Golang中如何从JWT的key中获取值

Golang中如何从JWT的key中获取值 在Echo框架网站上，我按照他们的指南创建了一个JWT，并定义了一个自定义声明类型来存储和传递用户的电子邮件到其他请求中。然而，在遵循指南后，我创建了一个函数来将令牌存储到数据库，但在尝试从“email”键中检索值时，它返回了一个错误，声称无法将声明转换为JWT。我测试了创建JWT的函数是否出了问题，但它返回的编码令牌是正常的。那么，我应该如何将JWT传递给我的电子邮件函数以从中提取值呢？

sessionmanager

type Session struct {
	Token  string
	Data   string
	Expiry time.Time
}

type UserCustomClaims struct {
	Email      string `json:"email"`
	jwt.RegisteredClaims
}

func Email(c echo.Context) (string, error) {
	user, ok := c.Get("user").(*jwt.Token)
	if !ok {
		return "", echo.NewHTTPError(http.StatusBadRequest, "error:sessionamanager: failed to convert to jwt token")
	}
	claims, ok := user.Claims.(*UserCustomClaims)
	if !ok {
		return "", echo.NewHTTPError(http.StatusBadRequest, "error:sessionamanager: failed to convert to customs claims type")
	}
	email := claims.Email
	if email == "" {
		return "", echo.NewHTTPError(http.StatusBadRequest, "failed to convert email")
	}
	return email, nil
}

// adds user token to sessions table in database
func CreateToken(usr string, c echo.Context) (*jwt.Token, error) {
	expirDate := time.Now().Add(time.Hour * 72).Unix()
	claims := &UserCustomClaims{
		Email:      usr,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Unix(expirDate, 0)),
		},
	}

	fmt.Printf("foo: %v\n", claims.Email)

	// Create token with claims
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)

	return token, nil
}

// adds user token to sessions table in database
func AddToken(tk *jwt.Token, c echo.Context) error {
	ctx, db := backend.Connect()
	defer db.Close()

	// Generate encoded token and send it as response.
	t, err := tk.SignedString([]byte("secret"))
	if err != nil {
		return err
	}

	email, emailErr := Email(c)
	if emailErr  != nil {
		return fmt.Errorf("error: failed to retreive to email from claim: %w", emailErr)
	}
	expTime, err := tk.Claims.GetExpirationTime()

	// err retrieving expiration time
	if err != nil {
		return errors.New("error: failed to get expiration time")
	}

	// insert token
	_, err = db.Exec(
		ctx,
		`INSERT INTO sessions (token, data, expiry) VALUES($1, $2, $3)`,
		t, email, expTime.Time,
	)

	// handle multiple errs when insertion goes wrong
	if err != nil {
		return fmt.Errorf("error: failed to add usersession: %w", err)
	}
	return nil
}

主文件

import (
	"errors"
	"fmt"
	"html/template"
	"io"
	"log"
	"net/http"

	"scriptmang/drumstick/internal/sessionmanager"

	"github.com/golang-jwt/jwt/v5"
	echojwt "github.com/labstack/echo-jwt/v4"
	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
)

type TemplateManager struct {
	templates *template.Template
}

func (tm *TemplateManager) Render(w io.Writer, name string, data interface{}, c echo.Context) error {
	if viewContext, isMap := data.(map[string]interface{}); isMap {
		viewContext["reverse"] = c.Echo().Reverse
	}
	err := tm.templates.ExecuteTemplate(w, name, data)

	if err != nil {
		log.Println("template not found")
	}

	return err
}

func loginForm(c echo.Context) error {
	str := "Login to Drumstick"
	return c.Render(http.StatusOK, "loginForm", str)
}

func vetLogin(c echo.Context) error {
	usr := c.FormValue("email")
	pswd := c.FormValue("password")

	rsltErr := accts.CompareUserCreds(usr, pswd)
	if rsltErr != nil {
		return echo.NewHTTPError(http.StatusUnauthorized, rsltErr)
	}

	tk, err := sessionmanager.CreateToken(usr, c)
	if err != nil {
		return echo.NewHTTPError(http.StatusBadRequest, err)
	}

    // store the token to the database
	err = sessionmanager.AddToken(tk, c)
	if err != nil {
		return echo.NewHTTPError(http.StatusBadRequest, err)
	}

	return c.Render(http.StatusOK, "posts", "Add Posts to Your Feed")
}

func main() {
	tm := &TemplateManager{
		templates: template.Must(template.ParseGlob("ui/html/pages/*[^#?!|].tmpl")),
	}
    router.Renderer = tm
	router := echo.New()

	router.Use(middleware.SecureWithConfig(middleware.DefaultSecureConfig))
	router.Use(middleware.Logger())
	router.Use(middleware.Recover())

    router.GET("/loginForm", loginForm)
	router.POST("/posts", vetLogin)

	// Configure middleware with the custom claims type
	config := echojwt.Config{
		NewClaimsFunc: func(c echo.Context) jwt.Claims {
			return new(sessionmanager.UserCustomClaims)
		},
		SigningKey: []byte("secret"),
	}
	router.Use(echojwt.WithConfig(config))

	router.Logger.Fatal(router.Start(":8080"))
}