Golang实现评论功能教程

type Comment struct {
    ID         int64     `json:"id"`
    Content    string    `json:"content"`
    AuthorID   int64     `json:"author_id"`
    TargetType string    `json:"target_type"`
    TargetID   int64     `json:"target_id"`
    ParentID   *int64    `json:"parent_id,omitempty"` // 可为空
    CreatedAt  time.Time `json:"created_at"`
}

r := mux.NewRouter()
r.HandleFunc("/comments", CreateComment).Methods("POST")
r.HandleFunc("/comments", ListComments).Queries("target_type", "{target_type}", "target_id", "{target_id}")
r.HandleFunc("/comments/{id}", DeleteComment).Methods("DELETE")

func CreateComment(w http.ResponseWriter, r *http.Request) {
    var comment Comment
    if err := json.NewDecoder(r.Body).Decode(&comment); err != nil {
        http.Error(w, "invalid JSON", http.StatusBadRequest)
        return
    }

    // 简单校验
    if comment.Content == "" || comment.TargetID == 0 || comment.AuthorID == 0 {
        http.Error(w, "missing required fields", http.StatusBadRequest)
        return
    }

    // 写入数据库（假设 db 是 *sql.DB）
    query := `INSERT INTO comments (content, author_id, target_type, target_id, parent_id, created_at)
              VALUES (?, ?, ?, ?, ?, ?)`
    _, err := db.Exec(query, comment.Content, comment.AuthorID, comment.TargetType,
                      comment.TargetID, comment.ParentID, time.Now())
    if err != nil {
        http.Error(w, "server error", http.StatusInternalServerError)
        return
    }

    w.WriteHeader(http.StatusCreated)
    json.NewEncoder(w).Encode(map[string]string{"status": "created"})
}