Handling Player Equipment Authoritatively #

The following example demonstrates how you can use an RPC to allow players to equip items authoritatively, ensuring the player owns the items before allowing them to equip them.

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// Declare struct for the expected input payload
type EquipPayload struct {
    Item string `json:"item"`
}

// Declare struct for the response payload
type EquipResponsePayload struct {
    Success bool `json:"success"`
}

// Declare a struct for hat unlocks
type HatUnlocks struct {
    Hats []string `json:"hats"`
}

// ...

// In your InitModule function
initializer.RegisterRpc("EquipHat", func(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error) {
    userID, _ := ctx.Value(runtime.RUNTIME_CTX_USER_ID).(string)

    // Deserialize the payload from the client
    equipPayload := &EquipPayload{}
    if err := json.Unmarshal([]byte(payload), equipPayload); err != nil {
        return "", errors.New("error deserializing client payload")
    }

    // Check if the player has unlocked the hat
    objects, err := nk.StorageRead(ctx, []*runtime.StorageRead{{
        Collection: "Unlocks",
        Key:        "Hats",
        UserID:     userID,
    }})
    if err != nil || len(objects) == 0 {
        return "", errors.New("error finding hat unlocks for user")
    }

    hatUnlocks := &HatUnlocks{}
    if err := json.Unmarshal([]byte(objects[0].Value), hatUnlocks); err != nil {
        return "", errors.New("error deserializing item unlocks")
    }

    hasHat := false
    for _, hat := range hatUnlocks.Hats {
        if hat == equipPayload.Item {
            hasHat = true
        }
    }

    if !hasHat {
        return "", errors.New("user has not unlocked the hat")
    }

    // Get the user's account details
    account, err := nk.AccountGetId(ctx, userID)
    if err != nil {
        return "", errors.New("error getting account data")
    }

    // Get the user's existing metadata
    metadata := make(map[string]interface{})
    if err := json.Unmarshal([]byte(account.User.Metadata), &metadata); err != nil {
        return "", errors.New("error deserializing metadata")
    }

    // Equip the hat and update the user's metadata
    metadata["hat"] = equipPayload.Item

    if err := nk.AccountUpdateId(ctx, userID, "", metadata, "", "", "", "", ""); err != nil {
        return "", errors.New("error updating account data")
    }

    // Return a response to the client
    bytes, err := json.Marshal(&EquipResponsePayload{Success: true})
    if err != nil {
        return "", errors.New("error serializing response")
    }

    return string(bytes), nil
})