Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 1 | #pragma once |
| 2 | |
Ed Tanous | 3ccb3ad | 2023-01-13 17:40:03 -0800 | [diff] [blame] | 3 | #include "http_request.hpp" |
| 4 | |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 5 | #include <boost/beast/http/fields.hpp> |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 6 | |
Ed Tanous | 3544d2a | 2023-08-06 18:12:20 -0700 | [diff] [blame] | 7 | #include <ranges> |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 8 | #include <string> |
| 9 | #include <string_view> |
| 10 | |
| 11 | enum class ParserError |
| 12 | { |
| 13 | PARSER_SUCCESS, |
| 14 | ERROR_BOUNDARY_FORMAT, |
| 15 | ERROR_BOUNDARY_CR, |
| 16 | ERROR_BOUNDARY_LF, |
| 17 | ERROR_BOUNDARY_DATA, |
| 18 | ERROR_EMPTY_HEADER, |
| 19 | ERROR_HEADER_NAME, |
| 20 | ERROR_HEADER_VALUE, |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 21 | ERROR_HEADER_ENDING, |
| 22 | ERROR_UNEXPECTED_END_OF_HEADER, |
| 23 | ERROR_UNEXPECTED_END_OF_INPUT, |
| 24 | ERROR_OUT_OF_RANGE |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 25 | }; |
| 26 | |
| 27 | enum class State |
| 28 | { |
| 29 | START, |
| 30 | START_BOUNDARY, |
| 31 | HEADER_FIELD_START, |
| 32 | HEADER_FIELD, |
| 33 | HEADER_VALUE_START, |
| 34 | HEADER_VALUE, |
| 35 | HEADER_VALUE_ALMOST_DONE, |
| 36 | HEADERS_ALMOST_DONE, |
| 37 | PART_DATA_START, |
| 38 | PART_DATA, |
| 39 | END |
| 40 | }; |
| 41 | |
| 42 | enum class Boundary |
| 43 | { |
| 44 | NON_BOUNDARY, |
| 45 | PART_BOUNDARY, |
| 46 | END_BOUNDARY, |
| 47 | }; |
| 48 | |
| 49 | struct FormPart |
| 50 | { |
| 51 | boost::beast::http::fields fields; |
| 52 | std::string content; |
| 53 | }; |
| 54 | |
| 55 | class MultipartParser |
| 56 | { |
| 57 | public: |
| 58 | MultipartParser() = default; |
| 59 | |
| 60 | [[nodiscard]] ParserError parse(const crow::Request& req) |
| 61 | { |
| 62 | std::string_view contentType = req.getHeaderValue("content-type"); |
| 63 | |
| 64 | const std::string boundaryFormat = "multipart/form-data; boundary="; |
Ed Tanous | 11ba397 | 2022-07-11 09:50:41 -0700 | [diff] [blame] | 65 | if (!contentType.starts_with(boundaryFormat)) |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 66 | { |
| 67 | return ParserError::ERROR_BOUNDARY_FORMAT; |
| 68 | } |
| 69 | |
| 70 | std::string_view ctBoundary = contentType.substr(boundaryFormat.size()); |
| 71 | |
| 72 | boundary = "\r\n--"; |
| 73 | boundary += ctBoundary; |
| 74 | indexBoundary(); |
| 75 | lookbehind.resize(boundary.size() + 8); |
| 76 | state = State::START; |
| 77 | |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 78 | const std::string& buffer = req.body(); |
| 79 | size_t len = buffer.size(); |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 80 | char cl = 0; |
| 81 | |
| 82 | for (size_t i = 0; i < len; i++) |
| 83 | { |
| 84 | char c = buffer[i]; |
| 85 | switch (state) |
| 86 | { |
| 87 | case State::START: |
| 88 | index = 0; |
| 89 | state = State::START_BOUNDARY; |
| 90 | [[fallthrough]]; |
| 91 | case State::START_BOUNDARY: |
| 92 | if (index == boundary.size() - 2) |
| 93 | { |
| 94 | if (c != cr) |
| 95 | { |
| 96 | return ParserError::ERROR_BOUNDARY_CR; |
| 97 | } |
| 98 | index++; |
| 99 | break; |
| 100 | } |
| 101 | else if (index - 1 == boundary.size() - 2) |
| 102 | { |
| 103 | if (c != lf) |
| 104 | { |
| 105 | return ParserError::ERROR_BOUNDARY_LF; |
| 106 | } |
| 107 | index = 0; |
| 108 | mime_fields.push_back({}); |
| 109 | state = State::HEADER_FIELD_START; |
| 110 | break; |
| 111 | } |
| 112 | if (c != boundary[index + 2]) |
| 113 | { |
| 114 | return ParserError::ERROR_BOUNDARY_DATA; |
| 115 | } |
| 116 | index++; |
| 117 | break; |
| 118 | case State::HEADER_FIELD_START: |
| 119 | currentHeaderName.resize(0); |
| 120 | state = State::HEADER_FIELD; |
| 121 | headerFieldMark = i; |
| 122 | index = 0; |
| 123 | [[fallthrough]]; |
| 124 | case State::HEADER_FIELD: |
| 125 | if (c == cr) |
| 126 | { |
| 127 | headerFieldMark = 0; |
| 128 | state = State::HEADERS_ALMOST_DONE; |
| 129 | break; |
| 130 | } |
| 131 | |
| 132 | index++; |
| 133 | if (c == hyphen) |
| 134 | { |
| 135 | break; |
| 136 | } |
| 137 | |
| 138 | if (c == colon) |
| 139 | { |
| 140 | if (index == 1) |
| 141 | { |
| 142 | return ParserError::ERROR_EMPTY_HEADER; |
| 143 | } |
