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pure nodejs evdev reader

JavaScript 90.10% Python 0.42% C++ 9.48%

node-evdev's Introduction

Evdev reader for nodeJS

An Evdev events reader.

Quick test : see index.js. Will open any plugged joystick and display events as they come.

node index.js event-<your_event_type>
#Example with joysticks/gamepads :
node index.js "event-joystick"
# If you have multiple similar devices, you can select by index with a third argument :
node index.js "event-joystick" 1

This app is dead simple on purpose to be easily customizable without having to read tons of source code. Please note that this module's main purpose is to provide an easy programming interface for nodejs modules, not a full-featured command line interface.

How it works

Internals

Basics are simple : find event devices, open them and listen for events.

Events are parsed in plain js. C++ native code is only used to make queries.

Options

Example :

{
  raw:false
}

Options Explained

Raw

get raw events or parsed (with string instead of uints).

Opening streams

You can specify evdev files to open in options. Or call the search method.

var reader = new EvdevReader();
reader.search("/dev/input/by-path","event-joystick",function(err){
  //Err should be null.
});

Events

Raw events

When in raw mode, events are emitted under the name "event" with the structure : { time : {tv_sec: , tv_usec: }, type : , code : , value : }

Parsed events

Events are emitted under an "event_type" name, with this structure : { time : {tv_sec: , tv_usec: }, code : , value : }

TODO

Add more tests
The app require the running user to be a member of the "input" group. A VM should be provided to allow for easy testing without risking to compromise the system. Alternatively, I'd be best to find a lightweight solution to safely provide inputs when testing.
Need a way to discover input capabilities and vendor infos like libevdev's libevdev_has_event_code().

Useful resources

Importing event codes

Event codes are found here

Use this regex : .#define (\w)\s*(0?x?[0-9a-f]{1,3}) replace with : $2:"$1",

node-evdev's People

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node-evdev's Issues

DeviceReader error events are not forwarded to EvdevReader

The following code throws Unhandled 'error' event error.

const EvdevReader = require("evdev");

const reader = new EvdevReader();
reader.on("error", (error) => console.log(error))

reader.open("/dev/null");

There is as expected a TypeError: Inappropriate ioctl for device error emitted by DeviceReader.init, but I would expect this error to be captured by the EvdevReader which in turn would emit an error event of its own.

index.js link on npmjs goes nowhere

Hey,
atyour npmjs entry you link your example like that which leads nowhere
https://github.com/klepthys/node-evdev/blob/HEAD/sdumetz/blob/master/index.js

Request: Implement EVIOCGRAB for exclusive control

Would it be possible to implement ioctl's EVIOCGRAB to provide exclusive control of a device so it doesn't send commands to the system at the same time as it is being monitored?

python-evdev has this feature implemented, I'm just not sure how to implement it here in Node.

https://python-evdev.readthedocs.io/en/latest/apidoc.html#evdev.device.InputDevice.grab

Thanks for the help!

Error: ESPIPE: invalid seek

This is likely not a library issue, but user error. I'm really not sure what I'm missing here, though.

I'm trying to recognize events coming from a simple USB gamepad under linux. I've got things working with the legacy, "jsdev" method via the node-joystick package, but I'm trying to switch to the evdev method.

I can cat /dev/input/by-id/usb-0810_usb_gamepad-event-joystick and see output as I press buttons, so it seems that the kernel is functioning properly, but when I run the index.js in this package, the output is as follows:

root@DietPi ~/t/n/evdev# ./index.js
searching for event streams matching undefined in : /dev/input/by-path
found 4 inputs
{ bustype: 3, vendor: 2064, product: 58625, version: 272 }
reader error :  { Error: ESPIPE: invalid seek, read errno: -29, code: 'ESPIPE', syscall: 'read' }
root@DietPi ~/t/n/evdev#

I would love a hint on this. What might be going wrong and what can I do about it?

Any help would be very much appreciated! Thanks!

multiple inputs same events

How can is isolate an event to a specific input? I'm monitoring events on multiple inputs with the same events so need to get a handle on both the event and the input that made it.

start reader when input device connects

Anyway to start a reader when the input device connects?