GetRequestFromContext pulls the request from context (set in middleware above).

Middleware adds request to context.

NewModifier returns a gateway input/output modifier.

ErrFailedTokenGeneration is to show when the token generation fails.

KeyAuthorization is the key to look for the authorization header.

KeyDeleteSession is the identifier to check whether the session should be deleted.

KeyUserCSRFToken is the identifier for csrf token.

KeyUserID is identifier to get the current user's ID from the session store.

KeyUserRole is the identifier to get the current user's role from the session store.

Modifier defines a store to save session.

Session is the structure holding session data that gorilla's session store will convert into a cookie.