Mazyar
106 lines
2.9 KiB
Go
106 lines
2.9 KiB
Go
package response
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import (
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"errors"
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"fmt"
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"strconv"
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"github.com/labstack/echo/v4"
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)
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const (
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// DefaultListLimit is the default page size for admin list endpoints.
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DefaultListLimit = 10
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// MaxListLimit is the maximum allowed page size.
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MaxListLimit = 100
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)
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var (
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// ErrInvalidPagination is returned when pagination query parameters are invalid.
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ErrInvalidPagination = errors.New("invalid pagination parameters")
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// ErrPaginationConflict is returned when cursor and offset are both supplied.
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ErrPaginationConflict = errors.New("cursor and offset pagination cannot be used together")
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)
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// NewPagination parses and validates hybrid pagination query parameters from the request.
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func NewPagination(c echo.Context) (*Pagination, error) {
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limit := DefaultListLimit
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if limitStr := c.QueryParam("limit"); limitStr != "" {
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parsed, err := strconv.Atoi(limitStr)
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if err != nil {
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return nil, fmt.Errorf("%w: limit must be an integer", ErrInvalidPagination)
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}
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limit = parsed
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}
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if limit < 1 || limit > MaxListLimit {
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return nil, fmt.Errorf("%w: limit must be between 1 and %d", ErrInvalidPagination, MaxListLimit)
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}
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cursor := c.QueryParam("cursor")
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offsetParam := c.QueryParam("offset")
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if cursor != "" && offsetParam != "" {
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return nil, ErrPaginationConflict
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}
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offset := 0
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if offsetParam != "" {
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parsed, err := strconv.Atoi(offsetParam)
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if err != nil {
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return nil, fmt.Errorf("%w: offset must be an integer", ErrInvalidPagination)
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}
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if parsed < 0 {
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return nil, fmt.Errorf("%w: offset cannot be negative", ErrInvalidPagination)
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}
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offset = parsed
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}
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sortBy := c.QueryParam("sort_by")
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if sortBy == "" {
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sortBy = "created_at"
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}
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sortOrder := c.QueryParam("sort_order")
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if sortOrder == "" {
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sortOrder = "desc"
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}
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return &Pagination{
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Limit: limit,
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Offset: offset,
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Cursor: cursor,
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SortBy: sortBy,
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SortOrder: sortOrder,
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}, nil
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}
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// ListMeta builds pagination metadata for a list page.
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// pageOffset is the zero-based index of the first item in this page (from offset or cursor).
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func (p *Pagination) ListMeta(total int64, nextCursor string, hasMore bool, pageOffset int) *Meta {
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meta := &Meta{
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Limit: p.Limit,
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Offset: pageOffset,
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HasMore: hasMore,
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}
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if hasMore && nextCursor != "" {
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meta.NextCursor = nextCursor
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}
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if total >= 0 {
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meta.Total = int(total)
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if p.Limit > 0 {
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meta.Page = pageOffset/p.Limit + 1
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meta.Pages = int((total + int64(p.Limit) - 1) / int64(p.Limit))
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}
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}
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return meta
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}
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// ListMetaFromPage builds metadata from a paginated repository result.
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func (p *Pagination) ListMetaFromPage(total int64, nextCursor string, hasMore bool, pageOffset int) *Meta {
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return p.ListMeta(total, nextCursor, hasMore, pageOffset)
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}
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// IsPaginationError reports whether err is a client-facing pagination error.
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func IsPaginationError(err error) bool {
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return errors.Is(err, ErrInvalidPagination) || errors.Is(err, ErrPaginationConflict)
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}
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