feat: Remove geometry and properties from GET /datasets/{id} endpoint, new endpoint for download cog file

internal/transport/http/dataset_handler.go

@@ -2,6 +2,7 @@ package http
 
 import (
 	"encoding/json"
+	"errors"
 	"io"
 	"net/http"
 	"strconv"
@@ -37,6 +38,7 @@ func (h *DatasetHandler) Register(r chi.Router) {
 	r.Post("/", h.upload)
 	r.Get("/{id}", h.get)
 	r.Get("/{id}.geojson", h.geojson)
+	r.Get("/{id}.cog", h.cog)
 	r.Get("/{id}/status", h.status)
 	r.Get("/{id}/download", h.download)
 	r.Post("/{id}/mapping", h.mapping)
@@ -324,6 +326,44 @@ func (h *DatasetHandler) geojson(w http.ResponseWriter, r *http.Request) {
 	_, _ = w.Write(fc)
 }
 
+// cog streams the raster dataset's Cloud-Optimized GeoTIFF. It responds 422 for
+// a non-raster dataset and 409 when the raster's COG has not been produced yet.
+func (h *DatasetHandler) cog(w http.ResponseWriter, r *http.Request) {
+	id, ok := parseUUIDParam(w, r, "id")
+	if !ok {
+		return
+	}
+	dataset, obj, err := h.svc.COG(r.Context(), id)
+	if err != nil {
+		switch {
+		case errors.Is(err, service.ErrNotRaster):
+			httputil.WriteError(w, http.StatusUnprocessableEntity, "dataset is not a raster")
+		case errors.Is(err, service.ErrCOGNotReady):
+			httputil.WriteError(w, http.StatusConflict, "cog is not ready")
+		default:
+			respondDomainError(w, err)
+		}
+		return
+	}
+	defer obj.Close()
+
+	w.Header().Set("Content-Type", "image/tiff")
+	w.Header().Set("Content-Disposition", `inline; filename="`+cogFilename(dataset.Filename)+`"`)
+	w.WriteHeader(http.StatusOK)
+	if _, err := io.Copy(w, obj); err != nil {
+		// Headers are already sent; nothing useful to return to the client.
+		return
+	}
+}
+
+// cogFilename derives a .cog.tif download name from the source filename.
+func cogFilename(filename string) string {
+	if i := strings.LastIndex(filename, "."); i > 0 {
+		filename = filename[:i]
+	}
+	return filename + ".cog.tif"
+}
+
 func (h *DatasetHandler) download(w http.ResponseWriter, r *http.Request) {
 	id, ok := parseUUIDParam(w, r, "id")
 	if !ok {