Golang实现短文本分享与存储功能

{
  "text": "这是一段秘密消息",
  "expire_after_views": 1,
  "expire_after_seconds": 3600
}

type Paste struct {
    Text               string `json:"text"`
    ExpireAfterViews   int    `json:"expire_after_views"`
    ExpireAfterSeconds int64  `json:"expire_after_seconds"`
    CreatedAt          int64  `json:"created_at"`
}

var (
    data = make(map[string]Paste)
    mu   = sync.RWMutex{}
)

func savePaste(id string, paste Paste) {
    mu.Lock()
    defer mu.Unlock()
    data[id] = paste
}

func getPaste(id string) (Paste, bool) {
    mu.RLock()
    defer mu.RUnlock()
    paste, exists := data[id]
    return paste, exists
}

func deletePaste(id string) {
    mu.Lock()
    defer mu.Unlock()
    delete(data, id)
}

func isExpired(paste Paste) bool {
    if paste.ExpireAfterSeconds > 0 {
        if time.Now().Unix()-paste.CreatedAt > paste.ExpireAfterSeconds {
            return true
        }
    }
    return false
}

func viewHandler(w http.ResponseWriter, r *http.Request) {
    id := strings.TrimPrefix(r.URL.Path, "/view/")

    paste, exists := getPaste(id)
    if !exists {
        http.Error(w, "内容不存在", http.StatusNotFound)
        return
    }

    if isExpired(paste) {
        deletePaste(id)
        http.Error(w, "内容已过期", http.StatusGone)
        return
    }

    // 减少可查看次数
    paste.ExpireAfterViews--
    if paste.ExpireAfterViews <= 0 {
        deletePaste(id)
    } else {
        savePaste(id, paste)
    }

    w.Header().Set("Content-Type", "application/json")
    json.NewEncoder(w).Encode(map[string]string{"text": paste.Text})
}

func createHandler(w http.ResponseWriter, r *http.Request) {
    var req struct {
        Text               string `json:"text"`
        ExpireAfterViews   int    `json:"expire_after_views"`
        ExpireAfterSeconds int64  `json:"expire_after_seconds"`
    }

    if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
        http.Error(w, "请求格式错误", http.StatusBadRequest)
        return
    }

    if req.Text == "" {
        http.Error(w, "文本不能为空", http.StatusBadRequest)
        return
    }

    if req.ExpireAfterViews == 0 {
        req.ExpireAfterViews = 1
    }

    id := generateShortID()
    paste := Paste{
        Text:               req.Text,
        ExpireAfterViews:   req.ExpireAfterViews,
        ExpireAfterSeconds: req.ExpireAfterSeconds,
        CreatedAt:          time.Now().Unix(),
    }

    savePaste(id, paste)

    w.Header().Set("Content-Type", "application/json")
    json.NewEncoder(w).Encode(map[string]string{"id": id})
}

func generateShortID() string {
    const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    bytes := make([]byte, 6)
    for i := range bytes {
        bytes[i] = letters[rand.Intn(len(letters))]
    }
    return string(bytes)
}

func main() {
    rand.Seed(time.Now().UnixNano())

    http.HandleFunc("/create", createHandler)
    http.HandleFunc("/view/", viewHandler)

    fmt.Println("服务启动在 :8080")
    log.Fatal(http.ListenAndServe(":8080", nil))
}

curl -X POST http://localhost:8080/create \
  -H "Content-Type: application/json" \
  -d '{"text":"你好世界","expire_after_seconds":60}'

{"id":"abc123"}

http://localhost:8080/view/abc123