mbot/node_modules/undici/lib/web/fetch/formdata-parser.js
2024-05-10 22:39:11 -07:00

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'use strict'
const { isUSVString, bufferToLowerCasedHeaderName } = require('../../core/util')
const { utf8DecodeBytes } = require('./util')
const { HTTP_TOKEN_CODEPOINTS, isomorphicDecode } = require('./data-url')
const { isFileLike, File: UndiciFile } = require('./file')
const { makeEntry } = require('./formdata')
const assert = require('node:assert')
const { File: NodeFile } = require('node:buffer')
const File = globalThis.File ?? NodeFile ?? UndiciFile
const formDataNameBuffer = Buffer.from('form-data; name="')
const filenameBuffer = Buffer.from('; filename')
const dd = Buffer.from('--')
const ddcrlf = Buffer.from('--\r\n')
/**
* @param {string} chars
*/
function isAsciiString (chars) {
for (let i = 0; i < chars.length; ++i) {
if ((chars.charCodeAt(i) & ~0x7F) !== 0) {
return false
}
}
return true
}
/**
* @see https://andreubotella.github.io/multipart-form-data/#multipart-form-data-boundary
* @param {string} boundary
*/
function validateBoundary (boundary) {
const length = boundary.length
// - its length is greater or equal to 27 and lesser or equal to 70, and
if (length < 27 || length > 70) {
return false
}
// - it is composed by bytes in the ranges 0x30 to 0x39, 0x41 to 0x5A, or
// 0x61 to 0x7A, inclusive (ASCII alphanumeric), or which are 0x27 ('),
// 0x2D (-) or 0x5F (_).
for (let i = 0; i < length; ++i) {
const cp = boundary.charCodeAt(i)
if (!(
(cp >= 0x30 && cp <= 0x39) ||
(cp >= 0x41 && cp <= 0x5a) ||
(cp >= 0x61 && cp <= 0x7a) ||
cp === 0x27 ||
cp === 0x2d ||
cp === 0x5f
)) {
return false
}
}
return true
}
/**
* @see https://andreubotella.github.io/multipart-form-data/#multipart-form-data-parser
* @param {Buffer} input
* @param {ReturnType<import('./data-url')['parseMIMEType']>} mimeType
*/
function multipartFormDataParser (input, mimeType) {
// 1. Assert: mimeTypes essence is "multipart/form-data".
assert(mimeType !== 'failure' && mimeType.essence === 'multipart/form-data')
const boundaryString = mimeType.parameters.get('boundary')
// 2. If mimeTypes parameters["boundary"] does not exist, return failure.
// Otherwise, let boundary be the result of UTF-8 decoding mimeTypes
// parameters["boundary"].
if (boundaryString === undefined) {
return 'failure'
}
const boundary = Buffer.from(`--${boundaryString}`, 'utf8')
// 3. Let entry list be an empty entry list.
const entryList = []
// 4. Let position be a pointer to a byte in input, initially pointing at
// the first byte.
const position = { position: 0 }
// Note: undici addition, allow \r\n before the body.
if (input[0] === 0x0d && input[1] === 0x0a) {
position.position += 2
}
// 5. While true:
while (true) {
// 5.1. If position points to a sequence of bytes starting with 0x2D 0x2D
// (`--`) followed by boundary, advance position by 2 + the length of
// boundary. Otherwise, return failure.
// Note: boundary is padded with 2 dashes already, no need to add 2.
if (input.subarray(position.position, position.position + boundary.length).equals(boundary)) {
position.position += boundary.length
} else {
return 'failure'
}
// 5.2. If position points to the sequence of bytes 0x2D 0x2D 0x0D 0x0A
// (`--` followed by CR LF) followed by the end of input, return entry list.
// Note: a body does NOT need to end with CRLF. It can end with --.
if (
(position.position === input.length - 2 && bufferStartsWith(input, dd, position)) ||
(position.position === input.length - 4 && bufferStartsWith(input, ddcrlf, position))
) {
return entryList
}
// 5.3. If position does not point to a sequence of bytes starting with 0x0D
// 0x0A (CR LF), return failure.
if (input[position.position] !== 0x0d || input[position.position + 1] !== 0x0a) {
return 'failure'
}
// 5.4. Advance position by 2. (This skips past the newline.)
position.position += 2
// 5.5. Let name, filename and contentType be the result of parsing
// multipart/form-data headers on input and position, if the result
// is not failure. Otherwise, return failure.
const result = parseMultipartFormDataHeaders(input, position)
if (result === 'failure') {
return 'failure'
}
let { name, filename, contentType, encoding } = result
// 5.6. Advance position by 2. (This skips past the empty line that marks
// the end of the headers.)
