Add handling of HTTP header "Expires"

runtime/bin/http_impl.dart

 // Copyright (c) 2012, 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.
 
 // Utility class for encoding a string into UTF-8 byte stream.
 class _UTF8Encoder {
   static List<int> encodeString(String string) {
     int size = _encodingSize(string);
     ByteArray result = new ByteArray(size);
     _encodeString(string, result);
@@ skipping 43 matching lines @@
   _HttpRequestResponseBase(_HttpConnectionBase this._httpConnection)
       : _contentLength = -1,
         _keepAlive = false,
         _headers = new Map();
 
   int get contentLength() => _contentLength;
   bool get keepAlive() => _keepAlive;
   Map get headers() => _headers;
 
   void _setHeader(String name, String value) {
-    _headers[name] = value;
+    _headers[name.toLowerCase()] = value;
   }
 
   bool _write(List<int> data, bool copyBuffer) {
     bool allWritten = true;
     if (data.length > 0) {
       if (_contentLength < 0) {
         // Write chunk size if transfer encoding is chunked.
         _writeHexString(data.length);
         _writeCRLF();
         _httpConnection.outputStream.write(data, copyBuffer);
@@ skipping 198 matching lines @@
     if (_outputStream != null) throw new HttpException("Header already sent");
     _statusCode = statusCode;
   }
 
   String get reasonPhrase() => _findReasonPhrase(_statusCode);
   void set reasonPhrase(String reasonPhrase) {
     if (_outputStream != null) throw new HttpException("Header already sent");
     _reasonPhrase = reasonPhrase;
   }
 
+  Date get expires() => _expires;
+  void set expires(Date expires) {
+    if (_outputStream != null) throw new HttpException("Header already sent");
+    _expires = expires;
+    // Format "Expires" header with date in Greenwich Mean Time (GMT).
+    String formatted =
+        _HttpUtils.formatDate(_expires.changeTimeZone(new TimeZone.utc()));
+    _setHeader("Expires", formatted);
+  }
+
   // Set a header on the response. NOTE: If the same header is set
   // more than once only the last one will be part of the response.
   void setHeader(String name, String value) {
     if (_outputStream != null) return new HttpException("Header already sent");
-    _setHeader(name, value);
+    if (name.toLowerCase() == "expires") {
+      expires = _HttpUtils.parseDate(value);
+    } else {
+      _setHeader(name, value);
+    }
   }
 
   OutputStream get outputStream() {
     if (_state == DONE) throw new HttpException("Response closed");
     if (_outputStream == null) {
       // Ensure that headers are written.
       if (_state == START) {
         _writeHeader();
       }
       _outputStream = new _HttpOutputStream(this);
@@ skipping 126 matching lines @@
 
     // Write headers.
     bool allWritten = _writeHeaders();
     _state = HEADERS_SENT;
     return allWritten;
   }
 
   // Response status code.
   int _statusCode;
   String _reasonPhrase;
+  Date _expires;
   _HttpOutputStream _outputStream;
   int _state;
 }
 
 
 class _HttpInputStream extends _BaseDataInputStream implements InputStream {
   _HttpInputStream(_HttpRequestResponseBase this._requestOrResponse) {
     _checkScheduleCallbacks();
   }
 
@@ skipping 315 matching lines @@
       if (_state == START) {
         _writeHeader();
       }
       _outputStream = new _HttpOutputStream(this);
     }
     return _outputStream;
   }
 
   _updateHostHeader() {
     String portPart = _port == HttpClient.DEFAULT_HTTP_PORT ? "" : ":$_port";
-    _setHeader("host", "$host$portPart");
+    _setHeader("Host", "$host$portPart");
   }
 
   // Delegate functions for the HttpOutputStream implementation.
   bool _streamWrite(List<int> buffer, bool copyBuffer) {
     return _write(buffer, copyBuffer);
   }
 
   bool _streamWriteFrom(List<int> buffer, int offset, int len) {
     return _writeList(buffer, offset, len);
   }
@@ skipping 68 matching lines @@
 class _HttpClientResponse
     extends _HttpRequestResponseBase implements HttpClientResponse {
   _HttpClientResponse(_HttpClientConnection connection)
       : super(connection) {
     _connection = connection;
   }
 
   int get statusCode() => _statusCode;
   String get reasonPhrase() => _reasonPhrase;
 
+  Date get expires() {
+    String str = _headers["expires"];
+    if (str == null) return null;
+    return _HttpUtils.parseDate(str);
+  }
+
+  Map get headers() => _headers;
+
   InputStream get inputStream() {
     if (_inputStream == null) {
       _inputStream = new _HttpInputStream(this);
     }
     return _inputStream;
   }
 
   void _onRequestStart(String method, String uri) {
     // TODO(sgjesse): Error handling
   }
@@ skipping 291 matching lines @@
     _onError = callback;
   }
 
   Function _onOpen;
   Function _onError;
   Map<String, Queue<_SocketConnection>> _openSockets;
   Set<_SocketConnection> _activeSockets;
   Timer _evictionTimer;
   bool _shutdown;  // Has this HTTP client been shutdown?
 }