feat: cache for get multi posts

src/api/post.rs

@@ -36,6 +36,7 @@ pub struct PostOutput {
     comments: Option<Vec<CommentOutput>>,
     can_del: bool,
     attention: bool,
+    hot_score: Option<i32>,
     // for old version frontend
     timestamp: i64,
     likenum: i32,
@@ -95,6 +96,7 @@ async fn p2output(
             .has(p.id)
             .await
             .unwrap_or_default(),
+        hot_score: if user.is_admin { Some(p.hot_score) } else { None },
         // for old version frontend
         timestamp: p.create_time.timestamp(),
         likenum: p.n_attentions,
@@ -185,7 +187,7 @@ pub async fn edit_cw(cwi: Form<CwInput>, user: CurrentUser, db: Db) -> JsonAPI {
 
 #[get("/getmulti?<pids>")]
 pub async fn get_multi(pids: Vec<i32>, user: CurrentUser, db: Db, rconn: RdsConn) -> JsonAPI {
-    let ps = Post::get_multi(&db, pids).await?;
+    let ps = Post::get_multi_with_cache(&db, &rconn, &pids).await?;
     let ps_data = ps2outputs(&ps, &user, &db, &rconn).await;
 
     Ok(json!({

src/cache.rs

@@ -5,53 +5,97 @@ use rocket::serde::json::serde_json;
 // can use rocket::serde::json::to_string in master version
 
 const INSTANCE_EXPIRE_TIME: usize = 60 * 60;
+macro_rules! post_cache_key {
+    ($id: expr) => {
+        format!("hole_v2:cache:post:{}", $id)
+    };
+}
 
 pub struct PostCache {
-    key: String,
     rconn: RdsConn,
 }
 
 impl PostCache {
-    pub fn init(pid: &i32, rconn: &RdsConn) -> Self {
+    pub fn init(rconn: &RdsConn) -> Self {
         PostCache {
-            key: format!("hole_v2:cache:post:{}", pid),
             rconn: rconn.clone(),
         }
     }
 
-    pub async fn set(&mut self, p: &Post) {
-        self.rconn
-            .set_ex(
-                &self.key,
+    pub async fn sets(&mut self, ps: &Vec<&Post>) {
+        if ps.is_empty() {
+            return;
+        }
+        let kvs: Vec<(String, String)> = ps
+            .iter()
+            .map(|p| (
+                post_cache_key!(p.id), 
                 serde_json::to_string(p).unwrap(),
-                INSTANCE_EXPIRE_TIME,
-            )
+            ) ).collect();
+        dbg!(&kvs);
+        let ret = self.rconn
+            .set_multiple(&kvs)
             .await
             .unwrap_or_else(|e| {
-                warn!("set post cache failed: {}, {}", e, p.id);
-            })
+                warn!("set post cache failed: {}", e);
+                "x".to_string()
+            });
+        dbg!(ret);
     }
 
