* initial stuff for oauth2 login, fails on:
* login button on the signIn page to start the OAuth2 flow and a callback for each provider
Only GitHub is implemented for now
* show login button only when the OAuth2 consumer is configured (and activated)
* create macaron group for oauth2 urls
* prevent net/http in modules (other then oauth2)
* use a new data sessions oauth2 folder for storing the oauth2 session data
* add missing 2FA when this is enabled on the user
* add password option for OAuth2 user , for use with git over http and login to the GUI
* add tip for registering a GitHub OAuth application
* at startup of Gitea register all configured providers and also on adding/deleting of new providers
* custom handling of errors in oauth2 request init + show better tip
* add ExternalLoginUser model and migration script to add it to database
* link a external account to an existing account (still need to handle wrong login and signup) and remove if user is removed
* remove the linked external account from the user his settings
* if user is unknown we allow him to register a new account or link it to some existing account
* sign up with button on signin page (als change OAuth2Provider structure so we can store basic stuff about providers)
* from gorilla/sessions docs:
"Important Note: If you aren't using gorilla/mux, you need to wrap your handlers with context.ClearHandler as or else you will leak memory!"
(we're using gorilla/sessions for storing oauth2 sessions)
* use updated goth lib that now supports getting the OAuth2 user if the AccessToken is still valid instead of re-authenticating (prevent flooding the OAuth2 provider)
* Correction LDAP username validation
As https://msdn.microsoft.com/en-us/library/aa366101(v=vs.85).aspx describe spaces should not be in start or at the end of username but they can be inside the username. So please check my solution for it.
* Check for zero length passwords in LDAP module.
According to https://tools.ietf.org/search/rfc4513#section-5.1.2 LDAP client should always check before bind whether a password is an empty value. There are at least one LDAP implementation which does not return error if you try to bind with DN set and empty password - AD.
* Clearing the login/email spaces at the [start/end]
* Write LDAP, SMTP, PAM, DLDAP back to all uppercase
* Fix type in unused constant name
* Other MixCased fixes
* Complete MixerCasing of template constants
* Re uppercase LTS and LDAPS suffixes
* Uppercase JSON suffix in constant names
* Proper case LoginNoType
* Prefix unexported template path constants with "tpl"
Consider following LDAP search query example:
(&(objectClass=Person)(|(uid=%s)(mail=%s)))
Right now on first login attempt Gogs will use the text supplied on login form
as the newly created user name. In example query above the text matches against
both e-mail or user name. So if user puts the e-mail then the new Gogs user
name will be e-mail which may be undesired.
Using optional user name attribute setting we can explicitly say we want Gogs
user name to be certain LDAP attribute eg. `uid`, so even user will use e-mail
to login 1st time, the new account will receive correct user name.
The IsAdmin flag is set based on whether the admin filter
returned any result. The admin filter is applied with the user dn
as the search root.
In the future, we should update IsAdmin as well on each login.
Alternately, we can have a periodic sync operation.