// Copyright (c) 2013, 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. import 'dart:async'; import 'dart:convert'; import 'dart:math'; import 'base_request.dart'; import 'byte_stream.dart'; import 'multipart_file.dart'; import 'utils.dart'; final RegExp _newlineRegExp = new RegExp(r"\r\n|\r|\n"); /// A `multipart/form-data` request. Such a request has both string [fields], /// which function as normal form fields, and (potentially streamed) binary /// [files]. /// /// This request automatically sets the Content-Type header to /// `multipart/form-data`. This value will override any value set by the user. /// /// var uri = Uri.parse("http://pub.dartlang.org/packages/create"); /// var request = new http.MultipartRequest("POST", url); /// request.fields['user'] = 'nweiz@google.com'; /// request.files.add(new http.MultipartFile.fromFile( /// 'package', /// new File('build/package.tar.gz'), /// contentType: new MediaType('application', 'x-tar')); /// request.send().then((response) { /// if (response.statusCode == 200) print("Uploaded!"); /// }); class MultipartRequest extends BaseRequest { /// The total length of the multipart boundaries used when building the /// request body. According to http://tools.ietf.org/html/rfc1341.html, this /// can't be longer than 70. static const int _BOUNDARY_LENGTH = 70; static final Random _random = new Random(); /// The form fields to send for this request. final Map<String, String> fields; /// The private version of [files]. final List<MultipartFile> _files; /// Creates a new [MultipartRequest]. MultipartRequest(String method, Uri url) : fields = <String, String>{}, _files = <MultipartFile>[], super(method, url); /// The list of files to upload for this request. List<MultipartFile> get files => _files; /// The total length of the request body, in bytes. This is calculated from /// [fields] and [files] and cannot be set manually. @override int get contentLength { int length = 0; fields.forEach((String name, String value) { length += "--".length + _BOUNDARY_LENGTH + "\r\n".length + UTF8.encode(_headerForField(name, value)).length + UTF8.encode(value).length + "\r\n".length; }); for (MultipartFile file in _files) { length += "--".length + _BOUNDARY_LENGTH + "\r\n".length + UTF8.encode(_headerForFile(file)).length + file.length + "\r\n".length; } return length + "--".length + _BOUNDARY_LENGTH + "--\r\n".length; } @override set contentLength(int value) { throw new UnsupportedError("Cannot set the contentLength property of " "multipart requests."); } /// Freezes all mutable fields and returns a single-subscription [ByteStream] /// that will emit the request body. @override ByteStream finalize() { // TODO(nweiz): freeze fields and files String boundary = _boundaryString(); headers['content-type'] = 'multipart/form-data; boundary="$boundary"'; super.finalize(); StreamController<List<int>> controller = new StreamController<List<int>>(sync: true); void writeAscii(String string) { controller.add(UTF8.encode(string)); } dynamic writeUtf8(String string) => controller.add(UTF8.encode(string)); dynamic writeLine() => controller.add(<int>[13, 10]); // \r\n fields.forEach((String name, String value) { writeAscii('--$boundary\r\n'); writeAscii(_headerForField(name, value)); writeUtf8(value); writeLine(); }); Future.forEach(_files, (MultipartFile file) { writeAscii('--$boundary\r\n'); writeAscii(_headerForFile(file)); return writeStreamToSink(file.finalize(), controller) .then((_) => writeLine()); }).then((_) { // TODO(nweiz): pass any errors propagated through this future on to // the stream. See issue 3657. writeAscii('--$boundary--\r\n'); controller.close(); }); return new ByteStream(controller.stream); } /// All character codes that are valid in multipart boundaries. From /// http://tools.ietf.org/html/rfc2046#section-5.1.1. static const List<int> _BOUNDARY_CHARACTERS = const <int>[ 39, 40, 41, 43, 95, 44, 45, 46, 47, 58, 61, 63, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122 ]; /// Returns the header string for a field. The return value is guaranteed to /// contain only ASCII characters. String _headerForField(String name, String value) { String header = 'content-disposition: form-data; name="${_browserEncode(name)}"'; if (!isPlainAscii(value)) { header = '$header\r\n' 'content-type: text/plain; charset=utf-8\r\n' 'content-transfer-encoding: binary'; } return '$header\r\n\r\n'; } /// Returns the header string for a file. The return value is guaranteed to /// contain only ASCII characters. String _headerForFile(MultipartFile file) { String header = 'content-type: ${file.contentType}\r\n' 'content-disposition: form-data; name="${_browserEncode(file.field)}"'; if (file.filename != null) { header = '$header; filename="${_browserEncode(file.filename)}"'; } return '$header\r\n\r\n'; } /// Encode [value] in the same way browsers do. String _browserEncode(String value) { // http://tools.ietf.org/html/rfc2388 mandates some complex encodings for // field names and file names, but in practice user agents seem not to // follow this at all. Instead, they URL-encode `\r`, `\n`, and `\r\n` as // `\r\n`; URL-encode `"`; and do nothing else (even for `%` or non-ASCII // characters). We follow their behavior. return value.replaceAll(_newlineRegExp, "%0D%0A").replaceAll('"', "%22"); } /// Returns a randomly-generated multipart boundary string String _boundaryString() { String prefix = "dart-http-boundary-"; List<int> list = new List<int>.generate(_BOUNDARY_LENGTH - prefix.length, (int index) => _BOUNDARY_CHARACTERS[_random.nextInt(_BOUNDARY_CHARACTERS.length)], growable: false); return "$prefix${new String.fromCharCodes(list)}"; } }