Retrieving Google account owner and contacts via OAuth2

All the inviter solutions for web apps that I have found on internet only provide the ability to import contacts. But how does the person who is receiving the invitation will know the sender's identity? Of course, if the contact import solution is an integrated module of an application A,  then you can use the user info within that application A to identify the sender.  However, this requires the user to get an account within that application A,  which reduces the range of people who can send non-anonymous invitations to use the app A. So I thought about a modification to fix that concern by allowing the public to send such invites. This is done by retrieving the full name and email of the Gmail/Google user whose contacts are imported via the OAuth2 protocol and thus suppressing the need to create an account within app A to send a non-incognito invites to use app A. The code is a modified version of the 25Labs' sample source.

But first, here is an illustration to quickly show how OAuth2 works.

Knowing the format of the Google API response, I simply store the response in a temporary XML file that I later parse to extract the name and email of the user who is sending the invite.
To reduce the probability of file conflict in the storage of the temporary XML file in case of multiple simultaneous imports, I add a unique prefix that I call "salt" and which I define as the MD5 hash of a unique string ; that string is the concatenation of the current Unix timestamp and IP of the user.

A slight modification for a big change. You can get the full code here. I expect to do the same for the other email services that provide an API.
Hope this helps some developers and engineers out there.

References:
- 25Labs.com
- Developers. google.com