Ed Tanous | ca45aa3 | 2022-01-07 09:28:45 -0800 | [diff] [blame] | 144 | |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 145 | currentHeaderName.append(&buffer[headerFieldMark], |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 146 | i - headerFieldMark); |
| 147 | state = State::HEADER_VALUE_START; |
| 148 | break; |
| 149 | } |
| 150 | cl = lower(c); |
| 151 | if (cl < 'a' || cl > 'z') |
| 152 | { |
| 153 | return ParserError::ERROR_HEADER_NAME; |
| 154 | } |
| 155 | break; |
| 156 | case State::HEADER_VALUE_START: |
| 157 | if (c == space) |
| 158 | { |
| 159 | break; |
| 160 | } |
| 161 | headerValueMark = i; |
| 162 | state = State::HEADER_VALUE; |
| 163 | [[fallthrough]]; |
| 164 | case State::HEADER_VALUE: |
| 165 | if (c == cr) |
| 166 | { |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 167 | std::string_view value(&buffer[headerValueMark], |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 168 | i - headerValueMark); |
| 169 | mime_fields.rbegin()->fields.set(currentHeaderName, |
| 170 | value); |
| 171 | state = State::HEADER_VALUE_ALMOST_DONE; |
| 172 | } |
| 173 | break; |
| 174 | case State::HEADER_VALUE_ALMOST_DONE: |
| 175 | if (c != lf) |
| 176 | { |
| 177 | return ParserError::ERROR_HEADER_VALUE; |
| 178 | } |
| 179 | state = State::HEADER_FIELD_START; |
| 180 | break; |
| 181 | case State::HEADERS_ALMOST_DONE: |
| 182 | if (c != lf) |
| 183 | { |
| 184 | return ParserError::ERROR_HEADER_ENDING; |
| 185 | } |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 186 | if (index > 0) |
| 187 | { |
| 188 | return ParserError::ERROR_UNEXPECTED_END_OF_HEADER; |
| 189 | } |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 190 | state = State::PART_DATA_START; |
| 191 | break; |
| 192 | case State::PART_DATA_START: |
| 193 | state = State::PART_DATA; |
| 194 | partDataMark = i; |
| 195 | [[fallthrough]]; |
| 196 | case State::PART_DATA: |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 197 | { |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 198 | if (index == 0) |
| 199 | { |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 200 | skipNonBoundary(buffer, boundary.size() - 1, i); |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 201 | c = buffer[i]; |
| 202 | } |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 203 | if (auto ec = processPartData(buffer, i, c); |
| 204 | ec != ParserError::PARSER_SUCCESS) |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 205 | { |
| 206 | return ec; |
| 207 | } |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 208 | break; |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 209 | } |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 210 | case State::END: |
| 211 | break; |
| 212 | } |
| 213 | } |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 214 | |
| 215 | if (state != State::END) |
| 216 | { |
| 217 | return ParserError::ERROR_UNEXPECTED_END_OF_INPUT; |
| 218 | } |
| 219 | |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 220 | return ParserError::PARSER_SUCCESS; |
| 221 | } |
| 222 | std::vector<FormPart> mime_fields; |
| 223 | std::string boundary; |
| 224 | |
| 225 | private: |
| 226 | void indexBoundary() |
| 227 | { |
Ed Tanous | 3544d2a | 2023-08-06 18:12:20 -0700 | [diff] [blame] | 228 | std::ranges::fill(boundaryIndex, 0); |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 229 | for (const char current : boundary) |
| 230 | { |
| 231 | boundaryIndex[static_cast<unsigned char>(current)] = true; |
| 232 | } |
| 233 | } |
| 234 | |
Ed Tanous | 56d2396 | 2022-02-14 20:42:02 -0800 | [diff] [blame] | 235 | static char lower(char c) |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 236 | { |
| 237 | return static_cast<char>(c | 0x20); |
| 238 | } |
| 239 | |
| 240 | inline bool isBoundaryChar(char c) const |
| 241 | { |
| 242 | return boundaryIndex[static_cast<unsigned char>(c)]; |
| 243 | } |
| 244 | |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 245 | void skipNonBoundary(const std::string& buffer, size_t boundaryEnd, |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 246 | size_t& i) |
| 247 | { |
| 248 | // boyer-moore derived algorithm to safely skip non-boundary data |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 249 | while (i + boundary.size() <= buffer.length()) |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 250 | { |
| 251 | if (isBoundaryChar(buffer[i + boundaryEnd])) |
| 252 | { |
