Give users the ability to transfer files during a chat so they can share
information about their issues.
The agent can request that the user transfer a file by clicking the Attach File button from the Service Cloud Console.
The user sees a FILE TRANSFER REQUESTED message in the app and can then send a file using the paperclip button.
No coding is necessary in your app to make this behavior work.
See Transfer Files During a Chat in Salesforce Help for details about setting up this functionality in the Service Cloud Console.