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