| 253 | break; |
| 254 | } |
| 255 | i += boundary.size(); |
| 256 | } |
| 257 | } |
| 258 | |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 259 | ParserError processPartData(const std::string& buffer, size_t& i, char c) |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 260 | { |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 261 | size_t prevIndex = index; |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 262 | |
| 263 | if (index < boundary.size()) |
| 264 | { |
| 265 | if (boundary[index] == c) |
| 266 | { |
| 267 | if (index == 0) |
| 268 | { |
Patrick Williams | 0e31e95 | 2023-05-10 19:40:27 -0500 | [diff] [blame] | 269 | const char* start = &buffer[partDataMark]; |
Ed Tanous | ca45aa3 | 2022-01-07 09:28:45 -0800 | [diff] [blame] | 270 | size_t size = i - partDataMark; |
Patrick Williams | 89492a1 | 2023-05-10 07:51:34 -0500 | [diff] [blame] | 271 | mime_fields.rbegin()->content += std::string_view(start, |
| 272 | size); |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 273 | } |
| 274 | index++; |
| 275 | } |
| 276 | else |
| 277 | { |
| 278 | index = 0; |
| 279 | } |
| 280 | } |
| 281 | else if (index == boundary.size()) |
| 282 | { |
| 283 | index++; |
| 284 | if (c == cr) |
| 285 | { |
| 286 | // cr = part boundary |
| 287 | flags = Boundary::PART_BOUNDARY; |
| 288 | } |
| 289 | else if (c == hyphen) |
| 290 | { |
| 291 | // hyphen = end boundary |
| 292 | flags = Boundary::END_BOUNDARY; |
| 293 | } |
| 294 | else |
| 295 | { |
| 296 | index = 0; |
| 297 | } |
| 298 | } |
| 299 | else |
| 300 | { |
| 301 | if (flags == Boundary::PART_BOUNDARY) |
| 302 | { |
| 303 | index = 0; |
| 304 | if (c == lf) |
| 305 | { |
| 306 | // unset the PART_BOUNDARY flag |
| 307 | flags = Boundary::NON_BOUNDARY; |
| 308 | mime_fields.push_back({}); |
| 309 | state = State::HEADER_FIELD_START; |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 310 | return ParserError::PARSER_SUCCESS; |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 311 | } |
| 312 | } |
| 313 | if (flags == Boundary::END_BOUNDARY) |
| 314 | { |
| 315 | if (c == hyphen) |
| 316 | { |
| 317 | state = State::END; |
| 318 | } |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 319 | else |
| 320 | { |
| 321 | flags = Boundary::NON_BOUNDARY; |
| 322 | index = 0; |
| 323 | } |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 324 | } |
| 325 | } |
| 326 | |
| 327 | if (index > 0) |
| 328 | { |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 329 | if ((index - 1) >= lookbehind.size()) |
| 330 | { |
| 331 | // Should never happen, but when it does it won't cause crash |
| 332 | return ParserError::ERROR_OUT_OF_RANGE; |
| 333 | } |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 334 | lookbehind[index - 1] = c; |
| 335 | } |
| 336 | else if (prevIndex > 0) |
| 337 | { |
| 338 | // if our boundary turned out to be rubbish, the captured |
| 339 | // lookbehind belongs to partData |
| 340 | |
| 341 | mime_fields.rbegin()->content += lookbehind.substr(0, prevIndex); |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 342 | partDataMark = i; |
| 343 | |
| 344 | // reconsider the current character even so it interrupted |
| 345 | // the sequence it could be the beginning of a new sequence |
| 346 | i--; |
| 347 | } |
Krzysztof Grobelny | 18e3f7f | 2022-08-24 09:24:33 +0200 | [diff] [blame] | 348 | return ParserError::PARSER_SUCCESS; |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 349 | } |
| 350 | |
| 351 | std::string currentHeaderName; |
| 352 | std::string currentHeaderValue; |
| 353 | |
| 354 | static constexpr char cr = '\r'; |
| 355 | static constexpr char lf = '\n'; |
| 356 | static constexpr char space = ' '; |
| 357 | static constexpr char hyphen = '-'; |
| 358 | static constexpr char colon = ':'; |
| 359 | |
Ed Tanous | d3a9e08 | 2022-01-07 09:30:41 -0800 | [diff] [blame] | 360 | std::array<bool, 256> boundaryIndex{}; |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 361 | std::string lookbehind; |
Ed Tanous | d3a9e08 | 2022-01-07 09:30:41 -0800 | [diff] [blame] | 362 | State state{State::START}; |
| 363 | Boundary flags{Boundary::NON_BOUNDARY}; |
Ed Tanous | af4edf6 | 2020-07-21 08:46:25 -0700 | [diff] [blame] | 364 | size_t index = 0; |
| 365 | size_t partDataMark = 0; |
| 366 | size_t headerFieldMark = 0; |
| 367 | size_t headerValueMark = 0; |
| 368 | }; |