aerc/lib/socket.go

package lib

import (
	"bufio"
	"errors"
	"fmt"
	"net"
	"net/url"
	"os"
	"path"
	"strings"
	"sync/atomic"
	"time"

	"git.sr.ht/~rjarry/aerc/logging"
	"github.com/kyoh86/xdg"
)

type AercServer struct {
	listener net.Listener
	OnMailto func(addr *url.URL) error
	OnMbox   func(source string) error
}

func StartServer() (*AercServer, error) {
	sockpath := path.Join(xdg.RuntimeDir(), "aerc.sock")
	// remove the socket if it is not connected to a session
	if err := ConnectAndExec(""); err != nil {
		os.Remove(sockpath)
	}
	logging.Infof("Starting Unix server: %s", sockpath)
	l, err := net.Listen("unix", sockpath)
	if err != nil {
		return nil, err
	}
	as := &AercServer{listener: l}
	// TODO: stash clients and close them on exit... bleh racey
	go func() {
		defer logging.PanicHandler()

		for {
			conn, err := l.Accept()
			if err != nil {
				// TODO: Something more useful, in some cases, on wednesdays,
				// after 2 PM, I guess?
				logging.Errorf("Closing Unix server: %v", err)
				return
			}
			go func() {
				defer logging.PanicHandler()

				as.handleClient(conn)
			}()
		}
	}()
	return as, nil
}

func (as *AercServer) Close() {
	as.listener.Close()
}

var lastId int64 = 0 // access via atomic

func (as *AercServer) handleClient(conn net.Conn) {
	clientId := atomic.AddInt64(&lastId, 1)
	logging.Debugf("unix:%d accepted connection", clientId)
	scanner := bufio.NewScanner(conn)
	err := conn.SetDeadline(time.Now().Add(1 * time.Minute))
	if err != nil {
		logging.Errorf("failed to set deadline: %v", err)
	}
	for scanner.Scan() {
		err = conn.SetDeadline(time.Now().Add(1 * time.Minute))
		if err != nil {
			logging.Errorf("failed to update deadline: %v", err)
		}
		msg := scanner.Text()
		logging.Debugf("unix:%d got message %s", clientId, msg)
		if !strings.ContainsRune(msg, ':') {
			_, innererr := conn.Write([]byte("error: invalid command\n"))
			if innererr != nil {
				logging.Errorf("failed to write error message: %v", innererr)
			}
			continue
		}
		prefix := msg[:strings.IndexRune(msg, ':')]
		var err error
		switch prefix {
		case "mailto":
			mailto, err := url.Parse(msg)
			if err != nil {
				_, innererr := conn.Write([]byte(fmt.Sprintf("error: %v\n", err)))
				if innererr != nil {
					logging.Errorf("failed to write error message: %v", innererr)
				}
				break
			}
			if as.OnMailto != nil {
				err = as.OnMailto(mailto)
				if err != nil {
					logging.Errorf("mailto failed: %v", err)
				}
			}
		case "mbox":
			if as.OnMbox != nil {
				err = as.OnMbox(msg)
			}
		}
		if err != nil {
			_, err = conn.Write([]byte(fmt.Sprintf("result: %v\n", err)))
			if err != nil {
				logging.Errorf("failed to send error: %v")
			}
		} else {
			_, err = conn.Write([]byte("result: success\n"))
			if err != nil {
				logging.Errorf("failed to send successmessage: %v")
			}
		}
	}
	logging.Debugf("unix:%d closed connection", clientId)
}

func ConnectAndExec(msg string) error {
	sockpath := path.Join(xdg.RuntimeDir(), "aerc.sock")
	conn, err := net.Dial("unix", sockpath)
	if err != nil {
		return err
	}
	_, err = conn.Write([]byte(msg + "\n"))
	if err != nil {
		return fmt.Errorf("failed to send message: %w", err)
	}
	scanner := bufio.NewScanner(conn)
	if !scanner.Scan() {
		return errors.New("No response from server")
	}
	result := scanner.Text()
	fmt.Println(result)
	return nil
}