Traewelling: replace legacy password login with OAuth2

This is a breaking change insofar as that traewelling support is no longer
provided automatically, but must be enabled by providing a traewelling.de
application ID and secret in travelynx.conf. However, as traewelling.de
password login is deprecated and wil soon be disabled, travelynx would break
either way. So we might or might not see travelynx 2.0.0 in the next days.

Automatic token refresh is still todo, but that was the case for password
login as well.

Closes #64

10 files changed, 179 insertions, 170 deletions

diff --git a/cpanfile b/cpanfile
index 8f72042..6bdba37 100644
--- a/cpanfile
+++ b/cpanfile
@@ -10,6 +10,7 @@ requires 'List::UtilsBy';
 requires 'MIME::Entity';
 requires 'Mojolicious';
 requires 'Mojolicious::Plugin::Authentication';
+requires 'Mojolicious::Plugin::OAuth2';
 requires 'Mojo::Pg';
 requires 'Text::CSV';
 requires 'Text::Markdown';
diff --git a/cpanfile.snapshot b/cpanfile.snapshot
index 198917d..5619f56 100644
--- a/cpanfile.snapshot
+++ b/cpanfile.snapshot
@@ -1915,6 +1915,15 @@ DISTRIBUTIONS
       ExtUtils::MakeMaker 0
       Mojolicious 8.0
       perl 5.016
+  Mojolicious-Plugin-OAuth2-2.02
+    pathname: J/JH/JHTHORSEN/Mojolicious-Plugin-OAuth2-2.02.tar.gz
+    provides:
+      Mojolicious::Plugin::OAuth2 2.02
+      Mojolicious::Plugin::OAuth2::Mock undef
+    requirements:
+      ExtUtils::MakeMaker 0
+      IO::Socket::SSL 1.94
+      Mojolicious 8.25
   Moo-2.005005
     pathname: H/HA/HAARG/Moo-2.005005.tar.gz
     provides:
diff --git a/examples/travelynx.conf b/examples/travelynx.conf
index c77e40f..f8eaac0 100644
--- a/examples/travelynx.conf
+++ b/examples/travelynx.conf
@@ -97,7 +97,31 @@
 		die("Changeme!"),
 	],
 
+	# optionally, users can link travelynx and traewelling accounts, and
+	# automatically synchronize check-ins.
+	# To do so, you need to create a travelynx application on
+	# <https://traewelling.de/settings/applications>. The application
+	# must be marked as "Confidential" and have a redirect URL that matches
+	# $base_url/oauth/traewelling, where $base_url refers to the URL configured
+	# above. For instance, travelynx.de uses
+	# 'https://travelynx.de/oauth/traewelling'. An incorrect redirect URL will
+	# cause OAuth2 to fail with unsupported_grant_type.
+	#
+	# Note that the travelynx/traewelling OAuth2 integration does not support
+	# travelynx installations that are reachable on multiple URLs at the
+	# moment -- linking a traewelling account is only possible when accessing
+	# travelynx via the base URL.
 	traewelling => {
+
+		# Uncomment the following block and insert the application ID and
+		# secret obtained from https://traewelling.de/settings/applications
+		# -> your application -> Edit.
+
+		#oauth => {
+		#	id => 1234,
+		#	secret => 'mysecret',
+		#}
+
 		# By default, the "work" or "worker" command does not just update
 		# real-time data of active journeys, but also performs push and pull
 		# synchronization with traewelling for accounts that have configured it.
@@ -110,7 +134,8 @@
 		# periodically runs "perl index.pl traewelling" (push and pull) or
 		# two separate cronjobs that run "perl index.pl traewelling push" and
 		# "perl index.pl traewelling pull", respectively.
-		## separate_worker => 1,
+
+		# separate_worker => 1,
 	},
 
 	version => qx{git describe --dirty} // 'experimental',
diff --git a/lib/Travelynx.pm b/lib/Travelynx.pm
index f5f56b7..551c061 100755
--- a/lib/Travelynx.pm
+++ b/lib/Travelynx.pm
@@ -100,6 +100,23 @@ sub startup {
 			},
 		}
 	);
+
+	if ( my $oa = $self->config->{traewelling}{oauth} ) {
+		$self->plugin(
+			OAuth2 => {
+				providers => {
+					traewelling => {
+						key           => $oa->{id},
+						secret        => $oa->{secret},
+						authorize_url =>
+'https://traewelling.de/oauth/authorize?response_type=code',
+						token_url => 'https://traewelling.de/oauth/token',
+					}
+				}
+			}
+		);
+	}
+
 	$self->sessions->default_expiration( 60 * 60 * 24 * 180 );
 
