Go App Engine 数据存储：生成唯一标识符

package main

import (
    "context"
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"

    "google.golang.org/appengine/datastore"
)

type Participant struct {
    ID        int64
    LastName  string
    FirstName string
    Birthdate string
    Email     string
    Cell      string
}

func serveError(c context.Context, w http.ResponseWriter, err error) {
    http.Error(w, err.Error(), http.StatusInternalServerError)
}

func handleParticipant(c context.Context, w http.ResponseWriter, r *http.Request) {
    switch r.Method {
    case "POST":
        d, _ := ioutil.ReadAll(r.Body)
        participant := new(Participant)
        err := json.Unmarshal(d, &participant)
        if err != nil {
            serveError(c, w, err)
            return
        }

        var key *datastore.Key
        parentKey := datastore.NewKey(c, "Parent", "default_parent", 0, nil) // 替换为你的父键

        if participant.ID == 0 {
            // no id yet .. create an incomplete key and allow the db to create one.
            key = datastore.NewIncompleteKey(c, "participant", parentKey)
        } else {
            // we have an id.  use that to update
            key = datastore.NewKey(c, "participant", "", participant.ID, parentKey)
        }
        // PERSIST!
        putKey, e := datastore.Put(c, key, participant)
        if e != nil {
            serveError(c, w, e)
            return
        }

        // ** 获取生成的 ID 并更新 participant 结构体 **
        participant.ID = putKey.IntID()

        // Fetch back out of the database, presumably with my new ID
        if e = datastore.Get(c, putKey, participant); e != nil {
            serveError(c, w, e)
            return
        }

        // send to the consumer
        jsonBytes, _ := json.Marshal(participant)
        w.Write(jsonBytes)

    default:
        http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
    }
}

func main() {
    http.HandleFunc("/participant", func(w http.ResponseWriter, r *http.Request) {
        // 在 App Engine 环境中，你可以直接使用 context.Background()
        // 但在本地开发环境中，你需要使用 appengine.NewContext(r)
        // 这里为了兼容性，我们使用 context.Background()
        ctx := context.Background()
        handleParticipant(ctx, w, r)
    })

    fmt.Println("Server listening on port 8080")
    http.ListenAndServe(":8080", nil)
}

import (
    "github.com/google/uuid"
)

func generateUUID() string {
    id, _ := uuid.NewUUID()
    return id.String()
}

// ... 在你的 Participant 结构体中使用 string 类型的 ID
type Participant struct {
    ID         string
    LastName   string
    FirstName  string
    Birthdate  string
    Email      string
    Cell       string
}

// ... 在创建新 Participant 时生成 UUID
participant.ID = generateUUID()
key = datastore.NewKey(c, "participant", participant.ID, 0, parentKey) // 使用字符串 ID 作为键名