backend: storage_paths.rs

backend/src/utils/mod.rs

@@ -1 +1,2 @@
 pub mod json;
+pub mod storage_paths;

backend/src/utils/storage_paths.rs

@@ -0,0 +1,115 @@
+//! Document storage path helpers.
+//!
+//! NOTE: The path layout produced here is part of the durable storage contract.
+//! External systems (presigned URLs, lifecycle jobs, migrations) expect the
+//! `documents/{document_id}/...` structure to remain stable. Coordinate before
+//! changing any of these helpers to avoid breaking compatibility with existing
+//! objects.
+
+use uuid::Uuid;
+
+const DOCUMENTS_PREFIX: &str = "documents";
+
+/// Returns the root prefix for all objects belonging to a document.
+pub fn document_prefix(document_id: Uuid) -> String {
+    format!("{DOCUMENTS_PREFIX}/{document_id}")
+}
+
+/// Returns the prefix for a specific document version (without the object id).
+pub fn document_version_prefix(document_id: Uuid, version_number: i32) -> String {
+    format!("{}/v{}", document_prefix(document_id), version_number)
+}
+
+/// Returns the storage key for a stored document version blob.
+pub fn document_version_object_key(
+    document_id: Uuid,
+    version_number: i32,
+    version_id: Uuid,
+) -> String {
+    format!(
+        "{}/{}",
+        document_version_prefix(document_id, version_number),
+        version_id
+    )
+}
+
+fn document_asset_prefix(document_id: Uuid, version_number: i32) -> String {
+    format!(
+        "{}/assets",
+        document_version_prefix(document_id, version_number)
+    )
+}
+
+fn document_asset_type_prefix(document_id: Uuid, version_number: i32, asset_type: &str) -> String {
+    format!(
+        "{}/{}",
+        document_asset_prefix(document_id, version_number),
+        asset_type
+    )
+}
+
+/// Returns the storage prefix under which the asset objects for a type/id pair live.
+pub fn document_asset_object_prefix(
+    document_id: Uuid,
+    version_number: i32,
+    asset_type: &str,
+    asset_id: Uuid,
+) -> String {
+    format!(
+        "{}/{}",
+        document_asset_type_prefix(document_id, version_number, asset_type),
+        asset_id
+    )
+}
+
+/// Returns the full storage key for a specific asset object (ordinal).
+pub fn document_asset_object_key(
+    document_id: Uuid,
+    version_number: i32,
+    asset_type: &str,
+    asset_id: Uuid,
+    ordinal: i32,
+) -> String {
+    format!(
+        "{}/{}",
+        document_asset_object_prefix(document_id, version_number, asset_type, asset_id),
+        ordinal
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn generates_expected_paths() {
+        let document_id = Uuid::nil();
+        let version_id = Uuid::nil();
+        let asset_id = Uuid::nil();
+
+        assert_eq!(
+            document_prefix(document_id),
+            format!("documents/{document_id}")
+        );
+
+        assert_eq!(
+            document_version_prefix(document_id, 3),
+            format!("documents/{document_id}/v3")
+        );
+
+        assert_eq!(
+            document_version_object_key(document_id, 3, version_id),
+            format!("documents/{document_id}/v3/{version_id}")
+        );
+
+        assert_eq!(
+            document_asset_object_prefix(document_id, 3, "preview", asset_id),
+            format!("documents/{document_id}/v3/assets/preview/{asset_id}")
+        );
+
+        assert_eq!(
+            document_asset_object_key(document_id, 3, "preview", asset_id, 2),
+            format!("documents/{document_id}/v3/assets/preview/{asset_id}/2")
+        );
+    }
+}