diff --git a/services/blob/src/s3.rs b/services/blob/src/s3.rs
--- a/services/blob/src/s3.rs
+++ b/services/blob/src/s3.rs
@@ -23,6 +23,9 @@
   EmptyUpload,
   #[display(fmt = "Missing upload ID")]
   MissingUploadID,
+  #[display(fmt = "Missing or invalid S3 object attribute: {}", "_0")]
+  #[error(ignore)]
+  InvalidAttribute(&'static str),
 }
 
 #[derive(Debug, derive_more::Error)]
@@ -144,6 +147,33 @@
     Ok(response)
   }
 
+  pub async fn get_object_size(&self, s3_path: &S3Path) -> S3Result<u64> {
+    trace!("Getting S3 object metadata...");
+    let object_metadata = self.get_object_metadata(s3_path).await?;
+    let blob_size = object_metadata
+      .content_length()
+      .ok_or_else(|| {
+        error!(
+          errorType = error_types::S3_ERROR,
+          "Failed to get S3 object content length"
+        );
+        Error::InvalidAttribute("content_length")
+      })
+      .and_then(|len| {
+        if len >= 0 {
+          Ok(len as u64)
+        } else {
+          error!(
+            errorType = error_types::S3_ERROR,
+            "S3 object content length is negative"
+          );
+          Err(Error::InvalidAttribute("content_length"))
+        }
+      })?;
+
+    Ok(blob_size)
+  }
+
   /// Downloads object and retrieves data bytes within provided range
   ///
   /// * `range` - Range of object bytes to download.
diff --git a/services/blob/src/service.rs b/services/blob/src/service.rs
--- a/services/blob/src/service.rs
+++ b/services/blob/src/service.rs
@@ -44,7 +44,6 @@
 pub enum BlobServiceError {
   BlobNotFound,
   BlobAlreadyExists,
-  InvalidState,
   DB(DBError),
   S3(S3Error),
   #[from(ignore)]
@@ -121,29 +120,8 @@
     }?;
     debug!("S3 path: {:?}", s3_path);
 
-    // 2. Get S3 Object metadata
-    trace!("Getting S3 object metadata...");
-    let object_metadata = self.s3.get_object_metadata(&s3_path).await?;
-    let blob_size = object_metadata
-      .content_length()
-      .ok_or_else(|| {
-        error!(
-          errorType = error_types::S3_ERROR,
-          "Failed to get S3 object content length"
-        );
-        BlobServiceError::InvalidState
-      })
-      .and_then(|len| {
-        if len >= 0 {
-          Ok(len as u64)
-        } else {
-          error!(
-            errorType = error_types::S3_ERROR,
-            "S3 object content length is negative"
-          );
-          Err(BlobServiceError::InvalidState)
-        }
-      })?;
+    // 2. Get S3 object size
+    let blob_size = self.s3.get_object_size(&s3_path).await?;
     debug!("S3 object size: {} bytes", blob_size);
 
     // 3. Create download session