List item update functionality from excel template in Office 365 environment.

Hi Everyone,

We have a requirement to update existing list item using an excel template. We have InfoPath list forms for this list and users are uploading data against that.

Now they want to upload excel template and the relevant data should be updated to required field for specific items. Each excel should update a single item. They want it in this way because they have lots of fields present in the excel template and want to reduce the efforts to fill the form again.

Any idea to develop such functionality in Office 365? We thought of having CSOM utility and schedule it but they want data to be reflected as soon as the excel gets uploaded.

Thank in advance

Akash