blobstrex4.go

blobstrex4.go

func handleServe(w http.ResponseWriter, r *http.Request) {
        // Instantiate blobstore reader
        reader := blobstore.NewReader(appengine.NewContext(r), 
                                      appengine.BlobKey(r.FormValue("blobKey")))
        
        lat, lng, _ := getLatLng(reader)
        
        blobstore.Delete(appengine.NewContext(r), 
                         appengine.BlobKey(r.FormValue("blobKey")))
        
        if lat == "" {
                io.WriteString(w, "Sorry but your photo has no GeoTag information...")
                return
        }        

        s := "http://maps.googleapis.com/maps/api/staticmap?zoom=5&size=600x300&maptype=roadmap&center="
        s = s + lat + "," + lng + "&markers=color:blue%7Clabel:I%7C" + lat + "," + lng

        img := "<img src='" + s + "' alt='map' />"
        fmt.Fprint(w, img)
        
}

func getLatLng(f io.Reader) (string, string, error) {
	// Decode parses EXIF-encoded data from f 
	// and returns a queryable Exif object.
	x, err := exif.Decode(f)
	if err != nil {
		return "", "", err
	}
	
        lat, lng, _ := x.LatLong()
        latstr := strconv.FormatFloat(lat, 'f', 15, 64)
        lngstr := strconv.FormatFloat(lng, 'f', 15, 64)
        
	return latstr, lngstr, nil
}