Fix preview grouping

src/dto_helpers.rs

@@ -32,7 +32,7 @@ pub fn load_title(db: &PgConnection, config: &Config, title: Title) -> QueryResu
         title, title_names, title_descriptions,
         title_cast, title_genres, title_ratings,
         title_images, title_media, title_subtitles,
-        title_preview,
+        Some(title_preview),
     ))
 }
 
@@ -63,8 +63,12 @@ pub fn load_titles(db: &PgConnection, config: &Config, titles: Vec<Title>) -> Qu
     let title_subtitles: Vec<Vec<TitleSubtitle>> = TitleSubtitle::belonging_to(&titles)
         .load::<TitleSubtitle>(db)?
         .grouped_by(&titles);
-    let title_preview: Vec<TitlePreview> = TitlePreview::belonging_to(&titles)
-        .load::<TitlePreview>(db)?;
+    let title_preview: Vec<Option<TitlePreview>> = TitlePreview::belonging_to(&titles)
+        .load::<TitlePreview>(db)?
+        .grouped_by(&titles)
+        .into_iter()
+        .map(|vec: Vec<TitlePreview>| vec.into_iter().next())
+        .collect::<Vec<_>>();
     Ok(titles.into_iter()
         .zip(title_names)
         .zip(title_descriptions)
@@ -94,7 +98,7 @@ fn process_title(
     title: Title, names: Vec<TitleName>, descriptions: Vec<TitleDescription>,
     cast: Vec<(TitleCast, Person)>, genres: Vec<(TitleGenre, Genre)>, ratings: Vec<TitleRating>,
     images: Vec<TitleImage>, media: Vec<TitleMedium>, subtitles: Vec<TitleSubtitle>,
-    preview: TitlePreview,
+    preview: Option<TitlePreview>,
 ) -> TitleDto {
     TitleDto::of(
         title,
@@ -123,7 +127,9 @@ fn process_title(
         subtitles.into_iter().filter_map(|src| {
             SubtitleDto::of(src, &config).ok()
         }).collect::<Vec<_>>(),
-        preview.src.and_then(|preview| absolute_url(config, preview).ok())
+        preview
+            .and_then(|preview| preview.src)
+            .and_then(|preview| absolute_url(config, preview).ok())
     )
 }