I haven't done lot of research on HTTPS yet so I have a question about it.
Is data integrity preserved using HTTPS or only confidentiality? For example on file upload, does HTTPS guarantee that no one can change the data on upload, or it only guarantees that no one can read it?
For the most part yes, but for maximum security, I would recommend in addition to using HTTPS, I would recommend configuring your server's SSL configuration to use a signed certificate and use the following SSL configurations:
Also, use SSL Version 3 if possible.