inter-process-messaging

Source code of released version | Source code of development version

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Support for sending messages between a parent process and a child process that was spawned (by the parent) with an IPC channel.

Usage

After spawning a child process, calling enable(childProcess) enables childProcess.sendMessage(topic, payload), which delivers payload to any listeners in the child process that were registered for the given topic string.

Child processes register themselves to receive messages by calling onMessage(topic, callback). The callback function may return a Promise, in which case the parent will receive an array of callback results from all children that subscribed to the given topic, after the results have been resolved.

Note that both payload and the response values from the child process listeners will be serialized for delivery between processes, though the serialization library used by this code is more robust than JSON, so it can handle circular and repeated references, Sets and Maps that contain themselves, etc.

The key features that differentiate this API from the native Node childProcess.send(message) and childProcess.on("message", callback) APIs are (1) restricting messages to a particular topic string, (2) more robust serialization logic thanks to arson, and (3) reliable responses from all listener callbacks in the child process, which lets the parent process proceed with confidence that the child is done with its work.