Improve add tag endpoint and add get tag endpoint

Flattened out the add tag logic to make it more functional.

src/main.rs

@@ -301,13 +301,13 @@ async fn add_tag(_: Claims, body: web::Json<AddTagRequest>) -> impl Responder {
     use database::schema::tags;
 
     let connection = &connect();
-    let tag_id = tags::table
+    match tags::table
         .filter(tags::name.eq(&tag))
         .get_result::<Tag>(connection)
         .optional()
-        .map_or(-1, |t| {
+        .and_then(|t| {
             if let Some(t) = t {
-                t.id
+                Ok(t.id)
             } else {
                 match diesel::insert_into(tags::table)
                     .values(InsertTag { name: tag.clone() })
@@ -318,23 +318,20 @@ async fn add_tag(_: Claims, body: web::Json<AddTagRequest>) -> impl Responder {
                             diesel::sql_types::Integer,
                             "Represents the SQL last_insert_row() function"
                         );
-                        diesel::select(last_insert_rowid).get_results::<i32>(connection)
+                        diesel::select(last_insert_rowid).get_result::<i32>(connection)
                     }) {
                     Err(e) => {
                         error!("Error inserting tag: '{}'. {:?}", tag, e);
-                        -1
+                        Err(e)
                     }
                     Ok(id) => {
                         debug!("Inserted tag: '{}' with id: {:?}", tag, id);
-                        *id.first().expect("We should have just inserted the row")
+                        Ok(id)
                     }
                 }
             }
-        });
+        })
-
+        .map(|tag_id| {
-    if tag_id == -1 {
-        HttpResponse::InternalServerError()
-    } else {
             use database::schema::tagged_photo;
 
             let file_name = body.file_name.clone();
@@ -370,6 +367,32 @@ async fn add_tag(_: Claims, body: web::Json<AddTagRequest>) -> impl Responder {
                     HttpResponse::InternalServerError()
                 }
             }
+        }) {
+        Ok(resp) => resp,
+        Err(e) => {
+            error!("{:?}", e);
+            HttpResponse::InternalServerError()
+        }
+    }
+}
+
+#[get("image/tags")]
+async fn get_tags(_: Claims, request: web::Query<ThumbnailRequest>) -> impl Responder {
+    use schema::tagged_photo;
+    use schema::tags;
+
+    match tags::table
+        .left_join(tagged_photo::table)
+        .filter(tagged_photo::photo_name.eq(&request.path))
+        .select((tags::id, tags::name))
+        .get_results::<Tag>(&connect())
+    {
+        Ok(tags) => HttpResponse::Ok().json(tags),
+        Err(e) => {
+            error!("Error getting tags for image: '{}'. {:?}", request.path, e);
+
+            HttpResponse::InternalServerError().finish()
+        }
     }
 }
 
@@ -556,6 +579,7 @@ fn main() -> std::io::Result<()> {
             .service(delete_favorite)
             .service(get_file_metadata)
             .service(add_tag)
+            .service(get_tags)
             .app_data(app_data.clone())
             .data::<Box<dyn UserDao>>(Box::new(user_dao))
             .data::<Box<dyn FavoriteDao>>(Box::new(favorites_dao))