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vendor/github.com/a-h/gemini/filesystem.go

@@ -0,0 +1,128 @@
+package gemini
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"mime"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"github.com/a-h/gemini/log"
+)
+
+type Dir string
+
+// Open implements FileSystem using os.Open, opening files for reading rooted
+// and relative to the directory d.
+func (d Dir) Open(name string) (File, error) {
+	dir := string(d)
+	if dir == "" {
+		dir = "."
+	}
+	fullName := filepath.Join(dir, filepath.FromSlash(path.Clean("/"+name)))
+	return os.Open(fullName)
+}
+
+// A FileSystem implements access to a collection of named files.
+// The elements in a file path are separated by slash ('/', U+002F)
+// characters, regardless of host operating system convention.
+type FileSystem interface {
+	Open(name string) (File, error)
+}
+
+// A File is returned by a FileSystem's Open method and can be
+// served by the FileServer implementation.
+//
+// The methods should behave the same as those on an *os.File.
+type File interface {
+	io.Closer
+	io.Reader
+	Readdir(count int) ([]os.FileInfo, error)
+	Stat() (os.FileInfo, error)
+}
+
+func DirectoryListingHandler(path string, f File) Handler {
+	return HandlerFunc(func(w ResponseWriter, r *Request) {
+		files, err := f.Readdir(-1)
+		if err != nil {
+			log.Warn("DirectoryListingHandler: readdir failed", log.String("reason", err.Error()), log.String("path", r.URL.Path), log.String("url", r.URL.String()))
+			w.SetHeader(CodeTemporaryFailure, "readdir failed")
+			return
+		}
+		sort.Slice(files, func(i, j int) bool { return files[i].Name() < files[j].Name() })
+		w.SetHeader(CodeSuccess, DefaultMIMEType)
+		fmt.Fprintf(w, "# Index of %s\n\n", path)
+		fmt.Fprintln(w, "=> ../")
+		for _, ff := range files {
+			name := ff.Name()
+			if ff.IsDir() {
+				name += "/"
+			}
+			url := url.URL{Path: name}
+			fmt.Fprintf(w, "=> %v\n", url.String())
+		}
+	})
+}
+
+func FileContentHandler(name string, f File) Handler {
+	return HandlerFunc(func(w ResponseWriter, r *Request) {
+		mType := mime.TypeByExtension(path.Ext(name))
+		if mType == "" {
+			mType = DefaultMIMEType
+		}
+		w.SetHeader(CodeSuccess, mType)
+		if _, err := io.Copy(w, f); err != nil {
+			log.Error("FileContentHandler: failed to write file", err, log.String("fileName", name))
+			panic("error returning file contents")
+		}
+	})
+}
+
+func FileSystemHandler(fs FileSystem) Handler {
+	return HandlerFunc(func(w ResponseWriter, r *Request) {
+		if strings.Contains(r.URL.Path, "..") {
+			log.Warn("FileSystemHandler: possible directory traversal attack", log.String("path", r.URL.Path), log.String("url", r.URL.String()))
+			BadRequest(w, r)
+			return
+		}
+		if !strings.HasPrefix(r.URL.Path, "/") {
+			r.URL.Path = "/" + r.URL.Path
+		}
+		f, err := fs.Open(r.URL.Path)
+		if err != nil {
+			if os.IsNotExist(err) {
+				NotFoundHandler().ServeGemini(w, r)
+				return
+			}
+			log.Warn("FileSystemHandler: file open failed", log.String("reason", err.Error()), log.String("path", r.URL.Path), log.String("url", r.URL.String()))
+			w.SetHeader(CodeTemporaryFailure, "file open failed")
+			return
+		}
+		stat, err := f.Stat()
+		if err != nil {
+			log.Warn("FileSystemHandler: file stat failed", log.String("reason", err.Error()), log.String("path", r.URL.Path), log.String("url", r.URL.String()))
+			w.SetHeader(CodeTemporaryFailure, "file stat failed")
+			return
+		}
+		if stat.IsDir() {
+			// Look for index.gmi first before listing contents.
+			if !strings.HasSuffix(r.URL.Path, "/") {
+				RedirectPermanentHandler(r.URL.Path+"/").ServeGemini(w, r)
+				return
+			}
+			index, err := fs.Open(r.URL.Path + "index.gmi")
+			if errors.Is(err, os.ErrNotExist) {
+				DirectoryListingHandler(r.URL.Path, f).ServeGemini(w, r)
+				return
+			}
+			FileContentHandler("index.gmi", index).ServeGemini(w, r)
+			return
+		}
+		FileContentHandler(stat.Name(), f).ServeGemini(w, r)
+	})
+}