position.position += 2
// 5.7. Let body be the empty byte sequence.
let body
// 5.8. Body loop: While position is not past the end of input:
// TODO: the steps here are completely wrong
{
const boundaryIndex = input.indexOf(boundary.subarray(2), position.position)
if (boundaryIndex === -1) {
return 'failure'
}
body = input.subarray(position.position, boundaryIndex - 4)
position.position += body.length
// Note: position must be advanced by the body's length before being
// decoded, otherwise the parsing will fail.
if (encoding === 'base64') {
body = Buffer.from(body.toString(), 'base64')
}
}
// 5.9. If position does not point to a sequence of bytes starting with
// 0x0D 0x0A (CR LF), return failure. Otherwise, advance position by 2.
if (input[position.position] !== 0x0d || input[position.position + 1] !== 0x0a) {
return 'failure'
} else {
position.position += 2
}
// 5.10. If filename is not null:
let value
if (filename !== null) {
// 5.10.1. If contentType is null, set contentType to "text/plain".
contentType ??= 'text/plain'
// 5.10.2. If contentType is not an ASCII string, set contentType to the empty string.
// Note: `buffer.isAscii` can be used at zero-cost, but converting a string to a buffer is a high overhead.
// Content-Type is a relatively small string, so it is faster to use `String#charCodeAt`.
if (!isAsciiString(contentType)) {
contentType = ''
}
// 5.10.3. Let value be a new File object with name filename, type contentType, and body body.
value = new File([body], filename, { type: contentType })
} else {
// 5.11. Otherwise:
// 5.11.1. Let value be the UTF-8 decoding without BOM of body.
value = utf8DecodeBytes(Buffer.from(body))
}
// 5.12. Assert: name is a scalar value string and value is either a scalar value string or a File object.
assert(isUSVString(name))
assert((typeof value === 'string' && isUSVString(value)) || isFileLike(value))
// 5.13. Create an entry with name and value, and append it to entry list.
entryList.push(makeEntry(name, value, filename))
}
}
/**
* @see https://andreubotella.github.io/multipart-form-data/#parse-multipart-form-data-headers
* @param {Buffer} input
* @param {{ position: number }} position
*/
function parseMultipartFormDataHeaders (input, position) {
// 1. Let name, filename and contentType be null.
let name = null
let filename = null
let contentType = null
let encoding = null
// 2. While true:
while (true) {
// 2.1. If position points to a sequence of bytes starting with 0x0D 0x0A (CR LF):
if (input[position.position] === 0x0d && input[position.position + 1] === 0x0a) {
// 2.1.1. If name is null, return failure.
if (name === null) {
return 'failure'
}
// 2.1.2. Return name, filename and contentType.
return { name, filename, contentType, encoding }
}
// 2.2. Let header name be the result of collecting a sequence of bytes that are
// not 0x0A (LF), 0x0D (CR) or 0x3A (:), given position.
let headerName = collectASequenceOfBytes(
(char) => char !== 0x0a && char !== 0x0d && char !== 0x3a,
input,
position
)
// 2.3. Remove any HTTP tab or space bytes from the start or end of header name.
headerName = removeChars(headerName, true, true, (char) => char === 0x9 || char === 0x20)
// 2.4. If header name does not match the field-name token production, return failure.
if (!HTTP_TOKEN_CODEPOINTS.test(headerName.toString())) {
return 'failure'
}
// 2.5. If the byte at position is not 0x3A (:), return failure.
if (input[position.position] !== 0x3a) {
return 'failure'
}
// 2.6. Advance position by 1.
position.position++
// 2.7. Collect a sequence of bytes that are HTTP tab or space bytes given position.
// (Do nothing with those bytes.)
collectASequenceOfBytes(
(char) => char === 0x20 || char === 0x09,
input,
position
)
// 2.8. Byte-lowercase header name and switch on the result:
switch (bufferToLowerCasedHeaderName(headerName)) {
case 'content-disposition': {
// 1. Set name and filename to null.
name = filename = null
// 2. If position does not point to a sequence of bytes starting with
// `form-data; name="`, return failure.
if (!bufferStartsWith(input, formDataNameBuffer, position)) {
return 'failure'
}
// 3. Advance position so it points at the byte after the next 0x22 (")
// byte (the one in the sequence of bytes matched above).
position.position += 17
// 4. Set name to the result of parsing a multipart/form-data name given
// input and position, if the result is not failure. Otherwise, return
// failure.
