562 lines
17 KiB
JavaScript
562 lines
17 KiB
JavaScript
'use strict';
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const {
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isUSVString,
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bufferToLowerCasedHeaderName,
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} = require('../../core/util');
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const { utf8DecodeBytes } = require('./util');
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const { HTTP_TOKEN_CODEPOINTS, isomorphicDecode } = require('./data-url');
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const { makeEntry } = require('./formdata');
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const { webidl } = require('./webidl');
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const assert = require('node:assert');
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const { File: NodeFile } = require('node:buffer');
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const File = globalThis.File ?? NodeFile;
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const formDataNameBuffer = Buffer.from('form-data; name="');
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const filenameBuffer = Buffer.from('filename');
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const dd = Buffer.from('--');
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const ddcrlf = Buffer.from('--\r\n');
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/**
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* @param {string} chars
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*/
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function isAsciiString(chars) {
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for (let i = 0; i < chars.length; ++i) {
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if ((chars.charCodeAt(i) & ~0x7f) !== 0) {
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return false;
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}
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}
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return true;
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}
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/**
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* @see https://andreubotella.github.io/multipart-form-data/#multipart-form-data-boundary
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* @param {string} boundary
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*/
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function validateBoundary(boundary) {
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const length = boundary.length;
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// - its length is greater or equal to 27 and lesser or equal to 70, and
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if (length < 27 || length > 70) {
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return false;
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}
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// - it is composed by bytes in the ranges 0x30 to 0x39, 0x41 to 0x5A, or
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// 0x61 to 0x7A, inclusive (ASCII alphanumeric), or which are 0x27 ('),
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// 0x2D (-) or 0x5F (_).
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for (let i = 0; i < length; ++i) {
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const cp = boundary.charCodeAt(i);
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if (
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!(
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(cp >= 0x30 && cp <= 0x39) ||
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(cp >= 0x41 && cp <= 0x5a) ||
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(cp >= 0x61 && cp <= 0x7a) ||
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cp === 0x27 ||
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cp === 0x2d ||
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cp === 0x5f
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)
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) {
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return false;
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}
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}
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return true;
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}
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/**
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* @see https://andreubotella.github.io/multipart-form-data/#multipart-form-data-parser
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* @param {Buffer} input
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* @param {ReturnType<import('./data-url')['parseMIMEType']>} mimeType
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*/
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function multipartFormDataParser(input, mimeType) {
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// 1. Assert: mimeType’s essence is "multipart/form-data".
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assert(mimeType !== 'failure' && mimeType.essence === 'multipart/form-data');
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const boundaryString = mimeType.parameters.get('boundary');
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// 2. If mimeType’s parameters["boundary"] does not exist, return failure.
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// Otherwise, let boundary be the result of UTF-8 decoding mimeType’s
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// parameters["boundary"].
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if (boundaryString === undefined) {
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throw parsingError('missing boundary in content-type header');
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}
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const boundary = Buffer.from(`--${boundaryString}`, 'utf8');
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// 3. Let entry list be an empty entry list.
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const entryList = [];
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// 4. Let position be a pointer to a byte in input, initially pointing at
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// the first byte.
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const position = { position: 0 };
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// Note: undici addition, allows leading and trailing CRLFs.
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while (
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input[position.position] === 0x0d &&
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input[position.position + 1] === 0x0a
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) {
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position.position += 2;
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}
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let trailing = input.length;
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while (input[trailing - 1] === 0x0a && input[trailing - 2] === 0x0d) {
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trailing -= 2;
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}
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if (trailing !== input.length) {
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input = input.subarray(0, trailing);
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}
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// 5. While true:
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while (true) {
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// 5.1. If position points to a sequence of bytes starting with 0x2D 0x2D
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// (`--`) followed by boundary, advance position by 2 + the length of
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// boundary. Otherwise, return failure.
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// Note: boundary is padded with 2 dashes already, no need to add 2.
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if (
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input
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.subarray(position.position, position.position + boundary.length)
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.equals(boundary)
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) {
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position.position += boundary.length;
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} else {
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throw parsingError('expected a value starting with -- and the boundary');
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}
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// 5.2. If position points to the sequence of bytes 0x2D 0x2D 0x0D 0x0A
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// (`--` followed by CR LF) followed by the end of input, return entry list.
