electron: Renderer IPC events in preload script not being delivered

Electron version: 1.3.2
Operating system: Windows

Hi All

I have followed the example for ipc communication here but it doesn’t seem to work.

my main process code:

const {ipcMain} = require('electron')
ipcMain.on('asynchronous-message', (event, arg) => {
  console.log(arg)  // prints "ping"
  event.sender.send('asynchronous-reply', 'async pong')
})

ipcMain.on('synchronous-message', (event, arg) => {
  console.log(arg)  // prints "ping"
  event.returnValue = 'sync pong'
})

my browser window code (inside a webview preload script):

const {ipcRenderer} = require('electron')
console.log(ipcRenderer.sendSync('synchronous-message', 'sync ping'))

ipcRenderer.on('asynchronous-reply', (event, arg) => {
  console.log(arg)
})
ipcRenderer.send('asynchronous-message', 'async ping')

I get the pings logged:

sync ping async ping

but only the synchronous pong:

sync pong

Is this a bug or am I doing something wrong?

About this issue

Original URL
State: closed
Created 8 years ago
Reactions: 4
Comments: 19 (5 by maintainers)

Commits related to this issue

Add FIXME link to #6828 — committed to electron/electron by kevinsawicki 7 years ago

Most upvoted comments

^^ 'did-finish-load' didnt work. Still having the same issue.

towfiqi on Aug 2, 2018

Thanks @riccardopiola , it was actually my misunderstanding of who will receive the event. I thought it will bubble up in the parent page, not in the main process. It works with both send and sendSync.

Just for future reference:

send and sendSync will send the message to the main process
sendToHost will send the message to the host webview and can be handled like in this example: https://electron.atom.io/docs/api/webview-tag/#event-ipc-message

victorhurdugaci on Nov 15, 2017

Can you test put your async code inside the listener did-finish-load:

window.webContents.on('did-finish-load', function() {
    /* your code here */
})

Reference: http://electron.atom.io/docs/api/web-contents/#contentssendchannel-arg1-arg2-

atilacamurca on Feb 22, 2017

@zcbenz any update on this issue?

MehediH on Dec 11, 2016

Hello @stilliard,

I tested with ipcRenderer.on(‘asynchronous-reply’, (arg) => {} Still reproduce the issue. It is reproduced with the following conditions:

IPCRenderer.send called in proload script
asynchronous callback comes back really fast from the other process

I debugged in the code of electron, and think the root cause is that when the message comes back from the other process too fast, document_created_ is false, so electron doesn’t passes the message to the above javascript layer.

void AtomRenderViewObserver::OnBrowserMessage(bool send_to_all, const base::string16& channel, const base::ListValue& args) { if (!document_created_) return;

if (!render_view()->GetWebView()) return; … }

chengxiaojiao on Nov 7, 2016

Similar issue here, except for me in the preload script it works if I change: ipcRenderer.on('asynchronous-reply', (event, arg) => { to ipcRenderer.on('asynchronous-reply', (arg) => {

Looks like the event isn’t being passed in here, instead just the data of the event. This is on electron v1.4.4 on xubuntu 16.04

stilliard on Oct 24, 2016