go-gemini/fs.go

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package gemini
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import (
"io"
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"mime"
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"os"
"path"
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"path/filepath"
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)
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func init() {
// Add Gemini mime types
mime.AddExtensionType(".gmi", "text/gemini")
mime.AddExtensionType(".gemini", "text/gemini")
}
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// FileServer takes a filesystem and returns a Handler which uses that filesystem.
// The returned Handler sanitizes paths before handling them.
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func FileServer(fsys FS) Responder {
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return fsHandler{fsys}
}
type fsHandler struct {
FS
}
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func (fsh fsHandler) Respond(w *ResponseWriter, r *Request) {
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path := path.Clean(r.URL.Path)
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f, err := fsh.Open(path)
if err != nil {
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NotFound(w, r)
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return
}
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// Detect mimetype
ext := filepath.Ext(path)
mimetype := mime.TypeByExtension(ext)
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w.SetMimetype(mimetype)
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// Copy file to response writer
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io.Copy(w, f)
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}
// TODO: replace with io/fs.FS when available
type FS interface {
Open(name string) (File, error)
}
// TODO: replace with io/fs.File when available
type File interface {
Stat() (os.FileInfo, error)
Read([]byte) (int, error)
Close() error
}
// Dir implements FS using the native filesystem restricted to a specific directory.
type Dir string
// Open tries to open the file with the given name.
// If the file is a directory, it tries to open the index file in that directory.
func (d Dir) Open(name string) (File, error) {
p := path.Join(string(d), name)
f, err := os.OpenFile(p, os.O_RDONLY, 0644)
if err != nil {
return nil, err
}
if stat, err := f.Stat(); err == nil {
if stat.IsDir() {
f, err := os.Open(path.Join(p, "index.gmi"))
if err != nil {
return nil, err
}
stat, err := f.Stat()
if err != nil {
return nil, err
}
if stat.Mode().IsRegular() {
return f, nil
}
return nil, ErrNotAFile
} else if !stat.Mode().IsRegular() {
return nil, ErrNotAFile
}
}
return f, nil
}