问题
If you use the http.FileServer in Go like:
func main() {
port := flag.String("p", "8100", "port to serve on")
directory := flag.String("d", ".", "the directory of static file to host")
flag.Parse()
http.Handle("/", http.FileServer(http.Dir(*directory)))
log.Printf("Serving %s on HTTP port: %s\n", *directory, *port)
log.Fatal(http.ListenAndServe(":"+*port, nil))
}
Then accessing a directory will give you a listing of files. Often this is disabled for web services and instead responds with 404 and I would like this behaviour too.
http.FileServer has no options for this AFAIK and I have seen a proposed way to solve this here https://groups.google.com/forum/#!topic/golang-nuts/bStLPdIVM6w what they do is wrapping the http.FileSystem type and implementing an own Open method. However this doesn't give a 404 when the path is a directory, it just gives a blank page, and it's unclear how to modify it to accomodate this. This is what they do:
type justFilesFilesystem struct {
fs http.FileSystem
}
func (fs justFilesFilesystem) Open(name string) (http.File, error) {
f, err := fs.fs.Open(name)
if err != nil {
return nil, err
}
return neuteredReaddirFile{f}, nil
}
type neuteredReaddirFile struct {
http.File
}
func (f neuteredReaddirFile) Readdir(count int) ([]os.FileInfo, error) {
return nil, nil
}
func main() {
fs := justFilesFilesystem{http.Dir("/tmp/")}
http.ListenAndServe(":8080", http.FileServer(fs))
}
Note: if you make Readdir return nil, os.ErrNotExist
then you get a 500 response with "Error reading directory" - not 404.
Any ideas on how to neatly present a 404 and still preserving the feature of automatically finding an index.html if present?
回答1:
This behavior can be changed if you substitute not a Readdir
method, but the Stat
.
Please take a look at working code below. It supports serving of index.html
files if they are inside of requested directory and returns 404
in case there is no index.html
and it is a directory.
package main
import (
"io"
"net/http"
"os"
)
type justFilesFilesystem struct {
fs http.FileSystem
// readDirBatchSize - configuration parameter for `Readdir` func
readDirBatchSize int
}
func (fs justFilesFilesystem) Open(name string) (http.File, error) {
f, err := fs.fs.Open(name)
if err != nil {
return nil, err
}
return neuteredStatFile{File: f, readDirBatchSize: fs.readDirBatchSize}, nil
}
type neuteredStatFile struct {
http.File
readDirBatchSize int
}
func (e neuteredStatFile) Stat() (os.FileInfo, error) {
s, err := e.File.Stat()
if err != nil {
return nil, err
}
if s.IsDir() {
LOOP:
for {
fl, err := e.File.Readdir(e.readDirBatchSize)
switch err {
case io.EOF:
break LOOP
case nil:
for _, f := range fl {
if f.Name() == "index.html" {
return s, err
}
}
default:
return nil, err
}
}
return nil, os.ErrNotExist
}
return s, err
}
func main() {
fs := justFilesFilesystem{fs: http.Dir("/tmp/"), readDirBatchSize: 2}
fss := http.FileServer(fs)
http.ListenAndServe(":8080", fss)
}
来源:https://stackoverflow.com/questions/49589685/good-way-to-disable-directory-listing-with-http-fileserver-in-go