90 lines
2.1 KiB
Markdown
90 lines
2.1 KiB
Markdown
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# Streaming keyboard input
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We use the Gorilla websocket library to handle the websocket connection.
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Most of the time, we can use sendkeys (which uses libinput) to effeciently press keys. However, if we need to send a character that sendkeys doesn't know about, we can use the xdotool command. xdotool is also useful if one does not want to use root.
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xdotool spawns a new process for each keypress, so it's not as effecient as sendkeys.
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To specify xdotool usage, the client should send a message with the format `{kb_cmd:xdotool}:message` where message is a utf-8 string.
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``` go
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--- streaming keyboard input
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func clientConnected(w http.ResponseWriter, r *http.Request) {
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// regex if string has characters we need to convert to key presses
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characterRegex, _ := regexp.Compile(`[^\x08]\x08|\t|\n`)
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keyboard, err := sendkeys.NewKBWrapWithOptions(sendkeys.Noisy)
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@{always use xdotool environment variable}
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if err != nil {
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panic(err)
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}
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c, err := upgrader.Upgrade(w, r, nil)
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if err != nil {
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log.Print("upgrade:", err)
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return
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}
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defer c.Close()
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// get auth token
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_, message, err := c.ReadMessage()
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if err != nil {
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log.Println("read:", err)
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return
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}
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if auth.CheckAuthToken(string(message)) != nil {
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log.Println("invalid token")
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c.WriteMessage(websocket.TextMessage, []byte("invalid token"))
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return
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}
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c.WriteMessage(websocket.TextMessage, []byte("authenticated"))
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for {
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time.Sleep(25 * time.Millisecond)
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_, message, err := c.ReadMessage()
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if err != nil {
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log.Println("read:", err)
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break
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}
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log.Printf("recv: %s", message)
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message_string := string(message)
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if message_string == "" {
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message_string = "\n"
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}
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@{send keys to system}
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}
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}
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---
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```
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# Sending the keys
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Sending the keys is a bit tricky as we need to manually convert backspace, tab, enter and modifier keys.
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``` go
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--- send keys to system
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doXDoTool := func(command string, keys string)(err error) {
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var cmd *exec.Cmd
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if command == "type" {
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cmd = exec.Command("xdotool", command, "--delay", "25", keys)
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} else {
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cmd = exec.Command("xdotool", command, keys)
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}
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return cmd.Run()
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}
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@{handle xdotoool commands}
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@{do streaming sendkeys approach}
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---
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```
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