1 // Copyright (c) 2012 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 // NOTE: based loosely on mozilla's nsDataChannel.cpp 6 7 #include <algorithm> 8 9 #include "net/base/data_url.h" 10 11 #include "base/base64.h" 12 #include "base/basictypes.h" 13 #include "base/strings/string_split.h" 14 #include "base/strings/string_util.h" 15 #include "net/base/escape.h" 16 #include "net/base/mime_util.h" 17 #include "url/gurl.h" 18 19 namespace net { 20 21 // static 22 bool DataURL::Parse(const GURL& url, std::string* mime_type, 23 std::string* charset, std::string* data) { 24 DCHECK(mime_type->empty()); 25 DCHECK(charset->empty()); 26 std::string::const_iterator begin = url.spec().begin(); 27 std::string::const_iterator end = url.spec().end(); 28 29 std::string::const_iterator after_colon = std::find(begin, end, ':'); 30 if (after_colon == end) 31 return false; 32 ++after_colon; 33 34 std::string::const_iterator comma = std::find(after_colon, end, ','); 35 if (comma == end) 36 return false; 37 38 std::vector<std::string> meta_data; 39 std::string unparsed_meta_data(after_colon, comma); 40 base::SplitString(unparsed_meta_data, ';', &meta_data); 41 42 std::vector<std::string>::iterator iter = meta_data.begin(); 43 if (iter != meta_data.end()) { 44 mime_type->swap(*iter); 45 StringToLowerASCII(mime_type); 46 ++iter; 47 } 48 49 static const char kBase64Tag[] = "base64"; 50 static const char kCharsetTag[] = "charset="; 51 const size_t kCharsetTagLength = arraysize(kCharsetTag) - 1; 52 53 bool base64_encoded = false; 54 for (; iter != meta_data.end(); ++iter) { 55 if (!base64_encoded && *iter == kBase64Tag) { 56 base64_encoded = true; 57 } else if (charset->empty() && 58 iter->compare(0, kCharsetTagLength, kCharsetTag) == 0) { 59 charset->assign(iter->substr(kCharsetTagLength)); 60 } 61 } 62 63 if (mime_type->empty()) { 64 // fallback to defaults if nothing specified in the URL: 65 mime_type->assign("text/plain"); 66 } else if (!ParseMimeTypeWithoutParameter(*mime_type, NULL, NULL)) { 67 return false; 68 } 69 if (charset->empty()) 70 charset->assign("US-ASCII"); 71 72 // The caller may not be interested in receiving the data. 73 if (!data) 74 return true; 75 76 // Preserve spaces if dealing with text or xml input, same as mozilla: 77 // https://bugzilla.mozilla.org/show_bug.cgi?id=138052 78 // but strip them otherwise: 79 // https://bugzilla.mozilla.org/show_bug.cgi?id=37200 80 // (Spaces in a data URL should be escaped, which is handled below, so any 81 // spaces now are wrong. People expect to be able to enter them in the URL 82 // bar for text, and it can't hurt, so we allow it.) 83 std::string temp_data = std::string(comma + 1, end); 84 85 // For base64, we may have url-escaped whitespace which is not part 86 // of the data, and should be stripped. Otherwise, the escaped whitespace 87 // could be part of the payload, so don't strip it. 88 if (base64_encoded) { 89 temp_data = UnescapeURLComponent(temp_data, 90 UnescapeRule::SPACES | UnescapeRule::URL_SPECIAL_CHARS | 91 UnescapeRule::CONTROL_CHARS); 92 } 93 94 // Strip whitespace. 95 if (base64_encoded || !(mime_type->compare(0, 5, "text/") == 0 || 96 mime_type->find("xml") != std::string::npos)) { 97 temp_data.erase(std::remove_if(temp_data.begin(), temp_data.end(), 98 IsAsciiWhitespace<wchar_t>), 99 temp_data.end()); 100 } 101 102 if (!base64_encoded) { 103 temp_data = UnescapeURLComponent(temp_data, 104 UnescapeRule::SPACES | UnescapeRule::URL_SPECIAL_CHARS | 105 UnescapeRule::CONTROL_CHARS); 106 } 107 108 if (base64_encoded) { 109 size_t length = temp_data.length(); 110 size_t padding_needed = 4 - (length % 4); 111 // If the input wasn't padded, then we pad it as necessary until we have a 112 // length that is a multiple of 4 as required by our decoder. We don't 113 // correct if the input was incorrectly padded. If |padding_needed| == 3, 114 // then the input isn't well formed and decoding will fail with or without 115 // padding. 116 if ((padding_needed == 1 || padding_needed == 2) && 117 temp_data[length - 1] != '=') { 118 temp_data.resize(length + padding_needed, '='); 119 } 120 return base::Base64Decode(temp_data, data); 121 } 122 123 temp_data.swap(*data); 124 return true; 125 } 126 127 } // namespace net 128