name = parseMultipartFormDataName(input, position)
if (name === null) {
return 'failure'
}
// 5. If position points to a sequence of bytes starting with `; filename="`:
if (bufferStartsWith(input, filenameBuffer, position)) {
// Note: undici also handles filename*
let check = position.position + filenameBuffer.length
if (input[check] === 0x2a) {
position.position += 1
check += 1
}
if (input[check] !== 0x3d || input[check + 1] !== 0x22) { // ="
return 'failure'
}
// 1. Advance position so it points at the byte after the next 0x22 (") byte
// (the one in the sequence of bytes matched above).
position.position += 12
// 2. Set filename to the result of parsing a multipart/form-data name given
// input and position, if the result is not failure. Otherwise, return failure.
filename = parseMultipartFormDataName(input, position)
if (filename === null) {
return 'failure'
}
}
break
}
case 'content-type': {
// 1. Let header value be the result of collecting a sequence of bytes that are
// not 0x0A (LF) or 0x0D (CR), given position.
let headerValue = collectASequenceOfBytes(
(char) => char !== 0x0a && char !== 0x0d,
input,
position
)
// 2. Remove any HTTP tab or space bytes from the end of header value.
headerValue = removeChars(headerValue, false, true, (char) => char === 0x9 || char === 0x20)
// 3. Set contentType to the isomorphic decoding of header value.
contentType = isomorphicDecode(headerValue)
break
}
case 'content-transfer-encoding': {
let headerValue = collectASequenceOfBytes(
(char) => char !== 0x0a && char !== 0x0d,
input,
position
)
headerValue = removeChars(headerValue, false, true, (char) => char === 0x9 || char === 0x20)
encoding = isomorphicDecode(headerValue)
break
}
default: {
// Collect a sequence of bytes that are not 0x0A (LF) or 0x0D (CR), given position.
// (Do nothing with those bytes.)
collectASequenceOfBytes(
(char) => char !== 0x0a && char !== 0x0d,
input,
position
)
}
}
// 2.9. If position does not point to a sequence of bytes starting with 0x0D 0x0A
// (CR LF), return failure. Otherwise, advance position by 2 (past the newline).
if (input[position.position] !== 0x0d && input[position.position + 1] !== 0x0a) {
return 'failure'
} else {
position.position += 2
}
}
}
/**
* @see https://andreubotella.github.io/multipart-form-data/#parse-a-multipart-form-data-name
* @param {Buffer} input
* @param {{ position: number }} position
*/
function parseMultipartFormDataName (input, position) {
// 1. Assert: The byte at (position - 1) is 0x22 (").
assert(input[position.position - 1] === 0x22)
// 2. Let name be the result of collecting a sequence of bytes that are not 0x0A (LF), 0x0D (CR) or 0x22 ("), given position.
/** @type {string | Buffer} */
let name = collectASequenceOfBytes(
(char) => char !== 0x0a && char !== 0x0d && char !== 0x22,
input,
position
)
// 3. If the byte at position is not 0x22 ("), return failure. Otherwise, advance position by 1.
if (input[position.position] !== 0x22) {
return null // name could be 'failure'
} else {
position.position++
}
// 4. Replace any occurrence of the following subsequences in name with the given byte:
// - `%0A`: 0x0A (LF)
// - `%0D`: 0x0D (CR)
// - `%22`: 0x22 (")
name = new TextDecoder().decode(name)
.replace(/%0A/ig, '\n')
.replace(/%0D/ig, '\r')
.replace(/%22/g, '"')
// 5. Return the UTF-8 decoding without BOM of name.
return name
}
/**
* @param {(char: number) => boolean} condition
* @param {Buffer} input
* @param {{ position: number }} position
*/
function collectASequenceOfBytes (condition, input, position) {
let start = position.position
while (start < input.length && condition(input[start])) {
++start
}
return input.subarray(position.position, (position.position = start))
}
/**
* @param {Buffer} buf
* @param {boolean} leading
* @param {boolean} trailing
* @param {(charCode: number) => boolean} predicate
* @returns {Buffer}
*/
function removeChars (buf, leading, trailing, predicate) {
let lead = 0
let trail = buf.length - 1
if (leading) {
while (lead < buf.length && predicate(buf[lead])) lead++
}
if (trailing) {
while (trail > 0 && predicate(buf[trail])) trail--
}
return lead === 0 && trail === buf.length - 1 ? buf : buf.subarray(lead, trail + 1)
}
/**
* Checks if {@param buffer} starts with {@param start}
* @param {Buffer} buffer
* @param {Buffer} start
* @param {{ position: number }} position
*/
function bufferStartsWith (buffer, start, position) {
if (buffer.length < start.length) {
return false
}
for (let i = 0; i < start.length; i++) {
if (start[i] !== buffer[position.position + i]) {
return false
}
}
return true
}
module.exports = {
multipartFormDataParser,
validateBoundary
}