electron/docs/api/parent-port.md
Robo da0fd286b4
feat: UtilityProcess API (#34980)
* chore: initial scaffolding

* chore: implement interface and docs

* chore: address code style review

* fix: cleanup of utility process on shutdown

* chore: simplify NodeBindings::CreateEnvironment

* chore: rename disableLibraryValidation => allowLoadingUnsignedLibraries

* chore: implement process.parentPort

* chore(posix): implement stdio pipe interface

* chore(win): implement stdio interface

* chore: reenable SetNodeOptions for utility process

* chore: add specs

* chore: fix lint

* fix: update kill API

* fix: update process.parentPort API

* fix: exit event

* docs: update exit event

* fix: tests on linux

* chore: expand on some comments

* fix: shutdown of pipe reader

Avoid logging since it is always the case that reader end of
pipe will terminate after the child process.

* fix: remove exit code check for crash spec

* fix: rm PR_SET_NO_NEW_PRIVS for unsandbox utility process

* chore: fix incorrect rebase

* fix: address review feedback

* chore: rename utility_process -> utility

* chore: update docs

* chore: cleanup c++ implemantation

* fix: leak in NodeServiceHost impl

* chore: minor cleanup

* chore: cleanup JS implementation

* chore: flip default stdio to inherit

* fix: some api improvements

* Support cwd option
* Remove path restriction for modulePath
* Rewire impl for env support

* fix: add tests for cwd and env option

* chore: alt impl for reading stdio handles

* chore: support message queuing

* chore: fix lint

* chore: new UtilityProcess => utilityProcess.fork

* fix: support for uncaught exception exits

* chore: remove process.execArgv as default

* fix: windows build

* fix: style changes

* fix: docs and style changes

* chore: update patches

* spec: disable flaky test on win32 arm CI

Co-authored-by: PatchUp <73610968+patchup[bot]@users.noreply.github.com>
2022-10-19 22:49:49 -07:00

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Markdown

# parentPort
> Interface for communication with parent process.
Process: [Utility](../glossary.md#utility-process)
`parentPort` is an [EventEmitter][event-emitter].
_This object is not exported from the `'electron'` module. It is only available as a property of the process object in the Electron API._
```js
// Main process
const child = utilityProcess.fork(path.join(__dirname, 'test.js'))
child.postMessage({ message: 'hello' })
child.on('message', (data) => {
console.log(data) // hello world!
})
// Child process
process.parentPort.on('message', (e) => {
process.parentPort.postMessage(`${e.data} world!`)
})
```
## Events
The `parentPort` object emits the following events:
### Event: 'message'
Returns:
* `messageEvent` Object
* `data` any
* `ports` MessagePortMain[]
Emitted when the process receives a message. Messages received on
this port will be queued up until a handler is registered for this
event.
## Methods
### `parentPort.postMessage(message)`
* `message` any
Sends a message from the process to its parent.