You can easily restrict the FileServer
, which is a HttpHandler
by wrapping another HttpHandler
around that. For example, take this wrapper which ONLY allows *.js
files to be served:
func GlobFilterHandler(h http.Handler, pattern string) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
path := r.URL.Path
fileName := filepath.Base(path)
if ok, err := filepath.Match(pattern, fileName); !ok || err != nil {
if err != nil {
log.Println("Error in pattern match:", err)
}
http.NotFound(w, r)
return
}
h.ServeHTTP(w, r)
})
}
func main() {
fileHandler := http.FileServer(http.Dir("/tmp/dtest"))
wrappedHandler := GlobFilterHandler(fileHandler, "*.js")
}
You can find a blog post here which describes the basic idea pretty good.
Another option you have is to extend on http.Dir
and make your own http.FileSystem
implementation which does exactly what you want:
type GlobDir struct {
Dir http.Dir
Pattern string
}
func (d GlobDir) Open(name string) (http.File, error) {
baseName := filepath.Base(name)
if ok, err := filepath.Match(d.Pattern, baseName); !ok || err != nil {
if err != nil {
return nil, err
}
return nil, fmt.Errorf("%s not match GlobDir pattern.", baseName)
}
return d.Dir.Open(name)
}
func main() {
fileHandler := http.FileServer(GlobDir{
Dir: http.Dir("/tmp/dtest"),
Pattern: "*.js",
})
http.ListenAndServe(":8080", fileHandler)
}
The second solution implements the http.FileSystem
interface which is accepted by http.FileServer
.
It checks whether the input file name matches the supplied pattern and then hands control down to the original http.Dir
. This is probably the way you want to go here.