forked from waja/action-debian-package
74 lines
1.7 KiB
JavaScript
74 lines
1.7 KiB
JavaScript
'use strict'
|
|
|
|
const { maxUnsigned16Bit } = require('./constants')
|
|
|
|
/** @type {import('crypto')} */
|
|
let crypto
|
|
try {
|
|
crypto = require('crypto')
|
|
} catch {
|
|
|
|
}
|
|
|
|
class WebsocketFrameSend {
|
|
/**
|
|
* @param {Buffer|undefined} data
|
|
*/
|
|
constructor (data) {
|
|
this.frameData = data
|
|
this.maskKey = crypto.randomBytes(4)
|
|
}
|
|
|
|
createFrame (opcode) {
|
|
const bodyLength = this.frameData?.byteLength ?? 0
|
|
|
|
/** @type {number} */
|
|
let payloadLength = bodyLength // 0-125
|
|
let offset = 6
|
|
|
|
if (bodyLength > maxUnsigned16Bit) {
|
|
offset += 8 // payload length is next 8 bytes
|
|
payloadLength = 127
|
|
} else if (bodyLength > 125) {
|
|
offset += 2 // payload length is next 2 bytes
|
|
payloadLength = 126
|
|
}
|
|
|
|
const buffer = Buffer.allocUnsafe(bodyLength + offset)
|
|
|
|
// Clear first 2 bytes, everything else is overwritten
|
|
buffer[0] = buffer[1] = 0
|
|
buffer[0] |= 0x80 // FIN
|
|
buffer[0] = (buffer[0] & 0xF0) + opcode // opcode
|
|
|
|
/*! ws. MIT License. Einar Otto Stangvik <einaros@gmail.com> */
|
|
buffer[offset - 4] = this.maskKey[0]
|
|
buffer[offset - 3] = this.maskKey[1]
|
|
buffer[offset - 2] = this.maskKey[2]
|
|
buffer[offset - 1] = this.maskKey[3]
|
|
|
|
buffer[1] = payloadLength
|
|
|
|
if (payloadLength === 126) {
|
|
buffer.writeUInt16BE(bodyLength, 2)
|
|
} else if (payloadLength === 127) {
|
|
// Clear extended payload length
|
|
buffer[2] = buffer[3] = 0
|
|
buffer.writeUIntBE(bodyLength, 4, 6)
|
|
}
|
|
|
|
buffer[1] |= 0x80 // MASK
|
|
|
|
// mask body
|
|
for (let i = 0; i < bodyLength; i++) {
|
|
buffer[offset + i] = this.frameData[i] ^ this.maskKey[i % 4]
|
|
}
|
|
|
|
return buffer
|
|
}
|
|
}
|
|
|
|
module.exports = {
|
|
WebsocketFrameSend
|
|
}
|