diff options
Diffstat (limited to 'node_modules/undici/lib/websocket/frame.js')
-rw-r--r-- | node_modules/undici/lib/websocket/frame.js | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/node_modules/undici/lib/websocket/frame.js b/node_modules/undici/lib/websocket/frame.js new file mode 100644 index 0000000..d867ad1 --- /dev/null +++ b/node_modules/undici/lib/websocket/frame.js @@ -0,0 +1,73 @@ +'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 +} |