Add content type to the files

app/services/collection_resources_service.rb

@@ -24,6 +24,7 @@ class CollectionResourcesService
   end
 
   def upload_collection_resource(filename, file)
-    @storage_service.write_file(filename, file)
+    content_type = MiniMime.lookup_by_filename(filename)&.content_type
+    @storage_service.write_file(filename, file, content_type:)
   end
 end

app/services/storage/local_disk_service.rb

@@ -19,7 +19,7 @@ module Storage
       File.open(path, "r")
     end
 
-    def write_file(filename, data)
+    def write_file(filename, data, _content_type: nil)
       path = Rails.root.join("tmp/storage", filename)
 
       FileUtils.mkdir_p(path.dirname)

app/services/storage/s3_service.rb

@@ -36,12 +36,21 @@ module Storage
              .body.read
     end
 
-    def write_file(file_name, data)
-      @client.put_object(
-        body: data,
-        bucket: @configuration.bucket_name,
-        key: file_name,
-      )
+    def write_file(file_name, data, content_type: nil)
+      if content_type.nil?
+        @client.put_object(
+          body: data,
+          bucket: @configuration.bucket_name,
+          key: file_name,
+        )
+      else
+        @client.put_object(
+          body: data,
+          bucket: @configuration.bucket_name,
+          key: file_name,
+          content_type:,
+        )
+      end
     end
 
     def get_file_metadata(file_name)

spec/services/collection_resources_service_spec.rb

@@ -12,7 +12,7 @@ describe CollectionResourcesService do
     end
 
     it "calls write_file on S3 service" do
-      expect(storage_service).to receive(:write_file).with("2025_26_lettings_paper_form.pdf", some_file)
+      expect(storage_service).to receive(:write_file).with("2025_26_lettings_paper_form.pdf", some_file, content_type: "application/pdf")
       service.upload_collection_resource("2025_26_lettings_paper_form.pdf", some_file)
     end
   end