clipboard 
Cross platform (macOS/Linux/Windows/Android/iOS) clipboard package in Go
import "golang.design/x/clipboard"
Features
- Cross platform supports: macOS, Linux (X11), Windows, iOS, and Android
- Copy/paste UTF-8 text
- Copy/paste PNG encoded images (Desktop-only)
- Command
gclipas a demo application - Mobile app
gclip-guias a demo application
API Usage
Package clipboard provides three major APIs for manipulating the clipboard: Read, Write, and Watch. The most common operations are Read and Write. To use them, you can:
// write/read text format data of the clipboard, and
// the byte buffer regarding the text are UTF8 encoded.
clipboard.Write(clipboard.FmtText, []byte("text data"))
clipboard.Read(clipboard.FmtText)
// write/read image format data of the clipboard, and
// the byte buffer regarding the image are PNG encoded.
clipboard.Write(clipboard.FmtImage, []byte("image data"))
clipboard.Read(clipboard.FmtImage)
Note that read/write regarding image format assumes that the bytes are PNG encoded since it serves the alpha blending purpose that might be used in other graphical software.
In addition, clipboard.Write returns a channel that can receive an empty struct as a signal, which indicates the corresponding write call to the clipboard is outdated, meaning the clipboard has been overwritten by others and the previously written data is lost. For instance:
changed := clipboard.Write(clipboard.FmtText, []byte("text data"))
select {
case <-changed:
println(`"text data" is no longer available from clipboard.`)
}
You can ignore the returning channel if you don't need this type of notification. Furthermore, when you need more than just knowing whether clipboard data is changed, use the watcher API:
ch := clipboard.Watch(context.TODO(), clipboard.FmtText)
for data := range ch {
// print out clipboard data whenever it is changed
println(string(data))
}
Demos
- A command line tool
gclipfor command line clipboard accesses, see document here. - A GUI application
gclip-guifor functionality verifications on mobile systems, see a document here.
Command Usage
gclip command offers the ability to interact with the system clipboard from the shell. To install:
$ go install golang.design/x/clipboard/cmd/gclip@latest
$ gclip
gclip is a command that provides clipboard interaction.
usage: gclip [-copy|-paste] [-f <file>]
options:
-copy
copy data to clipboard
-f string
source or destination to a given file path
-paste
paste data from clipboard
examples:
gclip -paste paste from clipboard and prints the content
gclip -paste -f x.txt paste from clipboard and save as text to x.txt
gclip -paste -f x.png paste from clipboard and save as image to x.png
cat x.txt | gclip -copy copy content from x.txt to clipboard
gclip -copy -f x.txt copy content from x.txt to clipboard
gclip -copy -f x.png copy x.png as image data to clipboard
If -copy is used, the command will exit when the data is no longer available from the clipboard. You can always send the command to the background using a shell & operator, for example:
$ cat x.txt | gclip -copy &
Platform Specific Details
This package spent efforts to provide cross platform abstraction regarding accessing system clipboards, but here are a few details you might need to know.
Dependency
- macOS: require Cgo, no dependency
- Linux: require X11 dev package. For instance, install
libx11-devorxorg-devorlibX11-develto access X window system. - Windows: no Cgo, no dependency
- iOS/Android: collaborate with
gomobile
Screenshot
In general, when you need test your implementation regarding images, There are system level shortcuts to put screenshot image into your system clipboard:
- On macOS, use
Ctrl+Shift+Cmd+4 - On Linux/Ubuntu, use
Ctrl+Shift+PrintScreen - On Windows, use
Shift+Win+s
As described in the API documentation, the package supports read/write UTF8 encoded plain text or PNG encoded image data. Thus, the other types of data are not supported yet, i.e. undefined behavior.
Who is using this package?
The main purpose of building this package is to support the midgard project, which offers clipboard-based features like universal clipboard service that syncs clipboard content across multiple systems, allocating public accessible for clipboard content, etc.
To know more projects, check our wiki page.
License
MIT | © 2021 The golang.design Initiative Authors, written by Changkun Ou.
