dlovely-websocket/lib/frame.js

WebSocket For Dlovely

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.createPongFrame = exports.createPingFrame = exports.createCloseFrame = exports.createBinaryFrame = exports.createTextFrame = void 0;
function createTextFrame(data, masked = false) {
    const payload = Buffer.from(data);
    const meta = generateMetaData(true, 1, masked, payload);
    return Buffer.concat([meta, payload], meta.length + payload.length);
}
exports.createTextFrame = createTextFrame;
function createBinaryFrame(data, masked = false, first = true, fin = true) {
    let payload;
    if (masked) {
        payload = Buffer.alloc(data.length);
        data.copy(payload);
    }
    else
        payload = data;
    const meta = generateMetaData(fin, first ? 2 : 0, masked, payload);
    return Buffer.concat([meta, payload], meta.length + payload.length);
}
exports.createBinaryFrame = createBinaryFrame;
function createCloseFrame(code, reason = '', masked = false) {
    let payload;
    if (code && code !== 1005) {
        payload = Buffer.from(`--${reason}`);
        payload.writeUInt16BE(code, 0);
    }
    else {
        payload = Buffer.alloc(0);
    }
    const meta = generateMetaData(true, 8, masked, payload);
    return Buffer.concat([meta, payload], meta.length + payload.length);
}
exports.createCloseFrame = createCloseFrame;
function createPingFrame(data, masked = false) {
    const payload = Buffer.from(data);
    const meta = generateMetaData(true, 9, masked, payload);
    return Buffer.concat([meta, payload], meta.length + payload.length);
}
exports.createPingFrame = createPingFrame;
function createPongFrame(data, masked = false) {
    const payload = Buffer.from(data);
    const meta = generateMetaData(true, 10, masked, payload);
    return Buffer.concat([meta, payload], meta.length + payload.length);
}
exports.createPongFrame = createPongFrame;
function generateMetaData(fin, opcode, masked, payload) {
    const len = payload.length;
    const meta = Buffer.alloc(2 + (len < 126 ? 0 : len < 65536 ? 2 : 8) + (masked ? 4 : 0));
    meta[0] = (fin ? 128 : 0) + opcode;
    meta[1] = masked ? 128 : 0;
    let start = 2;
    if (len < 126) {
        meta[1] += len;
    }
    else if (len < 65536) {
        meta[1] += 126;
        meta.writeUInt16BE(len, 2);
        start += 2;
    }
    else {
        meta[1] += 127;
        meta.writeUInt32BE(Math.floor(len / Math.pow(2, 32)), 2);
        meta.writeUInt32BE(len % Math.pow(2, 32), 6);
        start += 8;
    }
    if (masked) {
        const mask = Buffer.alloc(4);
        for (let i = 0; i < 4; i++) {
            meta[start + i] = mask[i] = Math.floor(Math.random() * 256);
        }
        for (let i = 0; i < payload.length; i++) {
            payload[i] ^= mask[i % 4];
        }
        start += 4;
    }
    return meta;
}