From ee413c5dee67ee1b7ff9e05435913ec6ecc45531 Mon Sep 17 00:00:00 2001
From: Lumither Tao <lumither@outlook.com>
Date: Mon, 22 Jul 2024 21:33:20 +0800
Subject: [PATCH] feat(blog) add pagination for get_post_list

---
 backend/src/api/get/get_post_list.rs | 72 +++++++++++++++-------------
 1 file changed, 39 insertions(+), 33 deletions(-)

diff --git a/backend/src/api/get/get_post_list.rs b/backend/src/api/get/get_post_list.rs
index af1dcc4..f4b87a5 100644
--- a/backend/src/api/get/get_post_list.rs
+++ b/backend/src/api/get/get_post_list.rs
@@ -1,17 +1,29 @@
 use axum::{extract::State, http::StatusCode, Json};
+use axum::extract::Query;
 use chrono::{DateTime, Utc};
 use futures::future::join_all;
+use serde::Deserialize;
 use serde_json::{json, Map, Value};
-use sqlx::{postgres::PgRow, query, PgPool, Row};
+use sqlx::{PgPool, postgres::PgRow, query, Row};
 use tracing::error;
 use uuid::Uuid;
 
+#[derive(Deserialize)]
+pub struct Params {
+    page: Option<u32>,
+}
+
+const PAGE_SIZE: u32 = 6;
+
 pub async fn get_post_list(
     State(db_connection): State<PgPool>,
+    Query(params): Query<Params>,
 ) -> Result<Json<Value>, (StatusCode, Json<Value>)> {
-    let post_list = sqlx::query(
-        "select post_id, title, sub_title, summary, last_update, first_update, header_img, category from post",
-    )
+    let offset = PAGE_SIZE * (params.page.unwrap_or(1) - 1);
+
+    let post_list = sqlx::query("SELECT * FROM post ORDER BY first_update DESC LIMIT $1 OFFSET $2")
+        .bind(PAGE_SIZE as i32)
+        .bind(offset as i32)
         .fetch_all(&db_connection)
         .await;
     let post_list = match post_list {
@@ -41,35 +53,29 @@ pub async fn get_post_list(
 }
 
 async fn analyze_post(db_connection: &PgPool, post: PgRow) -> Value {
-    let mut tmp = Map::new();
     let post_id: Uuid = post.get("post_id");
-    let title: String = post.get("title");
-    let category: String = post.get("category");
-    let header_img: String = post.get("header_img");
-    let sub_title: String = post.get("sub_title");
-    let summary: String = post.get("summary");
-    let last_update: DateTime<Utc> = post.get("last_update");
-    let first_update: DateTime<Utc> = post.get("first_update");
+    let tags = fetch_post_tags(db_connection, post_id).await;
 
-    let tags_future = query("SELECT tag FROM Tag WHERE post_id = $1")
-        .bind(post_id)
-        .fetch_all(db_connection);
-    let tags: Vec<String> = match tags_future.await {
-        Ok(res) => res.iter().map(|tag| tag.get::<String, _>("tag")).collect(),
-        Err(_) => {
-            vec![]
-        }
-    };
-
-    tmp.insert("post_id".to_string(), json!(post_id.to_string()));
-    tmp.insert("title".to_string(), json!(title));
-    tmp.insert("category".to_string(), json!(category));
-    tmp.insert("header_img".to_string(), json!(header_img));
-    tmp.insert("sub_title".to_string(), json!(sub_title));
-    tmp.insert("summary".to_string(), json!(summary));
-    tmp.insert("last_update".to_string(), json!(last_update));
-    tmp.insert("first_update".to_string(), json!(first_update));
-    tmp.insert("tags".to_string(), json!(tags));
-
-    Value::from(tmp)
+    json!({
+        "post_id": post_id.to_string(),
+        "title": post.get::<String, _>("title"),
+        "category": post.get::<String, _>("category"),
+        "header_img": post.get::<String, _>("header_img"),
+        "sub_title": post.get::<String, _>("sub_title"),
+        "summary": post.get::<String, _>("summary"),
+        "last_update": post.get::<DateTime<Utc>, _>("last_update"),
+        "first_update": post.get::<DateTime<Utc>, _>("first_update"),
+        "tags": tags,
+    })
+}
+
+async fn fetch_post_tags(db_connection: &PgPool, post_id: Uuid) -> Vec<String> {
+    match query("SELECT tag FROM Tag WHERE post_id = $1")
+        .bind(post_id)
+        .fetch_all(db_connection)
+        .await
+    {
+        Ok(res) => res.iter().map(|tag| tag.get::<String, _>("tag")).collect(),
+        Err(_) => vec![],
+    }
 }