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