Article directory
-
- Gin custom controller
-
- controller layering
- controller inheritance
- Gin middleware
-
- routing middleware
- c.Next() calls the remaining handlers for the request
- A route configures the execution order of multiple middleware
- global middleware
- Configure middleware in route grouping
- Data sharing between middleware and corresponding controllers
- Middleware Considerations
Gin custom controller
Controller layering
When the project is relatively large, it is necessary to group the controllers
Create a new controller in the root directory of the project, and create a new admin user … folder in the controller
Create a new indexController.go userController.go file in the admin file
indexController.go
package admin
import "github.com/gin-gonic/gin"
type IndexController struct {<!-- -->
}
func (con IndexController) Index(c *gin.Context) {<!-- -->
c.String(200, "background page")
}
userController.go
package admin
import "github.com/gin-gonic/gin"
type UserController struct {<!-- -->
}
func (con UserController) Index(c *gin.Context) {<!-- -->
c.String(200, "User List")
}
func (con UserController) Add(c *gin.Context) {<!-- -->
c.String(200, "User List---add")
}
func (con UserController) Edit(c *gin.Context) {<!-- -->
c.String(200, "User List---edit")
}
under the routes folder
Configure the corresponding route-adminRoutes.go
package routes
import (
"Gin_demo/controllers/admin"
"github.com/gin-gonic/gin"
)
func AdminRoutesInit(r *gin.Engine) {<!-- -->
adminRoutes := r. Group("/admin")
{<!-- -->
adminRoutes.GET("/", admin.IndexController{<!-- -->}.Index)
adminRoutes.GET("/user", admin.UserController{<!-- -->}.Index)
adminRoutes.GET("/user/add", admin.UserController{<!-- -->}.Add)
adminRoutes.GET("/user/edit", admin.UserController{<!-- -->}.Edit)
}
}
Controller Inheritance
1. Create a new controller/admin/baseController.go
package admin
import "github.com/gin-gonic/gin"
type BaseController struct {<!-- -->
}
func (con BaseController) success(c *gin.Context) {<!-- -->
c.String(200, "Success")
}
func (con BaseController) error(c *gin.Context) {<!-- -->
c.String(200, "Failed")
}
2. userController inherits baseController
package admin
import "github.com/gin-gonic/gin"
type UserController struct {<!-- -->
BaseController
}
func (con UserController) Index(c *gin.Context) {<!-- -->
//c.String(200, "User List")
con. success(c)
}
func (con UserController) Add(c *gin.Context) {<!-- -->
c.String(200, "User List---add")
}
func (con UserController) Edit(c *gin.Context) {<!-- -->
c.String(200, "User List---edit")
}
Gin middleware
Middleware is a series of operations performed before matching routes and after matching routes
Routing middleware
The middleware in Gin must be a gin.HandlerFunc type. When configuring the route, you can pass multiple func callback functions. The functions triggered before the last func callback function can be called middleware.
package main
import (
"fmt"
"github.com/gin-gonic/gin"
"time"
)
func InitMessage(c *gin.Context) {<!-- -->
fmt.Println("111")
}
func main() {<!-- -->
r := gin. Default()
r.LoadHTMLGlob("templates/*")
r.Static("/static", "./static")
r.GET("/", InitMessage, func(c *gin.Context) {<!-- -->
c.String(200, "Homepage")
})
r.GET("/news", InitMessage, func(c *gin.Context) {<!-- -->
c.String(200, "News")
})
r.Run()
}
c.Next() calls the remaining handlers for the request
Adding c.Next() to the middleware allows us to perform some operations after the route matching is completed
Count the execution time of a request
package main
import (
"fmt"
"github.com/gin-gonic/gin"
"time"
)
func InitMessage(c *gin.Context) {<!-- -->
fmt.Println("111")
start := time. Now(). Nanosecond()
// call the remaining handlers for the request
c. Next()
end := time. Now(). Nanosecond()
fmt.Println(end - start)
}
func main() {<!-- -->
r := gin. Default()
r.LoadHTMLGlob("templates/*")
r.Static("/static", "./static")
r.GET("/", InitMessage, func(c *gin.Context) {<!-- -->
c.String(200, "Homepage")
})
r.GET("/news", InitMessage, func(c *gin.Context) {<!-- -->
c.String(200, "News")
})
r.Run()
}
A route configures the execution order of multiple middleware
When there are multiple middleware in a request, what is the execution order?
