| // 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:convert'; |
| import 'dart:math'; |
| |
| import 'base_request.dart'; |
| import 'boundary_characters.dart'; |
| import 'byte_stream.dart'; |
| import 'multipart_file.dart'; |
| import 'utils.dart'; |
| |
| final _newlineRegExp = 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('https://example.com/create'); |
| /// var request = http.MultipartRequest('POST', uri) |
| /// ..fields['user'] = 'nweiz@google.com' |
| /// ..files.add(await http.MultipartFile.fromPath( |
| /// 'package', 'build/package.tar.gz', |
| /// contentType: MediaType('application', 'x-tar'))); |
| /// var response = await request.send(); |
| /// 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 _boundaryLength = 70; |
| |
| static final Random _random = Random(); |
| |
| /// The form fields to send for this request. |
| final fields = <String, String>{}; |
| |
| /// The list of files to upload for this request. |
| final files = <MultipartFile>[]; |
| |
| MultipartRequest(String method, Uri url) : super(method, url); |
| |
| /// 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 { |
| var length = 0; |
| |
| fields.forEach((name, value) { |
| length += '--'.length + |
| _boundaryLength + |
| '\r\n'.length + |
| utf8.encode(_headerForField(name, value)).length + |
| utf8.encode(value).length + |
| '\r\n'.length; |
| }); |
| |
| for (var file in files) { |
| length += '--'.length + |
| _boundaryLength + |
| '\r\n'.length + |
| utf8.encode(_headerForFile(file)).length + |
| file.length + |
| '\r\n'.length; |
| } |
| |
| return length + '--'.length + _boundaryLength + '--\r\n'.length; |
| } |
| |
| @override |
| set contentLength(int? value) { |
| throw 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: freeze fields and files |
| final boundary = _boundaryString(); |
| headers['content-type'] = 'multipart/form-data; boundary=$boundary'; |
| super.finalize(); |
| return ByteStream(_finalize(boundary)); |
| } |
| |
| Stream<List<int>> _finalize(String boundary) async* { |
| const line = [13, 10]; // \r\n |
| final separator = utf8.encode('--$boundary\r\n'); |
| final close = utf8.encode('--$boundary--\r\n'); |
| |
| for (var field in fields.entries) { |
| yield separator; |
| yield utf8.encode(_headerForField(field.key, field.value)); |
| yield utf8.encode(field.value); |
| yield line; |
| } |
| |
| for (final file in files) { |
| yield separator; |
| yield utf8.encode(_headerForFile(file)); |
| yield* file.finalize(); |
| yield line; |
| } |
| yield close; |
| } |
| |
| /// Returns the header string for a field. |
| /// |
| /// The return value is guaranteed to contain only ASCII characters. |
| String _headerForField(String name, String value) { |
| var header = |
| 'content-disposition: form-data; name="${_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) { |
| var 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 '$header\r\n\r\n'; |
| } |
| |
| /// Encode [value] in the same way browsers do. |
| String _browserEncode(String value) => |
| // http://tools.ietf.org/html/rfc2388 mandates some complex encodings for |
| // field names and file names, but in practice user agents seem not to |
| // follow this at all. Instead, they URL-encode `\r`, `\n`, and `\r\n` as |
| // `\r\n`; URL-encode `"`; and do nothing else (even for `%` or non-ASCII |
| // characters). We follow their behavior. |
| value.replaceAll(_newlineRegExp, '%0D%0A').replaceAll('"', '%22'); |
| |
| /// Returns a randomly-generated multipart boundary string |
| String _boundaryString() { |
| var prefix = 'dart-http-boundary-'; |
| var list = List<int>.generate( |
| _boundaryLength - prefix.length, |
| (index) => |
| boundaryCharacters[_random.nextInt(boundaryCharacters.length)], |
| growable: false); |
| return '$prefix${String.fromCharCodes(list)}'; |
| } |
| } |