Updated README to notify users of Dart SDK version requirements.

lib/src/sync_http.dart

Index: lib/src/sync_http.dart
diff --git a/lib/src/sync_http.dart b/lib/src/sync_http.dart
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+// Copyright (c) 2017, 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.
+
+part of sync.http;
+
+/// A simple synchronous HTTP client.
+///
+/// This is a two-step process. When a [SyncHttpClientRequest] is returned the
+/// underlying network connection has been established, but no data has yet been
+/// sent. The HTTP headers and body can be set on the request, and close is
+/// called to send it to the server and get the [SyncHttpClientResponse].
+abstract class SyncHttpClient {
+  /// Send a GET request to the provided URL.
+  static SyncHttpClientRequest getUrl(Uri uri) =>
+      new SyncHttpClientRequest._('GET', uri, false);
+
+  /// Send a POST request to the provided URL.
+  static SyncHttpClientRequest postUrl(uri) =>
+      new SyncHttpClientRequest._('POST', uri, true);
+
+  /// Send a DELETE request to the provided URL.
+  static SyncHttpClientRequest deleteUrl(uri) =>
+      new SyncHttpClientRequest._('DELETE', uri, false);
+
+  /// Send a PUT request to the provided URL.
+  static SyncHttpClientRequest putUrl(uri) =>
+      new SyncHttpClientRequest._('PUT', uri, true);
+}
+
+/// HTTP request for a synchronous client connection.
+class SyncHttpClientRequest {
+  static const String _protocolVersion = '1.1';
+
+  /// The length of the request body. Is set to null when no body exists.
+  int get contentLength => hasBody ? _body.length : null;
+
+  HttpHeaders _headers;
+
+  /// The headers associated with the HTTP request.
+  HttpHeaders get headers {
+    if (_headers == null) {
+      _headers = new _SyncHttpClientRequestHeaders(this);
+    }
+    return _headers;
+  }
+
+  /// The type of HTTP request being made.
+  final String method;
+
+  /// The Uri the HTTP request will be sent to.
+  final Uri uri;
+
+  /// The default encoding for the HTTP request (UTF8).
+  final Encoding encoding = UTF8;
+
+  /// The body of the HTTP request. This can be empty if there is no body
+  /// associated with the request.
+  final BytesBuilder _body;
+
+  /// The synchronous socket used to initiate the HTTP request.
+  final RawSynchronousSocket _socket;
+
+  SyncHttpClientRequest._(this.method, Uri uri, bool body)
+      : this.uri = uri,
+        this._body = body ? new BytesBuilder() : null,
+        this._socket = RawSynchronousSocket.connectSync(uri.host, uri.port);
+
+  /// Write content into the body of the HTTP request.
+  void write(Object obj) {
+    if (hasBody) {
+      _body.add(encoding.encoder.convert(obj.toString()));
+    } else {
+      throw new StateError('write not allowed for method $method');
+    }
+  }
+
+  /// Specifies whether or not the HTTP request has a body.
+  bool get hasBody => _body != null;
+
+  /// Send the HTTP request and get the response.
+  SyncHttpClientResponse close() {
+    StringBuffer buffer = new StringBuffer();
+    buffer.write('$method ${uri.path} HTTP/$_protocolVersion\r\n');
+    headers.forEach((name, values) {
+      values.forEach((value) {
+        buffer.write('$name: $value\r\n');
+      });
+    });
+    buffer.write('\r\n');
+    if (hasBody) {
+      buffer.write(new String.fromCharCodes(_body.takeBytes()));
+    }
+    _socket.writeFromSync(buffer.toString().codeUnits);
+    return new SyncHttpClientResponse(_socket);
+  }
+}
+
+class _SyncHttpClientRequestHeaders implements HttpHeaders {
+  Map<String, List> _headers = <String, List<String>>{};
+
+  final SyncHttpClientRequest _request;
+  ContentType contentType;
+
+  _SyncHttpClientRequestHeaders(this._request);
+
+  @override
+  List<String> operator [](String name) {
+    switch (name) {
+      case HttpHeaders.ACCEPT_CHARSET:
+        return ['utf-8'];
+      case HttpHeaders.ACCEPT_ENCODING:
+        return ['identity'];
+      case HttpHeaders.CONNECTION:
+        return ['close'];
+      case HttpHeaders.CONTENT_LENGTH:
+        if (!_request.hasBody) {
+          return null;
+        }
+        return [contentLength.toString()];
+      case HttpHeaders.CONTENT_TYPE:
+        if (contentType == null) {
+          return null;
+        }
+        return [contentType.toString()];
+      case HttpHeaders.HOST:
+        return ['$host:$port'];
+      default:
+        var values = _headers[name];
+        if (values == null || values.isEmpty) {
+          return null;
+        }
+        return values.map((e) => e.toString()).toList(growable: false);
+    }
+  }
+
+  /// Add [value] to the list of values associated with header [name].
