add cache

b4tman/qchgk_web#1
using moka

src/main.rs

@@ -15,11 +15,15 @@ use rocket_contrib::templates::Template;
 use rand::distributions::Uniform;
 use rand::Rng;
 
+use std::ops::Deref;
 use std::sync::Arc;
 
 use chgk_ledb_lib::db;
 use chgk_ledb_lib::questions::Question;
 
+use moka::sync::Cache;
+use std::time::Duration;
+
 const DB_FILENAME: &str = "db.dat";
 
 trait ErrorEmpty {
@@ -34,9 +38,27 @@ impl<T, E> ErrorEmpty for Result<T, E> {
     }
 }
 
+#[derive(Clone)]
+struct ArcTemplateData {
+    value: Arc<serde_json::Value>,
+}
+
+impl ArcTemplateData {
+    fn new(value: serde_json::Value) -> ArcTemplateData {
+        ArcTemplateData {
+            value: Arc::new(value),
+        }
+    }
+    fn render(&self, name: &'static str) -> Template {
+        Template::render(name, self.value.deref())
+    }
+}
+
+type TemplateCache = moka::sync::Cache<usize, ArcTemplateData>;
+
 type DataBaseInner = db::Reader<Question>;
 type DataBase = Arc<DataBaseInner>;
-struct AppState{
+struct AppState {
     db: DataBase,
     database_distribution: Uniform<usize>,
 }
@@ -49,7 +71,7 @@ impl From<DataBaseInner> for AppState {
 
         Self {
             db,
-            database_distribution
+            database_distribution,
         }
     }
 }
@@ -63,7 +85,16 @@ fn get_question(db: &DataBase, id: usize) -> Result<Question, ()> {
     db.get(id - 1).err_empty()
 }
 
-fn show_question_details(template_name: &'static str, data: &AppState, id: usize) -> Template {
+fn show_question_details(
+    template_name: &'static str,
+    data: &AppState,
+    cache: &TemplateCache,
+    id: usize,
+) -> Template {
+    if let Some(value) = cache.get(&id) {
+        return value.render(template_name);
+    }
+
     match get_question(&data.db, id) {
         Ok(question) => {
             let mut context = serde_json::to_value(question).expect("question serialize");
@@ -71,7 +102,12 @@ fn show_question_details(template_name: &'static str, data: &AppState, id: usize
                 let next_id = random_question_id(&data.database_distribution);
                 context["next"] = serde_json::to_value(next_id).expect("question id serialize");
             }
-            Template::render(template_name, &context)
+
+            let value = ArcTemplateData::new(context);
+            let result = value.render(template_name);
+            cache.insert(id, value);
+
+            result
         }
         Err(_) => {
             use std::collections::HashMap;
@@ -82,13 +118,13 @@ fn show_question_details(template_name: &'static str, data: &AppState, id: usize
 }
 
 #[get("/q/<id>")]
-fn show_question(data: State<AppState>, id: usize) -> Template {
-    show_question_details("question", data.inner(), id)
+fn show_question(data: State<AppState>, cache: State<TemplateCache>, id: usize) -> Template {
+    show_question_details("question", data.inner(), cache.inner(), id)
 }
 
 #[get("/q/<id>/a")]
-fn show_answer(data: State<AppState>, id: usize) -> Template {
-    show_question_details("answer", data.inner(), id)
+fn show_answer(data: State<AppState>, cache: State<TemplateCache>, id: usize) -> Template {
+    show_question_details("answer", data.inner(), cache.inner(), id)
 }
 
 #[get("/q/0")]
@@ -116,9 +152,14 @@ fn not_found(_req: &rocket::Request) -> Template {
 
 fn rocket() -> Rocket {
     let state: AppState = db::Reader::new(DB_FILENAME, 2048).expect("open db").into();
+    let cache: TemplateCache = Cache::builder()
+        .time_to_idle(Duration::from_secs(15 * 60))
+        .max_capacity(300)
+        .build();
 
     rocket::ignite()
         .manage(state)
+        .manage(cache)
         .register(catchers![not_found])
         .mount(
             "/",