simple query controller, handle GET-params

query_controller.go

package main

import (
	"fmt"
	"log"
	"time"

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

var db *gorm.DB

// ModelQuerer interface for GET-queries
type ModelQuerer interface {
	ExcludeFields() []string
	TableName() string
	BuildQuery() string
}

// User user model
type User struct {
	ID        uint
	Email     string
	Password  string
	Birthdate *time.Time
}

// ExcludeFields exclude fields
func (u *User) ExcludeFields() []string {
	return []string{"email"}
}

// TableName table name
func (u *User) TableName() string {
	return "users"
}

func (u *User) BuildQuery(fieldName string, value string) string {
	return fmt.Sprintf("%s = ?")
}

// QueryMiddleware middleware for GET-query
func QueryMiddleware(model ModelQuerer) gin.HandlerFunc {
	return func(c *gin.Context) {
		c.Next()
		if c.IsAborted() {
			return
		}

		scope, exists := c.Get("scope")
		if !exists {
			return
		}

		db.Table(model.TableName()).Raw(scope)
		// .Find(&values)

		// c.JSON(200, values)
		c.JSON(200, map[string]string{"result": "hello"})
	}
}

func main() {
	var err error
	db, err = gorm.Open("postgres", "user=gorm password=123 dbname=gorm sslmode=disable")
	if err != nil {
		log.Panicln(err)
	}

	app := gin.Default()
	app.GET("/users", QueryMiddleware(&User{}), func(c *gin.Context) {
		// c.Set("scope", db.Where("is_active = ?", true))
	})
	app.Run(":3000")
}