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
}

// Stream represents a liquidsoap stream. It contains information about the status and the nature of it
type Stream struct {
	Enabled bool `json:"enabled"`
	Up bool `json:"up"`
	Type string `json:"type"`
}

// 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]Stream, err error) {
	outputs = make(map[string]Stream)
	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 stream Stream
			stream.Type = parts[1][7:]
			enabled, err := c.GetOutput(name)
			if err == nil {
			stream.Enabled = enabled
			}
			up, err := c.GetOutputUp(name)
			if err == nil {
				stream.Up = up
			}
			outputs[name] = stream
		}
	}

	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
}

// GetOutput checks whether an output is up
//
// Please note that this relies on a custom convention proposed by direttoforo, where to every stream "x"
// there is an interactive boolean variable "x_up" that has its state
func (c *Client) GetOutputUp(name string) (bool, error) {
	return c.GetVar(name + "_up")
}

// GetVar reads an interactive variable
func (c *Client) GetVar(name string) (bool, error) {
	cmdout, err := c.Command("var.get " + name)
	if err != nil {
		return false, err
	}
	cmdout = strings.TrimSpace(cmdout)
	switch cmdout {
	case "true":
		return true, nil
	case "false":
		return false, nil
	default:
		return false, fmt.Errorf("Variable %s not set", name)
	}
}

// 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
}