92babe509f
Implement cursor-based pagination across multiple API endpoints to improve performance and enable efficient infinite scrolling. This replaces traditional offset-based pagination for high-volume data retrieval. Changes: - Add cursor pagination DTOs for all entity types (Post, Comment, Message, Conversation, Group, Notification, GroupMember, GroupAnnouncement) - Implement cursor pagination methods in repositories with support for various sort orders (created_at, updated_at, join_time, seq) - Add cursor pagination handlers that maintain backward compatibility with existing offset pagination - Add new API routes for cursor-based endpoints (/cursor suffix) - Add helper converter functions for pointer slice types in DTO conversions
139 lines
3.1 KiB
Go
139 lines
3.1 KiB
Go
package cursor
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import (
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"errors"
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)
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const (
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// DefaultPageSize 默认页面大小
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DefaultPageSize = 20
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// MaxPageSize 最大页面大小
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MaxPageSize = 100
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)
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// Direction 分页方向
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type Direction string
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const (
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// Forward 向前分页（下一页）
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Forward Direction = "forward"
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// Backward 向后分页（上一页）
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Backward Direction = "backward"
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)
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// IsValid 检查分页方向是否有效
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func (d Direction) IsValid() bool {
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return d == Forward || d == Backward
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}
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// PageRequest 游标分页请求参数
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type PageRequest struct {
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Cursor string // 游标字符串
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Direction Direction // 分页方向
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PageSize int // 每页数量
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}
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// NewPageRequest 创建新的游标请求
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func NewPageRequest(cursor string, direction Direction, pageSize int) *PageRequest {
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req := &PageRequest{
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Cursor: cursor,
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Direction: direction,
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PageSize: pageSize,
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}
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req.Normalize()
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return req
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}
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// Normalize 规范化分页参数
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func (r *PageRequest) Normalize() {
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if r.Direction == "" {
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r.Direction = Forward
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}
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if r.PageSize <= 0 {
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r.PageSize = DefaultPageSize
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}
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if r.PageSize > MaxPageSize {
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r.PageSize = MaxPageSize
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}
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}
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// GetPageSize 获取有效的页面大小（默认20，最大100）
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func (r *PageRequest) GetPageSize() int {
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if r.PageSize <= 0 {
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return DefaultPageSize
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}
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if r.PageSize > MaxPageSize {
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return MaxPageSize
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}
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return r.PageSize
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}
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// Validate 验证分页请求
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func (r *PageRequest) Validate() error {
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if r.Direction != "" && !r.Direction.IsValid() {
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return errors.New("invalid direction, must be 'forward' or 'backward'")
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}
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return nil
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}
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// GetCursor 解码游标
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func (r *PageRequest) GetCursor() (*Cursor, error) {
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return DecodeCursor(r.Cursor)
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}
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// IsForward 是否向前分页
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func (r *PageRequest) IsForward() bool {
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return r.Direction == Forward || r.Direction == ""
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}
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// IsBackward 是否向后分页
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func (r *PageRequest) IsBackward() bool {
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return r.Direction == Backward
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}
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// PageResponse 游标分页响应结构
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type PageResponse struct {
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Items interface{} `json:"items"`
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NextCursor string `json:"next_cursor"`
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PrevCursor string `json:"prev_cursor,omitempty"`
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HasMore bool `json:"has_more"`
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}
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// NewPageResponse 创建分页响应
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func NewPageResponse(items interface{}, nextCursor, prevCursor string, hasMore bool) *PageResponse {
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return &PageResponse{
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Items: items,
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NextCursor: nextCursor,
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PrevCursor: prevCursor,
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HasMore: hasMore,
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}
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}
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// CursorPageResult 游标分页结果（泛型版本，供内部使用）
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type CursorPageResult[T any] struct {
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Items []T
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NextCursor string
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PrevCursor string
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HasMore bool
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}
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// NewCursorPageResult 创建游标分页结果
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func NewCursorPageResult[T any](items []T, nextCursor, prevCursor string, hasMore bool) *CursorPageResult[T] {
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return &CursorPageResult[T]{
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Items: items,
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NextCursor: nextCursor,
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PrevCursor: prevCursor,
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HasMore: hasMore,
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}
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}
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// ToPageResponse 转换为通用分页响应
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func (r *CursorPageResult[T]) ToPageResponse() *PageResponse {
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return &PageResponse{
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Items: r.Items,
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NextCursor: r.NextCursor,
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PrevCursor: r.PrevCursor,
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HasMore: r.HasMore,
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}
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}
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