Firestore 读取文档

Question

我正在尝试从 Firestore 读取文档，但我遇到了这个问题

Error Domain=FIRFirestoreErrorDomain Code=14 “由于客户端离线，无法获取文档。” UserInfo={NSLocalizedDescription=获取文档失败，因为客户端离线。}

注意：集合和文档是现有的我使用的是 Firebase/Firestore 版本 1.17.1

谁能帮帮我？！

Answer 1

这是使用 Cloud Firestore 获取数据的示例（来源：firebase.google.com）

首先创建数据：

let citiesRef = db.collection("cities")

citiesRef.document("SF").setData([
    "name": "San Francisco",
    "state": "CA",
    "country": "USA",
    "capital": false,
    "population": 860000,
    "regions": ["west_coast", "norcal"]
    ])
citiesRef.document("LA").setData([
    "name": "Los Angeles",
    "state": "CA",
    "country": "USA",
    "capital": false,
    "population": 3900000,
    "regions": ["west_coast", "socal"]
    ])
citiesRef.document("DC").setData([
    "name": "Washington D.C.",
    "country": "USA",
    "capital": true,
    "population": 680000,
    "regions": ["east_coast"]
    ])
citiesRef.document("TOK").setData([
    "name": "Tokyo",
    "country": "Japan",
    "capital": true,
    "population": 9000000,
    "regions": ["kanto", "honshu"]
    ])
citiesRef.document("BJ").setData([
    "name": "Beijing",
    "country": "China",
    "capital": true,
    "population": 21500000,
    "regions": ["jingjinji", "hebei"]
    ])

然后以下示例显示如何使用get()检索单个文档的内容：

let docRef = db.collection("cities").document("SF")

docRef.getDocument { (document, error) in
    if let document = document, document.exists {
        let dataDescription = document.data().map(String.init(describing:)) ?? "nil"
        print("Document data: \(dataDescription)")
    } else {
        print("Document does not exist")
    }
}

如果您使用firebase.firestore() ，这也可能是一个错误，而firebase.database()运行良好。