Add Unix socket for communicating with aerc

lib/socket.go

@@ -0,0 +1,82 @@
+package lib
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"net"
+	"net/url"
+	"path"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/kyoh86/xdg"
+)
+
+type AercServer struct {
+	logger   *log.Logger
+	listener net.Listener
+	OnMailto func(addr *url.URL) error
+}
+
+func StartServer(logger *log.Logger) (*AercServer, error) {
+	sockpath := path.Join(xdg.RuntimeDir(), "aerc.sock")
+	l, err := net.Listen("unix", sockpath)
+	if err != nil {
+		return nil, err
+	}
+	as := &AercServer{
+		logger:   logger,
+		listener: l,
+	}
+	// TODO: stash clients and close them on exit... bleh racey
+	go func() {
+		for {
+			conn, err := l.Accept()
+			if err != nil {
+				// TODO: Something more useful, in some cases, on wednesdays,
+				// after 2 PM, I guess?
+				as.logger.Println("Closing Unix server: %v", err)
+				return
+			}
+			go 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)
+	as.logger.Printf("Accepted Unix connection %d", clientId)
+	scanner := bufio.NewScanner(conn)
+	conn.SetDeadline(time.Now().Add(1 * time.Minute))
+	for scanner.Scan() {
+		conn.SetDeadline(time.Now().Add(1 * time.Minute))
+		msg := scanner.Text()
+		if !strings.ContainsRune(msg, ':') {
+			conn.Write([]byte("error: invalid command\n"))
+		}
+		as.logger.Printf("unix:%d: got message %s", clientId, msg)
+		prefix := msg[:strings.IndexRune(msg, ':')]
+		switch prefix {
+		case "mailto":
+			mailto, err := url.Parse(msg)
+			if err != nil {
+				conn.Write([]byte(fmt.Sprintf("error: %v\n", err)))
+				break
+			}
+			if as.OnMailto != nil {
+				err = as.OnMailto(mailto)
+			}
+			conn.Write([]byte(fmt.Sprintf("result: %v\n", err)))
+		}
+	}
+	as.logger.Printf("Closed Unix connection %d", clientId)
+}