How to call a function from an outside httpHandler ?

[ghost]

Hello there !
I'm requesting help from the community about a problem I face since a few days...
Let me explain :

Context
I'm making a web-based game that is enriched with a Discord implementation.
I want to follow player movement to sync it with my Bot, for example, switch to another channel with the press of a button on the player view page.

Problem
When a player from my game change room it makes a POST request to a HTTP server listening in my Go package.
I don't know if I'm getting it right, but my guess is that when this request is handled and calls the Session.GuildMemberMove function, it doesn't wait for discordgo to make it's request to Discord's API, giving me the error down there 👇

I have tried a lot of ways to try to get around this, and maybe I'm missing something here that would make it very easy to implement. I hope you guys may find a solution !

mypackage/app (holds all the bot logic, including Session)

func MovePlayer(movement database.Movement) error {
	return Session.GuildMemberMove(
		config.GuildID,
		movement.MemberID,
		&database.Rooms[movement.RoomID].ChannelID,
	)
}

mypackage/api (holds all the logic for receiving requests)

func movementRequest(w http.ResponseWriter, r *http.Request) {
	fmt.Println("🧷 Movement request")

	// Read content of body
	body, err := io.ReadAll(r.Body)
	if err != nil {
		log.Fatal("❌ ReadAll: ", err)
		return
	}

	// Unmarshal the JSON into a struct
	var movement database.Movement
	err = json.Unmarshal(body, &movement)
	if err != nil {
		log.Fatal("❌ Unmarshal: ", err)
		return
	}

	fmt.Println("🧷 Sending movement")
	// Send movement to app
	err = app.MovePlayer(movement)
	if err != nil {
		log.Fatal("❌ MovePlayer: ", err)
		return
	}

	fmt.Fprintf(w, "OK")
}

🧷 Movement request
🧷 Sending movement
2022/11/22 23:54:49 http: panic serving 127.0.0.1:59907: runtime error: invalid memory address or nil pointer dereference
goroutine 66 [running]:
net/http.(*conn).serve.func1()
        C:/Program Files/Go/src/net/http/server.go:1850 +0xbf
panic({0x598aa0, 0x851c00})
        C:/Program Files/Go/src/runtime/panic.go:890 +0x262
github.com/bwmarrin/discordgo.(*Session).request(0x0, {0x5f5588, 0x5}, {0xc0003c6000, 0x4f}, {0x5f91f8, 0x10}, {0xc0003b2090, 0x24, 0x30}, ...)
        C:/Users/palim/go/pkg/mod/github.com/bwmarrin/[email protected]/restapi.go:120 +0x98
github.com/bwmarrin/discordgo.(*Session).RequestWithBucketID(0xc0000245a0?, {0x5f5588?, 0x5?}, {0xc0003c6000?, 0x4f?}, {0x59fd60?, 0xc00005a4a8?}, {0xc0003a4080?, 0x3d?})
        C:/Users/palim/go/pkg/mod/github.com/bwmarrin/[email protected]/restapi.go:110 +0x105
github.com/bwmarrin/discordgo.(*Session).GuildMemberMove(0x595be0?, {0xc0000245a0, 0x12}, {0xc000382138?, 0x1?}, 0xc0003820dd?)
        C:/Users/palim/go/pkg/mod/github.com/bwmarrin/[email protected]/restapi.go:846 +0xaf
concord-bot/app.MovePlayer(...)
        C:/Users/palim/.apps/concord/concord-bot/app/app.go:107
concord-bot/api.movementRequest({0x686d78?, 0xc0003b6000}, 0xc0003a0100)
        C:/Users/palim/.apps/concord/concord-bot/api/api.go:38 +0x285
net/http.HandlerFunc.ServeHTTP(0xc0003b6000?, {0x686d78?, 0xc0003b6000?}, 0x5f830d?)
        C:/Program Files/Go/src/net/http/server.go:2109 +0x2f
net/http.(*ServeMux).ServeHTTP(0x0?, {0x686d78, 0xc0003b6000}, 0xc0003a0100)
        C:/Program Files/Go/src/net/http/server.go:2487 +0x149
net/http.serverHandler.ServeHTTP({0x685568?}, {0x686d78, 0xc0003b6000}, 0xc0003a0100)
        C:/Program Files/Go/src/net/http/server.go:2947 +0x30c
net/http.(*conn).serve(0xc000328140, {0x6871e0, 0xc000094150})
        C:/Program Files/Go/src/net/http/server.go:1991 +0x607
created by net/http.(*Server).Serve
        C:/Program Files/Go/src/net/http/server.go:3102 +0x4db

Thanks in advance for the time you may take to read all of this.
Please ask me if you need any more code snippets or other files
Good night/day

[FedorLap2006]

The stack trace you have provided indicates that you're panicing on

discordgo/restapi.go

Line 120 in 128f34b

return s.RequestWithLockedBucket(method, urlStr, contentType, b, s.Ratelimiter.LockBucket(bucketID), sequence)

Therefore I'm assuming that your RateLimiter is nil. This could have happened if you manually instantiated Session object.
Can you show how it's initialized?

[ghost]

Hi @FedorLap2006 ! Thanks for your answer.
My Session object is initialized with the default parameters I guess ? It's made up in the Start function of my app module, called directly from the main function :

main.go

func main() {
	fmt.Print("\033[H\033[2J")
	fmt.Println("🤖 Booting system.")

	err := config.LoadConfig()
	if err != nil {
		fmt.Println("❌ Error loading config:", err)
		return
	}

	// Get rooms from API
	res, err := api.PerformRequest("http://127.0.0.1:9000/rooms")
	if err != nil {
		fmt.Println("❌ Error loading database:", err)
		return
	}
	// Load DB
	err = database.LoadDatabase(res.Data.([]interface{}))
	if err != nil {
		fmt.Println("❌ Error loading database:", err)
		return
	}

	go api.Start()
	app.Start()
}

myModule/app

unc Start() {
	// Create Discord session
	Session, e := discordgo.New("Bot " + config.Token)
	CheckError(e)
	user, e := Session.User("@me")
	CheckError(e)
	ID = user.ID

	e = Session.Open()
	CheckError(e)

	// Create channels from database rooms
	for _, room := range database.Rooms {
		// Create a new channel into category
		channel, e := Session.GuildChannelCreateComplex(config.GuildID, discordgo.GuildChannelCreateData{
			Name:     room.Name,
			Type:     discordgo.ChannelTypeGuildVoice,
			ParentID: config.CategoryID,
		})
		CheckError(e)
		// Set the channel ID
		room.ChannelID = channel.ID
		// Add the channel to the list of created channels
		CreatedChannels = append(CreatedChannels, channel)
	}

	// Register event handlers

	// Clean close
	defer Session.Close()

	stop := make(chan os.Signal, 1)
	signal.Notify(stop, os.Interrupt, syscall.SIGTERM, syscall.SIGINT)

	// Await interrupt
	fmt.Println("🤖 System is now running. Press CTRL+C to exit.")
	<-stop

	// Delete channels
	for _, channel := range CreatedChannels {
		_, e = Session.ChannelDelete(channel.ID)
		CheckError(e)
	}

	// And exit program
	fmt.Println("🤖 Shutting down system.")
	os.Exit(0)
}

Again, thanks for your time !
Good evening