Swift Firebase 查询

Question

我正在尝试根据他的电子邮件获取 uid。

我有这个:

let usersRef = Database.database().reference().child("users")

    usersRef.queryOrdered(byChild: "email").queryStarting(atValue: email).queryEnding(atValue: email).observeSingleEvent(of: .value, with: { (snapshot) in
        if let values = snapshot.value as? [String: Any]{
            print(values)
        }
    })

我的数据库如下所示:

用户

|-$uid

|--email: "一些电子邮件"

快照不返回任何内容。

另外，调试器告诉我:

Using an unspecified index. Your data will be downloaded and filtered on the client. Consider adding ".indexOn": "email" at /users to your security rules for better performance

我想我是这样做的:

{
  "rules": {
"users": {
  ".read": "auth != null",
  "$uid": {
    ".write": "$uid === auth.uid",
    ".indexOn": ["email"]
  }

但这也行不通。

Answer 1

您必须在执行查询的位置定义 Firebase 数据库索引。所以这比你目前拥有的级别高了一个级别:

{
  "rules": {
    "users": {
      ".indexOn": ["email"],
      ".read": "auth != null",
      "$uid": {
        ".write": "$uid === auth.uid",
      }
    }
  }
}