node-libsharedmemory

node-libsharedmemory is a native Node.js module that is based on libsharedmemory. It can be used to read and write to shared memory on Windows, Linux and macOS. node-libsharedmemory makes it easy to transfer data between isolated host OS processes and Node.js applications. It also helps inter-connecting modules of applications that are implemented in different programming languages.

Example

const {
    NodeSharedMemoryWriteStream,
    NodeSharedMemoryReadStream
} = require("node-libsharedmemory");

// this can happen in other Node.js processes or any other application
// using libsharedmemory to write data
const streamWriter = new NodeSharedMemoryWriteStream();

streamWriter.writeString(`{ remoteApp: { is: 'sending', data: 'ab😃ab😃ab😃' } }`);

const streamReader = new NodeSharedMemoryReadStream();

const data = streamReader.readString();

// data equals the data written via .write() before
console.log('Data received from shared memory', data);

Use

Just install it via:

npm install node-libsharedmemory

The example examples/basic should be pretty self-explanatory.

Limits

libsharedmemory does only support the following datatypes:

• String (readString, writeString)

• Float32Array (readFloatArray, writeFloatArray)

• Float64Array (readDoubleArray, writeDoubleArray)

• This library doesn't care for endinanness. This should be naturally fine because shared memory shouldn't be shared between different machine architectures. However, if you plan to copy the shared buffer onto a network layer prototcol, make sure to add an endianess indication bit.

• At the time of writing, there is no support for shared memory persistency on Windows. Shared memory is lost after the writing process is killed.

Build

To re-build the module from source call: npm run rebuild

Test

The module can be tested via: npm test

License

node-libsharedmemory is released under the MIT license, see the LICENSE file.

Roadmap

1. Native onChange() event handling abstraction (currently needs a for-loop change detection in V8)
2. Windows shared memory persistency support