api get transport stations endpoint

Author: roaldchristesen

api/get_transport_stations.go

@@ -0,0 +1,109 @@
+package api
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/sndcds/grains/grains_api"
+)
+
+type TransportStationResult struct {
+	Id                  int      `json:"id"`
+	Name                *string  `json:"name,omitempty"`
+	Lon                 *float64 `json:"lon,omitempty"`
+	Lat                 *float64 `json:"lat,omitempty"`
+	GtfsStationCode     *string  `json:"gtfs_station_code,omitempty"`
+	City                *string  `json:"city,omitempty"`
+	Country             *string  `json:"country,omitempty"`
+	GtfsParentStation   *string  `json:"gtfs_parent_station,omitempty"`
+	GtfsWheelchairBoard *int     `json:"gtfs_wheelchair_boarding,omitempty"`
+	GtfsZoneId          *string  `json:"gtfs_zone_id,omitempty"`
+	DistanceMeters      float64  `json:"distance_m"` // calculated
+}
+
+func (h *ApiHandler) GetTransportStations(gc *gin.Context) {
+	ctx := gc.Request.Context()
+	apiRequest := grains_api.NewRequest(gc, "transport-stations")
+
+	// Parse query params
+	latStr := gc.Query("lat")
+	lonStr := gc.Query("lon")
+	radius := GetContextParamIntDefault(gc, "radius", 5000)
+	apiRequest.SetMeta("radius", radius)
+
+	if latStr == "" || lonStr == "" {
+		apiRequest.Error(http.StatusBadRequest, "lat and lon are required")
+		return
+	}
+	apiRequest.SetMeta("lat", latStr)
+	apiRequest.SetMeta("lon", lonStr)
+
+	lat, err := strconv.ParseFloat(latStr, 64)
+	if err != nil {
+		apiRequest.Error(http.StatusBadRequest, "invalid lat")
+		return
+	}
+	lon, err := strconv.ParseFloat(lonStr, 64)
+	if err != nil {
+		apiRequest.Error(http.StatusBadRequest, "invalid lon")
+		return
+	}
+
+	// PostgreSQL query with ST_DWithin and distance
+	query := `
+	SELECT
+		id,
+		name,
+		gtfs_station_code,
+		city,
+		country,
+		gtfs_parent_station,
+		gtfs_wheelchair_boarding,
+		gtfs_zone_id,
+		ST_X(geo_pos) AS lon,
+		ST_Y(geo_pos) AS lat,
+		ST_Distance(
+			geo_pos::geography,
+			ST_SetSRID(ST_MakePoint($1, $2), 4326)::geography
+		) AS distance_m
+	FROM uranus.transport_station
+	WHERE ST_DWithin(
+		geo_pos::geography,
+		ST_SetSRID(ST_MakePoint($1, $2), 4326)::geography,
+		$3
+	)
+	ORDER BY distance_m;
+	`
+
+	rows, err := h.DbPool.Query(ctx, query, lon, lat, radius)
+	if err != nil {
+		apiRequest.InternalServerError()
+		return
+	}
+	defer rows.Close()
+
+	var results []TransportStationResult
+	for rows.Next() {
+		var s TransportStationResult
+		if err := rows.Scan(
+			&s.Id,
+			&s.Name,
+			&s.GtfsStationCode,
+			&s.City,
+			&s.Country,
+			&s.GtfsParentStation,
+			&s.GtfsWheelchairBoard,
+			&s.GtfsZoneId,
+			&s.Lon,
+			&s.Lat,
+			&s.DistanceMeters,
+		); err != nil {
+			apiRequest.InternalServerError()
+			return
+		}
+		results = append(results, s)
+	}
+
+	apiRequest.Success(http.StatusOK, results, "")
+}

uranus-api.go

@@ -112,6 +112,8 @@ func main() {
 
 	publicRoute.GET("/venue/:venueId", apiHandler.GetVenue)
 
+	publicRoute.GET("/transport/stations", apiHandler.GetTransportStations)
+
 	publicRoute.GET("/user/:userId/avatar/:size", apiHandler.GetUserAvatar) // TODO: check!
 	publicRoute.GET("/user/:userId/avatar", apiHandler.GetUserAvatar)       // TODO: check!