Fix /assets/ loading code

README.md

@@ -195,7 +195,9 @@ For example:
 
 ## Serving static files from a package
 
-The `Mux.pkgfiles` middleware (included in `Mux.defaults`) serves static files under the `assets` directory in any Julia package at `/pkg/<PACKAGE>/`.
+**DEPRECATED**: The `Mux.pkgfiles` middleware (included in `Mux.defaults`) serves static files under the `assets` directory in any Julia package at `/pkg/<PACKAGE>/`.
+
+Please use the package `AssetRegistry.jl` instead to register assets directory.
 
 ## Integrate with WebSocket
 

src/examples/files.jl

@@ -60,14 +60,14 @@ function packagefiles(dirs=true)
                 return dir
             end
         end
-        Pkg.dir(pkg, ASSETS_DIR)
+        Pkg.dir(String(pkg), ASSETS_DIR)  # Pkg.dir doesn't take SubString
     end
 
     branch(req -> validpath(absdir(req), joinpath(req[:path]...), dirs=dirs),
-           req -> (Base.warn_once("""
+           req -> (Base.@warn("""
                         Relying on /pkg/ is now deprecated. Please use the package
                         `AssetRegistry.jl` instead to register assets directory
-                        """);
+                        """, maxlog=1);
                    fresp(joinpath(absdir(req), req[:path]...))))
 end