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James Robinson646469d2014-10-03 15:33:28 -07001// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef NET_BASE_DATA_URL_H_
6#define NET_BASE_DATA_URL_H_
7
8#include <string>
9
10#include "net/base/net_export.h"
11
12class GURL;
13
14namespace net {
15
16// See RFC 2397 for a complete description of the 'data' URL scheme.
17//
18// Briefly, a 'data' URL has the form:
19//
20// data:[<mediatype>][;base64],<data>
21//
22// The <mediatype> is an Internet media type specification (with optional
23// parameters.) The appearance of ";base64" means that the data is encoded as
24// base64. Without ";base64", the data (as a sequence of octets) is represented
25// using ASCII encoding for octets inside the range of safe URL characters and
26// using the standard %xx hex encoding of URLs for octets outside that range.
27// If <mediatype> is omitted, it defaults to text/plain;charset=US-ASCII. As a
28// shorthand, "text/plain" can be omitted but the charset parameter supplied.
29//
30class NET_EXPORT DataURL {
31 public:
32 // This method can be used to parse a 'data' URL into its component pieces.
33 //
34 // The resulting mime_type is normalized to lowercase. The data is the
35 // decoded data (e.g.., if the data URL specifies base64 encoding, then the
36 // returned data is base64 decoded, and any %-escaped bytes are unescaped).
37 //
38 // If the media type value doesn't match the media-type production defined in
39 // RFC 7231, mime_type will be set to the default value "text/plain". We
40 // don't simply fail for this grammar violation since Chromium had been
41 // accepting such invalid values. For example, <img> element with the src
42 // attribute set to a data URL with an invalid media type "image" (without a
43 // slash and subtype) had been displayed. However, the value this method will
44 // store in mime_type argument can be used for generating other headers, etc.
45 // This could lead to security vulnerability. We don't want to accept
46 // arbitrary value and ask each caller to validate the return value.
47 //
48 // If the charset parameter is specified but its value doesn't match the
49 // token production defined in RFC 7230, this method simply fails and returns
50 // false.
51 //
52 // If there's any other grammar violation in the URL, then this method will
53 // return false. Output variables may be changed and contain invalid data. On
54 // success, true is returned.
55 //
56 // OPTIONAL: If |data| is NULL, then the <data> section will not be parsed
57 // or validated.
58 //
59 static bool Parse(const GURL& url,
60 std::string* mime_type,
61 std::string* charset,
62 std::string* data);
63};
64
65} // namespace net
66
67#endif // NET_BASE_DATA_URL_H_