feat: create a model for subtasks

src/query/subtasks.rs

@@ -0,0 +1,21 @@
+use crate::query::{QueryErrors, QueryKey, QueryValue};
+use crate::server::subtasks::get_subtasks_of_task;
+use dioxus::prelude::ServerFnError;
+use dioxus_query::prelude::{use_get_query, QueryResult, UseQuery};
+
+pub(crate) fn use_subtasks_of_task_query(task_id: i32)
+                                         -> UseQuery<QueryValue, QueryErrors, QueryKey> {
+    use_get_query([QueryKey::SubtasksOfTaskId(task_id)], fetch_subtasks_of_task)
+}
+
+async fn fetch_subtasks_of_task(keys: Vec<QueryKey>) -> QueryResult<QueryValue, QueryErrors> {
+    if let Some(QueryKey::SubtasksOfTaskId(task_id)) = keys.first() {
+        match get_subtasks_of_task(*task_id).await {
+            Ok(subtasks) => Ok(QueryValue::Subtasks(subtasks)),
+            Err(ServerFnError::WrappedServerError(errors)) => Err(QueryErrors::Error(errors)),
+            Err(error) => panic!("Unexpected error: {:?}", error)
+        }.into()
+    } else {
+        panic!("Unexpected query keys: {:?}", keys);
+    }
+}