rxws-recorder

rxws middleware for helping read websocket requests and responses.

Motivation

Browser devtool support for requests/responses over websockets is limited because the browser has no way of knowing which response corresponds to which request. Additionally, most of the common backends for rxws (such as sock.js) do not send pure JSON to the server, nor do they receive pure JSON, which means that browser devtools can only show the websocket frames as one big string (instead of an explorable json object).

Solution

rxws-recorder lets you explore the history of rxws requests, responses, and server pushes. It does this by exposing a global object, rxwsHistory (or the shorter version rh) on the window.

Quickstart

You must somehow include rxws-recorder into your app. Then you must call startRecording either on the global object or through the es6 module. This is usually done with:

import * as rxwsRecorder from 'rxws-recorder';
import rxws from 'rxws';
 
rxwsRecorder.startRecording(rxws);

Global Object API

window.rh

An array of request/response objects, ordered from most recent to least recent. Each object has the following schema:

// each object in the array looks like this
{
  resource: 'get.users', // a string
  request: {...}, // the request object
  response: {...}, // the response object
  statusCode: 200, // An integer representing the status code of the request
}

window.rh.mostRecent

Mostly equivalent to doing rh[0], but it handles not having any requests at all.

window.rh.isRecording

A boolean value that indicates whether rxws-recorder is recording all the request/responses. Instead of changing this value directly, you should call window.rh.startRecording or window.rh.stopRecording. Otherwise things will not work.

window.rh.startRecording(rxws)

Call this function when you want rxws-recorder to start recording all websocket requests.

Parameters

• rxws: the value that is the default export of the rxws npm package.

window.rh.stopRecording()

Call this function when you want rxws-recorder to stop recording all websocket requests. Already recorded requests will be preserved.

window.rh.MAX_REQUESTS_RECORDED

An integer that represents the maximum number of objects to keep in the window.rh array. Defaults to 50. This value can be mutated directly by the user.

window.rh.clear()

A function that clears out all request/response objects in the window.rh array. Does not change window.rh.isRecording.

ES6 Module API

rxws-recorder doesn't export a default export, but does export several named functions

startRecording(rxws)

See the global equivalent above.

stopRecording()

See the global equivalent above.

setMaxRequestsRecorded(max)

Call this only after you have called startRecording.

Parameters

• max: a positive integer that represents the maximum number of requests that will be in memory at any time.

clear()

See the global equivalent above.