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// Note: a body does NOT need to end with CRLF. It can end with --.
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if (
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(position.position === input.length - 2 &&
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bufferStartsWith(input, dd, position)) ||
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(position.position === input.length - 4 &&
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bufferStartsWith(input, ddcrlf, position))
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) {
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return entryList;
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}
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// 5.3. If position does not point to a sequence of bytes starting with 0x0D
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// 0x0A (CR LF), return failure.
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if (
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input[position.position] !== 0x0d ||
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input[position.position + 1] !== 0x0a
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) {
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throw parsingError('expected CRLF');
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}
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// 5.4. Advance position by 2. (This skips past the newline.)
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position.position += 2;
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// 5.5. Let name, filename and contentType be the result of parsing
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// multipart/form-data headers on input and position, if the result
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// is not failure. Otherwise, return failure.
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const result = parseMultipartFormDataHeaders(input, position);
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let { name, filename, contentType, encoding } = result;
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// 5.6. Advance position by 2. (This skips past the empty line that marks
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// the end of the headers.)
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position.position += 2;
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// 5.7. Let body be the empty byte sequence.
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let body;
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// 5.8. Body loop: While position is not past the end of input:
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// TODO: the steps here are completely wrong
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{
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const boundaryIndex = input.indexOf(
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boundary.subarray(2),
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position.position
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);
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if (boundaryIndex === -1) {
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throw parsingError('expected boundary after body');
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}
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body = input.subarray(position.position, boundaryIndex - 4);
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position.position += body.length;
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// Note: position must be advanced by the body's length before being
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// decoded, otherwise the parsing will fail.
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if (encoding === 'base64') {
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body = Buffer.from(body.toString(), 'base64');
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}
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}
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// 5.9. If position does not point to a sequence of bytes starting with
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// 0x0D 0x0A (CR LF), return failure. Otherwise, advance position by 2.
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if (
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input[position.position] !== 0x0d ||
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input[position.position + 1] !== 0x0a
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) {
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throw parsingError('expected CRLF');
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} else {
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position.position += 2;
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}
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// 5.10. If filename is not null:
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let value;
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if (filename !== null) {
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// 5.10.1. If contentType is null, set contentType to "text/plain".
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contentType ??= 'text/plain';
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// 5.10.2. If contentType is not an ASCII string, set contentType to the empty string.
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// Note: `buffer.isAscii` can be used at zero-cost, but converting a string to a buffer is a high overhead.
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// Content-Type is a relatively small string, so it is faster to use `String#charCodeAt`.
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if (!isAsciiString(contentType)) {
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contentType = '';
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}
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// 5.10.3. Let value be a new File object with name filename, type contentType, and body body.
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value = new File([body], filename, { type: contentType });
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} else {
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// 5.11. Otherwise:
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// 5.11.1. Let value be the UTF-8 decoding without BOM of body.
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value = utf8DecodeBytes(Buffer.from(body));
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}
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// 5.12. Assert: name is a scalar value string and value is either a scalar value string or a File object.
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assert(isUSVString(name));
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assert(
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(typeof value === 'string' && isUSVString(value)) || webidl.is.File(value)
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);
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// 5.13. Create an entry with name and value, and append it to entry list.
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entryList.push(makeEntry(name, value, filename));
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}
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}
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/**
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* @see https://andreubotella.github.io/multipart-form-data/#parse-multipart-form-data-headers
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* @param {Buffer} input
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* @param {{ position: number }} position
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*/
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function parseMultipartFormDataHeaders(input, position) {
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// 1. Let name, filename and contentType be null.
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let name = null;
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let filename = null;
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let contentType = null;
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let encoding = null;
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// 2. While true:
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while (true) {
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// 2.1. If position points to a sequence of bytes starting with 0x0D 0x0A (CR LF):
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if (
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input[position.position] === 0x0d &&
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input[position.position + 1] === 0x0a
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) {
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// 2.1.1. If name is null, return failure.
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if (name === null) {
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throw parsingError('header name is null');
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}
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// 2.1.2. Return name, filename and contentType.
