chore: generic error message for file load (#377)

* chore: generic error message for file load

Give a generic error message for file load failures to prevent file
system enumeration.

* chore: generalize Wasm component load error message

---------

Co-authored-by: Bo Lu <lv.patrick@gmail.com>

wrappers/src/fdw/wasm_fdw/mod.rs

@@ -14,6 +14,9 @@ use self::bindings::supabase::wrappers::types::FdwError as GuestFdwError;
 
 #[derive(Error, Debug)]
 enum WasmFdwError {
+    #[error("invalid WebAssembly component")]
+    InvalidWasmComponent,
+
     #[error("guest fdw error: {0}")]
     GuestFdw(GuestFdwError),
 

wrappers/src/fdw/wasm_fdw/wasm_fdw.rs

@@ -33,6 +33,14 @@ fn check_version_requirement(ver_req: &str) -> WasmFdwResult<()> {
     Ok(())
 }
 
+// compiles a new WebAssembly component from a wasm file
+fn load_component_from_file(
+    engine: &Engine,
+    file_path: impl AsRef<std::path::Path>,
+) -> WasmFdwResult<Component> {
+    Component::from_file(engine, file_path).map_err(|_| WasmFdwError::InvalidWasmComponent)
+}
+
 // Download wasm component package from warg registry or custom url.
 // The url protoal can be 'file://', 'warg(s)://' or 'http(s)://'.
 fn download_component(
@@ -44,7 +52,7 @@ fn download_component(
     checksum: Option<&str>,
 ) -> WasmFdwResult<Component> {
     if let Some(file_path) = url.strip_prefix("file://") {
-        return Ok(Component::from_file(engine, file_path)?);
+        return load_component_from_file(engine, file_path);
     }
 
     if url.starts_with("warg://") || url.starts_with("wargs://") {
@@ -69,7 +77,7 @@ fn download_component(
             .block_on(client.download(&pkg_name, &ver))?
             .ok_or(format!("{}@{} not found on {}", name, version, url))?;
 
-        return Ok(Component::from_file(engine, pkg.path)?);
+        return load_component_from_file(engine, pkg.path);
     }
 
     // otherwise, download from custom url if it is not in local cache
@@ -107,10 +115,10 @@ fn download_component(
         fs::write(&path, bytes)?;
     }
 
-    Ok(Component::from_file(engine, &path).inspect_err(|_| {
+    load_component_from_file(engine, &path).inspect_err(|_| {
         // remove the cache file if it cannot be loaded as component
         let _ = fs::remove_file(&path);
-    })?)
+    })
 }
 
 #[wrappers_fdw(