Handlers are _named operations_, which can be exposed via routes.

Each domain module that exposes handlers does so through a `handlers` child module, ideally as a top-level symbol that can be plugged directly into Axum's `MethodRouter`. Modules could make exceptions to this - kill the doctrinaire inside yourself, after all - but none of the API modules that actually exist need such exceptions, and consistency is useful.

The related details of request types, URL types, response types, errors, &c &c are then organized into modules under `handlers`, along with their respective tests.

2 files changed, 233 insertions, 0 deletions

diff --git a/src/channel/handlers/delete/mod.rs b/src/channel/handlers/delete/mod.rs
new file mode 100644
index 0000000..b986bec
--- /dev/null
+++ b/src/channel/handlers/delete/mod.rs
@@ -0,0 +1,59 @@
+use axum::{
+    extract::{Json, Path, State},
+    http::StatusCode,
+    response::{self, IntoResponse},
+};
+
+use crate::{
+    app::App,
+    channel::{self, app, handlers::PathInfo},
+    clock::RequestedAt,
+    error::{Internal, NotFound},
+    token::extract::Identity,
+};
+
+#[cfg(test)]
+mod test;
+
+pub async fn handler(
+    State(app): State<App>,
+    Path(channel): Path<PathInfo>,
+    RequestedAt(deleted_at): RequestedAt,
+    _: Identity,
+) -> Result<Response, Error> {
+    app.channels().delete(&channel, &deleted_at).await?;
+
+    Ok(Response { id: channel })
+}
+
+#[derive(Debug, serde::Serialize)]
+pub struct Response {
+    pub id: channel::Id,
+}
+
+impl IntoResponse for Response {
+    fn into_response(self) -> response::Response {
+        (StatusCode::ACCEPTED, Json(self)).into_response()
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+#[error(transparent)]
+pub struct Error(#[from] pub app::DeleteError);
+
+impl IntoResponse for Error {
+    fn into_response(self) -> response::Response {
+        let Self(error) = self;
+        match error {
+            app::DeleteError::NotFound(_) | app::DeleteError::Deleted(_) => {
+                NotFound(error).into_response()
+            }
+            app::DeleteError::NotEmpty(_) => {
+                (StatusCode::CONFLICT, error.to_string()).into_response()
+            }
+            app::DeleteError::Name(_) | app::DeleteError::Database(_) => {
+                Internal::from(error).into_response()
+            }
+        }
+    }
+}
diff --git a/src/channel/handlers/delete/test.rs b/src/channel/handlers/delete/test.rs
new file mode 100644
index 0000000..b1e42ea
--- /dev/null
+++ b/src/channel/handlers/delete/test.rs
@@ -0,0 +1,174 @@
+use axum::extract::{Path, State};
+
+use crate::{channel::app, test::fixtures};
+
+#[tokio::test]
+pub async fn valid_channel() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+    let channel = fixtures::channel::create(&app, &fixtures::now()).await;
+
+    // Send the request
+
+    let deleter = fixtures::identity::create(&app, &fixtures::now()).await;
+    let response = super::handler(
+        State(app.clone()),
+        Path(channel.id.clone()),
+        fixtures::now(),
+        deleter,
+    )
+    .await
+    .expect("deleting a valid channel succeeds");
+
+    // Verify the response
+
+    assert_eq!(channel.id, response.id);
+
+    // Verify the semantics
+
+    let snapshot = app.boot().snapshot().await.expect("boot always succeeds");
+    assert!(!snapshot.channels.contains(&channel));
+}
+
+#[tokio::test]
+pub async fn invalid_channel_id() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+
+    // Send the request
+
+    let deleter = fixtures::identity::create(&app, &fixtures::now()).await;
+    let channel = fixtures::channel::fictitious();
+    let super::Error(error) = super::handler(
+        State(app.clone()),
+        Path(channel.clone()),
+        fixtures::now(),
+        deleter,
+    )
+    .await
+    .expect_err("deleting a nonexistent channel fails");
+
+    // Verify the response
+
+    assert!(matches!(error, app::DeleteError::NotFound(id) if id == channel));
+}
+
+#[tokio::test]
+pub async fn channel_deleted() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+    let channel = fixtures::channel::create(&app, &fixtures::now()).await;
+
+    app.channels()
+        .delete(&channel.id, &fixtures::now())
+        .await
+        .expect("deleting a recently-sent channel succeeds");
+
+    // Send the request
+
+    let deleter = fixtures::identity::create(&app, &fixtures::now()).await;
+    let super::Error(error) = super::handler(
+        State(app.clone()),
+        Path(channel.id.clone()),
+        fixtures::now(),
+        deleter,
+    )
+    .await
+    .expect_err("deleting a deleted channel fails");
+
+    // Verify the response
+
+    assert!(matches!(error, app::DeleteError::Deleted(id) if id == channel.id));
+}
+
+#[tokio::test]
+pub async fn channel_expired() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+    let channel = fixtures::channel::create(&app, &fixtures::ancient()).await;
+
+    app.channels()
+        .expire(&fixtures::now())
+        .await
+        .expect("expiring channels always succeeds");
+
+    // Send the request
+
+    let deleter = fixtures::identity::create(&app, &fixtures::now()).await;
+    let super::Error(error) = super::handler(
+        State(app.clone()),
+        Path(channel.id.clone()),
+        fixtures::now(),
+        deleter,
+    )
+    .await
+    .expect_err("deleting an expired channel fails");
+
+    // Verify the response
+
+    assert!(matches!(error, app::DeleteError::Deleted(id) if id == channel.id));
+}
+
+#[tokio::test]
+pub async fn channel_purged() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+    let channel = fixtures::channel::create(&app, &fixtures::ancient()).await;
+
+    app.channels()
+        .expire(&fixtures::old())
+        .await
+        .expect("expiring channels always succeeds");
+
+    app.channels()
+        .purge(&fixtures::now())
+        .await
+        .expect("purging channels always succeeds");
+
+    // Send the request
+
+    let deleter = fixtures::identity::create(&app, &fixtures::now()).await;
+    let super::Error(error) = super::handler(
+        State(app.clone()),
+        Path(channel.id.clone()),
+        fixtures::now(),
+        deleter,
+    )
+    .await
+    .expect_err("deleting a purged channel fails");
+
+    // Verify the response
+
+    assert!(matches!(error, app::DeleteError::NotFound(id) if id == channel.id));
+}
+
+#[tokio::test]
+pub async fn channel_not_empty() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+    let channel = fixtures::channel::create(&app, &fixtures::now()).await;
+    let sender = fixtures::user::create(&app, &fixtures::now()).await;
+    fixtures::message::send(&app, &channel, &sender, &fixtures::now()).await;
+
+    // Send the request
+
+    let deleter = fixtures::identity::create(&app, &fixtures::now()).await;
+    let super::Error(error) = super::handler(
+        State(app.clone()),
+        Path(channel.id.clone()),
+        fixtures::now(),
+        deleter,
+    )
+    .await
+    .expect_err("deleting a channel with messages fails");
+
+    // Verify the response
+
+    assert!(matches!(error, app::DeleteError::NotEmpty(id) if id == channel.id));
+}