 	# Starting with v8.11, Mojolicious sends SameSite=Lax Cookies by default.
@@ -2140,6 +2157,11 @@ sub startup {
 	$r->post('/login')->to('account#do_login');
 	$r->post('/recover')->to('account#request_password_reset');
 
+	if ( $self->config->{traewelling}{oauth} ) {
+		$r->get('/oauth/traewelling')->to('traewelling#oauth');
+		$r->post('/oauth/traewelling')->to('traewelling#oauth');
+	}
+
 	if ( not $self->config->{registration}{disabled} ) {
 		$r->get('/register')->to('account#registration_form');
 		$r->post('/register')->to('account#register');
diff --git a/lib/Travelynx/Command/database.pm b/lib/Travelynx/Command/database.pm
index 10732ec..b45a02f 100644
--- a/lib/Travelynx/Command/database.pm
+++ b/lib/Travelynx/Command/database.pm
@@ -1815,6 +1815,25 @@ my @migrations = (
 			}
 		);
 	},
+
+	# v45 -> v46
+	# Switch to Traewelling OAuth2 authentication.
+	# E-Mail is no longer needed.
+	sub {
+		my ($db) = @_;
+		$db->query(
+			qq{
+				drop view traewelling_str;
+				create view traewelling_str as select
+					user_id, push_sync, pull_sync, errored, token, data,
+					extract(epoch from latest_run) as latest_run_ts
+					from traewelling
+				;
+				alter table traewelling drop column email;
+				update schema_version set version = 46;
+			}
+		);
+	},
 );
 
 # TODO add 'hafas' column to in_transit (and maybe journeys? undo/redo needs something to work with...)
diff --git a/lib/Travelynx/Controller/Traewelling.pm b/lib/Travelynx/Controller/Traewelling.pm
index 4c6bc64..e14872d 100644
--- a/lib/Travelynx/Controller/Traewelling.pm
+++ b/lib/Travelynx/Controller/Traewelling.pm
@@ -6,11 +6,9 @@ package Travelynx::Controller::Traewelling;
 use Mojo::Base 'Mojolicious::Controller';
 use Mojo::Promise;
 
-sub settings {
+sub oauth {
 	my ($self) = @_;
 
-	my $uid = $self->current_user->{id};
-
 	if (    $self->param('action')
 		and $self->validation->csrf_protect->has_error('csrf_token') )
 	{
@@ -22,38 +20,68 @@ sub settings {
 		return;
 	}
 
-	if ( $self->param('action') and $self->param('action') eq 'login' ) {
-		my $email    = $self->param('email');
-		my $password = $self->param('password');
-		$self->render_later;
-		$self->traewelling_api->login_p(
-			uid      => $uid,
-			email    => $email,
-			password => $password
-		)->then(
-			sub {
-				my $traewelling = $self->traewelling->get( uid => $uid );
-				$self->param( sync_source => 'none' );
-				$self->render(
-					'traewelling',
-					traewelling     => $traewelling,
-					new_traewelling => 1,
-				);
+	$self->render_later;
+
+	my $oa = $self->config->{traewelling}{oauth};
+
+	return $self->oauth2->get_token_p(
+		traewelling => { scope => 'read-statuses write-statuses' } )->then(
+		sub {
+			my ($provider) = @_;
+			if ( not defined $provider ) {
+
+				# OAuth2 plugin performed a redirect, no need to render
+				return;
 			}
-		)->catch(
-			sub {
-				my ($err) = @_;
-				$self->render(
-					'traewelling',
-					traewelling     => {},
-					new_traewelling => 1,
-					login_error     => $err,
-				);
+			if ( not $provider or not $provider->{access_token} ) {
+				$self->flash( new_traewelling => 1 );
+				$self->flash( login_error     => 'no token received' );
+				$self->redirect_to('/account/traewelling');
+				return;
 			}
-		)->wait;
+			my $uid   = $self->current_user->{id};
+			my $token = $provider->{access_token};
+			$self->traewelling->link(
+				uid        => $self->current_user->{id},
+				token      => $provider->{access_token},
+				expires_in => $provider->{expires_in},
+			);
+			return $self->traewelling_api->get_user_p( $uid, $token )->then(
+				sub {
+					$self->flash( new_traewelling => 1 );
+					$self->redirect_to('/account/traewelling');
+				}
+			);
+		}
+	)->catch(
+		sub {
+			my ($err) = @_;
+			say "error $err";
+			$self->flash( new_traewelling => 1 );
+			$self->flash( login_error     => $err );
+			$self->redirect_to('/account/traewelling');
+			return;
+		}
+	);
+}
+
+sub settings {
+	my ($self) = @_;
+
+	my $uid = $self->current_user->{id};
+
+	if (    $self->param('action')
+		and $self->validation->csrf_protect->has_error('csrf_token') )
+	{
+		$self->render(
+			'bad_request',
+			csrf   => 1,
+			status => 400
+		);
 		return;
 	}
-	elsif ( $self->param('action') and $self->param('action') eq 'logout' ) {
+
+	if ( $self->param('action') and $self->param('action') eq 'logout' ) {
 		$self->render_later;
 		my $traewelling = $self->traewelling->get( uid => $uid );
 		$self->traewelling_api->logout_p(
diff --git a/lib/Travelynx/Helper/Traewelling.pm b/lib/Travelynx/Helper/Traewelling.pm
index 23170eb..18edc18 100644
--- a/lib/Travelynx/Helper/Traewelling.pm
+++ b/lib/Travelynx/Helper/Traewelling.pm
@@ -199,84 +199,6 @@ sub get_user_p {
 	return $promise;
 }
 