+  @override
+  void add(String name, Object value) {
+    switch (name) {
+      case HttpHeaders.ACCEPT_CHARSET:
+      case HttpHeaders.ACCEPT_ENCODING:
+      case HttpHeaders.CONNECTION:
+      case HttpHeaders.CONTENT_LENGTH:
+      case HttpHeaders.DATE:
+      case HttpHeaders.EXPIRES:
+      case HttpHeaders.IF_MODIFIED_SINCE:
+      case HttpHeaders.HOST:
+        throw new UnsupportedError('Unsupported or immutable property: $name');
+      case HttpHeaders.CONTENT_TYPE:
+        contentType = value;
+        break;
+      default:
+        if (_headers[name] == null) {
+          _headers[name] = [];
+        }
+        _headers[name].add(value);
+    }
+  }
+
+  /// Remove [value] from the list associated with header [name].
+  @override
+  void remove(String name, Object value) {
+    switch (name) {
+      case HttpHeaders.ACCEPT_CHARSET:
+      case HttpHeaders.ACCEPT_ENCODING:
+      case HttpHeaders.CONNECTION:
+      case HttpHeaders.CONTENT_LENGTH:
+      case HttpHeaders.DATE:
+      case HttpHeaders.EXPIRES:
+      case HttpHeaders.IF_MODIFIED_SINCE:
+      case HttpHeaders.HOST:
+        throw new UnsupportedError('Unsupported or immutable property: $name');
+      case HttpHeaders.CONTENT_TYPE:
+        if (contentType == value) {
+          contentType = null;
+        }
+        break;
+      default:
+        if (_headers[name] != null) {
+          _headers[name].remove(value);
+          if (_headers[name].isEmpty) {
+            _headers.remove(name);
+          }
+        }
+    }
+  }
+
+  /// Remove all headers associated with key [name].
+  @override
+  void removeAll(String name) {
+    switch (name) {
+      case HttpHeaders.ACCEPT_CHARSET:
+      case HttpHeaders.ACCEPT_ENCODING:
+      case HttpHeaders.CONNECTION:
+      case HttpHeaders.CONTENT_LENGTH:
+      case HttpHeaders.DATE:
+      case HttpHeaders.EXPIRES:
+      case HttpHeaders.IF_MODIFIED_SINCE:
+      case HttpHeaders.HOST:
+        throw new UnsupportedError('Unsupported or immutable property: $name');
+      case HttpHeaders.CONTENT_TYPE:
+        contentType = null;
+        break;
+      default:
+        _headers.remove(name);
+    }
+  }
+
+  /// Replace values associated with key [name] with [value].
+  @override
+  void set(String name, Object value) {
+    removeAll(name);
+    add(name, value);
+  }
+
+  /// Returns the values associated with key [name], if it exists, otherwise
+  /// returns null.
+  @override
+  String value(String name) {
+    var val = this[name];
+    if (val == null || val.isEmpty) {
+      return null;
+    } else if (val.length == 1) {
+      return val[0];
+    } else {
+      throw new HttpException('header $name has more than one value');
+    }
+  }
+
+  /// Iterates over all header key-value pairs and applies [f].
