From 5f92125e449878d0156c56faa4a35bb028a22039 Mon Sep 17 00:00:00 2001
From: Jared Schneiderman <plunk00@gmail.com>
Date: Mon, 12 Jun 2023 17:48:02 -0400
Subject: [PATCH] Add limit and pagination to feeds (#2980)

* adds limit and pagination to all rss feeds

* consistent ordering

* refactor page and limit and add after

* revert back to using page

* remove offset change

* refactor to impl adding helper methods

* clippy
---
 crates/routes/src/feeds.rs | 97 +++++++++++++++++++++++++++++---------
 1 file changed, 75 insertions(+), 22 deletions(-)

diff --git a/crates/routes/src/feeds.rs b/crates/routes/src/feeds.rs
index 5d1f285ca..74821354c 100644
--- a/crates/routes/src/feeds.rs
+++ b/crates/routes/src/feeds.rs
@@ -31,13 +31,30 @@ use rss::{
 };
 use serde::Deserialize;
 use std::{collections::BTreeMap, str::FromStr};
-use strum::ParseError;
 
 const RSS_FETCH_LIMIT: i64 = 20;
 
 #[derive(Deserialize)]
 struct Params {
   sort: Option<String>,
+  limit: Option<i64>,
+  page: Option<i64>,
+}
+
+impl Params {
+  fn sort_type(&self) -> Result<SortType, Error> {
+    let sort_query = self
+      .sort
+      .clone()
+      .unwrap_or_else(|| SortType::Hot.to_string());
+    SortType::from_str(&sort_query).map_err(ErrorBadRequest)
+  }
+  fn get_limit(&self) -> i64 {
+    self.limit.unwrap_or(RSS_FETCH_LIMIT)
+  }
+  fn get_page(&self) -> i64 {
+    self.page.unwrap_or(1)
+  }
 }
 
 enum RequestType {
@@ -68,8 +85,16 @@ async fn get_all_feed(
   info: web::Query<Params>,
   context: web::Data<LemmyContext>,
 ) -> Result<HttpResponse, Error> {
-  let sort_type = get_sort_type(info).map_err(ErrorBadRequest)?;
-  Ok(get_feed_data(&context, ListingType::All, sort_type).await?)
+  Ok(
+    get_feed_data(
+      &context,
+      ListingType::All,
+      info.sort_type()?,
+      info.get_limit(),
+      info.get_page(),
+    )
+    .await?,
+  )
 }
 
 #[tracing::instrument(skip_all)]
@@ -77,8 +102,16 @@ async fn get_local_feed(
   info: web::Query<Params>,
   context: web::Data<LemmyContext>,
 ) -> Result<HttpResponse, Error> {
-  let sort_type = get_sort_type(info).map_err(ErrorBadRequest)?;
-  Ok(get_feed_data(&context, ListingType::Local, sort_type).await?)
+  Ok(
+    get_feed_data(
+      &context,
+      ListingType::Local,
+      info.sort_type()?,
+      info.get_limit(),
+      info.get_page(),
+    )
+    .await?,
+  )
 }
 
 #[tracing::instrument(skip_all)]
@@ -86,6 +119,8 @@ async fn get_feed_data(
   context: &LemmyContext,
   listing_type: ListingType,
   sort_type: SortType,
+  limit: i64,
+  page: i64,
 ) -> Result<HttpResponse, LemmyError> {
   let site_view = SiteView::read_local(context.pool()).await?;
 
@@ -93,7 +128,8 @@ async fn get_feed_data(
     .pool(context.pool())
     .listing_type(Some(listing_type))
     .sort(Some(sort_type))
-    .limit(Some(RSS_FETCH_LIMIT))
+    .limit(Some(limit))
+    .page(Some(page))
     .build()
     .list()
     .await?;
@@ -125,8 +161,6 @@ async fn get_feed(
   info: web::Query<Params>,
   context: web::Data<LemmyContext>,
 ) -> Result<HttpResponse, Error> {
-  let sort_type = get_sort_type(info).map_err(ErrorBadRequest)?;
-
   let req_type: String = req.match_info().get("type").unwrap_or("none").parse()?;
   let param: String = req.match_info().get("name").unwrap_or("none").parse()?;
 
@@ -143,16 +177,34 @@ async fn get_feed(
 
   let builder = match request_type {
     RequestType::User => {
-      get_feed_user(context.pool(), &sort_type, &param, &protocol_and_hostname).await
+      get_feed_user(
+        context.pool(),
+        &info.sort_type()?,
+        &info.get_limit(),
+        &info.get_page(),
+        &param,
+        &protocol_and_hostname,
+      )
+      .await
     }
     RequestType::Community => {
-      get_feed_community(context.pool(), &sort_type, &param, &protocol_and_hostname).await
+      get_feed_community(
+        context.pool(),
+        &info.sort_type()?,
+        &info.get_limit(),
+        &info.get_page(),
+        &param,
+        &protocol_and_hostname,
+      )
+      .await
     }
     RequestType::Front => {
       get_feed_front(
         context.pool(),
         &jwt_secret,
-        &sort_type,
+        &info.sort_type()?,
+        &info.get_limit(),
+        &info.get_page(),
         &param,
         &protocol_and_hostname,
       )
@@ -173,18 +225,12 @@ async fn get_feed(
   )
 }
 
-fn get_sort_type(info: web::Query<Params>) -> Result<SortType, ParseError> {
-  let sort_query = info
-    .sort
-    .clone()
-    .unwrap_or_else(|| SortType::Hot.to_string());
-  SortType::from_str(&sort_query)
-}
-
 #[tracing::instrument(skip_all)]
 async fn get_feed_user(
   pool: &DbPool,
   sort_type: &SortType,
+  limit: &i64,
+  page: &i64,
   user_name: &str,
   protocol_and_hostname: &str,
 ) -> Result<ChannelBuilder, LemmyError> {
@@ -196,7 +242,8 @@ async fn get_feed_user(
     .listing_type(Some(ListingType::All))
     .sort(Some(*sort_type))
     .creator_id(Some(person.id))
-    .limit(Some(RSS_FETCH_LIMIT))
+    .limit(Some(*limit))
+    .page(Some(*page))
     .build()
     .list()
     .await?;
@@ -217,6 +264,8 @@ async fn get_feed_user(
 async fn get_feed_community(
   pool: &DbPool,
   sort_type: &SortType,
+  limit: &i64,
+  page: &i64,
   community_name: &str,
   protocol_and_hostname: &str,
 ) -> Result<ChannelBuilder, LemmyError> {
@@ -227,7 +276,8 @@ async fn get_feed_community(
     .pool(pool)
     .sort(Some(*sort_type))
     .community_id(Some(community.id))
-    .limit(Some(RSS_FETCH_LIMIT))
+    .limit(Some(*limit))
+    .page(Some(*page))
     .build()
     .list()
     .await?;
@@ -253,6 +303,8 @@ async fn get_feed_front(
   pool: &DbPool,
   jwt_secret: &str,
   sort_type: &SortType,
+  limit: &i64,
+  page: &i64,
   jwt: &str,
   protocol_and_hostname: &str,
 ) -> Result<ChannelBuilder, LemmyError> {
@@ -265,7 +317,8 @@ async fn get_feed_front(
     .listing_type(Some(ListingType::Subscribed))
     .local_user(Some(&local_user))
     .sort(Some(*sort_type))
-    .limit(Some(RSS_FETCH_LIMIT))
+    .limit(Some(*limit))
+    .page(Some(*page))
     .build()
     .list()
     .await?;