Chrome，允许自动连接 HID 设备

Question

So I'm trying to read out a USB-scale thats connected to my pc. I use chrome's experimental HID api.

I use Tampermonekey as userscript injector to extend a website's functionality.

The script I inject looks like this:

navigator.hid.requestDevice({ filters: [{ vendorId: 0x0922, productId: 0x8003}] }).then((devices) => {   
    if (devices.length == 0) return;
    devices[0].open().then(() => {
        if(disconnected) {
            disconnected = false
        }
        console.log("Opened device: " + devices[0].productName);
        devices[0].addEventListener("inputreport", handleInputReport);
        devices[0].sendReport(outputReportId, outputReport).then(() => {
            console.log("Sent output report " + outputReportId);
        });
    });
});

When I run it just like this(inline) I get the message in chrome:

DOMException: Failed to execute 'requestDevice' on 'HID': Must be handling a user gesture to show a permission request.

Basically, the code needs to be inside an event listener and the listener needs to be triggered by user input to run.

Al fine and dandy, except that this has to be initialized hundreds of times a day. I tried running this code in edge and here it just works without user input.

Is there a way I can disable this security feature(completely or only for the site im using it on) in chrome? I know edge is based on chromium so I expect it to be possible, but am unable to find how/where

Answer 1

You can useHID.getDevices() to retrieve an HID device that the user has already granted access to.

My suggestion would be to check for the device you want with getDevices first. If you can't find the device, then make something the user can interact with that will allow you to use requestDevice to connect to the device.