+  @override
+  void forEach(void f(String name, List<String> values)) {
+    var forEachFunc = (String name) {
+      var values = this[name];
+      if (values != null && values.isNotEmpty) {
+        f(name, values);
+      }
+    };
+
+    [
+      HttpHeaders.ACCEPT_CHARSET,
+      HttpHeaders.ACCEPT_ENCODING,
+      HttpHeaders.CONNECTION,
+      HttpHeaders.CONTENT_LENGTH,
+      HttpHeaders.CONTENT_TYPE,
+      HttpHeaders.HOST
+    ].forEach(forEachFunc);
+    _headers.keys.forEach(forEachFunc);
+  }
+
+  @override
+  bool get chunkedTransferEncoding => null;
+
+  @override
+  void set chunkedTransferEncoding(bool _chunkedTransferEncoding) {
+    throw new UnsupportedError('chunked transfer is unsupported');
+  }
+
+  @override
+  int get contentLength => _request.contentLength;
+
+  @override
+  void set contentLength(int _contentLength) {
+    throw new UnsupportedError('content length is automatically set');
+  }
+
+  @override
+  void set date(DateTime _date) {
+    throw new UnsupportedError('date is unsupported');
+  }
+
+  @override
+  DateTime get date => null;
+
+  @override
+  void set expires(DateTime _expires) {
+    throw new UnsupportedError('expires is unsupported');
+  }
+
+  @override
+  DateTime get expires => null;
+
+  @override
+  void set host(String _host) {
+    throw new UnsupportedError('host is automatically set');
+  }
+
+  @override
+  String get host => _request.uri.host;
+
+  @override
+  DateTime get ifModifiedSince => null;
+
+  @override
+  void set ifModifiedSince(DateTime _ifModifiedSince) {
+    throw new UnsupportedError('if modified since is unsupported');
+  }
+
+  @override
+  void noFolding(String name) {
+    throw new UnsupportedError('no folding is unsupported');
+  }
+
+  @override
+  bool get persistentConnection => false;
+
+  @override
+  void set persistentConnection(bool _persistentConnection) {
+    throw new UnsupportedError('persistence connections are unsupported');
+  }
+
+  @override
+  void set port(int _port) {
+    throw new UnsupportedError('port is automatically set');
+  }
+
+  @override
+  int get port => _request.uri.port;
+
+  /// Clear all header key-value pairs.
+  @override
+  void clear() {
+    contentType = null;
+    _headers.clear();
+  }
+}
+
+/// HTTP response for a client connection.
+class SyncHttpClientResponse {
+  /// The length of the body associated with the HTTP response.
+  int get contentLength => headers.contentLength;
+
+  /// The headers associated with the HTTP response.
+  final HttpHeaders headers;
+
+  /// A short textual description of the status code associated with the HTTP
+  /// response.
+  final String reasonPhrase;
+
+  /// The resulting HTTP status code associated with the HTTP response.
+  final int statusCode;
+
+  /// The body of the HTTP response.
+  final String body;
+
+  /// Creates an instance of [SyncHttpClientResponse] that contains the response
+  /// sent by the HTTP server over [socket].
+  factory SyncHttpClientResponse(RawSynchronousSocket socket) {
+    int statusCode;
+    String reasonPhrase;
+    StringBuffer body = new StringBuffer();
+    Map<String, List<String>> headers = {};
+
+    bool inHeader = false;
+    bool inBody = false;
+    int contentLength = 0;
+    int contentRead = 0;
+
+    void processLine(String line, int bytesRead, _LineDecoder decoder) {
+      if (inBody) {
+        body.write(line);
+        contentRead += bytesRead;
+      } else if (inHeader) {
+        if (line.trim().isEmpty) {
+          inBody = true;
+          if (contentLength > 0) {
+            decoder.expectedByteCount = contentLength;
+          }
+          return;
+        }
+        int separator = line.indexOf(':');
+        String name = line.substring(0, separator).toLowerCase().trim();
+        String value = line.substring(separator + 1).trim();
+        if (name == HttpHeaders.TRANSFER_ENCODING &&
+            value.toLowerCase() != 'identity') {
+          throw new UnsupportedError(
+              'only identity transfer encoding is accepted');
+        }
+        if (name == HttpHeaders.CONTENT_LENGTH) {
+          contentLength = int.parse(value);
+        }
+        if (!headers.containsKey(name)) {
+          headers[name] = [];
+        }
+        headers[name].add(value);
+      } else if (line.startsWith('HTTP/1.1') || line.startsWith('HTTP/1.0')) {
+        statusCode = int
+            .parse(line.substring('HTTP/1.x '.length, 'HTTP/1.x xxx'.length));
