Refetch transit leg with a leg query of GTFS GraphQL API

src/main/java/org/opentripplanner/apis/gtfs/datafetchers/LegImpl.java

@@ -23,6 +23,7 @@
 import org.opentripplanner.model.plan.StreetLeg;
 import org.opentripplanner.model.plan.TransitLeg;
 import org.opentripplanner.model.plan.WalkStep;
+import org.opentripplanner.model.plan.legreference.LegReferenceSerializer;
 import org.opentripplanner.routing.alertpatch.TransitAlert;
 import org.opentripplanner.routing.alternativelegs.AlternativeLegs;
 import org.opentripplanner.routing.alternativelegs.AlternativeLegsFilter;
@@ -189,10 +190,12 @@ public DataFetcher<Boolean> realTime() {
     return environment -> getSource(environment).getRealTime();
   }
 
-  // TODO
   @Override
   public DataFetcher<String> realtimeState() {
-    return environment -> null;
+    return environment -> {
+      var state = getSource(environment).getRealTimeState();
+      return (state != null) ? state.name() : null;
+    };
   }
 
   @Override
@@ -324,4 +327,15 @@ public DataFetcher<Iterable<Leg>> nextLegs() {
   public DataFetcher<Double> accessibilityScore() {
     return environment -> NumberMapper.toDouble(getSource(environment).accessibilityScore());
   }
+
+  @Override
+  public DataFetcher<String> id() {
+    return environment -> {
+      var ref = getSource(environment).getLegReference();
+      if (ref == null) {
+        return null;
+      }
+      return LegReferenceSerializer.encode(ref);
+    };
+  }
 }

src/main/java/org/opentripplanner/apis/gtfs/datafetchers/QueryTypeImpl.java

@@ -42,6 +42,9 @@
 import org.opentripplanner.graph_builder.issue.api.DataImportIssueStore;
 import org.opentripplanner.gtfs.mapping.DirectionMapper;
 import org.opentripplanner.model.TripTimeOnDate;
+import org.opentripplanner.model.plan.Leg;
+import org.opentripplanner.model.plan.legreference.LegReference;
+import org.opentripplanner.model.plan.legreference.LegReferenceSerializer;
 import org.opentripplanner.routing.alertpatch.EntitySelector;
 import org.opentripplanner.routing.alertpatch.TransitAlert;
 import org.opentripplanner.routing.api.request.RouteRequest;
@@ -362,6 +365,20 @@ public DataFetcher<Connection<PlaceAtDistance>> nearest() {
     };
   }
 
+  @Override
+  public DataFetcher<Leg> leg() {
+    return environment -> {
+      TransitService transitService = getTransitService(environment);
+      var args = new GraphQLTypes.GraphQLQueryTypeLegArgs(environment.getArguments());
+      String id = args.getGraphQLId();
+      LegReference ref = LegReferenceSerializer.decode(id);
+      if (ref == null) {
+        return null;
+      }
+      return ref.getLeg(transitService);
+    };
+  }
+
   @Override
   public DataFetcher<Object> node() {
     return environment -> {

src/main/java/org/opentripplanner/apis/gtfs/generated/GraphQLDataFetchers.java

@@ -482,6 +482,8 @@ public interface GraphQLLeg {
 
     public DataFetcher<String> headsign();
 
+    public DataFetcher<String> id();
+
     public DataFetcher<Boolean> interlineWithPreviousLeg();
 
     public DataFetcher<Boolean> intermediatePlace();
@@ -779,6 +781,8 @@ public interface GraphQLQueryType {
 
     public DataFetcher<Trip> fuzzyTrip();
 
+    public DataFetcher<Leg> leg();
+
     public DataFetcher<Connection<PlaceAtDistance>> nearest();
 
     public DataFetcher<Object> node();

src/main/java/org/opentripplanner/apis/gtfs/generated/GraphQLTypes.java

@@ -2432,6 +2432,25 @@ public void setGraphQLTime(Integer time) {
     }
   }
 
+  public static class GraphQLQueryTypeLegArgs {
+
+    private String id;
+
+    public GraphQLQueryTypeLegArgs(Map<String, Object> args) {
+      if (args != null) {
+        this.id = (String) args.get("id");
+      }
+    }
+
+    public String getGraphQLId() {
+      return this.id;
+    }
+
+    public void setGraphQLId(String id) {
+      this.id = id;
+    }
+  }
+
   public static class GraphQLQueryTypeNearestArgs {
 
     private String after;

src/main/java/org/opentripplanner/apis/transmodel/TransmodelGraphQLSchema.java

@@ -1596,7 +1596,7 @@ private GraphQLSchema create() {
         GraphQLFieldDefinition
           .newFieldDefinition()
           .name("leg")
-          .description("Refetch a single leg based on its id")
+          .description("Refetch a single transit leg based on its id")
           .withDirective(gqlUtil.timingData)
           .type(LegType.REF)
           .argument(

src/main/java/org/opentripplanner/apis/transmodel/model/plan/LegType.java

@@ -63,7 +63,9 @@ public static GraphQLObjectType create(
         GraphQLFieldDefinition
           .newFieldDefinition()
           .name("id")
-          .description("An identifier for the leg, which can be used to re-fetch the information.")
+          .description(
+            "An identifier for the leg, which can be used to re-fetch transit leg information."
+          )
           .type(Scalars.GraphQLID)
           .dataFetcher(env -> LegReferenceSerializer.encode(leg(env).getLegReference()))
           .build()

src/main/java/org/opentripplanner/model/plan/Leg.java

@@ -22,6 +22,7 @@
 import org.opentripplanner.transit.model.organization.Agency;
 import org.opentripplanner.transit.model.organization.Operator;
 import org.opentripplanner.transit.model.site.FareZone;
+import org.opentripplanner.transit.model.timetable.RealTimeState;
 import org.opentripplanner.transit.model.timetable.Trip;
 import org.opentripplanner.transit.model.timetable.TripOnServiceDate;
 import org.opentripplanner.transit.model.timetable.booking.BookingInfo;
@@ -244,6 +245,10 @@ default boolean getRealTime() {
     return false;
   }
 
