Add implementations for Headers, Request, Response and dart:io/dart:html clients to http_base

dart/pkg/http_base/lib/http_base_html.dart

+library http_base.http_base_html;
+
+import 'dart:html';
+import 'dart:async';
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'http_base.dart';
+export 'http_base.dart';
+
+/// The following headers will be blocked by browsers. See:
+/// http://www.w3.org/TR/XMLHttpRequest/
+const List<String> _BLOCKED_HEADERS = const [
+    'accept-charset', 'accept-encoding', 'access-control-request-headers',
+    'access-control-request-method', 'connection', 'content-length', 'cookie',
+    'cookie2', 'date', 'dnt', 'expect', 'host', 'keep-alive', 'origin',
+    'referer', 'te', 'trailer', 'transfer-encoding', 'upgrade', 'user-agent',
+    'via'];
+
+/// An implementation for [RequestHandler]. It uses dart:html to make http
+/// requests.
+class Client {
+  Future<Response> call(Request request) {
+    return _bufferData(request.read()).then((Uint8List data) {
+      var url = request.url.toString();
+      return _request(url, request.method, request.headers, data).then((xhr) {
+        var headers = HeadersImpl.Empty.replace(xhr.responseHeaders);
+        var body = _readResponse(xhr);
+        return new ResponseImpl(xhr.status, headers: headers, body: body);
+      });
+    });
+  }
+
+  Future<Uint8List> _bufferData(Stream<List<int>> stream) {
+    int size = 0;
+
+    return stream.fold([], (buffer, data) {
+      size += data.length;
+      return buffer..add(data);
+    }).then((List<List<int>> buffer) {
+      if (size > 0) {
+        var data;
+        if (buffer.length == 0 && buffer[0] is Uint8List) {
+          data = buffer[0];
+        } else {
+          data = new Uint8List(size);
+          int offset = 0;
+          for (var bytes in buffer) {
+            var end = offset + bytes.length;
+            data.setRange(offset, end, bytes);
+            offset = end;
+          }
+        }
+        return data;
+      }
+      return null;
+    });
+  }
+
+  Future<HttpRequest> _request(String url,
+                               String method,
+                               Headers headers,
+                               Uint8List sendData) {
+    var completer = new Completer<HttpRequest>();
+
+    var xhr = new HttpRequest();
+    xhr.open(method, url, async: true);
+
+    // Maybe we should use 'arraybuffer' instead?
+    xhr.responseType = 'blob';
+
+    // TODO: Special case Cookie/Set-Cookie here!
+    for (var name in headers.names) {
+      xhr.setRequestHeader(name, headers[name]);
+    }
+
+    xhr.onLoad.first.then((_) => completer.complete(xhr));
+    xhr.onError.first.then(completer.completeError);
+    xhr.send(sendData);
+
+    return completer.future;
+  }
+
+  Stream<List<int>> _readResponse(HttpRequest request) {
+    var controller = new StreamController<List<int>>();
+
+    var data = request.response;
+    assert (data is Blob);
+
+    var reader = new FileReader();
+    reader.onLoad.first.then((_) {
+      controller.add(reader.result);
+      controller.close();
+    });
+    reader.readAsArrayBuffer(data);
+
+    return controller.stream;
+  }
+}