feat(blog::api) pagination

backend/server/src/modules/blog/api/get_page_count/mod.rs

@@ -1,25 +0,0 @@
-use crate::constants::blog::PAGE_SIZE;
-
-use axum::{Json, extract::State};
-use serde_json::{Value, json};
-use sqlx::{PgPool, Row, query};
-use tracing::error;
-
-const GET_PAGE_COUNT_QUERY: &str = include_str!("post_page_count.sql");
-
-pub async fn handler(State(db_connection): State<PgPool>) -> Result<Json<Value>, Json<Value>> {
-    match query(GET_PAGE_COUNT_QUERY)
-        .bind(PAGE_SIZE as i64)
-        .fetch_one(&db_connection)
-        .await
-    {
-        Ok(res) => {
-            let res: i32 = res.get("count");
-            Ok(Json::from(json!({"res": res})))
-        }
-        Err(e) => {
-            error!("failed to get blog page count: {}", e.to_string());
-            Err(Json::from(json!({"error": e.to_string()})))
-        }
-    }
-}

backend/server/src/modules/blog/api/get_page_count/post_page_count.sql

@@ -1,2 +0,0 @@
-SELECT cast(ceil(count(*) / cast($1 AS FLOAT)) AS INTEGER) AS count
-FROM posts;

backend/server/src/modules/blog/api/get_post_list.rs

@@ -1,130 +0,0 @@
-use std::error::Error;
-
-use crate::constants::blog::PAGE_SIZE;
-
-use axum::{extract::Query, extract::State, http::StatusCode, Json};
-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 tracing::error;
-use uuid::Uuid;
-
-#[derive(Deserialize)]
-pub struct Params {
-    page: Option<u32>,
-}
-
-#[axum::debug_handler]
-pub async fn get_post_list(
-    State(db_connection): State<PgPool>,
-    Query(params): Query<Params>,
-) -> Result<Json<Value>, (StatusCode, Json<Value>)> {
-    let search_param_page = params.page.unwrap_or(1);
-    if search_param_page < 1 {
-        return Err((
-            StatusCode::BAD_REQUEST,
-            Json::from(json!({"error": "`page` should be greater than 0"})),
-        ));
-    }
-
-    let offset = PAGE_SIZE * (search_param_page - 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 {
-        Ok(post_list) => post_list,
-        Err(e) => {
-            error!(
-                "Database query error on fetching post list: {}",
-                e.to_string()
-            );
-            return Err((
-                StatusCode::INTERNAL_SERVER_ERROR,
-                Json::from(json!({"error": e.to_string()})),
-            ));
-        }
-    };
-
-    let mut res = Vec::new();
-    let posts: Vec<_> = post_list
-        .into_iter()
-        .map(|post| async { analyze_post(&db_connection, post).await })
-        .collect();
-    let posts = join_all(posts).await;
-    for post in posts {
-        match post {
-            Ok(p) => res.push(p),
-            Err(e) => {
-                return Err((
-                    StatusCode::INTERNAL_SERVER_ERROR,
-                    Json::from(json!(("error", e.to_string()))),
-                ))
-            }
-        }
-    }
-
-    // res.insert("posts".to_string(), Value::from(posts));
-    Ok(Json::from(Value::from(res)))
-}
-
-async fn analyze_post(db_connection: &PgPool, post: PgRow) -> Result<Value, Box<dyn Error + Send>> {
-    let post_id: Uuid = post.get("post_id");
-    let tags = fetch_post_tags(db_connection, post_id).await;
-    let meta = fetch_post_meta(db_connection, post_id).await.unwrap();
-    let header_img = meta.get("header_img");
-    let last_update = meta.get("last_update");
-
-    Ok(json!({
-        "post_id": post_id.to_string(),
-        "title": post.get::<String, _>("title"),
-        "category": post.get::<String, _>("category"),
-        "header_img": header_img,
-        "sub_title": post.get::<String, _>("sub_title"),
-        "summary": post.get::<String, _>("summary"),
-        "last_update": last_update,
-        "first_update": post.get::<DateTime<Utc>, _>("first_update"),
-        "tags": tags,
-    }))
-}
-
-async fn fetch_post_meta(db_connection: &PgPool, post_id: Uuid) -> Option<Value> {
-    match query(
-        r#"
-SELECT jsonb_strip_nulls(to_jsonb(t.*)) - 'post_id' AS meta
-FROM meta t
-WHERE post_id = $1;
-        "#,
-    )
-    .bind(post_id)
-    .fetch_one(db_connection)
-    .await
-    {
-        Ok(value) => Some(value.get::<Value, _>("meta")),
-        Err(e) => {
-            error!(
-                "Database error on Reading `{}` from table `{}`: <{}>: {}",
-                "post meta data",
-                "meta",
-                post_id.to_string(),
-                e.to_string()
-            );
-            None
-        }
-    }
-}
-
-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![],
-    }
-}

