Retrieve value from gin context

I have this code

package middleware

import (
	"net/http"

	"github.com/dgrijalva/jwt-go"
	"github.com/gin-gonic/gin"
	"github.com/irohitb/EmpAdmin/backend/domain"
)




type UserToken struct {
	jwt.StandardClaims
	User domain.UserToken
}


func SessionMiddleware(supabase_secret string) gin.HandlerFunc {
	return func(c *gin.Context) {
		userCookie, err := c.Cookie("user")
		if err != nil {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"success": false, "message": "Missing user cookie"})
			return
		}

		token, err := jwt.ParseWithClaims(userCookie, &UserToken{}, func(token *jwt.Token) (interface{}, error) {
			return []byte(supabase_secret), nil
		})
		if err != nil {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"success": false, "message": "Invalid user cookie"})
			return
		}

		claims, ok := token.Claims.(*UserToken)
		if !ok || !token.Valid {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"success": false, "message": "Invalid user token"})
			return
		}

		if !claims.User.IsAdmin {
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"success": false, "message": "Only Admins can perform this action"})
			return
		}

		c.Set("user", claims)
		c.Next()
	}
}

Now, in my router, how can I get value set using c.Get("user")?

package services

import (
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/irohitb/EmpAdmin/backend/config"
	"github.com/irohitb/EmpAdmin/backend/domain"
	"github.com/supabase/postgrest-go"
)


func GetAllUsers(env *config.Env, db *postgrest.Client, group *gin.RouterGroup) {
	group.GET("/:services", func (router *gin.Context) {
		services := strings.Split(router.Param("service"), ",")
		user, exists := router.Get("user")
		if !exists {
        	router.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"error": "user information not found in context"})
        	return
    	}

	
		workspaceId, exists := user.(middleware.UserToken).WorkspaceID
		 if !exists {
			router.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"error": "workspace_id not found in user information"})
			return
    	}
		
	})
}

This line here is throwing the following error:

routes/services/users.go:16:3: services declared and not used
routes/services/users.go:24:54: user.(middleware.UserToken).WorkspaceID undefined (type middleware.UserToken has no field or method WorkspaceID)

This is a compile time error instead of a runtime error. It's misleading to say that "This line here is throwing following error".

> services declared and not used

This is an implementation restriction in Go, A compiler may make it illegal to declare a variable inside a function body if the variable is never used (see the language spec). To fix this issue, either remove services or use it.

> user.(middleware.UserToken).WorkspaceID undefined (type middleware.UserToken has no field or method WorkspaceID)

Let's correct some other issues first.

1. There is a syntax error in the type assertion:

   > go
> workspaceId, exists := user.(middleware.UserToken).WorkspaceID
>

   should be written as:

   > ```go
   > userToken, exists := user.(middleware.UserToken)
   > if exists {
   > workspaceId := userToken.WorkspaceID
   > }

2. According to claims, ok := token.Claims.(*UserToken), the claims has the type *UserToken instead of UserToken. So user.(middleware.UserToken) should be user.(*middleware.UserToken).

Now let's turn back to the error. That means the struct middleware.UserToken does not have the field WorkspaceID. Maybe it's a field of the struct domain.UserToken. Let's assume this is the case, then the overall fix should be:

userToken, ok := user.(*middleware.UserToken)
if !ok {
	router.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"error": `router.Get("user") is not a UserToken`})
	return
}
workspaceId := userToken.User.WorkspaceId
// use workspaceId below