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return { name, filename, contentType, encoding };
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}
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// 2.2. Let header name be the result of collecting a sequence of bytes that are
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// not 0x0A (LF), 0x0D (CR) or 0x3A (:), given position.
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let headerName = collectASequenceOfBytes(
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(char) => char !== 0x0a && char !== 0x0d && char !== 0x3a,
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input,
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position
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);
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// 2.3. Remove any HTTP tab or space bytes from the start or end of header name.
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headerName = removeChars(
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headerName,
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true,
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true,
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(char) => char === 0x9 || char === 0x20
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);
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// 2.4. If header name does not match the field-name token production, return failure.
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if (!HTTP_TOKEN_CODEPOINTS.test(headerName.toString())) {
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throw parsingError(
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'header name does not match the field-name token production'
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);
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}
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// 2.5. If the byte at position is not 0x3A (:), return failure.
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if (input[position.position] !== 0x3a) {
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throw parsingError('expected :');
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}
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// 2.6. Advance position by 1.
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position.position++;
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// 2.7. Collect a sequence of bytes that are HTTP tab or space bytes given position.
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// (Do nothing with those bytes.)
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collectASequenceOfBytes(
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(char) => char === 0x20 || char === 0x09,
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input,
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position
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);
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// 2.8. Byte-lowercase header name and switch on the result:
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switch (bufferToLowerCasedHeaderName(headerName)) {
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case 'content-disposition': {
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// 1. Set name and filename to null.
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name = filename = null;
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// 2. If position does not point to a sequence of bytes starting with
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// `form-data; name="`, return failure.
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if (!bufferStartsWith(input, formDataNameBuffer, position)) {
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throw parsingError(
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'expected form-data; name=" for content-disposition header'
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);
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}
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// 3. Advance position so it points at the byte after the next 0x22 (")
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// byte (the one in the sequence of bytes matched above).
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position.position += 17;
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// 4. Set name to the result of parsing a multipart/form-data name given
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// input and position, if the result is not failure. Otherwise, return
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// failure.
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name = parseMultipartFormDataName(input, position);
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// 5. If position points to a sequence of bytes starting with `; filename="`:
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if (
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input[position.position] === 0x3b /* ; */ &&
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input[position.position + 1] === 0x20 /* ' ' */
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) {
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const at = { position: position.position + 2 };
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if (bufferStartsWith(input, filenameBuffer, at)) {
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if (input[at.position + 8] === 0x2a /* '*' */) {
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at.position += 10; // skip past filename*=
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// Remove leading http tab and spaces. See RFC for examples.
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// https://datatracker.ietf.org/doc/html/rfc6266#section-5
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collectASequenceOfBytes(
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(char) => char === 0x20 || char === 0x09,
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input,
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at
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);
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const headerValue = collectASequenceOfBytes(
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(char) => char !== 0x20 && char !== 0x0d && char !== 0x0a, // ' ' or CRLF
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input,
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at
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);
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if (
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(headerValue[0] !== 0x75 && headerValue[0] !== 0x55) || // u or U
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(headerValue[1] !== 0x74 && headerValue[1] !== 0x54) || // t or T
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(headerValue[2] !== 0x66 && headerValue[2] !== 0x46) || // f or F
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headerValue[3] !== 0x2d || // -
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headerValue[4] !== 0x38 // 8
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) {
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throw parsingError("unknown encoding, expected utf-8''");
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}
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// skip utf-8''
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filename = decodeURIComponent(
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new TextDecoder().decode(headerValue.subarray(7))
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);
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position.position = at.position;
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} else {
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// 1. Advance position so it points at the byte after the next 0x22 (") byte
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// (the one in the sequence of bytes matched above).
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position.position += 11;
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// Remove leading http tab and spaces. See RFC for examples.
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// https://datatracker.ietf.org/doc/html/rfc6266#section-5
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collectASequenceOfBytes(
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(char) => char === 0x20 || char === 0x09,
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input,
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position
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);
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position.position++; // skip past " after removing whitespace
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// 2. Set filename to the result of parsing a multipart/form-data name given
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// input and position, if the result is not failure. Otherwise, return failure.
