utilityProcess
utilityProcess
creates a child process with Node.js and Message ports enabled. It provides the equivalent of child_process.fork
API from Node.js but instead uses Services API from Chromium to launch the child process.
Prozess: Haupt
Methoden
utilityProcess.fork(modulePath[, args][, options])
modulePath
string - Path to the script that should run as entrypoint in the child process.args
string[] (optional) - List of string arguments that will be available asprocess.argv
in the child process.
Gibt UtilityProcess
zurück
Class: UtilityProcess
Instances of the
UtilityProcess
represent the Chromium spawned child process with Node.js integration.
UtilityProcess
ist ein EventEmitter.
Beispiel Methoden
child.postMessage(message, [transfer])
message
anytransfer
MessagePortMain[] (optional)
Send a message to the child process, optionally transferring ownership of zero or more MessagePortMain
objects.
Ein Beispiel:
// Main process
const { port1, port2 } = new MessageChannelMain()
const child = utilityProcess.fork(path.join(__dirname, 'test.js'))
child.postMessage({ message: 'hello' }, [port1])
// Child process
process.parentPort.once('message', (e) => {
const [port] = e.ports
// ...
})
child.kill()
Gibt boolean
zurück
Terminates the process gracefully. On POSIX, it uses SIGTERM but will ensure the process is reaped on exit. This function returns true if the kill is successful, and false otherwise.
Instanz Eigenschaften
child.pid
A Integer | undefined
representing the process identifier (PID) of the child process. Until the child process has spawned successfully, the value is undefined
. When the child process exits, then the value is undefined
after the exit
event is emitted.
const child = utilityProcess.fork(path.join(__dirname, 'test.js'))
console.log(child.pid) // undefined
child.on('spawn', () => {
console.log(child.pid) // Integer
})
child.on('exit', () => {
console.log(child.pid) // undefined
})
Note: You can use the pid
to determine if the process is currently running.
child.stdout
A NodeJS.ReadableStream | null
that represents the child process's stdout. If the child was spawned with options.stdio[1] set to anything other than 'pipe', then this will be null
. When the child process exits, then the value is null
after the exit
event is emitted.
// Main process
const { port1, port2 } = new MessageChannelMain()
const child = utilityProcess.fork(path.join(__dirname, 'test.js'))
child.stdout.on('data', (data) => {
console.log(`Received chunk ${data}`)
})
child.stderr
A NodeJS.ReadableStream | null
that represents the child process's stderr. If the child was spawned with options.stdio[2] set to anything other than 'pipe', then this will be null
. When the child process exits, then the value is null
after the exit
event is emitted.
Instanz-Ereignisse
Event: 'spawn'
Emitted once the child process has spawned successfully.
Event: 'error' Experimental
Kehrt zurück:
type
string - Type of error. Einer der folgenden Werte:FatalError
location
string - Source location from where the error originated.report
string -Node.js diagnostic report
.
Emitted when the child process needs to terminate due to non continuable error from V8.
No matter if you listen to the error
event, the exit
event will be emitted after the child process terminates.
Event: 'exit'
Kehrt zurück:
code
number - Contains the exit code for the process obtained from waitpid on POSIX, or GetExitCodeProcess on Windows.
Emitted after the child process ends.
Event: 'message'
Kehrt zurück:
message
any
Emitted when the child process sends a message using process.parentPort.postMessage()
.