From e43e6c3d0a26a7a28067022c2154c78a3b0cfaf1 Mon Sep 17 00:00:00 2001
From: silverpill <silverpill@firemail.cc>
Date: Wed, 1 Dec 2021 21:55:38 +0000
Subject: [PATCH] Paginate home timeline

---
 src/mastodon_api/timelines/mod.rs   |  1 +
 src/mastodon_api/timelines/types.rs | 12 ++++++++++++
 src/mastodon_api/timelines/views.rs | 11 +++++++++--
 src/models/posts/queries.rs         |  8 ++++++--
 4 files changed, 28 insertions(+), 4 deletions(-)
 create mode 100644 src/mastodon_api/timelines/types.rs

diff --git a/src/mastodon_api/timelines/mod.rs b/src/mastodon_api/timelines/mod.rs
index 38b4403..718ba5f 100644
--- a/src/mastodon_api/timelines/mod.rs
+++ b/src/mastodon_api/timelines/mod.rs
@@ -1 +1,2 @@
+mod types;
 pub mod views;
diff --git a/src/mastodon_api/timelines/types.rs b/src/mastodon_api/timelines/types.rs
new file mode 100644
index 0000000..db149e9
--- /dev/null
+++ b/src/mastodon_api/timelines/types.rs
@@ -0,0 +1,12 @@
+use serde::Deserialize;
+use uuid::Uuid;
+
+fn default_page_size() -> i64 { 20 }
+
+#[derive(Deserialize)]
+pub struct TimelineQueryParams {
+    pub max_id: Option<Uuid>,
+
+    #[serde(default = "default_page_size")]
+    pub limit: i64,
+}
diff --git a/src/mastodon_api/timelines/views.rs b/src/mastodon_api/timelines/views.rs
index cfd3b6d..0d7b601 100644
--- a/src/mastodon_api/timelines/views.rs
+++ b/src/mastodon_api/timelines/views.rs
@@ -1,3 +1,4 @@
+/// https://docs.joinmastodon.org/methods/timelines/
 use actix_web::{get, web, HttpResponse, Scope};
 use actix_web_httpauth::extractors::bearer::BearerAuth;
 
@@ -11,17 +12,23 @@ use crate::models::posts::helpers::{
     get_reposted_posts,
 };
 use crate::models::posts::queries::get_home_timeline;
+use super::types::TimelineQueryParams;
 
-/// https://docs.joinmastodon.org/methods/timelines/
 #[get("/home")]
 async fn home_timeline(
     auth: BearerAuth,
     config: web::Data<Config>,
     db_pool: web::Data<Pool>,
+    query_params: web::Query<TimelineQueryParams>,
 ) -> Result<HttpResponse, HttpError> {
     let db_client = &**get_database_client(&db_pool).await?;
     let current_user = get_current_user(db_client, auth.token()).await?;
-    let mut posts = get_home_timeline(db_client, &current_user.id).await?;
+    let mut posts = get_home_timeline(
+        db_client,
+        &current_user.id,
+        query_params.limit,
+        query_params.max_id,
+    ).await?;
     get_reposted_posts(db_client, posts.iter_mut().collect()).await?;
     get_actions_for_posts(
         db_client,
diff --git a/src/models/posts/queries.rs b/src/models/posts/queries.rs
index c267c3a..2e4aed7 100644
--- a/src/models/posts/queries.rs
+++ b/src/models/posts/queries.rs
@@ -178,6 +178,8 @@ pub const RELATED_MENTIONS: &str =
 pub async fn get_home_timeline(
     db_client: &impl GenericClient,
     current_user_id: &Uuid,
+    limit: i64,
+    max_post_id: Option<Uuid>,
 ) -> Result<Vec<Post>, DatabaseError> {
     // Select posts from follows + own posts.
     // Exclude direct messages where current user is not mentioned.
@@ -204,7 +206,9 @@ pub async fn get_home_timeline(
                     WHERE post_id = post.id AND profile_id = $1
                 )
             )
-        ORDER BY post.created_at DESC
+            AND ($3::uuid IS NULL OR post.id < $3)
+        ORDER BY post.id DESC
+        LIMIT $2
         ",
         related_attachments=RELATED_ATTACHMENTS,
         related_mentions=RELATED_MENTIONS,
@@ -212,7 +216,7 @@ pub async fn get_home_timeline(
     );
     let rows = db_client.query(
         statement.as_str(),
-        &[&current_user_id],
+        &[&current_user_id, &limit, &max_post_id],
     ).await?;
     let posts: Vec<Post> = rows.iter()
         .map(Post::try_from)