support showing geolocation on map

pkg/api/map_image_proxies.go

@@ -0,0 +1,41 @@
+package api
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+
+	"github.com/mayswind/ezbookkeeping/pkg/core"
+	"github.com/mayswind/ezbookkeeping/pkg/errs"
+)
+
+const openStreetMapTileImageUrlFormat = "https://tile.openstreetmap.org/%s/%s/%s" // https://tile.openstreetmap.org/{z}/{x}/{y}.png
+
+// MapImageProxy represents map image proxy
+type MapImageProxy struct {
+}
+
+// Initialize a map image proxy singleton instance
+var (
+	MapImages = &MapImageProxy{}
+)
+
+// OpenStreetMapTileImageProxyHandler returns open street map tile image
+func (p *MapImageProxy) OpenStreetMapTileImageProxyHandler(c *core.Context) (*httputil.ReverseProxy, *errs.Error) {
+	director := func(req *http.Request) {
+		zoomLevel := c.Param("zoomLevel")
+		coordinateX := c.Param("coordinateX")
+		fileName := c.Param("fileName")
+
+		imageRawUrl := fmt.Sprintf(openStreetMapTileImageUrlFormat, zoomLevel, coordinateX, fileName)
+		imageUrl, _ := url.Parse(imageRawUrl)
+
+		req.Header.Del("Authorization")
+		req.URL = imageUrl
+		req.RequestURI = req.URL.RequestURI()
+		req.Host = imageUrl.Host
+	}
+
+	return &httputil.ReverseProxy{Director: director}, nil
+}