From global vars to

Getting Help
1

Hello.

I’m trying to cut off all global vars in project. I found this example http://elithrar.github.io/article/custom-handlers-avoiding-globals/. It works when the “IndexHandler” is in the main file but it doesn’t work in another one (undefined: AppContext).

package main

import (	
    "fmt"
    "log"
    "net/http"

    "html/template"

    "github.com/gorilla/sessions"
    "github.com/zenazn/goji/graceful"
    "github.com/zenazn/goji/web"

	"github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/mysql"

	"server/routes"
)

const (
	DB_DATABASE = "go"
	DB_USER = "root"
	DB_PASSWORD = "123321wsx"
)

type AppContext struct {
    DB        *gorm.DB
    Store     *sessions.CookieStore
}

type AppHandler struct {
    *AppContext
    H func(*AppContext, http.ResponseWriter, *http.Request) (int, error)
}


func (ah AppHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    status, err := ah.H(ah.AppContext, w, r)
    if err != nil {
        log.Printf("HTTP %d: %q", status, err)
        switch status {
        case http.StatusNotFound:
            http.NotFound(w, r)
        case http.StatusInternalServerError:
            http.Error(w, http.StatusText(status), status)
        default:
            http.Error(w, http.StatusText(status), status)
        }
    }
}

func main() {
	db, err := gorm.Open("mysql", DB_USER + ":" + DB_PASSWORD + "@/" + DB_DATABASE + "?charset=utf8&parseTime=True&loc=Local")
	if err != nil {
    	panic(err.Error())
	}
	defer db.Close()
    context := &AppContext{DB: db, Store: nil} 

    r := web.New()
    r.Get("/", AppHandler{context, routes.IndexHandler})
    graceful.ListenAndServe(":3000", r)
}

best regards

2

If you’re using go run, don’t. Or at least give it all files on the command line. If you’re doing something else, show us what you’re doing and what happens. :wink:

1 Like
3 
package routes

import ( 
	"fmt"
    "net/http"
    _ "github.com/jinzhu/gorm/dialects/mysql"	
    "server/models"
)

func IndexHandler (a *AppContext, w http.ResponseWriter, r *http.Request) { //error here
	DBPosts := []models.DBPostModel{}
	a.DB.Where("published = ?", 1).Find(&DBPosts)

	posts := []models.DBPostModel{}
	for _, post := range DBPosts {
		posts = append(posts, post)
	}

	model := models.PostListModel{}
	model.IsAuthorized = true
	model.Posts = posts 

	fmt.Println(posts)
}

#error
“C:\gopath\src\server>go build main.go
server/routes
routes\home.go:10: undefined: AppContext”

4

Don’t give go build a file name.

5

the result is the same

6

You’re doing something weird or unusual with your file layouts. Read and following this article, and things should clarify: https://golang.org/doc/code.html

1 Like
7

you must import the package from where AppContext is coming.

8

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