Add new HttpMultipartFormData, used for parsing a MimeMultipart and extracting either text or binar…

sdk/lib/io/http_multipart_form_data_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.
+
+part of dart.io;
+
+
+class _HttpMultipartFormData extends Stream implements HttpMultipartFormData {
+  final ContentType contentType;
+  final HeaderValue contentDisposition;
+  final HeaderValue contentTransferEncoding;
+
+  final MimeMultipart _mimeMultipart;
+
+  bool _isText = false;
+
+  Stream _stream;
+
+  _HttpMultipartFormData(ContentType this.contentType,
+                         HeaderValue this.contentDisposition,
+                         HeaderValue this.contentTransferEncoding,
+                         MimeMultipart this._mimeMultipart) {
+    _stream = _mimeMultipart;
+    if (contentTransferEncoding != null) {
+      // TODO(ajohnsen): Support BASE64, etc.
+      throw new HttpException("Unsupported contentTransferEncoding: "
+                              "${contentTransferEncoding.value}");
+    }
+
+    if (contentType == null || contentType.primaryType == 'text') {
+      _isText = true;
+      StringBuffer buffer = new StringBuffer();
+      Encoding encoding;
+      if (contentType != null) {
+        encoding = Encoding.fromName(contentType.charset);
+      }
+      if (encoding == null) encoding = Encoding.ISO_8859_1;
+      _stream = _stream
+          .transform(new StringDecoder(encoding))
+          .expand((data) {
+            buffer.write(data);
+            var out = _HttpUtils.parseHttpEntityString(buffer.toString());
+            if (out != null) {
+              buffer = new StringBuffer();
+              return [out];
+            }
+            return const [];
+          });
+    }
+  }
+
+  bool get isText => _isText;
+  bool get isBinary => !_isText;
+
+  static HttpMultipartFormData parse(MimeMultipart multipart) {
+    var type;
+    var encoding;
+    var disposition;
+    var remaining = new Map<String, String>();
+    for (String key in multipart.headers.keys) {
+      switch (key) {
+        case HttpHeaders.CONTENT_TYPE:
+          type = ContentType.parse(multipart.headers[key]);
+          break;
+
+        case 'content-transfer-encoding':
+          encoding = HeaderValue.parse(multipart.headers[key]);
+          break;
+
+        case 'content-disposition':
+          disposition = HeaderValue.parse(multipart.headers[key]);
+          break;
+
+        default:
+          remaining[key] = multipart.headers[key];
+          break;
+      }
+    }
+    if (disposition == null) {
+      throw new HttpException(
+          "Mime Multipart doesn't contain a Content-Disposition header value");
+    }
+    return new _HttpMultipartFormData(type, disposition, encoding, multipart);
+  }
+
+  StreamSubscription listen(void onData(data),
+                            {void onDone(),
+                             void onError(error),
+                             bool cancelOnError}) {
+    return _stream.listen(onData,
+                          onDone: onDone,
+                          onError: onError,
+                          cancelOnError: cancelOnError);
+  }
+
+  String value(String name) {
+    return _mimeMultipart.headers[name];
+  }
+}
+