-    pub async fn get(&mut self) -> Option<Post> {
-        let rds_result = self.rconn.get::<&String, String>(&self.key).await;
-        if let Ok(s) = rds_result {
-            debug!("hint user cache");
-            self.rconn
-                .expire::<&String, bool>(&self.key, INSTANCE_EXPIRE_TIME)
-                .await
-                .unwrap_or_else(|e| {
-                    warn!(
-                        "get post cache, set new expire failed: {}, {}, {} ",
-                        e, &self.key, &s
-                    );
-                    false
-                });
+    pub async fn get(&mut self, pid: &i32) -> Option<Post> {
+        let key = post_cache_key!(pid);
+        let rds_result: Option<String> = self
+            .rconn
+            .get::<String, Option<String>>(key)
+            .await
+            .unwrap_or_else(|e| {
+                warn!("try to get post cache, connect rds fail, {}", e);
+                None
+            });
+
+        rds_result.and_then(|s| {
             serde_json::from_str(&s).unwrap_or_else(|e| {
                 warn!("get post cache, decode failed {}, {}", e, s);
                 None
             })
-        } else {
-            None
+        })
+    }
+
+    pub async fn gets(&mut self, pids: &Vec<i32>) -> Vec<Option<Post>> {
+        // 长度为1时会走GET而非MGET，返回值格式不兼容。愚蠢的设计。
+        match pids.len() {
+            0 => vec![],
+            1 => vec![self.get(&pids[0]).await],
+            _ => {
+                let ks: Vec<String> = pids.iter().map(|pid| post_cache_key!(pid)).collect();
+                // dbg!(&ks);
+                // Vec is single arg, while &Vec is not. Seems a bug.
+                let rds_result: Vec<Option<String>> = self
+                    .rconn
+                    .get::<Vec<String>, Vec<Option<String>>>(ks)
+                    .await
+                    .unwrap_or_else(|e| {
+                        warn!("try to get posts cache, connect rds fail, {}", e);
+                        vec![None; pids.len()]
+                    });
+                // dbg!(&rds_result);
+
+                // 定期热度衰减的时候会清空缓存，这里设不设置过期时间影响不大
+
+                rds_result
+                    .into_iter()
+                    .map(|x| {
+                        // dbg!(&x);
+                        x.and_then(|s| {
+                            serde_json::from_str(&s).unwrap_or_else(|e| {
+                                warn!("get post cache, decode failed {}, {}", e, s);
+                                None
+                            })
+                        })
+                    })
+                    .collect()
+            }
         }
     }
 }
@@ -85,19 +129,19 @@ impl UserCache {
     pub async fn get(&mut self) -> Option<User> {
         let rds_result = self.rconn.get::<&String, String>(&self.key).await;
         if let Ok(s) = rds_result {
-            debug!("hint post cache");
+            debug!("hint user cache");
             self.rconn
                 .expire::<&String, bool>(&self.key, INSTANCE_EXPIRE_TIME)
                 .await
                 .unwrap_or_else(|e| {
                     warn!(
-                        "get post cache, set new expire failed: {}, {}, {} ",
+                        "get user cache, set new expire failed: {}, {}, {} ",
                         e, &self.key, &s
                     );
                     false
                 });
             serde_json::from_str(&s).unwrap_or_else(|e| {
-                warn!("get post cache, decode failed {}, {}", e, s);
+                warn!("get user cache, decode failed {}, {}", e, s);
                 None
             })
         } else {

src/models.rs

@@ -1,17 +1,19 @@
 #![allow(clippy::all)]
 
+use crate::cache::{PostCache, UserCache};
 use crate::db_conn::Db;
 use crate::libs::diesel_logger::LoggingConnection;
 use crate::rds_conn::RdsConn;
-use crate::cache::{PostCache, UserCache};
 use crate::schema::*;
 use chrono::{offset::Utc, DateTime};
+use diesel::dsl::any;
 use diesel::{
     insert_into, BoolExpressionMethods, ExpressionMethods, QueryDsl, QueryResult, RunQueryDsl,
     TextExpressionMethods,
 };
-use diesel::dsl::any;
 use rocket::serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+use std::convert::identity;
 
 no_arg_sql_function!(RANDOM, (), "Represents the sql RANDOM() function");
 
@@ -28,12 +30,14 @@ macro_rules! get {
 macro_rules! get_multi {
     ($table:ident) => {
         pub async fn get_multi(db: &Db, ids: Vec<i32>) -> QueryResult<Vec<Self>> {
+            if ids.is_empty() {
+                return Ok(vec![]);
+            }
             // eq(any()) is only for postgres
             db.run(move |c| {
                 $table::table
                     .filter($table::id.eq(any(ids)))
                     .filter($table::is_deleted.eq(false))
-                    .order($table::id.desc())
                     .load(with_log!(c))
             })
             .await
@@ -83,7 +87,7 @@ pub struct Comment {
     pub post_id: i32,
 }
 
