Trusted proxies, unauthenticated rate limits and various fixes

src/db/models/send.rs

@@ -231,6 +231,37 @@ impl Send {
         }
     }
 
+    /// Registers an access, incrementing `access_count` only while below `max_access_count`.
+    /// Returns false when the limit was already reached. The check and the increment are a single
+    /// statement, otherwise concurrent accesses can both pass the check and exceed the limit.
+    pub async fn register_access(&mut self, conn: &DbConn) -> Result<bool, crate::Error> {
+        self.update_users_revision(conn).await;
+
+        let revision_date = Utc::now().naive_utc();
+        let uuid = self.uuid.clone();
+        let updated = conn
+            .run(move |conn| {
+                diesel::update(sends::table)
+                    .filter(sends::uuid.eq(uuid))
+                    .filter(
+                        sends::max_access_count
+                            .is_null()
+                            .or(sends::access_count.nullable().lt(sends::max_access_count)),
+                    )
+                    .set((sends::access_count.eq(sends::access_count + 1), sends::revision_date.eq(revision_date)))
+                    .execute(conn)
+            })
+            .await?;
+
+        if updated == 0 {
+            return Ok(false);
+        }
+
+        self.access_count += 1;
+        self.revision_date = revision_date;
+        Ok(true)
+    }
+
     pub async fn delete(&self, conn: &DbConn) -> EmptyResult {
         self.update_users_revision(conn).await;