LCU Request

Making API request

Just use fetch to make LCU requests:

function acceptMatchFound() {
  fetch('/lol-matchmaking/v1/ready-check/accept', {
    method: 'POST',
  })
}

Note that fetch returns a Promise for async context, you should wrap it inside an async function.

async function getSummonerName() {
  const res = await fetch('/lol-summoner/v1/current-summoner')
  const data = await res.json()
  return data['displayName']
}

With LCDS (RTMP) calls, you can use URLSearchParams and JSON.strigify to construct call parameters.

async function quitLobby() { // dont know why people call it 'dodge'
  const params = new URLSearchParams({
    destination: 'lcdsServiceProxy',
    method: 'call',
    args: JSON.stringify(['', 'teambuilder-draft', 'quitV2', '']),
  })
  const url = '/lol-login/v1/session/invoke?' + params.toString()
  await fetch(url, { method: 'POST' })
}

LCU API docs

LCU WebSocket

When the WebSocket is ready, this link tag will appear:

html

<link rel="riot:plugins:websocket" href="wss://riot:.../">

Getting its URI with a simple query.

document.querySelector('link[rel="riot:plugins:websocket"]').href

Here is an example that subscribes to all API calls:

function subscribe() {
  const uri = document.querySelector('link[rel="riot:plugins:websocket"]').href
  const socket = new WebSocket(uri, 'wamp')

  socket.onopen = () => socket.send(JSON.stringify([5, 'OnJsonApiEvent']))
  socket.onmessage = async (message) => {
    const data = JSON.parse(message.data)
    console.log(data)
    // @todo process data
  }
}

window.addEventListener('load', () => {
  subscribe()
})

Listening a single API call, e.g /lol-gameflow/v1/gameflow-phase.

const TARGET_API = '/lol-gameflow/v1/gameflow-phase'
const TARGET_EVENT = TARGET_API.replace(/\//g, '_')
// OnJsonApiEvent_lol-gameflow_v1_gameflow-phase

socket.send(JSON.stringify([5, 'OnJsonApiEvent' + TARGET_EVENT]))

Send 6 to unsubscribe from a specific API call, or OnJsonApiEvent for all.

socket.send(JSON.stringify([6, '<EventName>']))

TIP

Since v1.1.0, we have introduced context.socket to for easier socket observation.

Unauthenticated issue

In some cases that the Ux loads faster than the LCU server, many API that require authentication will result in wrong value. You need to wait for this to be done before you start plugin initialization.

const delay = (t) => new Promise((r) => setTimeout(r, t))

async function init() {
  while (!await getSummonerName()) {
    await delay(500)
  }

  // continue
}

window.addEventListener('load', init)

TIP

You can do it with the WebSocket way.

RiotClient API

We provided a riotclient domain which helps you to make request to RiotClient API.

//riotclient/<api>
https://riotclient/<api>

For example:

function getAuthStatus() {
  return fetch('//riotclient/app-command/v1/auth/status')
    .then((res) => res.json())
}

RiotClient API docs

LCU Request ​

Making API request ​

LCU WebSocket ​

Unauthenticated issue ​

RiotClient API ​

LCU Request

Making API request

LCU WebSocket

Unauthenticated issue

RiotClient API