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fs: Refactor

This commit is contained in:
Adnan Maolood 2021-04-21 12:14:56 -04:00
parent 3bc243dd66
commit 507773618b

133
fs.go
View File

@ -29,58 +29,7 @@ type fileServer struct {
fs.FS
}
func (fs fileServer) ServeGemini(ctx context.Context, w ResponseWriter, r *Request) {
serveFile(w, r, fs, path.Clean(r.URL.Path), true)
}
// ServeFile responds to the request with the contents of the named file
// or directory.
//
// If the provided file or directory name is a relative path, it is interpreted
// relative to the current directory and may ascend to parent directories. If
// the provided name is constructed from user input, it should be sanitized
// before calling ServeFile.
//
// As a precaution, ServeFile will reject requests where r.URL.Path contains a
// ".." path element; this protects against callers who might unsafely use
// path.Join on r.URL.Path without sanitizing it and then use that
// path.Join result as the name argument.
//
// As another special case, ServeFile redirects any request where r.URL.Path
// ends in "/index.gmi" to the same path, without the final "index.gmi". To
// avoid such redirects either modify the path or use ServeContent.
//
// Outside of those two special cases, ServeFile does not use r.URL.Path for
// selecting the file or directory to serve; only the file or directory
// provided in the name argument is used.
func ServeFile(w ResponseWriter, r *Request, fsys fs.FS, name string) {
if containsDotDot(r.URL.Path) {
// Too many programs use r.URL.Path to construct the argument to
// serveFile. Reject the request under the assumption that happened
// here and ".." may not be wanted.
// Note that name might not contain "..", for example if code (still
// incorrectly) used path.Join(myDir, r.URL.Path).
w.WriteHeader(StatusBadRequest, "invalid URL path")
return
}
serveFile(w, r, fsys, name, false)
}
func containsDotDot(v string) bool {
if !strings.Contains(v, "..") {
return false
}
for _, ent := range strings.FieldsFunc(v, isSlashRune) {
if ent == ".." {
return true
}
}
return false
}
func isSlashRune(r rune) bool { return r == '/' || r == '\\' }
func serveFile(w ResponseWriter, r *Request, fsys fs.FS, name string, redirect bool) {
func (fsys fileServer) ServeGemini(ctx context.Context, w ResponseWriter, r *Request) {
const indexPage = "/index.gmi"
// Redirect .../index.gmi to .../
@ -89,6 +38,7 @@ func serveFile(w ResponseWriter, r *Request, fsys fs.FS, name string, redirect b
return
}
name := path.Clean(r.URL.Path)
if name == "/" {
name = "."
} else {
@ -109,49 +59,80 @@ func serveFile(w ResponseWriter, r *Request, fsys fs.FS, name string, redirect b
}
// Redirect to canonical path
if redirect {
url := r.URL.Path
if len(name) != 0 {
if stat.IsDir() {
// Add trailing slash
if len(url) != 0 && url[len(url)-1] != '/' {
w.WriteHeader(StatusPermanentRedirect, path.Base(url)+"/")
if name[len(name)-1] != '/' {
w.WriteHeader(StatusPermanentRedirect, path.Base(name)+"/")
return
}
} else {
} else if name[len(name)-1] == '/' {
// Remove trailing slash
if len(url) != 0 && url[len(url)-1] == '/' {
w.WriteHeader(StatusPermanentRedirect, "../"+path.Base(url))
return
}
w.WriteHeader(StatusPermanentRedirect, "../"+path.Base(name))
return
}
}
if stat.IsDir() {
// Redirect if the directory name doesn't end in a slash
url := r.URL.Path
if len(url) != 0 && url[len(url)-1] != '/' {
w.WriteHeader(StatusRedirect, path.Base(url)+"/")
return
}
// Use contents of index.gmi if present
name = path.Join(name, indexPage)
index, err := fsys.Open(name)
if err == nil {
defer index.Close()
istat, err := index.Stat()
if err == nil {
f = index
stat = istat
}
f = index
} else {
// Failed to find index file
dirList(w, f)
return
}
}
if stat.IsDir() {
// Failed to find index file
dirList(w, f)
// Detect mimetype from file extension
ext := path.Ext(name)
mimetype := mime.TypeByExtension(ext)
w.SetMediaType(mimetype)
io.Copy(w, f)
}
// ServeFile responds to the request with the contents of the named file
// or directory. If the provided name is constructed from user input, it should
// be sanitized before calling ServeFile.
func ServeFile(w ResponseWriter, fsys fs.FS, name string) {
const indexPage = "/index.gmi"
// Ensure name is relative
if name == "/" {
name = "."
} else {
name = strings.TrimLeft(name, "/")
}
f, err := fsys.Open(name)
if err != nil {
w.WriteHeader(toGeminiError(err))
return
}
defer f.Close()
stat, err := f.Stat()
if err != nil {
w.WriteHeader(toGeminiError(err))
return
}
if stat.IsDir() {
// Use contents of index file if present
name = path.Join(name, indexPage)
index, err := fsys.Open(name)
if err == nil {
defer index.Close()
f = index
} else {
// Failed to find index file
dirList(w, f)
return
}
}
// Detect mimetype from file extension
ext := path.Ext(name)