如何使用golang杜松子酒创建针对静态API的身份验证模型？

I hope to create a authentication model to my restful API. Hope to use API token and I'm using MVC in web service and I created a auth.go controller like this.

package controllers

import (

    "github.com/gin-gonic/gin"
    "os"
    //"github.com/jinzhu/gorm"

)

type AdsControllerAuth struct {

}


func (ac *AdsControllerAuth)TokenAuthMiddleware gin.HandlerFunc {
  return func(c *gin.Context) {
    token := c.Request.FormValue("api_token")

    if token == "" {
      respondWithError(401, "API token required", c)
      return 
    }

    if token != os.Getenv("API_TOKEN") {
      respondWithError(401, "Invalid API token", c)
      return
    }

    c.Next()
  }
}

func respondWithError(code int,message string,c *gin.Context) {
  resp := map[string]string{"error": message}

  c.JSON(code, resp)
  //c.Abort(code)
}

It doesn't working for now can some one help do this or is there are any examples to refer?

I made my own middleware to check token like below:

package main

import (
    "github.com/gin-gonic/gin"
)

//JWTAuthMiddleware middleware
func JWTAuthMiddleware() gin.HandlerFunc {
    return func(c *gin.Context) {
        validateToken(c)
        c.Next()
    }
}

func validateToken(c *gin.Context) {
    token := c.Request.Header.Get("X-Auth-Token")

    if token == "" {
        c.AbortWithStatus(401)
    } else if checkToken(token) {
        c.Next()
    } else {
        c.AbortWithStatus(401)
    }
}

In the example, I'm using Header instead of FormValue.

Try out Chrome DHC extension to test: https://chrome.google.com/webstore/detail/dhc-rest-client/aejoelaoggembcahagimdiliamlcdmfm