backend/server/src/modules/blog/api/mod.rs

@@ -1,6 +1,3 @@
-pub mod get_page_count;
-
 // todo: remove exception tag
 #[allow(dead_code)]
-pub mod get_post;
-// pub mod get_post_list;
+pub mod posts;

backend/server/src/modules/blog/api/posts/get.rs

@@ -9,9 +9,6 @@ use serde_json::json;
 use sqlx::PgPool;
 use uuid::Uuid;
 
-const GET_POST_BY_UUID: &str = include_str!("get_post_by_uuid.sql");
-const GET_POST_BY_STR_ID: &str = include_str!("get_post_by_str_id.sql");
-
 pub async fn handler(
     State(db_connection): State<PgPool>,
     Path(identifier): Path<String>,

backend/server/src/modules/blog/api/posts/mod.rs

@@ -0,0 +1,2 @@
+pub mod get;
+pub mod pagination;

backend/server/src/modules/blog/api/posts/pagination/mod.rs

@@ -0,0 +1,42 @@
+use crate::{
+    constants::blog::PAGE_SIZE,
+    utils::axum_response::{err_resp, succ_resp},
+};
+
+use axum::{extract::State, http::StatusCode, response::Response};
+use serde::Serialize;
+use serde_json::{Value, json};
+use sqlx::{FromRow, PgPool, Row, query_as};
+
+#[derive(FromRow, Serialize)]
+struct DBPaginationRow {
+    page_count: i32,
+    total_count: i64,
+}
+
+impl From<DBPaginationRow> for Value {
+    fn from(value: DBPaginationRow) -> Self {
+        json!({
+            "page_count": value.page_count,
+            "total_count": value.total_count
+        })
+    }
+}
+
+pub async fn handler(State(db_connection): State<PgPool>) -> Response<String> {
+    match query_as::<_, DBPaginationRow>(
+        r#"
+        SELECT 
+            cast(ceil(count(*) / cast($1 AS FLOAT)) AS INTEGER) AS page_count,
+            count(*) AS total_count
+        FROM posts;
+    "#,
+    )
+    .bind(PAGE_SIZE as i64)
+    .fetch_one(&db_connection)
+    .await
+    {
+        Ok(res) => succ_resp(StatusCode::OK, res.into()),
+        Err(e) => err_resp(StatusCode::INTERNAL_SERVER_ERROR, e.to_string()),
+    }
+}

backend/server/src/modules/blog/mod.rs

@@ -5,7 +5,7 @@ use crate::{
     modules::{
         Module,
         blog::{
-            api::{get_page_count, get_post},
+            api::{posts, posts::pagination},
             components::{check_update, consistency_guard},
         },
     },
@@ -28,8 +28,10 @@ impl Module for Blog {
         // todo: remove debug comment
         Router::new()
             // .route("/get_post_list", get(get_post_list))
-            .route("/get_page_count", get(get_page_count::handler))
-            .route("/get_post/{identifier}", get(get_post::handler))
+            // .route("/posts/pagination", get(...))
+            // .route("/posts", get(...)) // get posts
+            .route("/posts/pagination", get(pagination::handler))
+            .route("/posts/{identifier}", get(posts::get::handler))
             .with_state(db_handler)
     }