+        reasonPhrase = line.substring('HTTP/1.x xxx '.length);
+        inHeader = true;
+      } else {
+        throw new UnsupportedError('unsupported http response format');
+      }
+    }
+
+    var lineDecoder = new _LineDecoder.withCallback(processLine);
+
+    try {
+      while (!inHeader ||
+          !inBody ||
+          ((contentRead + lineDecoder.bufferedBytes) < contentLength)) {
+        var bytes = socket.readSync(1024);
+
+        if (bytes == null || bytes.length == 0) {
+          break;
+        }
+        lineDecoder.add(bytes);
+      }
+    } finally {
+      try {
+        lineDecoder.close();
+      } finally {
+        socket.closeSync();
+      }
+    }
+
+    return new SyncHttpClientResponse._(
+        reasonPhrase: reasonPhrase,
+        statusCode: statusCode,
+        body: body.toString(),
+        headers: headers);
+  }
+
+  SyncHttpClientResponse._(
+      {this.reasonPhrase, this.statusCode, this.body, headers})
+      : this.headers = new _SyncHttpClientResponseHeaders(headers);
+}
+
+class _SyncHttpClientResponseHeaders implements HttpHeaders {
+  final Map<String, List<String>> _headers;
+
+  _SyncHttpClientResponseHeaders(this._headers);
+
+  @override
+  List<String> operator [](String name) => _headers[name];
+
+  @override
+  void add(String name, Object value) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  bool get chunkedTransferEncoding => null;
+
+  @override
+  void set chunkedTransferEncoding(bool _chunkedTransferEncoding) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  int get contentLength {
+    String val = value(HttpHeaders.CONTENT_LENGTH);
+    if (val != null) {
+      return int.parse(val, onError: (_) => null);
+    }
+    return null;
+  }
+
+  @override
+  void set contentLength(int _contentLength) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  ContentType get contentType {
+    var val = value(HttpHeaders.CONTENT_TYPE);
+    if (val != null) {
+      return ContentType.parse(val);
+    }
+    return null;
+  }
+
+  @override
+  void set contentType(ContentType _contentType) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  void set date(DateTime _date) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  DateTime get date {
+    var val = value(HttpHeaders.DATE);
+    if (val != null) {
+      return DateTime.parse(val);
+    }
+    return null;
+  }
+
+  @override
+  void set expires(DateTime _expires) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  DateTime get expires {
+    var val = value(HttpHeaders.EXPIRES);
+    if (val != null) {
+      return DateTime.parse(val);
+    }
+    return null;
+  }
+
+  @override
+  void forEach(void f(String name, List<String> values)) => _headers.forEach(f);
+
+  @override
+  void set host(String _host) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  String get host {
+    var val = value(HttpHeaders.HOST);
+    if (val != null) {
+      return Uri.parse(val).host;
+    }
+    return null;
+  }
+
+  @override
+  DateTime get ifModifiedSince {
+    var val = value(HttpHeaders.IF_MODIFIED_SINCE);
+    if (val != null) {
+      return DateTime.parse(val);
+    }
+    return null;
+  }
+
+  @override
+  void set ifModifiedSince(DateTime _ifModifiedSince) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  void noFolding(String name) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  bool get persistentConnection => false;
+
+  @override
+  void set persistentConnection(bool _persistentConnection) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  void set port(int _port) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  int get port {
+    var val = value(HttpHeaders.HOST);
+    if (val != null) {
+      return Uri.parse(val).port;
+    }
+    return null;
+  }
+
+  @override
+  void remove(String name, Object value) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  void removeAll(String name) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  void set(String name, Object value) {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+
+  @override
+  String value(String name) {
+    var val = this[name];
+    if (val == null || val.isEmpty) {
+      return null;
+    } else if (val.length == 1) {
+      return val[0];
+    } else {
+      throw new HttpException('header $name has more than one value');
+    }
+  }
+
+  @override
+  void clear() {
+    throw new UnsupportedError('Response headers are immutable');
+  }
+}