🤗 [Question]: Lost MAP data

[RhaPT]

Question Description

Sorry about my English. I created a page with javascript where it creates a websocket and receives a unique id ("Sec-Websocket-Key") for that instance, then it uses this id whenever it makes a request to the api (sends in the header an X-Id with this value), the api stores data within a map indexed by X-Id

If you open another window in the same browser (if use other browser no problem) and call the same page, it will create a new instance for in websocket and at that time it automatically changes the MAP.

Example the first time you open the page: map[] after adding a value : map[GlYkSNQ6GQMFtdkHGqlxZw==:GlYkSNQ6GQMFtdkHGqlxZw==] after open new window in same browser: map[keep-aliveMFtdkHGqlxZw==:keep-aliveMFtdkHGqlxZw==]

Does anyone know why the Map changes?

Code Snippet (optional)

package main

import (
    "log"
    "github.com/gofiber/contrib/websocket"
    "github.com/gofiber/fiber/v2"
)

var Xpto map[string]string

func init() {
    Xpto = make(map[string]string)
}

func main() {
    app := fiber.New()

    app.Static("/", ".")

    api := app.Group("/api")
    api.Post("/add", setXpto)

    app.Use("/ws", func(c *fiber.Ctx) error {
        if websocket.IsWebSocketUpgrade(c) {
            return c.Next()
        }
        return fiber.ErrUpgradeRequired
    })
    app.Get("/ws", websocket.New(func(c *websocket.Conn) {
        var (
            mt  int
            msg []byte
            err error
        )
        for {
            if mt, msg, err = c.ReadMessage(); err != nil {
                log.Println("read:", err)
                break
            }
            if string(msg) == "1" {
                newID := c.Headers("Sec-Websocket-Key", "")
                c.WriteMessage(mt, []byte(newID))
            }
            log.Println(Xpto)
        }
    }))
    log.Fatal(app.Listen(":3000"))

    log.Panicln(Xpto)
}

func setXpto(c *fiber.Ctx) error {
    xID := c.Get("X-Id", "")
    Xpto[xID] = xID
    log.Println(Xpto)
    c.Status(fiber.StatusOK)
    return c.JSON(Xpto)
}

Checklist:

• [X] I agree to follow Fiber's Code of Conduct.
• [X] I have checked for existing issues that describe my questions prior to opening this one.
• [X] I understand that improperly formatted questions may be closed without explanation.

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[gaby]

@RhaPT First you never call init(). Second, the values from the context are only valid during the handler execution.

Here:

func setXpto(c *fiber.Ctx) error {
    xID := c.Get("X-Id", "")
    Xpto[xID] = xID
    log.Println(Xpto)
    c.Status(fiber.StatusOK)
    return c.JSON(Xpto)
}

You have to copy the value form the context like this:

xID := utils.CopyString(c.Get("X-Id", ""))

Documentation is here: https://docs.gofiber.io/#zero-allocation

[gaby]

@RhaPT Did that fix your issue?

[RhaPT]

Thanks for your help

[gaby]

Awesome 💪