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filename = parseMultipartFormDataName(input, position);
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}
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}
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}
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break;
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}
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case 'content-type': {
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// 1. Let header value be the result of collecting a sequence of bytes that are
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// not 0x0A (LF) or 0x0D (CR), given position.
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let headerValue = collectASequenceOfBytes(
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(char) => char !== 0x0a && char !== 0x0d,
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input,
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position
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);
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// 2. Remove any HTTP tab or space bytes from the end of header value.
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headerValue = removeChars(
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headerValue,
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false,
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true,
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(char) => char === 0x9 || char === 0x20
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);
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// 3. Set contentType to the isomorphic decoding of header value.
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contentType = isomorphicDecode(headerValue);
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break;
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}
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case 'content-transfer-encoding': {
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let headerValue = collectASequenceOfBytes(
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(char) => char !== 0x0a && char !== 0x0d,
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input,
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position
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);
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headerValue = removeChars(
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headerValue,
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false,
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true,
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(char) => char === 0x9 || char === 0x20
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);
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encoding = isomorphicDecode(headerValue);
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break;
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}
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default: {
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// Collect a sequence of bytes that are not 0x0A (LF) or 0x0D (CR), given position.
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// (Do nothing with those bytes.)
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collectASequenceOfBytes(
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(char) => char !== 0x0a && char !== 0x0d,
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input,
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position
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);
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}
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}
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// 2.9. If position does not point to a sequence of bytes starting with 0x0D 0x0A
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// (CR LF), return failure. Otherwise, advance position by 2 (past the newline).
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if (
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input[position.position] !== 0x0d &&
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input[position.position + 1] !== 0x0a
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) {
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throw parsingError('expected CRLF');
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} else {
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position.position += 2;
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}
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}
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}
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/**
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* @see https://andreubotella.github.io/multipart-form-data/#parse-a-multipart-form-data-name
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* @param {Buffer} input
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* @param {{ position: number }} position
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*/
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function parseMultipartFormDataName(input, position) {
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// 1. Assert: The byte at (position - 1) is 0x22 (").
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assert(input[position.position - 1] === 0x22);
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// 2. Let name be the result of collecting a sequence of bytes that are not 0x0A (LF), 0x0D (CR) or 0x22 ("), given position.
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/** @type {string | Buffer} */
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let name = collectASequenceOfBytes(
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(char) => char !== 0x0a && char !== 0x0d && char !== 0x22,
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input,
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position
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);
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// 3. If the byte at position is not 0x22 ("), return failure. Otherwise, advance position by 1.
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if (input[position.position] !== 0x22) {
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throw parsingError('expected "');
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} else {
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position.position++;
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}
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// 4. Replace any occurrence of the following subsequences in name with the given byte:
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// - `%0A`: 0x0A (LF)
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// - `%0D`: 0x0D (CR)
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// - `%22`: 0x22 (")
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name = new TextDecoder()
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.decode(name)
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.replace(/%0A/gi, '\n')
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.replace(/%0D/gi, '\r')
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.replace(/%22/g, '"');
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// 5. Return the UTF-8 decoding without BOM of name.
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return name;
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}
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/**
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* @param {(char: number) => boolean} condition
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* @param {Buffer} input
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* @param {{ position: number }} position
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*/
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function collectASequenceOfBytes(condition, input, position) {
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let start = position.position;
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while (start < input.length && condition(input[start])) {
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++start;
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}
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return input.subarray(position.position, (position.position = start));
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}
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/**
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* @param {Buffer} buf
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* @param {boolean} leading
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* @param {boolean} trailing
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* @param {(charCode: number) => boolean} predicate
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* @returns {Buffer}
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*/
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function removeChars(buf, leading, trailing, predicate) {
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let lead = 0;
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let trail = buf.length - 1;
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if (leading) {
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while (lead < buf.length && predicate(buf[lead])) lead++;
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}
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if (trailing) {
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||
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;
|
||
}
|
||
|
||
function parsingError(cause) {
|
||
return new TypeError('Failed to parse body as FormData.', {
|
||
cause: new TypeError(cause),
|
||
});
|
||
}
|
||
|
||
module.exports = {
|
||
multipartFormDataParser,
|
||
validateBoundary,
|
||
};
|