ch9.6

internal/data/filters.go

@@ -1,6 +1,10 @@
 package data
 
-import "gitea.local.lab/Lbenedar/greenlight/internal/validator"
+import (
+	"strings"
+
+	"gitea.local.lab/Lbenedar/greenlight/internal/validator"
+)
 
 type Filters struct {
 	Page         int
@@ -17,3 +21,20 @@ func ValidateFilters(v *validator.Validator, f Filters) {
 
 	v.Check(validator.PermittedValue(f.Sort, f.SortSafelist...), "sort", "invalid sort values")
 }
+
+func (f Filters) sortColumn() string {
+	for _, safeValue := range f.SortSafelist {
+		if f.Sort == safeValue {
+			return strings.TrimPrefix(f.Sort, "-")
+		}
+	}
+
+	panic("unsafe sort parameter: " + f.Sort)
+}
+
+func (f Filters) sortDirection() string {
+	if strings.HasPrefix(f.Sort, "-") {
+		return "DESC"
+	}
+	return "ASC"
+}

internal/data/movies.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"errors"
+	"fmt"
 	"time"
 
 	"gitea.local.lab/Lbenedar/greenlight/internal/validator"
@@ -135,12 +136,12 @@ func (m MovieModel) Delete(id int64) error {
 }
 
 func (m MovieModel) GetAll(title string, genres []string, filter Filters) ([]*Movie, error) {
-	query := `
+	query := fmt.Sprintf(`
 		SELECT id, created_at, title, year, runtime, genres, version
 		FROM movies
 		WHERE (to_tsvector('simple', title) @@ plainto_tsquery('simple', $1) OR $1 = '')
 		AND (genres @> $2 OR $2 = '{}')
-		ORDER BY id`
+		ORDER BY %s %s, id ASC`, filter.sortColumn(), filter.sortDirection())
 
 	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
 	defer cancel()