IPC between window and main

The window cannot touch files, the network or the database. It asks main through IPC channels, each a named request with an answer.

#The pieces

#The guard

src/main/ipc.ts wraps Electron's ipcMain with guardedIpcMain (src/main/ipc/guard.ts) before any handler is registered:

• handle checks that the sender is the app's own page (the built index.html or the app scheme; the Vite server in development). Any other frame, an iframe, or a page that navigated away gets the error "The request did not come from the app window." and the handler never runs.
• on, once, addListener, prependListener and handleOnce throw: they would carry no sender check. Use handle for every channel.

Inside the handler, treat every argument as untrusted: parse it with a zod schema and return a fixed error for anything that does not fit.

#Adding a channel

1. Add the name to IPC_CHANNELS in src/shared/ipc-channels.ts, and the same line to the copy in src/preload/index.ts.
2. Add the types to src/shared/contracts/ if the call carries more than a string.
3. In src/preload/index.ts, add a method to the electronAPI object and its line to the ElectronAPI type.
4. In main, add ipcMain.handle(IPC_CHANNELS.YOUR_CHANNEL, handler) to the right register…Ipc function. Parse the arguments; never return a secret.
5. Call it from a service in src/renderer/services/, not from a component.
6. Test the handler in tests/unit (call the function the handler uses), and the path through the window in an e2e test if a person can see the result.

Example in the code: the Help reader's help:tree, help:page and help:search in src/main/ipc/aboutIpc.ts.

#Streams

The assistant's answer comes back in pieces: the window sends a request on llm:stream-chat, and main sends chunks back to that window until the turn ends (src/main/ipc/agentIpc.ts, src/renderer/services/llm/chatService.ts).

#See also

• For developers
• Architecture
• Security