-sub login_p {
-	my ( $self, %opt ) = @_;
-
-	my $uid      = $opt{uid};
-	my $email    = $opt{email};
-	my $password = $opt{password};
-
-	my $ua = $self->{user_agent}->request_timeout(20);
-
-	my $request = {
-		login    => $email,
-		password => $password,
-	};
-
-	my $promise = Mojo::Promise->new;
-	my $token;
-
-	$ua->post_p(
-		"https://traewelling.de/api/v1/auth/login" => $self->{header},
-		json                                       => $request
-	)->then(
-		sub {
-			my ($tx) = @_;
-			if ( my $err = $tx->error ) {
-				my $err_msg
-				  = "v1/auth/login: HTTP $err->{code} $err->{message}";
-				$promise->reject($err_msg);
-				return;
-			}
-			else {
-				my $res = $tx->result->json->{data};
-				$token = $res->{token};
-				my $expiry_dt = $self->parse_datetime( $res->{expires_at} );
-
-				# Fall back to one year expiry
-				$expiry_dt //= DateTime->now( time_zone => 'Europe/Berlin' )
-				  ->add( years => 1 );
-				$self->{model}->link(
-					uid     => $uid,
-					email   => $email,
-					token   => $token,
-					expires => $expiry_dt
-				);
-				return $self->get_user_p( $uid, $token );
-			}
-		}
-	)->then(
-		sub {
-			$promise->resolve;
-			return;
-		}
-	)->catch(
-		sub {
-			my ($err) = @_;
-			if ($token) {
-
-				# We have a token, but couldn't complete the login. For now, we
-				# solve this by logging out and invalidating the token.
-				$self->logout_p(
-					uid   => $uid,
-					token => $token
-				)->finally(
-					sub {
-						$promise->reject("v1/auth/login: $err");
-						return;
-					}
-				);
-			}
-			else {
-				$promise->reject("v1/auth/login: $err");
-			}
-			return;
-		}
-	)->wait;
-
-	return $promise;
-}
-
 sub logout_p {
 	my ( $self, %opt ) = @_;
 
diff --git a/lib/Travelynx/Model/Traewelling.pm b/lib/Travelynx/Model/Traewelling.pm
index 1939374..72ee92d 100644
--- a/lib/Travelynx/Model/Traewelling.pm
+++ b/lib/Travelynx/Model/Traewelling.pm
@@ -38,16 +38,15 @@ sub now {
 sub link {
 	my ( $self, %opt ) = @_;
 
