feat: implement server error handling

src/server/comments.rs

@@ -10,17 +10,12 @@ pub fn app(ctx: crate::Context) -> axum::Router {
 async fn post_comment(
     State(ctx): State<crate::Context>,
     Form(comment): Form<NewComment>,
-) -> Html<String> {
+) -> super::Result<Html<String>> {
     let comment = tokio::task::spawn_blocking(move || comment.insert(&ctx.pool))
         .await
-        .unwrap()
+        .unwrap()?;
-        .unwrap();
 
     let mut context = Context::new();
     context.insert("comment", &comment);
-    Html(
+    Ok(Html(ctx.tera.render("partials/comment_li.html", &context)?))
-        ctx.tera
-            .render("partials/comment_li.html", &context)
-            .unwrap(),
-    )
 }

src/server/error.rs

@@ -0,0 +1,75 @@
+use std::fmt::{self, Write};
+
+use axum::{http::StatusCode, response::IntoResponse};
+
+use crate::db;
+
+#[derive(Debug)]
+pub enum AppError {
+    Db(db::DbError),
+    Tera(tera::Error),
+    NotFound,
+}
+
+impl fmt::Display for AppError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Db(_) => write!(f, "database error"),
+            Self::Tera(_) => write!(f, "error rendering template"),
+            Self::NotFound => write!(f, "not found"),
+        }
+    }
+}
+
+impl std::error::Error for AppError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        match self {
+            Self::Db(err) => Some(err),
+            Self::Tera(err) => Some(err),
+            Self::NotFound => None,
+        }
+    }
+}
+
+pub trait ErrorExt: std::error::Error {
+    /// Return the full chain of error messages
+    fn stack(&self) -> String {
+        let mut msg = format!("{}", self);
+        let mut err = self.source();
+
+        while let Some(src) = err {
+            write!(msg, " - {}", src).unwrap();
+
+            err = src.source();
+        }
+
+        msg
+    }
+}
+
+impl<E: std::error::Error> ErrorExt for E {}
+
+impl From<db::DbError> for AppError {
+    fn from(value: db::DbError) -> Self {
+        Self::Db(value)
+    }
+}
+
+impl From<tera::Error> for AppError {
+    fn from(value: tera::Error) -> Self {
+        Self::Tera(value)
+    }
+}
+
+impl IntoResponse for AppError {
+    fn into_response(self) -> axum::response::Response {
+        match self {
+            Self::NotFound => StatusCode::NOT_FOUND.into_response(),
+            _ => {
+                tracing::error!("{}", self.stack());
+
+                StatusCode::INTERNAL_SERVER_ERROR.into_response()
+            }
+        }
+    }
+}

src/server/mod.rs

@@ -1,4 +1,5 @@
 mod comments;
+mod error;
 mod plants;
 
 use axum::{
@@ -13,6 +14,8 @@ use tower_http::set_header::SetResponseHeaderLayer;
 
 use crate::db::Plant;
 
+pub type Result<T> = std::result::Result<T, error::AppError>;
+
 const HX_REQUEST_HEADER: &str = "HX-Request";
 const HX_HISTORY_RESTORE_HEADER: &str = "HX-History-Restore-Request";
 
@@ -47,13 +50,12 @@ pub fn app(ctx: crate::Context) -> axum::Router {
     ))
 }
 
-async fn get_index(State(ctx): State<crate::Context>) -> Html<String> {
+async fn get_index(State(ctx): State<crate::Context>) -> Result<Html<String>> {
     let plants = tokio::task::spawn_blocking(move || Plant::all(&ctx.pool))
         .await
-        .unwrap()
+        .unwrap()?;
-        .unwrap();
 
     let mut context = Context::new();
     context.insert("plants", &plants);
-    Html(ctx.tera.render("index.html", &context).unwrap())
+    Ok(Html(ctx.tera.render("index.html", &context)?))
 }

src/server/plants.rs

@@ -9,7 +9,7 @@ use tera::Context;
 
 use crate::db::{self, DbError, Plant};
 
-use super::render_partial;
+use super::{error::AppError, render_partial};
 
 pub fn app(ctx: crate::Context) -> axum::Router {
     Router::new()
@@ -22,17 +22,23 @@ async fn get_plant_page(
     State(ctx): State<crate::Context>,
     headers: HeaderMap,
     Path(plant_id): Path<i32>,
-) -> Html<String> {
+) -> super::Result<Html<String>> {
-    let (plant, comments) = tokio::task::spawn_blocking(move || {
+    let res = tokio::task::spawn_blocking(move || {
-        let plant = Plant::by_id(&ctx.pool, plant_id)?.unwrap();
+        let plant = Plant::by_id(&ctx.pool, plant_id)?;
+
+        if let Some(plant) = plant {
             let comments = plant.comments(&ctx.pool)?;
 
-        Ok::<_, DbError>((plant, comments))
+            Ok::<_, DbError>(Some((plant, comments)))
+        } else {
+            Ok(None)
+        }
     })
     .await
-    .unwrap()
+    .unwrap()?;
-    .unwrap();
 
+    match res {
+        Some((plant, comments)) => {
             let mut context = Context::new();
             context.insert("plant", &plant);
             context.insert("comments", &comments);
@@ -43,19 +49,21 @@ async fn get_plant_page(
                 "plant_page.html"
             };
 
-    Html(ctx.tera.render(tmpl, &context).unwrap())
+            Ok(Html(ctx.tera.render(tmpl, &context)?))
+        }
+        None => Err(AppError::NotFound),
+    }
 }
 
 async fn post_plant(
     State(ctx): State<crate::Context>,
     Form(plant): Form<db::NewPlant>,
-) -> Html<String> {
+) -> super::Result<Html<String>> {
     let plant = tokio::task::spawn_blocking(move || plant.insert(&ctx.pool))
         .await
-        .unwrap()
+        .unwrap()?;
-        .unwrap();
 
     let mut context = Context::new();
     context.insert("plant", &plant);
-    Html(ctx.tera.render("partials/plant_li.html", &context).unwrap())
+    Ok(Html(ctx.tera.render("partials/plant_li.html", &context)?))
 }