Example: local strategy

Each strategy has it's own options, but a common and required option is the Verify function. Which has to verify the incoming credentials, and return a response (including a JWT token).

// Creating a local strategy
func localStrategy() *local.Strategy {
	opt := &local.StrategyOptions{
		UsernameField: "username",
		PasswordField: "password",
		Verify: func(username, password string) *passport.Result {
            // check if username/password is valid

			token, err := getJWT(username)
			if err != nil {
				return &passport.Result{
					Code: http.StatusBadRequest,
					Message: err.Error(),
				}
            }

			return &passport.Result{
				Code: http.StatusOK,
				Data: AuthResponse{
					Token: token,
					Email: profile.Email,
				},
			}
		},
	}

	return local.New(opt)
}

Once you have created your strategy, you can attach them to your router. This example uses chi router.

func main() {
    r := chi.NewRouter()

    // Create passport instance
    p := passport.New(&passport.Options{
		Deserializer: deserializer,
    })

    // Attach the strategy, via a name
    p.Use("local", localStrategy())

    // Assign a endpoint
    r.Route("/auth", func(r chi.Router) {
		r.Get("/login", p.Authenticate("local", nil))
    })

    // Authenticated routes
    r.Group(func(r chi.Router) {
		r.Use(p.AuthRequired)
		r.Get("/home", HomeHandler)
	})

	http.ListenAndServe(":5000", r)
}

Creating a Deserializer

Deserializer function is required to create a instance of passport. Responsibility of deserializer function is to verify the JWT, and return some data about the user, which is then available to other http.Handler in context with key passport.Ctxkey

This example uses "github.com/dgrijalva/jwt-go" to parse the JWT

func deserializer(tokstr string) (interface{}, error) {
	token, err := jwt.Parse(tokstr, func(token *jwt.Token) (interface{}, error) {
		return []byte(Secret), nil
	})
	if err != nil {
		return nil, err
	}

	m := token.Claims.(jwt.MapClaims)
	return AuthResponse{
		Email: m["email"].(string),
	}, nil
}