v0.0.372 sq.Paginate

sq/paginate.go

@@ -0,0 +1,126 @@
+package sq
+
+import (
+	"context"
+	"fmt"
+	ct "gogs.mikescher.com/BlackForestBytes/goext/cursortoken"
+	"gogs.mikescher.com/BlackForestBytes/goext/exerr"
+	"gogs.mikescher.com/BlackForestBytes/goext/langext"
+	pag "gogs.mikescher.com/BlackForestBytes/goext/pagination"
+)
+
+type PaginateFilter interface {
+	SQL(params PP) (filterClause string, joinClause string, joinTables []string)
+	Sort() []FilterSort
+}
+
+type FilterSort struct {
+	Field     string
+	Direction ct.SortDirection
+}
+
+func Paginate[TData any](ctx context.Context, q Queryable, table string, filter PaginateFilter, scanMode StructScanMode, scanSec StructScanSafety, page int, limit *int) ([]TData, pag.Pagination, error) {
+	prepParams := PP{}
+
+	sortOrder := filter.Sort()
+	sortCond := ""
+	if len(sortOrder) > 0 {
+		sortCond = "ORDER BY "
+		for i, v := range sortOrder {
+			if i > 0 {
+				sortCond += ", "
+			}
+			sortCond += v.Field + " " + string(v.Direction)
+		}
+	}
+
+	pageCond := ""
+	if limit != nil {
+		pageCond += fmt.Sprintf("LIMIT :%s OFFSET :%s", prepParams.Add(*limit+1), prepParams.Add(*limit*(page-1)))
+	}
+
+	filterCond, joinCond, joinTables := filter.SQL(prepParams)
+
+	selectCond := table + ".*"
+	for _, v := range joinTables {
+		selectCond += ", " + v + ".*"
+	}
+
+	sqlQueryData := "SELECT " + selectCond + " FROM " + table + " " + joinCond + " WHERE ( " + filterCond + " ) " + sortCond + " " + pageCond
+	sqlQueryCount := "SELECT " + "COUNT(*)" + " FROM " + table + " " + joinCond + " WHERE ( " + filterCond + " ) "
+
+	rows, err := q.Query(ctx, sqlQueryData, prepParams)
+	if err != nil {
+		return nil, pag.Pagination{}, exerr.Wrap(err, "failed to list paginated entries from DB").Str("table", table).Any("filter", filter).Int("page", page).Any("limit", limit).Build()
+	}
+
+	entities, err := ScanAll[TData](ctx, q, rows, scanMode, scanSec, true)
+	if err != nil {
+		return nil, pag.Pagination{}, exerr.Wrap(err, "failed to decode paginated entries from DB").Str("table", table).Int("page", page).Any("limit", limit).Str("scanMode", string(scanMode)).Str("scanSec", string(scanSec)).Build()
+	}
+
+	if page == 1 && (limit == nil || len(entities) <= *limit) {
+		return entities, pag.Pagination{
+			Page:             1,
+			Limit:            langext.Coalesce(limit, len(entities)),
+			TotalPages:       1,
+			TotalItems:       len(entities),
+			CurrentPageCount: 1,
+		}, nil
+	} else {
+
+		countRows, err := q.Query(ctx, sqlQueryCount, prepParams)
+		if err != nil {
+			return nil, pag.Pagination{}, exerr.Wrap(err, "failed to query total-count of paginated entries from DB").Str("table", table).Build()
+		}
+
+		if !countRows.Next() {
+			return nil, pag.Pagination{}, exerr.New(exerr.TypeSQLQuery, "SQL COUNT(*) query returned no rows").Str("table", table).Any("filter", filter).Build() //TODO TypeSQLDecode
+		}
+
+		var countRes int
+		err = countRows.Scan(&countRes)
+		if err != nil {
+			return nil, pag.Pagination{}, exerr.Wrap(err, "failed to decode total-count of paginated entries from DB").Str("table", table).Build()
+		}
+
+		if len(entities) > *limit {
+			entities = entities[:*limit]
+		}
+
+		paginationObj := pag.Pagination{
+			Page:             page,
+			Limit:            langext.Coalesce(limit, countRes),
+			TotalPages:       pag.CalcPaginationTotalPages(countRes, langext.Coalesce(limit, countRes)),
+			TotalItems:       countRes,
+			CurrentPageCount: len(entities),
+		}
+
+		return entities, paginationObj, nil
+	}
+}
+
+func Count(ctx context.Context, q Queryable, table string, filter PaginateFilter) (int, error) {
+	prepParams := PP{}
+
+	filterCond, joinCond, _ := filter.SQL(prepParams)
+
+	sqlQueryCount := "SELECT " + "COUNT(*)" + " FROM " + table + " " + joinCond + " WHERE ( " + filterCond + " )"
+
+	countRows, err := q.Query(ctx, sqlQueryCount, prepParams)
+	if err != nil {
+		return 0, exerr.Wrap(err, "failed to query count of entries from DB").Str("table", table).Build()
+	}
+
+	if !countRows.Next() {
+		return 0, exerr.New(exerr.TypeSQLQuery, "SQL COUNT(*) query returned no rows").Str("table", table).Any("filter", filter).Build() //TODO TypeSQLDecode
+	}
+
+	var countRes int
+	err = countRows.Scan(&countRes)
+	if err != nil {
+		return 0, exerr.Wrap(err, "failed to decode count of entries from DB").Str("table", table).Build()
+	}
+
+	return countRes, nil
+}