refactor: move db stuff into own module

.gitignore

@@ -1 +1,2 @@
 /target
+db.sqlite

src/db.rs

@@ -0,0 +1,97 @@
+use std::{error::Error, fmt};
+
+use r2d2_sqlite::{
+    rusqlite::{self, Row},
+    SqliteConnectionManager,
+};
+use serde::{Deserialize, Serialize};
+
+pub type DbPool = r2d2::Pool<SqliteConnectionManager>;
+
+#[derive(Debug)]
+pub enum DbError {
+    Pool(r2d2::Error),
+    Db(rusqlite::Error),
+}
+
+impl fmt::Display for DbError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Pool(_) => write!(f, "failed to acquire connection from pool"),
+            Self::Db(_) => write!(f, "error while accessing the database"),
+        }
+    }
+}
+
+impl Error for DbError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        match self {
+            Self::Pool(err) => Some(err),
+            Self::Db(err) => Some(err),
+        }
+    }
+}
+
+impl From<r2d2::Error> for DbError {
+    fn from(value: r2d2::Error) -> Self {
+        Self::Pool(value)
+    }
+}
+
+impl From<rusqlite::Error> for DbError {
+    fn from(value: rusqlite::Error) -> Self {
+        Self::Db(value)
+    }
+}
+
+#[derive(Serialize)]
+pub struct Plant {
+    id: i32,
+    name: String,
+    species: String,
+    description: String,
+}
+
+impl Plant {
+    pub fn from_row(row: &Row<'_>) -> Result<Self, rusqlite::Error> {
+        Ok(Self {
+            id: row.get(0)?,
+            name: row.get(1)?,
+            species: row.get(2)?,
+            description: row.get(3)?,
+        })
+    }
+}
+
+#[derive(Deserialize)]
+pub struct NewPlant {
+    name: String,
+    species: String,
+    description: String,
+}
+
+pub fn list_plants(pool: &DbPool) -> Result<Vec<Plant>, DbError> {
+    let conn = pool.get()?;
+    let mut stmt = conn.prepare("select * from plants")?;
+
+    let mut plants = Vec::new();
+
+    for plant in stmt.query_map((), |row| Plant::from_row(row))? {
+        plants.push(plant?);
+    }
+
+    Ok(plants)
+}
+
+pub fn insert_plant(pool: &DbPool, plant: &NewPlant) -> Result<Plant, DbError> {
+    let conn = pool.get()?;
+
+    let mut stmt = conn.prepare(
+        "insert into plants (name, species, description) values ($1, $2, $3) returning *",
+    )?;
+    Ok(
+        stmt.query_row((&plant.name, &plant.species, &plant.description), |row| {
+            Plant::from_row(row)
+        })?,
+    )
+}

src/main.rs

@@ -1,3 +1,4 @@
+mod db;
 mod server;
 
 use std::sync::Arc;
@@ -6,8 +7,6 @@ use r2d2_sqlite::{rusqlite, SqliteConnectionManager};
 use tera::Tera;
 use tower_http::compression::CompressionLayer;
 
-pub type DbPool = r2d2::Pool<SqliteConnectionManager>;
-
 const MIGRATIONS: [&str; 2] = [
     include_str!("migrations/000_initial.sql"),
     include_str!("migrations/001_plants.sql"),
@@ -19,7 +18,7 @@ const STATIC_FILES: [(&str, &'static str); 1] = [(
 
 #[derive(Clone)]
 pub struct Context {
-    pool: crate::DbPool,
+    pool: db::DbPool,
     tera: Arc<Tera>,
 }
 
@@ -48,7 +47,7 @@ async fn main() {
         .unwrap();
 }
 
-fn run_migrations(pool: &DbPool) -> rusqlite::Result<()> {
+fn run_migrations(pool: &db::DbPool) -> rusqlite::Result<()> {
     let mut conn = pool.get().unwrap();
 
     // If the migration version query fails, we assume it's because the table isn't there yet so we

src/server/mod.rs

@@ -4,30 +4,9 @@ use axum::{
     routing::{get, post},
     Form, Router,
 };
-use r2d2_sqlite::rusqlite::{self, Row};
-use serde::{Deserialize, Serialize};
 use tera::Context;
 
-#[derive(Serialize)]
-struct Plant {
-    id: i32,
-    name: String,
-    species: String,
-    description: String,
-}
-
-impl TryFrom<&Row<'_>> for Plant {
-    type Error = rusqlite::Error;
-
-    fn try_from(row: &Row<'_>) -> Result<Self, Self::Error> {
-        Ok(Self {
-            id: row.get(0)?,
-            name: row.get(1)?,
-            species: row.get(2)?,
-            description: row.get(3)?,
-        })
-    }
-}
+use crate::db;
 
 pub fn app(ctx: crate::Context) -> axum::Router {
     let mut router = Router::new()
@@ -42,19 +21,9 @@ pub fn app(ctx: crate::Context) -> axum::Router {
 }
 
 async fn get_index(State(ctx): State<crate::Context>) -> Html<String> {
-    let plants = tokio::task::spawn_blocking(move || {
-        let conn = ctx.pool.get().unwrap();
-
-        let mut stmt = conn.prepare("select * from plants").unwrap();
-        let mut plants = Vec::new();
-
-        for plant in stmt.query_map((), |row| Plant::try_from(row)).unwrap() {
-            plants.push(plant.unwrap());
-        }
-
-        plants
-    })
+    let plants = tokio::task::spawn_blocking(move || db::list_plants(&ctx.pool))
         .await
+        .unwrap()
         .unwrap();
 
     let mut context = Context::new();
@@ -62,34 +31,13 @@ async fn get_index(State(ctx): State<crate::Context>) -> Html<String> {
     Html(ctx.tera.render("index.html", &context).unwrap())
 }
 
-#[derive(Deserialize)]
-struct NewPlant {
-    name: String,
-    species: String,
-    description: String,
-}
-
 async fn post_plants(
     State(ctx): State<crate::Context>,
-    Form(plant): Form<NewPlant>,
+    Form(plant): Form<db::NewPlant>,
 ) -> Html<String> {
-    let plant = tokio::task::spawn_blocking(move || {
-        let conn = ctx.pool.get().unwrap();
-
-        let mut stmt = conn
-            .prepare(
-                "insert into plants (name, species, description) values ($1, $2, $3) returning *",
-            )
-            .unwrap();
-        let plant = stmt
-            .query_row((&plant.name, &plant.species, &plant.description), |row| {
-                Plant::try_from(row)
-            })
-            .unwrap();
-
-        plant
-    })
+    let plant = tokio::task::spawn_blocking(move || db::insert_plant(&ctx.pool, &plant))
         .await
+        .unwrap()
         .unwrap();
 
     let mut context = Context::new();