first commit

backend/src/db/mod.rs

@@ -0,0 +1,88 @@
+use std::{error::Error, fmt::Display};
+
+use deadpool_postgres::{Object, Pool};
+use serde::{Deserialize, Serialize};
+
+use crate::error::{AppError, AppResult};
+
+pub mod models;
+pub mod querys;
+
+#[derive(Clone)]
+pub struct Db {
+    pool: Pool,
+}
+
+impl Db {
+    pub fn new(pool: Pool) -> Self {
+        Self { pool }
+    }
+
+    pub fn pool(&self) -> &Pool {
+        &self.pool
+    }
+
+    pub async fn client(&self) -> AppResult<Object> {
+        self.pool.get().await.map_err(db_error)
+    }
+
+    pub async fn health(&self) -> AppResult<()> {
+        let client = self.client().await?;
+        client.simple_query("SELECT 1").await.map_err(db_error)?;
+        Ok(())
+    }
+}
+
+#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
+pub struct Pagination {
+    pub limit: i64,
+    pub offset: i64,
+}
+
+impl Pagination {
+    pub const DEFAULT_LIMIT: i64 = 50;
+    pub const MAX_LIMIT: i64 = 250;
+
+    pub fn new(limit: i64, offset: i64) -> Self {
+        Self {
+            limit: limit.clamp(1, Self::MAX_LIMIT),
+            offset: offset.max(0),
+        }
+    }
+}
+
+impl Default for Pagination {
+    fn default() -> Self {
+        Self::new(Self::DEFAULT_LIMIT, 0)
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Page<T> {
+    pub items: Vec<T>,
+    pub total: i64,
+    pub limit: i64,
+    pub offset: i64,
+}
+
+impl<T> Page<T> {
+    pub fn new(items: Vec<T>, total: i64, pagination: Pagination) -> Self {
+        Self {
+            items,
+            total,
+            limit: pagination.limit,
+            offset: pagination.offset,
+        }
+    }
+}
+
+pub(crate) fn db_error(error: impl Display + Error) -> AppError {
+    let mut message = error.to_string();
+    let mut source = error.source();
+    while let Some(cause) = source {
+        message.push_str(": ");
+        message.push_str(&cause.to_string());
+        source = cause.source();
+    }
+    AppError::Database(message)
+}