Note: Designed for Windows

node-hidspy

An event based node.js c++ addon/binding to detect the hid device insertion/removal and notify the subscribed apps.

Prerequisties for installation

Before installing this package, make sure you have Node.js addon build tool node-gyp installed in your machine.

As node-gyp uses Python 2.x, make sure it is installed in your machine and it is on your EVN path.

If you dont have the python installed, then it is recommanded to install the windows-build-tools. To installl windows build tool, open CLI as adminstrator and execute the below command as per the issue discussed here.

npm --add-python-to-path='true' --debug install --global windows-build-tools

The above command would install pythin 2.x and build tools needed for windows. It would take few mins to complete the installation.

Installation

To install node-hidspy execute the below command

if you prefer npm

npm install node-hidspy

for yarn,

yarn add node-hidspy

Upon installation, node-gyp would start generating the c++ addon project as per the configuration we set in binding.gyp and compile the same. If the compilation is successfull, it would have generated the executable lib files in the buildfolder with Release configuration.

How to use it

require('node-hidspy') would populate the hidspy object which is of event type.

Activating the detection(spying on the usb controller)

var hidspy = require('node-hidspy');

hidspy.spyOn().then(() => {
    ...
})

Deactivating the detection

hidspy.spyOff() // would stop listening for the usb detection.

Listening for change

There is an event change which would be emitted when a usb device is inserted or removed. You can subscribe for the event and do necessory action upon the event.

hidspy.on('change', (device) => {
    console.log(device);
    /* { 
        name: '\\\\?\\HID#VID_1044&PID_7A13&MI_03#8&2346c4b6&0&0000#{4d1e55b2-f16f-11cf-88cb-001111000030}',
        vid: 4164,
        pid: 31251,
        hid: 0,
        guid: '4d1e55b2-f16f-11cf-001111000030',
        status: 1 
    } */
});

hidspy.on('end', () => {
    // would be triggered when you call `spyOff` function.
})

API

Properties

When an usb device is inserted, an Device object would be generated and emitted.

Device object has,

• device_status - It is an integer type property. The possible values for this property is 0 or 1 when 0 indicates the device is been removed from the system and the 1 indicates the device is been added.
• guid - It is an string type property. The unique numeric assigned to the usb storage device by the windows.
• vid - It is an integer type property. The vendor id is assigned by the USB Implementers Forum to a specific company.
• pid - It is an integer type property. The product id is assigned by the company for the individual product.
• interface - It is an integer type property. It is the interface index of the hid device.
• name - It is an string type property. It is the device name in device manager of windows.

Methods

There are four methods available in hidspy.

spyOn([callback])

spyOn method takes a callback as parameter and returns a promise object. Here callback is optional. Since spyOn returns promise, you can use then to kick start the detection.

When the addon is ready, callback would be called with true which indicates everything is OK if passed otherwise the promise would be resolve/rejected.

spyOff()

spyOff should be called when you wanted to stop listening for the usb device change.

Events

There are two events emitted from the hidspy module.

change - hidspy.on('change' callback(device))

When any usb storage device is been inserted/removed into/from the machine, change event would be triggered with the Device object.

end - hidspy.on('end', callback)

When the spyOff method is called, the end event would be triggered.

Example

You can have a look into example/test.js for usage and example.

var hidspy = require('../index');

hidspy.spyOn().then(function() {

    hidspy.on('change', function(data) {
        console.log(data);
    });
    
    hidspy.on("end", function() {
        console.log('Stop to listen');
    });
});

setTimeout(() => {
    hidspy.spyOff();
}, 5000); // after 5 secs, would stop wathcing for device change.

Note:

When you DEBUG the c++ code, you have to comment the line#16 in the usbspy.h