将项目附加到获取的项目数组 Parse Cloud Code

Question

• Javascript
• 解析云代码

---

在我的应用程序中，User 可以请求加入另一个 Users 帐户。其伪代码如下：

1. 发送我们要加入的帐户的username
2. 搜索数据库中是否存在username
3. 如果no返回
4. 如果yes 创建一个新的AccountRequest 对象
5. 将新创建的AccountRequest 对象添加到我们正在搜索的用户。

我可以执行第 1-4 步，但我无法完成第 5 步。

这是我正在使用的代码。

Parse.Cloud.define("sendAccountAdditionRequest", function(request, response) {

  console.log("-sendAccountAdditionRequest");

  // Create the query on the User class
  var query = new Parse.Query(Parse.User);

  // Set our parameters to search on
  query.equalTo("username", request.params.adminUsername);

  // Perform search
  query.find({

    // We found a matching user
    success: function(results) {

        Parse.Cloud.useMasterKey();

        var fetchedUser = results[0]

        console.log("--found user");
        console.log("--creating new AccountRequest");

        // Create a new instance of AccountRequest
        var AccountRequestClass = Parse.Object.extend("AccountRequest");
        var accountRequest = new AccountRequestClass();

        // Set the User it is related to. Our User class has a 1..n relationship to AccountRequest
        accountRequest.set("user", fetchedUser);

        // Set out other values for the AccountRequest
        accountRequest.set("phone", request.params.adminUsername);
        accountRequest.set("dateSent", Date.now());

        // Save the new AccountRequest
        accountRequest.save(null,{

            // Once the new AccountRequest has been saved we need to add it to our fetched User
            success:function(savedRequest) { 

                console.log("---adding AccountRequest to fetched User");

                //
                // === This is where stuff breaks
                //

                var requestRelation = fetchedUser.relation("accountRequest");

                // Now we need to add the new AccountRequest to the fetched User. The accountRequest property for a User is array...I'm not sure how I'm suppose to append a new item to that. I think I need to somehow cast results[0] to a User object? Maybe? 
                requestRelation.add(savedRequest);

                // We perform a save on the User now that the accountRequest has been added.
                fetchedUser.save(null, {

                    success:function(response) { 
                        console.log("----AccountRequest complete");
                        response.success("A request has been sent!");
                    },

                    error:function(error) {
                        // This is printing out: ParseUser { _objCount: 2, className: '_User', id: 'QjhQxWCFWs' }
                        console.log(error);
                        response.error(error);
                    }
                });


                //
                // ================================
                //


                //response.success("A request has been sent!");
            },

            // There was an error saving the new AccountRequest
            error:function(error) {
                response.error(error);
            }
        });
    },

    // We were not able to find an account with the supplied username
    error: function() {
      response.error("An account with that number does not exist. Please tell your administrator to sign up before you are added.");
    }
  });
});

我相信我的问题是从初始查询返回的搜索结果中获取accountRequest 关系。还有一点需要注意的是，我还没有创建PFUser 的accountRequest 属性，我的理解是当我执行save 函数时，Parse 会自动完成。

Answer 1

是否会为您创建 accountRequest 取决于是否将类级别权限设置为允许客户端应用程序添加字段。这可能为您的 Parse.User 设置为 NO。

但无论如何都不需要 Parse.User 上的关系，因为您已经在 AccountRequest 类上建立了它。给定一个用户，您可以通过以下方式获取它的 accountRequests：

PFQuery *query = [PFQuery queryWithClassName:@"AccountRequest"];
[query whereKey:@"user" equalTo:aUser];
query.find()...

这相当于获取用户的关系，获取它的查询并运行它。

关于您的代码的几点注意事项：(a) findOne 会在您知道只有一个结果时为您节省一行，(b) 使用 Parse.Promise 会真正整理一下。