// An HTTP handler which returns a tileset's `layer.json` file
func LayerHandler(store stores.Storer) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
var (
err error
layer []byte
)
defer func() {
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
log.Err(err.Error())
}
}()
vars := mux.Vars(r)
// Try and get a `layer.json` from the stores
layer, err = store.Layer(vars["tileset"])
if err == stores.ErrNoItem {
err = nil // don't persist this error
if store.TilesetStatus(vars["tileset"]) == stores.NOT_FOUND {
http.Error(w,
fmt.Errorf("The tileset `%s` does not exist", vars["tileset"]).Error(),
http.StatusNotFound)
return
}
// the directory exists: send the default `layer.json`
layer = []byte(`{
"tilejson": "2.1.0",
"format": "heightmap-1.0",
"version": "1.0.0",
"scheme": "tms",
"tiles": ["{z}/{x}/{y}.terrain"]
}`)
} else if err != nil {
return
}
headers := w.Header()
headers.Set("Content-Type", "application/json")
w.Write(layer)
}
}
// An HTTP handler which returns a terrain tile resource
func TerrainHandler(store stores.Storer) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
var (
t stores.Terrain
err error
)
defer func() {
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
log.Err(err.Error())
}
}()
// get the tile coordinate from the URL
vars := mux.Vars(r)
err = t.ParseCoord(vars["x"], vars["y"], vars["z"])
if err != nil {
return
}
// Try and get a tile from the store
err = store.Tile(vars["tileset"], &t)
if err == stores.ErrNoItem {
if store.TilesetStatus(vars["tileset"]) == stores.NOT_FOUND {
err = nil
http.Error(w,
fmt.Errorf("The tileset `%s` does not exist", vars["tileset"]).Error(),
http.StatusNotFound)
return
}
if t.IsRoot() {
// serve up a blank tile as it is a missing root tile
data, err := assets.Asset("data/smallterrain-blank.terrain")
if err != nil {
return
} else {
err = t.UnmarshalBinary(data)
if err != nil {
return
}
}
} else {
err = nil
http.Error(w, errors.New("The terrain tile does not exist").Error(), http.StatusNotFound)
return
}
} else if err != nil {
return
}
body, err := t.MarshalBinary()
if err != nil {
return
}
// send the tile to the client
headers := w.Header()
headers.Set("Content-Type", "application/octet-stream")
headers.Set("Content-Encoding", "gzip")
headers.Set("Content-Disposition", "attachment;filename="+vars["y"]+".terrain")
w.Write(body)
}
}