I need to login users via Instagram for my mobile application so I can make calls to Instagram API and get some information from the Instagram. Simply, my application will ask user to authorize Instagram access and able to get access token for API calls. Application should not ask user to login again once the user is authorized. I already setup my Instagram client-app to implement server-side authentication flow.
My challenge is I want to do this on by using AWS mobile services. I already setup custom authentication from MobileHub and came to point where I need to define my custom authentication flow (in this case it is Instagram authentication flow). Under AWS Cognito app when I go to Triggers tab, I see different options for defining lambda functions associated with my authentication (such as pre/post auth or define / create / verify auth challenge). I am not sure how to align Instagram Authentication flow with these functions. Or should I use something else. Also I am not clear how does AWS Cognito manages authentication flow: I don't want my users to go through authorization process every time they start my application. I believe AWS Cognito link users from my custom flow to some Cognito identity and able to authenticate when they use my application. I really appreciate any suggestions, or even code sample (if available).
Check this Document for Cognito Identity. Instagram is not there by default. So you have to use External Identity Provider, most probably using Open ID Connect Providers.