gosmartkeyboard/Client.md

GoSmartKeyboard Client

When GoSmartKeyboard is started in client mode, it does the following:

1. Load the connection URL from the second CLI argument.
2. Load the auth token from the environment variable KEYBOARD_AUTH or stdin.
3. Connect to the server. 4 Send the auth token to the server.
4. If the server responds with "authenticated", we start reading keys from stdin and sending them to the server until EOF.
5. If KEYBOARD_FIFO is specified as an environment variable, we read from the path specified there instead as a named pipe.

--- handle client command

if len(os.Args) > 1 && os.Args[1] == "connect" {
    @{get client fifo input file from environment}
    @{setup client}
    if clientFifoInputFileExists {
        @{start client with fifo}
        os.Exit(0)
    }
    @{start client with stdin}
    os.Exit(0)
}

---

Connecting

The base64 authentication token is loaded from the environment variable KEYBOARD_AUTH, if it does not exist we read it from stdin (base64 encoded), ended with a newline.

--- setup client

@{load connection URL from second CLI argument}
@{get authTokenInput from environment}
@{add xdotool if non qwerty function}

if !authTokenInputExists {
    fmt.Print("Enter authentication token: ")
    _, err := fmt.Scanln(&authTokenInput)
    if err != nil {
        log.Fatal(err)
    }
}

client, _, err := websocket.DefaultDialer.Dial(connectionURL, nil)
if err != nil {
    log.Fatal("dial:", err)
}
defer client.Close()

err = client.WriteMessage(websocket.TextMessage, []byte(authTokenInput))

if err != nil {
    log.Fatal("write:", err)
}

_, authResponse, err := client.ReadMessage()
if err != nil {
    log.Fatal("read:", err)
}
if string(authResponse) == "authenticated" {
    fmt.Println("authenticated")
} else {
    log.Fatal("authentication failed")
}


---

--- load connection URL from second CLI argument --- noWeave

if len(os.Args) < 3 {
    log.Fatal("missing connection URL")
}

connectionURL := os.Args[2]

if !strings.HasPrefix(connectionURL, "ws://") && !strings.HasPrefix(connectionURL, "wss://") {
    log.Fatal("connection URL must start with ws:// or wss://")
}

---

Sending keys from a named pipe

--- start client with fifo


var inputString string

for {
    input, err := ioutil.ReadFile(clientFifoInputFile)
    if err != nil {
        log.Fatal(err)
    }
    inputString = addXDoToolIfNonQWERTY(string(input))
    input = []byte(inputString)
    if len(input) > 0 {
        fmt.Println("send" + strings.Replace(string(input), " ", "space", 10))
        err = client.WriteMessage(websocket.TextMessage, input)
        if err != nil {
            log.Fatal("write:", err)
        }
    }

}

---

Sending keys from stdin

We read keys from stdin and send them to the server until we get EOF

--- start client with stdin

reader := bufio.NewReader(os.Stdin)
for {
    var key string
    
    
    rune, _, err := reader.ReadRune() //:= fmt.Scan(&key)
    key = addXDoToolIfNonQWERTY(string(rune))

    if err != nil {
        if err == io.EOF {
            break
        }
        log.Fatal(err)
    }
    fmt.Println("send" + strings.Replace(key, " ", "space", 10))
    err = client.WriteMessage(websocket.TextMessage, []byte(key))
    if err != nil {
        log.Fatal("write:", err)
    }
}

---

Handling unicode outside of the ASCII set

--- add xdotool if non qwerty function --- noWeave
addXDoToolIfNonQWERTY := func(message string)(string) {
    if strings.HasPrefix(message, "{kb_cmd:xdotool}:") {
        return message
    }
    for _, char := range message {
        if char < 32 || char > 126  {
            if char != 8 && char != 9 && char != 10 {
                return "{kb_cmd:xdotool}:" + message
            }
        }
    }
    return message

}

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