Add an HTTP library that wraps dart:io.

pkg/http/lib/src/utils.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.
+
+library utils;
+
+import 'dart:io';
+import 'dart:isolate';
+import 'dart:scalarlist';
+import 'dart:uri';
+
+/// Converts a URL query string (or `application/x-www-form-urlencoded` body)
+/// into a [Map] from parameter names to values.
+///
+///     queryToMap("foo=bar&baz=bang&qux");
+///     //=> {"foo": "bar", "baz": "bang", "qux": ""}
+Map<String, String> queryToMap(String queryList) {
+  var map = <String>{};
+  for (var pair in queryList.split("&")) {
+    var split = split1(pair, "=");
+    if (split.isEmpty) continue;
+    var key = urlDecode(split[0]);
+    var value = urlDecode(split.length > 1 ? split[1] : "");
+    map[key] = value;
+  }
+  return map;
+}
+
+/// Converts a [Map] from parameter names to values to a URL query string.
+///
+///     mapToQuery({"foo": "bar", "baz": "bang"});
+///     //=> "foo=bar&baz=bang"
+String mapToQuery(Map<String, String> map) {
+  var pairs = <List<String>>[];
+  map.forEach((key, value) =>
+      pairs.add([encodeUriComponent(key), encodeUriComponent(value)]));
+  return Strings.join(pairs.map((pair) => "${pair[0]}=${pair[1]}"), "&");
+}
+
+/// Adds all key/value pairs from [source] to [destination], overwriting any
+/// pre-existing values.
+///
+///     var a = {"foo": "bar", "baz": "bang"};
+///     mapAddAll(a, {"baz": "zap", "qux": "quux"});
+///     a; //=> {"foo": "bar", "baz": "zap", "qux": "quux"}
+void mapAddAll(Map destination, Map source) =>
+  source.forEach((key, value) => destination[key] = value);
+
+/// Decodes a URL-encoded string. Unlike [decodeUriComponent], this includes
+/// replacing `+` with ` `.
+String urlDecode(String encoded) =>
+  decodeUriComponent(encoded.replaceAll("+", " "));
+
+/// Like [String.split], but only splits on the first occurrence of the pattern.
+/// This will always return an array of two elements or fewer.
+///
+///     split1("foo,bar,baz", ","); //=> ["foo", "bar,baz"]
+///     split1("foo", ","); //=> ["foo"]
+///     split1("", ","); //=> []
+List<String> split1(String toSplit, String pattern) {
+  if (toSplit.isEmpty) return <String>[];
+
+  var index = toSplit.indexOf(pattern);
+  if (index == -1) return [toSplit];
+  return [
+    toSplit.substring(0, index),
+    toSplit.substring(index + pattern.length)
+  ];
+}
+
+/// Returns the [Encoding] that corresponds to [charset]. Returns
+/// [Encoding.ISO_8859_1] if [charset] is null or if no [Encoding] was found
+/// that corresponds to [charset].
+Encoding encodingForCharset(String charset) {
+  if (charset == null) return Encoding.ISO_8859_1;
+  var encoding = _encodingForCharset(charset);
+  return encoding == null ? Encoding.ISO_8859_1 : encoding;
+}
+
+/// Returns the [Encoding] that corresponds to [charset]. Throws a [FormatException]
+/// if no [Encoding] was found that corresponds to [charset]. [charset] may not
+/// be null.
+Encoding requiredEncodingForCharset(String charset) {
+  var encoding = _encodingForCharset(charset);
+  if (encoding != null) return encoding;
+  throw new FormatException('Unsupported encoding "$charset".');
+}
+
+/// Returns the [Encoding] that corresponds to [charset]. Returns null if no
+/// [Encoding] was found that corresponds to [charset]. [charset] may not be
+/// null.
+Encoding _encodingForCharset(String charset) {
+  charset = charset.toLowerCase();
+  if (charset == 'ascii' || charset == 'us-ascii') return Encoding.ASCII;
+  if (charset == 'utf-8') return Encoding.UTF_8;
+  if (charset == 'iso-8859-1') return Encoding.ISO_8859_1;
+  return null;
+}
+
+/// Converts [bytes] into a [String] according to [encoding].
+String decodeString(List<int> bytes, Encoding encoding) {
+  // TODO(nweiz): implement this once issue 6284 is fixed.
+  return new String.fromCharCodes(bytes);
+}
+
+/// Converts [string] into a byte array according to [encoding].
+List<int> encodeString(String string, Encoding encoding) {
+  // TODO(nweiz): implement this once issue 6284 is fixed.
+  return string.charCodes;
+}
+
+/// Converts [input] into a [Uint8List]. If [input] is a [ByteArray] or
+/// [ByteArrayViewable], this just returns a view on [input].
+Uint8List toUint8List(List<int> input) {
+  if (input is Uint8List) return input;
+  if (input is ByteArrayViewable) input = input.asByteArray();
+  if (input is ByteArray) return new Uint8List.view(input);
+  var output = new Uint8List(input.length);
+  output.setRange(0, input.length, input);
+  return output;
+}
+
+/// Buffers all input from an InputStream and returns it as a future.
+Future<List<int>> consumeInputStream(InputStream stream) {
+  var completer = new Completer<List<int>>();
+  /// TODO(nweiz): use BufferList when issue 6409 is fixed
+  var buffer = <int>[];
+  stream.onClosed = () => completer.complete(buffer);
+  stream.onData = () => buffer.addAll(stream.read());
+  stream.onError = completer.completeException;
+  return completer.future;
+}
+
+/// Takes all input from [source] and writes it to [sink].
+void pipeInputToInput(InputStream source, ListInputStream sink) {
+  source.onClosed = () => sink.markEndOfStream();
+  source.onData = () => sink.write(source.read());
+  // TODO(nweiz): propagate source errors to the sink. See issue 3657.
+}
+
+/// Returns a [Future] that asynchronously completes to `null`.
+Future get async {
+  var completer = new Completer();
+  new Timer(0, (_) => completer.complete(null));
+  return completer.future;
+}