gpx-utils/pkg/cafes/ctccam.go
Ray Miller f09fd9a418 Set a custom user-agent header when fetching CTC Cambridge stops data
This is required because their hosting provider is returning a 503
"service unavailable" when the user agent is Go-http-client.
2024-04-17 17:19:42 +01:00

76 lines
1.9 KiB
Go

package cafes
import (
"encoding/xml"
"fmt"
"io"
"log"
"net/http"
"github.com/dhconnelly/rtreego"
"github.com/fofanov/go-osgb"
)
const ctcCamWaypointsUrl = "https://ctccambridge.org.uk/ctccambridge-waypoints.gpx"
type Waypoint struct {
Lat float64 `xml:"lat,attr"`
Lon float64 `xml:"lon,attr"`
Name string `xml:"name"`
Url string `xml:"url"`
}
type Waypoints struct {
Waypoints []Waypoint `xml:"wpt"`
}
func BuildCtcCamIndex(r io.Reader) (*rtreego.Rtree, error) {
dec := xml.NewDecoder(r)
var wpt Waypoints
err := dec.Decode(&wpt)
if err != nil {
return nil, err
}
trans, err := osgb.NewOSTN15Transformer()
if err != nil {
return nil, err
}
stops := make([]rtreego.Spatial, len(wpt.Waypoints))
for i, w := range wpt.Waypoints {
gpsCoord := osgb.NewETRS89Coord(w.Lon, w.Lat, 0)
ngCoord, err := trans.ToNationalGrid(gpsCoord)
if err != nil {
return nil, fmt.Errorf("Error translating coordinates %v: %v", gpsCoord, err)
}
stops[i] = &RefreshmentStop{
Name: w.Name,
Url: w.Url,
Easting: ngCoord.Easting,
Northing: ngCoord.Northing,
}
}
return rtreego.NewTree(2, 25, 50, stops...), nil
}
func FetchCtcCamIndex() (*rtreego.Rtree, error) {
log.Printf("Fetching %s", ctcCamWaypointsUrl)
req, err := http.NewRequest(http.MethodGet, ctcCamWaypointsUrl, nil)
if err != nil {
return nil, fmt.Errorf("error constructing waypoints request: %v", err)
}
req.Header.Set("User-Agent", "gpx-utils")
res, err := http.DefaultClient.Do(req)
if err != nil {
return nil, fmt.Errorf("error getting %s: %v", ctcCamWaypointsUrl, err)
}
defer res.Body.Close()
if res.StatusCode != http.StatusOK {
return nil, fmt.Errorf("unexpected status fetching %s: %s", ctcCamWaypointsUrl, res.Status)
}
index, err := BuildCtcCamIndex(res.Body)
if err != nil {
return nil, fmt.Errorf("error building CTC Cambridge stops index: %v", err)
}
log.Printf("Loaded %d CTC Cambridge stops", index.Size())
return index, nil
}