| 'use strict'; |
| |
| const { tokenChars } = require('./validation'); |
| |
| /** |
| * Parses the `Sec-WebSocket-Protocol` header into a set of subprotocol names. |
| * |
| * @param {String} header The field value of the header |
| * @return {Set} The subprotocol names |
| * @public |
| */ |
| function parse(header) { |
| const protocols = new Set(); |
| let start = -1; |
| let end = -1; |
| let i = 0; |
| |
| for (i; i < header.length; i++) { |
| const code = header.charCodeAt(i); |
| |
| if (end === -1 && tokenChars[code] === 1) { |
| if (start === -1) start = i; |
| } else if ( |
| i !== 0 && |
| (code === 0x20 /* ' ' */ || code === 0x09) /* '\t' */ |
| ) { |
| if (end === -1 && start !== -1) end = i; |
| } else if (code === 0x2c /* ',' */) { |
| if (start === -1) { |
| throw new SyntaxError(`Unexpected character at index ${i}`); |
| } |
| |
| if (end === -1) end = i; |
| |
| const protocol = header.slice(start, end); |
| |
| if (protocols.has(protocol)) { |
| throw new SyntaxError(`The "${protocol}" subprotocol is duplicated`); |
| } |
| |
| protocols.add(protocol); |
| start = end = -1; |
| } else { |
| throw new SyntaxError(`Unexpected character at index ${i}`); |
| } |
| } |
| |
| if (start === -1 || end !== -1) { |
| throw new SyntaxError('Unexpected end of input'); |
| } |
| |
| const protocol = header.slice(start, i); |
| |
| if (protocols.has(protocol)) { |
| throw new SyntaxError(`The "${protocol}" subprotocol is duplicated`); |
| } |
| |
| protocols.add(protocol); |
| return protocols; |
| } |
| |
| module.exports = { parse }; |