Add the unregister channel route (#194)

Closes #180

autoendpoint/src/db/client.rs

@@ -46,6 +46,9 @@ pub trait DbClient: Send + Sync {
     /// Get the set of channel IDs for a user
     async fn get_channels(&self, uaid: Uuid) -> DbResult<HashSet<Uuid>>;
 
+    /// Remove a channel from a user. Returns if the removed channel did exist.
+    async fn remove_channel(&self, uaid: Uuid, channel_id: Uuid) -> DbResult<bool>;
+
     /// Remove the node ID from a user in the router table.
     /// The node ID will only be cleared if `connected_at` matches up with the
     /// item's `connected_at`.
@@ -244,7 +247,7 @@ impl DbClient for DbClientImpl {
             },
             update_expression: Some("ADD chids :channel_id SET expiry = :expiry".to_string()),
             expression_attribute_values: Some(hashmap! {
-                ":channel_id".to_string() => val!(SS => Some(channel_id.to_hyphenated())),
+                ":channel_id".to_string() => val!(SS => Some(channel_id)),
                 ":expiry".to_string() => val!(N => sec_since_epoch() + MAX_CHANNEL_TTL)
             }),
             ..Default::default()
@@ -298,6 +301,39 @@ impl DbClient for DbClientImpl {
         Ok(channels)
     }
 
+    async fn remove_channel(&self, uaid: Uuid, channel_id: Uuid) -> DbResult<bool> {
+        let input = UpdateItemInput {
+            table_name: self.message_table.clone(),
+            key: ddb_item! {
+                uaid: s => uaid.to_simple().to_string(),
+                chidmessageid: s => " ".to_string()
+            },
+            update_expression: Some("DELETE chids :channel_id SET expiry = :expiry".to_string()),
+            expression_attribute_values: Some(hashmap! {
+                ":channel_id".to_string() => val!(SS => Some(channel_id)),
+                ":expiry".to_string() => val!(N => sec_since_epoch() + MAX_CHANNEL_TTL)
+            }),
+            return_values: Some("UPDATED_OLD".to_string()),
+            ..Default::default()
+        };
+
+        let output = retry_policy()
+            .retry_if(
+                || self.ddb.update_item(input.clone()),
+                retryable_updateitem_error(self.metrics.clone()),
+            )
+            .await?;
+
+        // Check if the old channel IDs contain the removed channel
+        Ok(output
+            .attributes
+            .as_ref()
+            .and_then(|map| map.get("chids"))
+            .and_then(|item| item.ss.as_ref())
+            .map(|channel_ids| channel_ids.contains(&channel_id.to_string()))
+            .unwrap_or(false))
+    }
+
     async fn remove_node_id(&self, uaid: Uuid, node_id: String, connected_at: u64) -> DbResult<()> {
         let input = UpdateItemInput {
             key: ddb_item! { uaid: s => uaid.to_simple().to_string() },

autoendpoint/src/db/mock.rs

@@ -27,6 +27,8 @@ mockall::mock! {
 
         fn get_channels(&self, uaid: Uuid) -> DbResult<HashSet<Uuid>>;
 
+        fn remove_channel(&self, uaid: Uuid, channel_id: Uuid) -> DbResult<bool>;
+
         fn remove_node_id(&self, uaid: Uuid, node_id: String, connected_at: u64) -> DbResult<()>;
 
         fn save_message(&self, uaid: Uuid, message: Notification) -> DbResult<()>;
@@ -69,6 +71,10 @@ impl DbClient for Arc<MockDbClient> {
         Arc::as_ref(self).get_channels(uaid)
     }
 
+    async fn remove_channel(&self, uaid: Uuid, channel_id: Uuid) -> DbResult<bool> {
+        Arc::as_ref(self).remove_channel(uaid, channel_id)
+    }
+
     async fn remove_node_id(&self, uaid: Uuid, node_id: String, connected_at: u64) -> DbResult<()> {
         Arc::as_ref(self).remove_node_id(uaid, node_id, connected_at)
     }

autoendpoint/src/routes/registration.rs

@@ -156,6 +156,36 @@ pub async fn get_channels_route(
     })))
 }
 
+/// Handle the `DELETE /v1/{router_type}/{app_id}/registration/{uaid}/subscription/{chid}` route
+pub async fn unregister_channel_route(
+    _auth: AuthorizationCheck,
+    path_args: RegistrationPathArgsWithUaid,
+    state: Data<ServerState>,
+    request: HttpRequest,
+) -> ApiResult<HttpResponse> {
+    let channel_id = request
+        .match_info()
+        .get("chid")
+        .expect("{chid} must be part of the path")
+        .parse::<Uuid>()
+        .map_err(|_| ApiErrorKind::NoSubscription)?;
+
+    debug!(
+        "Unregistering CHID {} for UAID {}",
+        channel_id, path_args.uaid
+    );
+
+    incr_metric("ua.command.unregister", &state.metrics, &request);
+    let channel_did_exist = state.ddb.remove_channel(path_args.uaid, channel_id).await?;
+
+    if channel_did_exist {
+        Ok(HttpResponse::Ok().finish())
+    } else {
+        debug!("Channel did not exist");
+        Err(ApiErrorKind::NoSubscription.into())
+    }
+}
+
 /// Increment a metric with data from the request
 fn incr_metric(name: &str, metrics: &StatsdClient, request: &HttpRequest) {
     metrics

autoendpoint/src/server.rs

@@ -8,7 +8,8 @@ use crate::routers::apns::router::ApnsRouter;
 use crate::routers::fcm::router::FcmRouter;
 use crate::routes::health::{health_route, lb_heartbeat_route, status_route, version_route};
 use crate::routes::registration::{
-    get_channels_route, new_channel_route, register_uaid_route, update_token_route,
+    get_channels_route, new_channel_route, register_uaid_route, unregister_channel_route,
+    update_token_route,
 };
 use crate::routes::webpush::{delete_notification_route, webpush_route};
 use crate::settings::Settings;
@@ -109,6 +110,12 @@ impl Server {
                     web::resource("/v1/{router_type}/{app_id}/registration/{uaid}/subscription")
                         .route(web::post().to(new_channel_route)),
                 )
+                .service(
+                    web::resource(
+                        "/v1/{router_type}/{app_id}/registration/{uaid}/subscription/{chid}",
+                    )
+                    .route(web::delete().to(unregister_channel_route)),
+                )
                 // Health checks
                 .service(web::resource("/status").route(web::get().to(status_route)))
                 .service(web::resource("/health").route(web::get().to(health_route)))