Swift 4的JSONDecoder可以与Firebase Realtime Database一起使用吗? [英] Can Swift 4's JSONDecoder be used with Firebase Realtime Database?

问题描述

我正在尝试从Firebase DataSnapshot解码数据，以便可以使用JSONDecoder对其进行解码.

I am trying to decode data from a Firebase DataSnapshot so that it can be decoded using JSONDecoder.

当我使用URL通过网络请求(获取Data对象)访问数据时，我可以很好地解码该数据.

I can decode this data fine when I use a URL to access it with a network request (obtaining a Data object).

但是，我想使用Firebase API通过如

However, I want to use the Firebase API to directly obtain the data, using observeSingleEvent as described on this page.

但是，当我这样做时，似乎无法将结果转换为Data对象，而我需要使用JSONDecoder.

But, when I do this, I cannot seem to convert the result into a Data object, which I need to use JSONDecoder.

是否可以使用DataSnapshot进行JSON解码的新样式?这怎么可能?我似乎无法弄清楚.

Is it possible to do the new style of JSON decoding with a DataSnapshot? How is it possible? I can't seem to figure it out.

推荐答案

我创建了一个名为 CodableFirebase 提供专门为Firebase设计的Encoders和Decoders.

I have created a library called CodableFirebase that provides Encoders and Decoders that are designed specifically for Firebase.

因此，对于上面的示例:

So for the example above:

import Firebase
import CodableFirebase

let item: GroceryItem = // here you will create an instance of GroceryItem
let data = try! FirebaseEncoder().encode(item)

Database.database().reference().child("pathToGraceryItem").setValue(data)

以下是读取相同数据的方式:

And here's how you will read the same data:

Database.database().reference().child("pathToGraceryItem").observeSingleEvent(of: .value, with: { (snapshot) in
    guard let value = snapshot.value else { return }
    do {
        let item = try FirebaseDecoder().decode(GroceryItem.self, from: value)
        print(item)
    } catch let error {
        print(error)
    }
})

这篇关于Swift 4的JSONDecoder可以与Firebase Realtime Database一起使用吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！