Updating a post with authentication and user validation

update-post.go

    //Update a post
    m.Put("/posts/:id", binding.Bind(Post{}), func(args martini.Params, post Post, r render.Render, authuser sessionauth.User) {

        //capture passed in parameters from Ajax call
        var newTitle = post.Title
        var newBody = post.Body

        //retrieve the post to retrieve original owner
        err = dbmap.SelectOne(&post, "select * from posts where post_id=?", args["id"])

        //simple DB error check
        if err != nil {

          newmap := map[string]interface{}{"message":"Something went wrong."}
          r.JSON(400, newmap)

        } else {

          //owner check
          if(authuser.UniqueId() == post.UserId){

              //assign new values to the retrieved post
              post.Title=newTitle
              post.Body=newBody

              //update the post
              count, err := dbmap.Update(&post)
              checkErr(err, "Update failed")
              
              if count == 1 {
                 newmap := map[string]interface{}{"responseText":"success"}
                 r.JSON(200, newmap)
              } else {
                  newmap := map[string]interface{}{"responseText":"error"}
                  r.JSON(400, newmap)
              }  

          } else {
            
            newmap := map[string]interface{}{"responseText":"You are not allowed to modify this resource."}
            r.JSON(403, newmap)
            
          }

      } 
        
  })

Learn more about this code here: http://techslides.com/martini-app-with-ajax-json-and-user-sessions/