-	my $log = [ [ $self->now->epoch, "Erfolgreich angemeldet" ] ];
+	my $log = [ [ $self->now->epoch, "Erfolgreich mittels OAuth2 verbunden" ] ];
 
 	my $data = {
 		log     => $log,
-		expires => $opt{expires}->epoch,
+		expires => $self->now->epoch + $opt{expires_in},
 	};
 
 	my $user_entry = {
 		user_id   => $opt{uid},
-		email     => $opt{email},
 		push_sync => 0,
 		pull_sync => 0,
 		token     => $opt{token},
@@ -59,7 +58,7 @@ sub link {
 		$user_entry,
 		{
 			on_conflict => \
-'(user_id) do update set email = EXCLUDED.email, token = EXCLUDED.token, push_sync = false, pull_sync = false, data = null, errored = false, latest_run = null'
+'(user_id) do update set token = EXCLUDED.token, push_sync = false, pull_sync = false, data = null, errored = false, latest_run = null'
 		}
 	);
 
diff --git a/templates/account.html.ep b/templates/account.html.ep
index c27e0f5..b64869a 100644
--- a/templates/account.html.ep
+++ b/templates/account.html.ep
@@ -122,33 +122,35 @@
 					% }
 				</td>
 			</tr>
-			<tr>
-				<th scope="row">Träwelling</th>
-				<td>
-					<a href="/account/traewelling"><i class="material-icons">edit</i></a>
-					% if (not ($traewelling->{token})) {
-						<span style="color: #999999;">Nicht verknüpft</span>
-					% }
-					% elsif ($traewelling->{errored}) {
-						Fehlerhaft <i class="material-icons" aria-hidden="true">error</i>
-					% }
-					% else {
-						Verknüpft mit <%= $traewelling->{data}{user_name} // $traewelling->{email} %>
-						% if ($traewelling->{expired}) {
-							– Login-Token abgelaufen <i class="material-icons" aria-hidden="true">error</i>
-						% }
-						% elsif ($traewelling->{expiring}) {
-							– Login-Token läuft bald ab <i class="material-icons" aria-hidden="true">warning</i>
+			% if (config->{traewelling}{oauth}) {
+				<tr>
+					<th scope="row">Träwelling</th>
+					<td>
+						<a href="/account/traewelling"><i class="material-icons">edit</i></a>
+						% if (not ($traewelling->{token})) {
+							<span style="color: #999999;">Nicht verknüpft</span>
 						% }
-						% elsif ($traewelling->{pull_sync}) {
-							– Checkins in Träwelling werden von travelynx übernommen
+						% elsif ($traewelling->{errored}) {
+							Fehlerhaft <i class="material-icons" aria-hidden="true">error</i>
 						% }
-						% elsif ($traewelling->{push_sync}) {
-							– Checkins in travelynx werden zu Träwelling weitergereicht
+						% else {
+							Verknüpft mit <%= $traewelling->{data}{user_name} // $traewelling->{email} %>
+							% if ($traewelling->{expired}) {
+								– Login-Token abgelaufen <i class="material-icons" aria-hidden="true">error</i>
+							% }
+							% elsif ($traewelling->{expiring}) {
+								– Login-Token läuft bald ab <i class="material-icons" aria-hidden="true">warning</i>
+							% }
+							% elsif ($traewelling->{pull_sync}) {
+								– Checkins in Träwelling werden von travelynx übernommen
+							% }
+							% elsif ($traewelling->{push_sync}) {
+								– Checkins in travelynx werden zu Träwelling weitergereicht
+							% }
 						% }
-					% }
-				</td>
-			</tr>
+					</td>
+				</tr>
+			% }
 			<tr>
 				<th scope="row">Externe Dienste</th>
 				<td>
diff --git a/templates/traewelling.html.ep b/templates/traewelling.html.ep
index 23e2e35..4147140 100644
--- a/templates/traewelling.html.ep
+++ b/templates/traewelling.html.ep
@@ -4,20 +4,20 @@
 
