canonical map' to align with |
| // similiar implementation in http pkg [BaseRequest]. |
| var map = new LinkedHashMap<String, String>( |
| equals: (key1, key2) => key1.toLowerCase() == key2.toLowerCase(), |
| hashCode: (key) => key.toLowerCase().hashCode); |
| |
| map.addAll(headers); |
| |
| return new pc.UnmodifiableMapView<String, String>(map); |
| } |