Oauth2 consumer (#679)

* 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)

2 files changed, 53 insertions, 0 deletions

diff --git a/templates/admin/auth/edit.tmpl b/templates/admin/auth/edit.tmpl
index 0879b274b1..84b62f6e87 100644
--- a/templates/admin/auth/edit.tmpl
+++ b/templates/admin/auth/edit.tmpl
@@ -142,6 +142,32 @@
 							</div>
 						{{end}}
 
+						<!-- OAuth2 -->
+						{{if .Source.IsOAuth2}}
+							{{ $cfg:=.Source.OAuth2 }}
+							<div class="inline required field">
+								<label>{{.i18n.Tr "admin.auths.oauth2_provider"}}</label>
+								<div class="ui selection type dropdown">
+									<input type="hidden" id="oauth2_provider" name="oauth2_provider" value="{{$cfg.Provider}}" required>
+									<div class="text">{{.CurrentOAuth2Provider.DisplayName}}</div>
+									<i class="dropdown icon"></i>
+									<div class="menu">
+										{{range $key, $value := .OAuth2Providers}}
+											<div class="item" data-value="{{$key}}">{{$value.DisplayName}}</div>
+										{{end}}
+									</div>
+								</div>
+							</div>
+							<div class="required field">
+								<label for="oauth2_key">{{.i18n.Tr "admin.auths.oauth2_clientID"}}</label>
+								<input id="oauth2_key" name="oauth2_key" value="{{$cfg.ClientID}}" required>
+							</div>
+							<div class="required field">
+								<label for="oauth2_secret">{{.i18n.Tr "admin.auths.oauth2_clientSecret"}}</label>
+								<input id="oauth2_secret" name="oauth2_secret" value="{{$cfg.ClientSecret}}" required>
+							</div>
+						{{end}}
+
 						<div class="inline field {{if not .Source.IsSMTP}}hide{{end}}">
 							<div class="ui checkbox">
 								<label><strong>{{.i18n.Tr "admin.auths.enable_tls"}}</strong></label>
diff --git a/templates/admin/auth/new.tmpl b/templates/admin/auth/new.tmpl
index 1edec0cb34..24257a1b65 100644
--- a/templates/admin/auth/new.tmpl
+++ b/templates/admin/auth/new.tmpl
@@ -133,6 +133,31 @@
 							<input id="pam_service_name" name="pam_service_name" value="{{.pam_service_name}}" />
 						</div>
 
+						<!-- OAuth2 -->
+						<div class="oauth2 field {{if not (eq .type 6)}}hide{{end}}">
+							<div class="inline required field">
+								<label>{{.i18n.Tr "admin.auths.oauth2_provider"}}</label>
+								<div class="ui selection type dropdown">
+									<input type="hidden" id="oauth2_provider" name="oauth2_provider" value="{{.oauth2_provider}}">
+									<div class="text">{{.oauth2_provider}}</div>
+									<i class="dropdown icon"></i>
+									<div class="menu">
+										{{range $key, $value := .OAuth2Providers}}
+											<div class="item" data-value="{{$key}}">{{$value.DisplayName}}</div>
+										{{end}}
+									</div>
+								</div>
+							</div>
+							<div class="required field">
+								<label for="oauth2_key">{{.i18n.Tr "admin.auths.oauth2_clientID"}}</label>
+								<input id="oauth2_key" name="oauth2_key" value="{{.oauth2_key}}">
+							</div>
+							<div class="required field">
+								<label for="oauth2_secret">{{.i18n.Tr "admin.auths.oauth2_clientSecret"}}</label>
+								<input id="oauth2_secret" name="oauth2_secret" value="{{.oauth2_secret}}">
+							</div>
+						</div>
+
 						<div class="ldap field">
 							<div class="ui checkbox">
 								<label><strong>{{.i18n.Tr "admin.auths.attributes_in_bind"}}</strong></label>
@@ -170,6 +195,8 @@
 				<div class="ui attached segment">
 					<h5>GMail Settings:</h5>
 					<p>Host: smtp.gmail.com, Port: 587, Enable TLS Encryption: true</p>
+					<h5>OAuth GitHub:</h5>
+					<p>{{.i18n.Tr "admin.auths.tip.github"}}</p>
 				</div>
 			</div>
 		</div>