+  default RealTimeState getRealTimeState() {
+    return null;
+  }
+
   /**
    * Whether this Leg describes a flexible trip. The reason we need this is that FlexTrip does not
    * inherit from Trip, so that the information that the Trip is flexible would be lost when

src/main/java/org/opentripplanner/model/plan/ScheduledTransitLeg.java

@@ -34,6 +34,7 @@
 import org.opentripplanner.transit.model.organization.Agency;
 import org.opentripplanner.transit.model.organization.Operator;
 import org.opentripplanner.transit.model.site.StopLocation;
+import org.opentripplanner.transit.model.timetable.RealTimeState;
 import org.opentripplanner.transit.model.timetable.Trip;
 import org.opentripplanner.transit.model.timetable.TripOnServiceDate;
 import org.opentripplanner.transit.model.timetable.TripTimes;
@@ -227,6 +228,11 @@ public boolean getRealTime() {
     );
   }
 
+  @Override
+  public RealTimeState getRealTimeState() {
+    return tripTimes.getRealTimeState();
+  }
+
   @Override
   public double getDistanceMeters() {
     return distanceMeters;

src/main/resources/org/opentripplanner/apis/gtfs/schema.graphqls

@@ -670,6 +670,11 @@ type Leg {
   """
   headsign: String
   """
+  An identifier for the leg, which can be used to re-fetch transit leg information.
+  Re-fetching fails when the underlying transit data no longer exists.
+  """
+  id: String
+  """
   Interlines with previous leg.
   This is true when the same vehicle is used for the previous leg as for this leg
   and passenger can stay inside the vehicle.
@@ -1166,6 +1171,11 @@ type QueryType {
     time: Int!
   ): Trip
   """
+  Try refetching the current state of a transit leg using its id.
+  This fails when the underlying transit data (mostly IDs) has changed or are no longer available.
+  """
+  leg(id: String!): Leg
+  """
   Get all places (stops, stations, etc. with coordinates) within the specified
   radius from a location. The returned type is a Relay connection (see
   https://facebook.github.io/relay/graphql/connections.htm). The placeAtDistance

src/main/resources/org/opentripplanner/apis/transmodel/schema.graphql

@@ -325,7 +325,7 @@ type Leg {
   fromPlace: Place!
   "Generalized cost or weight of the leg. Used for debugging."
   generalizedCost: Int
-  "An identifier for the leg, which can be used to re-fetch the information."
+  "An identifier for the leg, which can be used to re-fetch transit leg information."
   id: ID
   interchangeFrom: Interchange
   interchangeTo: Interchange
@@ -647,7 +647,7 @@ type QueryType {
   groupOfLines(id: String!): GroupOfLines
   "Get all groups of lines"
   groupsOfLines: [GroupOfLines!]!
-  "Refetch a single leg based on its id"
+  "Refetch a single transit leg based on its id"
   leg(id: ID!): Leg @timingData
   "Get a single line based on its id"
   line(id: ID!): Line @timingData

src/test/resources/org/opentripplanner/apis/gtfs/expectations/plan-extended.json

@@ -64,7 +64,9 @@
               "intermediatePlaces" : null,
               "alerts" : [ ],
               "rideHailingEstimate" : null,
-              "accessibilityScore" : null
+              "accessibilityScore" : null,
+              "id": null,
+              "realtimeState": null
             },
             {
               "mode" : "BUS",
@@ -154,7 +156,9 @@
               ],
               "alerts" : [ ],
               "rideHailingEstimate" : null,
-              "accessibilityScore" : null
+              "accessibilityScore" : null,
+              "id": "rO0ABXdBABhTQ0hFRFVMRURfVFJBTlNJVF9MRUdfVjMABUY6MTIyAAoyMDIwLTAyLTAyAAAABQAAAAcAA0Y6QgADRjpDAAA=",
+              "realtimeState": "UPDATED"
             },
             {
               "mode" : "RAIL",
@@ -264,7 +268,9 @@
                 }
               ],
               "rideHailingEstimate" : null,
-              "accessibilityScore" : null
+              "accessibilityScore" : null,
+              "id": "rO0ABXdBABhTQ0hFRFVMRURfVFJBTlNJVF9MRUdfVjMABUY6NDM5AAoyMDIwLTAyLTAyAAAABQAAAAcAA0Y6QwADRjpEAAA=",
+              "realtimeState": "UPDATED"
             },
             {
               "mode" : "CAR",
@@ -334,11 +340,13 @@
                 },
                 "arrival" : "PT10M"
               },
-              "accessibilityScore" : null
+              "accessibilityScore" : null,
+              "id": null,
+              "realtimeState": null
             }
           ]
         }
       ]
     }
   }
-}
+}

src/test/resources/org/opentripplanner/apis/gtfs/queries/plan-extended.graphql

@@ -151,6 +151,8 @@
           arrival
         }
         accessibilityScore
+        id
+        realtimeState
       }
     }
   }