1 // 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 12 class GURL; 13 14 namespace 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 // 30 class 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_ 68
