sort episodes by pubdate

main.go

@@ -11,6 +11,7 @@ import (
 	"os"
 	"path"
 	"strconv"
+	"strings"
 	"time"
 
 	_ "time/tzdata"
@@ -19,6 +20,24 @@ import (
 	_ "github.com/mattn/go-sqlite3"
 )
 
+type OrderType = string
+
+const (
+	OrderTypeAsc  OrderType = "ASC"
+	OrderTypeDesc OrderType = "DESC"
+)
+
+func validateOrderType(orderType string) OrderType {
+	switch strings.ToLower(orderType) {
+	case "asc":
+		return OrderTypeAsc
+	case "desc":
+		return OrderTypeDesc
+	default:
+		return OrderTypeAsc
+	}
+}
+
 type Podcast struct {
 	ID          int64     `json:"id" db:"id"`
 	Name        string    `json:"name" db:"name"`
@@ -198,8 +217,23 @@ func downloadEpisodeAudioFile(url string) ([]byte, error) {
 	return data, nil
 }
 
-func getPodcastEpisodes(db *sqlx.DB, podcastId int64) ([]*Episode, error) {
+func getPodcastEpisodes(db *sqlx.DB, podcastId int64, orderBy string, orderType OrderType) ([]*Episode, error) {
-	rows, err := db.Queryx("SELECT * FROM episodes WHERE podcast_id = ?", podcastId)
+	allowedColumns := map[string]bool{
+		"title":      true,
+		"pubdate":    true,
+		"number":     true,
+		"created_at": true,
+	}
+	if !allowedColumns[orderBy] {
+		orderBy = "pubdate"
+	}
+
+	orderType = validateOrderType(orderType)
+
+	query := fmt.Sprintf("SELECT * FROM episodes WHERE podcast_id = :podcast_id ORDER BY %s %s", orderBy, orderType)
+	rows, err := db.NamedQuery(query, map[string]any{
+		"podcast_id": podcastId,
+	})
 	if err != nil {
 		return nil, fmt.Errorf("failed to query db: %v", err)
 	}
@@ -425,7 +459,7 @@ func main() {
 			return
 		}
 
-		episodes, err := getPodcastEpisodes(db, int64(id))
+		episodes, err := getPodcastEpisodes(db, int64(id), "pubdate", OrderTypeDesc)
 		if err != nil {
 			http.Error(w, err.Error(), 500)
 			return