@signalr-devtools/analysis

Decode and analyze captured ASP.NET Core SignalR traffic in Node using the same protocol and analysis modules shipped by the SignalR Inspector browser extension.

This package is the headless analysis core. It does not install or expose the Chrome/Edge DevTools panel, capture browser traffic, connect to Chrome DevTools Protocol, or run an MCP server.

Install

npm install @signalr-devtools/analysis

The package is CommonJS and can also be imported from an ES module. The root export is the conversation analysis API; protocol parsing, MessagePack decoding, and session handling are available through explicit subpaths.

ES modules can use named imports from both the root and the explicit subpaths:

import { analyze } from '@signalr-devtools/analysis';
import { parsePayload } from '@signalr-devtools/analysis/signalrProtocol';

const result = analyze(messages, parsePayload);

The same APIs are available to CommonJS consumers:

const analysis = require('@signalr-devtools/analysis');
const protocol = require('@signalr-devtools/analysis/signalrProtocol');

const separator = '\u001e';
const invocationPayload =
  JSON.stringify({
    type: 1,
    invocationId: '1',
    target: 'SendMessage',
    arguments: ['Ada', 'Hello'],
  }) + separator;
const completionPayload = JSON.stringify({ type: 3, invocationId: '1' }) + separator;
const messages = [
  {
    id: 1,
    direction: 'outgoing',
    endpoint: 'https://localhost/chatHub',
    transport: 'websocket',
    timestamp: 100,
    encoding: 'text',
    size: invocationPayload.length,
    textPayload: invocationPayload,
  },
  {
    id: 2,
    direction: 'incoming',
    endpoint: 'https://localhost/chatHub',
    transport: 'websocket',
    timestamp: 145,
    encoding: 'text',
    size: completionPayload.length,
    textPayload: completionPayload,
  },
];

const result = analysis.analyze(messages, protocol.parsePayload);
console.log(result.insights.summary.hubMessages); // 2
console.log(result.insights.methods[0].target); // SendMessage

Public modules

• @signalr-devtools/analysis or /signalrAnalysis: analyze, formatDuration
• /signalrProtocol: parsePayload, formatPayload
• /msgpackDecoder: decode, decodeVarIntFrames
• /sessionFormat: create, parse, serialize, FORMAT, VERSION, MAX_FILE_CHARACTERS

Load /msgpackDecoder before parsing binary payloads with /signalrProtocol, matching the script order used by the extension. Importing it registers the decoder used by the shared protocol module.

The exported SignalR Inspector session format is currently version 1. Package versions and session-format versions are independent.

This project is not affiliated with or endorsed by Microsoft.

License

MIT