-#[derive(Queryable, Insertable, Serialize, Deserialize)]
+#[derive(Queryable, Insertable, Serialize, Deserialize, Debug)]
 #[serde(crate = "rocket::serde")]
 pub struct Post {
     pub id: i32,
@@ -131,15 +135,52 @@ impl Post {
 
     set_deleted!(posts);
 
-    pub async fn get_with_cache(db: &Db, rconn: &RdsConn, id: i32) -> QueryResult<Self> {
-        let mut cacher = PostCache::init(&id, &rconn);
-        if let Some(p) = cacher.get().await {
-            Ok(p)
-        } else {
-            let p = Self::get(db, id).await?;
-            cacher.set(&p).await;
-            Ok(p)
+    pub async fn get_multi_with_cache(
+        db: &Db,
+        rconn: &RdsConn,
+        ids: &Vec<i32>,
+    ) -> QueryResult<Vec<Self>> {
+        let mut cacher = PostCache::init(&rconn);
+        let mut cached_posts = cacher.gets(ids).await;
+        let mut id2po = HashMap::<i32, &mut Option<Post>>::new();
+
+        // dbg!(&cached_posts);
+
+        let missing_ids = ids
+            .iter()
+            .zip(cached_posts.iter_mut())
+            .filter_map(|(pid, p)| match p {
+                None => {
+                    id2po.insert(pid.clone(), p);
+                    Some(pid)
+                },
+                _ => None,
+            })
+            .copied()
+            .collect();
+
+        dbg!(&missing_ids);
+        let missing_ps = Self::get_multi(db, missing_ids).await?;
+        // dbg!(&missing_ps);
+        
+        cacher.sets(&missing_ps.iter().map(identity).collect()).await;
+
+        for p in missing_ps.into_iter() {
+            if let Some(op) = id2po.get_mut(&p.id) {
+                **op = Some(p);
+            }
         }
+        // dbg!(&cached_posts);
+        Ok(
+            cached_posts.into_iter().filter_map(identity).collect()
+        )
+    }
+
+    pub async fn get_with_cache(db: &Db, rconn: &RdsConn, id: i32) -> QueryResult<Self> {
+        Self::get_multi_with_cache(db, rconn, &vec![id])
+            .await?
+            .pop()
+            .ok_or(diesel::result::Error::NotFound)
     }
 
     pub async fn gets_by_page(
@@ -177,9 +218,7 @@ impl Post {
         let search_text2 = search_text.replace("%", "\\%");
         db.run(move |c| {
             let pat;
-            let mut query = base_query!(posts)
-                .distinct()
-                .left_join(comments::table);
+            let mut query = base_query!(posts).distinct().left_join(comments::table);
             // 先用搜索+缓存，性能有问题了再真的做tag表
             query = match search_mode {
                 0 => {
@@ -188,7 +227,11 @@ impl Post {
                         .filter(posts::cw.eq(&search_text))
                         .or_filter(posts::cw.eq(format!("#{}", &search_text)))
                         .or_filter(posts::content.like(&pat))
-                        .or_filter(comments::content.like(&pat).and(comments::is_deleted.eq(false)))
+                        .or_filter(
+                            comments::content
+                                .like(&pat)
+                                .and(comments::is_deleted.eq(false)),
+                        )
                 }
                 1 => {
                     pat = format!("%{}%", search_text2.replace(" ", "%"));
@@ -262,7 +305,7 @@ impl Post {
     }
 
     pub async fn set_instance_cache(&self, rconn: &RdsConn) {
-        PostCache::init(&self.id, rconn).set(self).await;
+        PostCache::init(rconn).sets(&vec![self]).await;
     }
     pub async fn refresh_cache(&self, rconn: &RdsConn, is_new: bool) {
         self.set_instance_cache(rconn).await;