docs: example showing how to handle user identity (#54)

* docs: example showing how to handle user identity

An simple example showing how to handle user identity.

Signed-off-by: Carlos A Becker <caarlos0@users.noreply.github.com>

* fix: use ssh.KeysEqual

Co-authored-by: Ayman Bagabas <ayman.bagabas@gmail.com>

.gitignore

@@ -1,5 +1,6 @@
 examples/*
 !examples/simple
+!examples/identity
 !examples/bubbletea
 examples/bubbletea/bubbletea
 examples/bubbletea/.ssh
@@ -13,4 +14,4 @@ examples/git/.repos
 coverage.txt
 
 # MacOS specific
-.DS_Store
+.DS_Store

examples/identity/main.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/charmbracelet/wish"
+	"github.com/charmbracelet/wish/logging"
+	"github.com/gliderlabs/ssh"
+)
+
+const (
+	host = "localhost"
+	port = 23234
+)
+
+func main() {
+	s, err := wish.NewServer(
+		wish.WithAddress(fmt.Sprintf("%s:%d", host, port)),
+		wish.WithHostKeyPath(".ssh/term_info_ed25519"),
+		wish.WithPublicKeyAuth(func(ctx ssh.Context, key ssh.PublicKey) bool {
+			return true
+		}),
+		wish.WithMiddleware(
+			logging.Middleware(),
+			func(h ssh.Handler) ssh.Handler {
+				return func(s ssh.Session) {
+					carlos, _, _, _, _ := ssh.ParseAuthorizedKey(
+						[]byte("ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILxWe2rXKoiO6W14LYPVfJKzRfJ1f3Jhzxrgjc/D4tU7"),
+					)
+					switch {
+					case ssh.KeysEqual(s.PublicKey(), carlos):
+						wish.Println(s, "Hey Carlos!")
+					default:
+						wish.Println(s, "Hey, I don't know who you are!")
+					}
+					h(s)
+				}
+			},
+		),
+	)
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	done := make(chan os.Signal, 1)
+	signal.Notify(done, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
+	log.Printf("Starting SSH server on %s:%d", host, port)
+	go func() {
+		if err = s.ListenAndServe(); err != nil {
+			log.Fatalln(err)
+		}
+	}()
+
+	<-done
+	log.Println("Stopping SSH server")
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer func() { cancel() }()
+	if err := s.Shutdown(ctx); err != nil {
+		log.Fatalln(err)
+	}
+}