Question

我是一个刚刚开始使用Parse进行休闲手机游戏的新手。

我正在编写一个云代码，客户可以通过该代码请求购买卡座。由于代码对于解释我的问题非常重要，因此我将问题移到了代码下面。

我有以下课程：

    1. User :
        coin(Number)

    2. Deck :
        priceCoin(Number)
        nickname(String)

    3. User_Deck :
        userId(Pointer to User)
        deckId(Pointer to Deck)

类和客户请求的数据：

用户和套牌类每个都有一行，用户请求购买套牌。
发送到云功能的参数是deck，它是Deck的objectId。

这就是云功能：

Parse.Cloud.define("req_purchase_deck", function(request, response) {
    var purchaseDeck;
    var deckQuery = new Parse.Query("Deck");
    deckQuery.get( request.params.deck, function(result) {
        purchaseDeck = result; // Q2 : is this valid in the scope of this function?
        var userHasQuery = new Parse.Query("User_Deck");
        userHasQuery.equalTo("userId", request.user);
        userHasQuery.equalTo("deckId", result);
        return userHasQuery.find();
    }).then( function( results ) { // Q1 : Why results undefined?
        if( results == null || results.length == 0 ) {
            var userCoin = request.user.get("coin");
            var priceCoin = purchaseDeck.get("priceCoin");
            if( userCoin >= priceCoin ) {
                console.log("/purchase made/" + userCoin + " - " + priceCoin + " = " + userCoin - priceCoin);
                request.user.set("coin", userCoin - priceCoin);
                return request.user.save();
            }
            else {
                return Parse.Promise.error("not enough coins");
            }
        }
        else {
            return Parse.Promise.error("already has deck");
        }
    }).then( function(result) {
        var newUserDeckObject = new Parse.Object("User_Deck");
        newUserDeckObject.set("userId", request.user);
        newUserDeckObject.set("deckId", purchaseDeck);
        console.log("/purchase deck added");
        return newUserDeckObject.save();
    }).then( function(result) {
        var returns = {};
        returns["userCoins"] = request.user.get("coin");
        returns["purchasedDeck"] = purchaseDeck.get("nickname");
        response.success(returns);
        console.log(request.user.username + "/purchase deck succeeded--/");
    }, function(error) {
        response.error(error);
    });
});

结果：已经有了deck //即使User_Deck类中根本没有行。我发现“结果”未定义。

问题1：deckQuery制作精良，但userDeckQuery导致未定义的结果：我的代码出了什么问题？我放了很多日志来弄清楚原因，但这是我找到的唯一的东西。

问题2：我正在将deckQuery结果缓存到purchaseDeck，并且该对象在该云函数结束时是否有效？

提前致谢！

Answer 1

我意识到了原因我为我的查询使用了回调样式返回，并期望获得promise样式的结果。我标有评论

Parse.Cloud.define("req_purchase_deck", function(request, response) {
    var purchaseDeck;
    var deckQuery = new Parse.Query("Deck");
    //deckQuery.get( request.params.deck, function(result) {
    deckQuery.get( request.params.deck ).then( function(result) { // Q1 solved.
        purchaseDeck = result; // Q2 : @Fosco answered that it's fine.
        var userHasQuery = new Parse.Query("User_Deck");
        userHasQuery.equalTo("userId", request.user);
        userHasQuery.equalTo("deckId", result);
        return userHasQuery.find();
    }).then( function( results ) {
        if( /*results == null ||*/results.length == 0 ) { // results never be null
            var userCoin = request.user.get("coin");
            var priceCoin = purchaseDeck.get("priceCoin");
            if( userCoin >= priceCoin ) {
                console.log("/purchase made/" + userCoin + " - " + priceCoin + " = " + userCoin - priceCoin);
                request.user.set("coin", userCoin - priceCoin);
                return request.user.save();
            }
            else {
                return Parse.Promise.error("not enough coins");
            }
        }
        else {
            return Parse.Promise.error("already has deck");
        }
    }).then( function(result) {
        var newUserDeckObject = new Parse.Object("User_Deck");
        newUserDeckObject.set("userId", request.user);
        newUserDeckObject.set("deckId", purchaseDeck);
        console.log("/purchase deck added");
        return newUserDeckObject.save();
    }).then( function(result) {
        var returns = {};
        returns["userCoins"] = request.user.get("coin");
        returns["purchasedDeck"] = purchaseDeck.get("nickname");
        response.success(returns);
        console.log(request.user.username + "/purchase deck succeeded--/");
    }, function(error) {
        response.error(error);
    });
});

现在的结果是＆＃34;没有足够的硬币＆＃34;

Parse.Query.find的结果在我的云函数中是未定义的

1 个答案: