hid

README

Gopher Interface Devices (USB HID)

The hid package is a cross platform library for accessing and communicating with USB Human Interface Devices (HID). It is an alternative package to gousb for use cases where devices support this ligher mode of operation (e.g. input devices, hardware crypto wallets).

The package wraps hidapi for accessing OS specific USB HID APIs directly instead of using low level USB constructs, which might have permission issues on some platforms. On Linux the package also wraps libusb. Both of these dependencies are vendored directly into the repository and wrapped using CGO, making the hid package self-contained and go-gettable.

Supported platforms at the moment are Linux, macOS and Windows (exclude constraints are also specified for Android and iOS to allow smoother vendoring into cross platform projects).

Cross-compiling

Using go get the embedded C library is compiled into the binary format of your host OS. Cross compiling to a different platform or architecture entails disabling CGO by default in Go, causing device enumeration hid.Enumerate() to yield no results.

To cross compile a functional version of this library, you'll need to enable CGO during cross compilation via CGO_ENABLED=1 and you'll need to install and set a cross compilation enabled C toolkit via CC=your-cross-gcc.

Acknowledgements

Although the hid package is an implementation from scratch, it was heavily inspired by the existing go.hid library, which seems abandoned since 2015; is incompatible with Go 1.6+; and has various external dependencies. Given its inspirational roots, I thought it important to give credit to the author of said package too.

Wide character support in the hid package is done via the gowchar library, unmaintained since 2013; non buildable with a modern Go release and failing go vet checks. As such, gowchar was also vendored in inline (copyright headers and origins preserved).

License

The components of hid are licensed as such:

• hidapi is released under the 3-clause BSD license.
• libusb is released under the GNU LGPL 2.1license.
• go.hid is released under the 2-clause BSD license.
• gowchar is released under the 3-clause BSD license.

Given the above, hid is licensed under GNU LGPL 2.1 or later on Linux and 3-clause BSD on other platforms.

Documentation

Overview

Package hid provides an interface for USB HID devices.

Index

• Variables
• type DeviceInfo

Variables

var ErrDeviceClosed = errors.New("hid: device closed")

ErrDeviceClosed is returned for operations where the device closed before or during the execution.

var ErrUnsupportedPlatform = errors.New("hid: unsupported platform")

ErrUnsupportedPlatform is returned for all operations where the underlying operating system is not supported by the library.

Types

type DeviceInfo

type DeviceInfo struct {
	Path         string // Platform-specific device path
	VendorID     uint16 // Device Vendor ID
	ProductID    uint16 // Device Product ID
	Release      uint16 // Device Release Number in binary-coded decimal, also known as Device Version Number
	Serial       string // Serial Number
	Manufacturer string // Manufacturer String
	Product      string // Product string
	UsagePage    uint16 // Usage Page for this Device/Interface (Windows/Mac only)
	Usage        uint16 // Usage for this Device/Interface (Windows/Mac only)

	// The USB interface which this logical device
	// represents. Valid on both Linux implementations
	// in all cases, and valid on the Windows implementation
	// only if the device contains more than one interface.
	Interface int
}

DeviceInfo is a hidapi info structure.