英文:
Get a single item from the query Firestore
问题
我正在尝试使用Golang从Firestore Firebase获取单个文档。我知道如果有一个id，这很容易实现，你可以像这样编写代码：
database.Collection("profiles").Doc(userId).Get(ctx)
在我的情况下，我需要使用Where条件来查找特定的文档，这就是我卡住的地方。到目前为止，我只能想到以下的解决方案：
database.Collection("users").Where("name", "==", "Mark").Limit(1).Documents(ctx).GetAll()
显然，这不是最好的解决方案，因为我只需要找到符合条件的一个（基本上是第一个）文档，并且使用GetAll()看起来非常奇怪。什么是最佳的方法呢？
英文:
I'm trying to get a single document from the Firestore Firebase using Golang. I know that it is easy if you have an id, you can write something like this:
database.Collection("profiles").Doc(userId).Get(ctx)
In my case I need to find a specific document using a Where condition, and this is where I get stuck. So far I was able to come up only with the following:
database.Collection("users").Where("name", "==", "Mark").Limit(1).Documents(ctx).GetAll()
And it is obviously not the best solution since I am looking only for one (basically the first) document which follows the condition and using GetAll() seems really weird. What would be the best approach?
答案1
得分: 3
func getOne(ctx context.Context, q firestore.Query) (*firestore.DocumentSnapshot, error) {
it := q.Limit(1).Documents(ctx)
defer it.Stop()
snap, err := it.Next()
if err == iterator.Done {
err = fmt.Errorf("没有匹配的文档")
}
return snap, err
}
英文:
The application can call Next and Stop to get a single document:
func getOne(ctx context.Context, q firestore.Query) (*firestore.DocumentSnapshot, error) {
it := q.Limit(1).Documents(ctx)
defer it.Stop()
snap, err := it.Next()
if err == iterator.Done {
err = fmt.Errorf("no matching documents")
}
return snap, err
}
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