#306

backend/app/services/material_file_sha256.rb

@@ -1,16 +1,39 @@
 require 'digest'
+require 'json'
 
 class MaterialFileSha256
+  def self.blob_metadata blob
+    metadata = blob.metadata
+    return metadata if metadata.is_a?(Hash)
+    return { } if metadata.blank?
+
+    JSON.parse(metadata)
+  rescue JSON::ParserError
+    { }
+  end
+
+  def self.metadata_sha256 blob
+    blob_metadata(blob)['sha256'].presence
+  end
+
+  def self.assign_metadata_sha256! blob, sha256
+    return if sha256.blank?
+
+    metadata = blob_metadata(blob)
+    metadata['sha256'] = sha256
+    blob.metadata = metadata
+    blob.save! if blob.changed?
+  end
+
   def self.from_blob blob, allow_download: false
-    sha256 = blob.metadata['sha256']
+    sha256 = metadata_sha256(blob)
     return sha256 if sha256.present?
     return nil unless allow_download
 
     begin
       blob.open do |file|
         sha256 = Digest::SHA256.file(file.path).hexdigest
-        blob.metadata['sha256'] = sha256
-        blob.save! if blob.changed?
+        assign_metadata_sha256!(blob, sha256)
         sha256
       end
     rescue ActiveStorage::FileNotFoundError, ArgumentError => error

backend/app/services/material_sync_importer.rb

@@ -148,8 +148,7 @@ class MaterialSyncImporter
         io: tempfile,
         filename: @attributes[:filename],
         content_type: @attributes[:content_type])
-    blob.metadata['sha256'] = file_sha256 if file_sha256.present?
-    blob.save! if blob.changed?
+    MaterialFileSha256.assign_metadata_sha256!(blob, file_sha256)
     tempfile.rewind
     blob
   end
@@ -226,7 +225,7 @@ class MaterialSyncImporter
     if expected_sha256.present?
       return false unless material.file.attached?
 
-      return material.file.blob.metadata['sha256'] == expected_sha256
+      return MaterialFileSha256.metadata_sha256(material.file.blob) == expected_sha256
     end
 
     !material.file.attached?

backend/app/services/material_version_recorder.rb

@@ -57,7 +57,7 @@ class MaterialVersionRecorder < VersionRecorder
       file_content_type: blob.content_type,
       file_byte_size: blob.byte_size,
       file_checksum: blob.checksum,
-      file_sha256: blob.metadata['sha256'] }
+      file_sha256: MaterialFileSha256.metadata_sha256(blob) }
   end
 
   def empty_file_snapshot