Various messages can be printed to the console to determine the order in which programs are executed.
package main
import (
"fmt"
"github.com/gin-gonic/gin"
)
func InitMiddlewareOne(c *gin.Context) {<!-- -->
fmt.Println("1")
// call the remaining handlers for the request
c. Next()
fmt.Println("2")
}
func InitMiddlewareTwo(c *gin.Context) {<!-- -->
fmt.Println("3")
// call the remaining handlers for the request
c. Next()
fmt.Println("4")
}
func main() {<!-- -->
r := gin. Default()
r.LoadHTMLGlob("templates/*")
r.Static("/static", "./static")
r.GET("/", InitMiddlewareOne, InitMiddlewareTwo, func(c *gin.Context) {<!-- -->
fmt.Println("Homepage...")
c.String(200, "Homepage")
})
r.GET("/news", InitMiddlewareOne, InitMiddlewareTwo, func(c *gin.Context) {<!-- -->
c.String(200, "News")
})
r.Run()
}
Console content:
1 3 front page... 4 2
Global middleware
You can use r.Use(middleware name) to define global middleware
package main
import (
"fmt"
"github.com/gin-gonic/gin"
)
func InitMiddleware(c *gin.Context) {<!-- -->
fmt.Println("1")
// call the remaining handlers for the request
c. Next()
fmt.Println("2")
}
func main() {<!-- -->
r := gin. Default()
r.LoadHTMLGlob("templates/*")
r.Static("/static", "./static")
// define global middleware
r.Use(InitMiddleware)
r.GET("/", func(c *gin.Context) {<!-- -->
fmt.Println("Homepage...")
c.String(200, "Homepage")
})
r.GET("/news", func(c *gin.Context) {<!-- -->
c.String(200, "News")
})
r.Run()
}
Configure middleware in routing group
Create a new middlewares folder in the project root directory and create a new middleware
package middlewares
import (
"fmt"
"github.com/gin-gonic/gin"
"time"
)
func InitMiddleware(c *gin.Context) {<!-- -->
fmt. Println(time. Now())
fmt.Println(c.Request.URL)
}
Routing files in the routes file use middleware
package routes
import (
"Gin_demo/controllers/admin"
"Gin_demo/middlewares"
"github.com/gin-gonic/gin"
)
func AdminRoutesInit(r *gin.Engine) {<!-- -->
// use middleware
adminRoutes := r.Group("/admin", middlewares.InitMiddleware)
{<!-- -->
adminRoutes.GET("/", admin.IndexController{<!-- -->}.Index)
adminRoutes.GET("/user", admin.UserController{<!-- -->}.Index)
adminRoutes.GET("/user/add", admin.UserController{<!-- -->}.Add)
adminRoutes.GET("/user/edit", admin.UserController{<!-- -->}.Edit)
adminRoutes.GET("/article", admin.ArticleController{<!-- -->}.Index)
adminRoutes.GET("/article/add", admin.ArticleController{<!-- -->}.Add)
adminRoutes.GET("/article/edit", admin.ArticleController{<!-- -->}.Edit)
}
}
Share data between middleware and corresponding controller
Set value in middleware
package middlewares
import (
"fmt"
"github.com/gin-gonic/gin"
"time"
)
func InitMiddleware(c *gin.Context) {<!-- -->
c. Set("username", "zhangsan")
}
Get the value in the controller
package admin
import (
"fmt"
"github.com/gin-gonic/gin"
)
type UserController struct {<!-- -->
BaseController
}
func (con UserController) Index(c *gin.Context) {<!-- -->
//c.String(200, "User List")
//con. success(c)
username, _ := c. Get("username")
v, ok := username.(string)
if ok {<!-- -->
c. String(200, v)
} else {<!-- -->
c.String(200, "Failed to get user")
}
fmt.Println("username==>", username)
}
func (con UserController) Add(c *gin.Context) {<!-- -->
c.String(200, "User List---add")
}
func (con UserController) Edit(c *gin.Context) {<!-- -->
c.String(200, "User List---edit")
}
Middleware Considerations
1. gin.Default() uses Logger and Recovery middleware by default, among which:
- Logger middleware writes logs to gin.DefaultWriter even if GIN_MODE=release is configured.
- Recovery middleware will recover any panic. If there is a panic, a 500 response code will be written.
If you don’t want to use the above two default middleware, you can use gin.New() to create a new route without any default middleware. Generally, gin.Default() is recommended.
2. When starting a new goroutine in middleware or handler, the original context (c *gin.Context) cannot be used, its read-only copy (c.Copy()) must be used
r.GET("/", func(c *gin.Context) {<!-- -->
cCp := c.Copy()
go func() {<!-- -->
// simulate a long task with time. Sleep(). 5 seconds
time. Sleep(5 * time. Second)
// use the copy you created here
fmt.Println("Done! in path " + cCp.Request.URL.Path)
}()
c.String(200, "Homepage")
})