如何使用分页处理来自 API 的条件 JSON 响应

Question

我有一个场景，我向第三方 API 发送请求，提供如下响应：

data: [
    {
        id: 111,
        highPriorityItems: [
            {
                "time": "2022-01-01T00:00:50Z",
                "price": 5000.55
            },
            {
                "time": "2022-01-02T13:00:50Z",
                "price": 5600.55
            },
            ...
        ],
        lowPriorityItems: [
            {
                "time": "2022-03-01T00:12:50Z",
                "price": 9000.55
            },
            {
                "time": "2022-03-02T22:00:50Z",
                "price": 6700.55
            },
            ...
        ]
    },
    ...
]

lowPriorityItems

总是在那里，而

highPriorityItems

并不总是在那里。我想要的结果是使用

highPriorityItems

（如果存在）并捕获该数据。

棘手的部分是 API 是分页的，可以返回许多带有这些嵌入式 priorityItem 数组的单独对象，这意味着一个响应可能只显示特定

lowPriorityItems

的

id

，而下一个分页响应可能显示

 highPriorityItems

相同的

id

.

数组

我想得到一个最终结果，我只有 ID 和

lowPriorityItems

和

highPriorityItems

切片在一个

struct

中。如果

highPriorityItems

是空的，我可以在结果中并排放置两个切片后选择使用

lowPriorityItems

。

试图想出一种简洁有效的方法来处理这个想法。目前的想法：

package main


type Payload struct {
    Data []Entity `json:"data"`
}

type Entity struct {
    Id string `json:"id"`
    HighPriorityItems []Item `json:"highPriorityItems"`
    LowPriorityItems []Item `json:"lowPriorityItems"`
}

type Item struct {
    time string
    price float64
}

func main() {

    payloads := []&Payload{}
    
    for _, req := requests {
        // Boilerplate to unmarshal response into Payload struct and append to our slice of Payloads
        // Each response gets appended to our slice of payloads
        payloads = append(payloads, payload)
    
    }    

    // Here is where I am thinking that I need logic to essentially check if I have already 
    // Received a payload that has an object with the Id of the paginated payload, and if it does, append to our ```Entity``` priorityItem slices for that specific idea (so I can maintain a complete collection of both item types for the same ```id```
    // Does it make sense to each time loop over my current payload list and check for Ids (seems expensive) or maybe utilize another data structure (map w/ structs?) in some way?
  
}

Answer 1

在由 id 键控的实体映射中记录项目：

entities := make(map[string]*Entity)

对于每个响应，遍历实体。如果第一个实体将实体添加到地图，否则将项目附加到第一个实体。

for i := range resp.Data {
    e := &p.Data[i]
    if me, ok := entities[e.Id]; !ok {
        entities[e.Id] = me
    } else {
        me.LowPriorityItems = append(me.LowPriorityItems, e.LowPriorityItems...)
        me.HighPriorityItems = append(me.HighPriorityItems, e.HighPriorityItems...)
    }
}

遍历地图值以访问实体：

for _, e := range entities {
    // do something with e
}