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Golang Gin Middleware pass Data to Template

Time:03-04

Hi currently i am doing a little project and i have question.

Is there a way to pass Data to a template from a Middleware?

For Example:

func CheckAuth(c *gin.Context) { //This Middleware gets the user from the session and passes it to the template 
session := sessions.Default(c)
user := session.Get(userkey)

// Get if possible the user from the database with id = user
var account models.Account
if err := models.DB.Where("id = ?", user).First(&account).Error; err != nil {

    _ = 1
}
// pass the account into every temaplte

c.Next()

The reason is that i use the user in my layout and have to check his username or if he is just nil etc and doing the pass in every functions feels wrong? I know Laravel has something like this.

I am using the c.HTML to display the html file

Thanks in advance!

CodePudding user response:

You can use SetFuncMap or FuncMap to create custom functions on templates.

You must set it before calling LoadHTMLFiles or LoadHTMLGlob.

Middleware is for control value, ie: struct

This is the example

main.go

package main

import (
    "html/template"
    "log"
    "strconv"

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

type User struct {
    Username string

    Age int
}

func setUser(u *User) gin.HandlerFunc {
    return func(ctx *gin.Context) {
        // u.Age = 100
        // u.Username = "Default"
        if s, b := ctx.GetQuery("username"); b {
            u.Username = s
        }
        if s, b := ctx.GetQuery("age"); b {
            i, err := strconv.Atoi(s)
            if err != nil {
                panic(err.Error())
            }
            u.Age = i
        }
    }
}

var user = &User{"Default", 100}

func GetUsername() string {
    return user.Username
}

func GetAge() int {
    return user.Age
}

func main() {
    r := gin.New()

    r.SetFuncMap(template.FuncMap{
        "Username": GetUsername,
        "Age":      GetAge,
    })
    r.LoadHTMLGlob("*.tmpl")

    r.GET("/", setUser(user), func(ctx *gin.Context) {
        data := map[string]interface{}{
            "title": "Learning Golang Web",
            "name":  "Batman",
        }

        ctx.HTML(200, "index.tmpl", data)
    })

    log.Fatalln(r.Run())
}

index.tmpl

<!DOCTYPE html>
<html>
  <head>
    <title>{{.title}}</title>
  </head>
  <body>
    <p>Welcome {{.name}}</p>
    <p>Your Username is {{ Username }}</p>
    <p>Your Age is {{ Age }}</p>
  </body>
</html>

if you go to http://localhost:8080/?username=admin&age=50 it will show different display

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