Rails 3.2 Email Address "If Blank" - facebook

Question

So I had a problem where Omni-Auth Facebook wasn't returning an email address for SOME (20-30%) user accounts, therefore the accounts wouldn't be registered because of an "email can't be blank error."
So I decided to solve this by automatically generating an email address based on the user's facebook ID if omniauth couldn't get the email address...
Now... of course... the problem with my solution (as you'll see below) is that it started saving the auto-generated email address REGARDLESS of whether or not omniauth was returning an email address. (For example my email always worked fine, but it was replaced with 123213#facebook.com)
Basically what I want is this: if a user has already supplied an email address then it just stays with the original. If they haven't, and the email address can't be gotten from omniauth, then it generates a new one.
def self.from_omniauth(auth)
where(auth.slice(:provider, :uid)).first_or_initialize.tap do |user|
user.provider = auth.provider
user.uid = auth.uid
user.email = "#{auth.provider}-#{auth.uid}#liquid-radio.com"
user.password = user.password_confirmation = SecureRandom.urlsafe_base64(n=6)
if auth.provider == "facebook"
user.name = auth.info.name
user.email = auth.info.email = "#{auth.uid}#facebook.com"
else
user.oauth_token = auth.credentials.token
user.oauth_expires_at = Time.at(auth.credentials.expires_at)
end
user.save
end
end

Answer 1

You'll probably want to move this line:
user.email = "#{auth.provider}-#{auth.uid}#liquid-radio.com"
down into the "else" case, since it only (presumably) applies to non-Facebook users.
Aside from that, try changing this:
user.email = auth.info.email = "#{auth.uid}#facebook.com"
to this:
user.email ||= auth.info.email || "#{auth.uid}#facebook.com"
A breakdown of what this does:
if the user already has an email, it doesn't change it
if there's a value in auth.info.email and the user doesn't have an email yet, set it
if there isn't a value in auth.info.email, punt and use the generated version
You could write this out long-form in Ruby as:
if user.email
# do nothing
elsif auth.info.email
user.email = auth.info.email
else
user.email = "#{auth.uid}#facebook.com"
end
Note: the solution above will not work if the liquid-radio.com line is still above the if auth.provider part - the user will ALWAYS have a value in the email field in that case.
Another note: this code will not update a user's email from their Facebook auth if it changes. This may or may not be what you want.