direttoforo/liquidsoap/telnet.go

package liquidsoap

import (
	"bufio"
	"fmt"
	"net"
	"strings"
)

// Client represents a telnet/unix domain connection to Liquidsoap
//
// A Client can perform low-level operations, such as Command(), or high-level operations such as Outputs()
type Client struct {
	Conn net.Conn
}

// NewTelnet returns a liquidsoap.Client created using telnet on the given parameters
func NewTelnet(host string, port int) (Client, error) {
	conn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", host, port))
	if err != nil {
		return Client{}, err
	}
	return Client{Conn: conn}, nil
}

// Close closes the connection
func (c *Client) Close() {
	if c.Conn != nil {
		c.Conn.Write([]byte("quit\n"))
		c.Conn.Close()
	}
}

// Command run a command, wait for output response to come and returns it
func (c *Client) Command(cmdline string) (string, error) {
	c.Conn.Write([]byte(cmdline + "\n"))
	var out, line string
	var err error
	reader := bufio.NewReader(c.Conn)
	for {
		if line, err = reader.ReadString('\n'); err != nil {
			return "", err
		}
		line = line[:len(line)-2] + "\n" // \r\n -> \n
		if line == "END\n" {
			return out, nil
		}
		out += line
	}
}

// Outputs will return a map of outputs that liquidsoap is handling.
// An output is set to true if it is enabled
func (c *Client) Outputs() (outputs map[string]bool, err error) {
	outputs = make(map[string]bool)
	var cmdout string
	cmdout, err = c.Command("list")
	if err != nil {
		return
	}
	lines := strings.Split(cmdout, "\n")
	for _, l := range lines {
		parts := strings.SplitN(l, " : ", 2)
		if len(parts) < 2 {
			continue
		}
		if strings.Index(parts[1], "output.") == 0 {
			name := strings.TrimSpace(parts[0])
			var enabled bool
			enabled, err = c.GetOutput(name)
			if err != nil {
				return
			}
			outputs[name] = enabled
		}
	}

	return
}

// GetOutput checks whether an output is enabled
func (c *Client) GetOutput(name string) (bool, error) {
	cmdout, err := c.Command(name + ".status")
	if err != nil {
		return false, err
	}
	return strings.TrimSpace(cmdout) == "on", nil
}

// SetOutput enables or disables an output
func (c *Client) SetOutput(name string, enabled bool) error {
	action := "stop"
	if enabled {
		action = "start"
	}
	cmdout, err := c.Command(fmt.Sprintf("%s.%s", name, action))
	if err != nil {
		return err
	}
	if strings.TrimSpace(cmdout) != "OK" {
		return fmt.Errorf("Error: liquidsoap replied '%s'", cmdout)
	}
	return nil
}