Fix occasionally incorrect TripIDs (and thus incorrect polylines)3.0.3

Until now, tripIDs were cached based on station and departure timestamp.
These are identical for any two trains departing at the same time at the same
station, leading to one of those getting being assigned a wrong tripID.

From now on, only the JSON reported by transport.rest is cached -- tripIDs
are always recomputed based on it.

1 files changed, 30 insertions, 21 deletions

diff --git a/lib/DBInfoscreen/Controller/Stationboard.pm b/lib/DBInfoscreen/Controller/Stationboard.pm
index e40fda3..8ac8101 100644
--- a/lib/DBInfoscreen/Controller/Stationboard.pm
+++ b/lib/DBInfoscreen/Controller/Stationboard.pm
@@ -137,27 +137,10 @@ sub get_hafas_trip_id {
 		  = "https://2.db.transport.rest/stations/${eva}/arrivals?duration=5&when=$dep_ts";
 	}
 
-	if ( my $content = $cache->get($url) ) {
-		return $content;
-	}
-
-	$ua->request_timeout(2);
-	my $res = eval {
-		$ua->get(
-			$url => { 'User-Agent' => "dbf.finalrewind.org/${dbf_version}" } )
-		  ->result;
-	};
-	if ($@) {
-		return;
-	}
-	if ( $res->is_error ) {
-		return;
-	}
+	my $json = hafas_rest_req( $ua, $cache, $url );
 
-	my $json = decode_json( $res->body );
-
-	#say "looking for " . $train->train_no;
-	for my $result ( @{$json} ) {
+	#say "looking for " . $train->train_no . " in $url";
+	for my $result ( @{ $json // [] } ) {
 		my $trip_id = $result->{tripId};
 		my $fahrt   = $result->{line}{fahrtNr};
 
@@ -165,7 +148,6 @@ sub get_hafas_trip_id {
 		if ( $result->{line} and $result->{line}{fahrtNr} == $train->train_no )
 		{
 			#say "Trip ID is $trip_id";
-			$cache->set( $url, $trip_id );
 			return $trip_id;
 		}
 		else {
@@ -201,6 +183,33 @@ sub check_wagonorder {
 	}
 }
 
+sub hafas_rest_req {
+	my ( $ua, $cache, $url ) = @_;
+
+	if ( my $content = $cache->thaw($url) ) {
+		return $content;
+	}
+
+	my $res = eval {
+		$ua->get(
+			$url => { 'User-Agent' => "dbf.finalrewind.org/${dbf_version}" } )
+		  ->result;
+	};
+
+	if ($@) {
+		return;
+	}
+	if ( $res->is_error ) {
+		return;
+	}
+
+	my $json = decode_json( $res->body );
+
+	$cache->freeze( $url, $json );
+
+	return $json;
+}
+
 sub hafas_json_req {
 	my ( $ua, $cache, $url ) = @_;