Make MultipartRequest more closely adhere to browsers' behavior.

pkg/http/lib/src/multipart_request.dart

 // 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.
 
 library multipart_request;
 
 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 _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` and the Content-Transfer-Encoding header to `binary`.
 /// These values will override any values set by the user.
 ///
 ///     var uri = Uri.parse("http://pub.dartlang.org/packages/create");
 ///     var request = new http.MultipartRequest("POST", url);
@@ skipping 28 matching lines @@
   /// 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.
   int get contentLength {
     var length = 0;
 
     fields.forEach((name, value) {
       length += "--".length + _BOUNDARY_LENGTH + "\r\n".length +
-          _headerForField(name, value).length +
+          UTF8.encode(_headerForField(name, value)).length +
           UTF8.encode(value).length + "\r\n".length;
     });
 
     for (var file in _files) {
       length += "--".length + _BOUNDARY_LENGTH + "\r\n".length +
-          _headerForFile(file).length +
+          UTF8.encode(_headerForFile(file)).length +
           file.length + "\r\n".length;
     }
 
     return length + "--".length + _BOUNDARY_LENGTH + "--\r\n".length;
   }
 
   void 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.
   ByteStream finalize() {
     // TODO(nweiz): freeze fields and files
     var boundary = _boundaryString();
     headers['content-type'] = 'multipart/form-data; boundary="$boundary"';
     headers['content-transfer-encoding'] = 'binary';
     super.finalize();
 
     var controller = new StreamController<List<int>>(sync: true);
 
     void writeAscii(String string) {
-      assert(isPlainAscii(string));
-      controller.add(string.codeUnits);
+      controller.add(UTF8.encode(string));
     }
 
     writeUtf8(String string) => controller.add(UTF8.encode(string));
     writeLine() => controller.add([13, 10]); // \r\n
 
     fields.forEach((name, value) {
       writeAscii('--$boundary\r\n');
       writeAscii(_headerForField(name, value));
       writeUtf8(value);
       writeLine();
@@ skipping 20 matching lines @@
     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) {
-    // http://tools.ietf.org/html/rfc2388 mandates some complex encodings for
-    // field names and file names, but in practice user agents seem to just
-    // URL-encode them so we do the same.
     var header =
-        'content-disposition: form-data; name="${Uri.encodeFull(name)}"';
+        'content-disposition: form-data; name="${_browserEncode(name)}"';
     if (!isPlainAscii(value)) {
       header = '$header\r\ncontent-type: text/plain; charset=utf-8';
     }
     return '$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: ${file.contentType}\r\n'
-      'content-disposition: form-data; name="${Uri.encodeFull(file.field)}"';
+      'content-disposition: form-data; name="${_browserEncode(file.field)}"';
 
     if (file.filename != null) {
-      header = '$header; filename="${Uri.encodeFull(file.filename)}"';
+      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 thing else (even for `%` or non-ASCII

[Bob Nystrom, 2014/04/01 19:45:26]

thing -> nothing.

[nweiz, 2014/04/02 01:09:44]

Done.

+    // characters). We follow their behavior.
+    return value.replaceAll(_newlineRegExp, "%0D%0A").replaceAll('"', "%22");
+  }
+
   /// Returns a randomly-generated multipart boundary string
   String _boundaryString() {
     var prefix = "dart-http-boundary-";
     var list = new List<int>.generate(_BOUNDARY_LENGTH - prefix.length,
         (index) =>
             _BOUNDARY_CHARACTERS[_random.nextInt(_BOUNDARY_CHARACTERS.length)],
         growable: false);
     return "$prefix${new String.fromCharCodes(list)}";
   }
 }