 <h1>Träwelling</h1>
 
-% if (stash('new_traewelling')) {
+% if (flash('new_traewelling')) {
 	<div class="row">
 		<div class="col s12">
 			% if ($traewelling->{token}) {
 				<div class="card success-color">
 					<div class="card-content white-text">
 						<span class="card-title">Träwelling verknüpft</span>
-						% my $user = $traewelling->{data}{user_name} // $traewelling->{email};
+						% my $user = $traewelling->{data}{user_name} // '???';
 						<p>Dein travelynx-Account hat nun ein Jahr lang Zugriff auf 
 							den Träwelling-Account <b>@<%= $user %></b>.</p>
 					</div>
 				</div>
 			% }
-			% elsif (my $login_err = stash('login_error')) {
+			% elsif (my $login_err = flash('login_error')) {
 				<div class="card caution-color">
 					<div class="card-content white-text">
 						<span class="card-title">Login-Fehler</span>
@@ -30,7 +30,7 @@
 					<div class="card-content white-text">
 						<span class="card-title">Logout-Fehler</span>
 						<p>Der Logout bei Träwelling ist fehlgeschlagen: <%= $logout_err %>.
-							Dein Login-Token bei travelynx wurde dennoch gelöscht, so
+							Dein Token bei travelynx wurde dennoch gelöscht, so
 							dass nun kein Zugriff von travelynx auf Träwelling mehr
 							möglich ist. In den <a
 							href="https://traewelling.de/settings">Träwelling-Einstellungen</a>
@@ -73,10 +73,10 @@
 			<div class="card caution-color">
 				<div class="card-content white-text">
 					% if ($traewelling->{expired}) {
-						<span class="card-title">Login-Token abgelaufen</span>
+						<span class="card-title">Token abgelaufen</span>
 					% }
 					% else {
-						<span class="card-title">Login-Token läuft bald ab</span>
+						<span class="card-title">Token läuft bald ab</span>
 					% }
 					<p>Melde deinen travelynx-Account von Träwelling ab und
 						verbinde ihn mit deinem Träwelling-Passwort erneut,
@@ -105,37 +105,19 @@
 				verknüpfen. Dies erlaubt die automatische Übernahme zukünftiger
 				Checkins zwischen den beiden Diensten. Träwelling-Checkins in
 				Nahverkehrsmittel und Züge außerhalb des deutschen Schienennetzes
-				werden nicht unterstützt und ignoriert. Checkins, die vor dem
-				Verknüpfen der Accounts stattgefunden haben, werden nicht
-				synchronisiert. Bei synchronisierten Checkins wird der zugehörige
-				Träwelling-Status von deiner travelynx-Statusseite aus verlinkt.
-			</p>
-			<p>
-				Mit E-Mail und Passwort wird ein Login über die Träwelling-API
-				durchgeführt. Die E-Mail und das dabei generierte Token werden
-				von travelynx gespeichert. Das Passwort wird ausschließlich für
-				den Login verwendet und nicht gespeichert. Der Login kann jederzeit
-				sowohl auf dieser Seite als auch über die <a
-				href="https://traewelling.de/settings">Träwelling-Einstellungen</a>
-				widerrufen werden. Nach einem Jahr läuft er automatisch ab.
+				werden (noch) nicht unterstützt und ignoriert. Checkins, die
+				vor dem Verknüpfen der Accounts stattgefunden haben, werden
+				nicht synchronisiert. Bei synchronisierten Checkins wird der
+				zugehörige Träwelling-Status von deiner travelynx-Statusseite
+				aus verlinkt.
 			</p>
 		</div>
 	</div>
 	<div class="row">
-		%= form_for '/account/traewelling' => (method => 'POST') => begin
+		%= form_for '/oauth/traewelling' => (method => 'POST') => begin
 			%= csrf_field
-			<div class="input-field col s12">
-				<i class="material-icons prefix">account_circle</i>
-				%= text_field 'email', id => 'email', class => 'validate', required => undef, maxlength => 250
-				<label for="email">Login (Name oder E-Mail)</label>
-			</div>
-			<div class="input-field col s12">
-				<i class="material-icons prefix">lock</i>
-				%= password_field 'password', id => 'password', class => 'validate', required => undef
-				<label for="password">Passwort</label>
-			</div>
 			<div class="col s12 center-align">
-				<button class="btn waves-effect waves-light" type="submit" name="action" value="login">
+				<button class="btn waves-effect waves-light" type="submit" name="action" value="connect">
 					Verknüpfen
 					<i class="material-icons right">send</i>
 				</button>
@@ -154,7 +136,7 @@
 				% else {
 					%= $traewelling->{email}
 				% }
-				verknüpft. Der Login-Token läuft <%= $traewelling->{expires_on}->strftime('am %d.%m.%Y um %H:%M Uhr') %> ab.
+				verknüpft. Der Token läuft <%= $traewelling->{expires_on}->strftime('am %d.%m.%Y um %H:%M Uhr') %> ab.
 			</p>
 		</div>
 	</div>