Alpha WebDAV support (#37)

webdav/fs.go

@@ -0,0 +1,238 @@
+package webdav
+
+import (
+	"context"
+	"io"
+	"os"
+	"path"
+	"sync"
+	"time"
+
+	"github.com/distribyted/distribyted/fs"
+	"github.com/distribyted/distribyted/iio"
+	"golang.org/x/net/webdav"
+)
+
+var _ webdav.FileSystem = &WebDAV{}
+
+type WebDAV struct {
+	fss []fs.Filesystem
+}
+
+func newFS(mFss map[string][]fs.Filesystem) *WebDAV {
+	for _, fss := range mFss {
+		return &WebDAV{fss: fss}
+	}
+
+	return nil
+}
+
+func (wd *WebDAV) OpenFile(ctx context.Context, name string, flag int, perm os.FileMode) (webdav.File, error) {
+	p := "/" + name
+	// TODO handle flag and permissions
+	f, err := wd.lookupFile(p)
+	if err != nil {
+		return nil, err
+	}
+
+	var dirContent []os.FileInfo
+	if f.IsDir() {
+		dir, err := wd.listDir(p)
+		if err != nil {
+			return nil, err
+		}
+
+		dirContent = dir
+	}
+
+	wdf := newFile(path.Base(p), f, dirContent)
+	return wdf, nil
+}
+
+func (wd *WebDAV) Stat(ctx context.Context, name string) (os.FileInfo, error) {
+	p := "/" + name
+	f, err := wd.lookupFile(p)
+	if err != nil {
+		return nil, err
+	}
+	fi := newFileInfo(name, f.Size(), f.IsDir())
+	return fi, nil
+}
+
+func (wd *WebDAV) Mkdir(ctx context.Context, name string, perm os.FileMode) error {
+	return webdav.ErrNotImplemented
+}
+
+func (wd *WebDAV) RemoveAll(ctx context.Context, name string) error {
+	return webdav.ErrNotImplemented
+}
+
+func (wd *WebDAV) Rename(ctx context.Context, oldName, newName string) error {
+	return webdav.ErrNotImplemented
+}
+
+func (wd *WebDAV) lookupFile(path string) (fs.File, error) {
+	for _, f := range wd.fss {
+		file, err := f.Open(path)
+		if err == os.ErrNotExist {
+			continue
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		if file != nil {
+			return file, nil
+		}
+	}
+
+	return nil, os.ErrNotExist
+}
+
+func (wd *WebDAV) listDir(path string) ([]os.FileInfo, error) {
+	var out []os.FileInfo
+	for _, ifs := range wd.fss {
+		files, err := ifs.ReadDir(path)
+		if err != nil {
+			return nil, err
+		}
+
+		for n, f := range files {
+			out = append(out, newFileInfo(n, f.Size(), f.IsDir()))
+		}
+	}
+
+	return out, nil
+}
+
+var _ webdav.File = &webDAVFile{}
+
+type webDAVFile struct {
+	iio.Reader
+
+	fi os.FileInfo
+
+	mu sync.Mutex
+	// dirPos and pos are protected by mu.
+	dirPos     int
+	pos        int64
+	dirContent []os.FileInfo
+}
+
+func newFile(name string, f fs.File, dir []os.FileInfo) *webDAVFile {
+	return &webDAVFile{
+		fi:         newFileInfo(name, f.Size(), f.IsDir()),
+		dirContent: dir,
+		Reader:     f,
+	}
+}
+
+func (wdf *webDAVFile) Readdir(count int) ([]os.FileInfo, error) {
+	wdf.mu.Lock()
+	defer wdf.mu.Unlock()
+
+	if !wdf.fi.IsDir() {
+		return nil, os.ErrInvalid
+	}
+
+	old := wdf.dirPos
+	if old >= len(wdf.dirContent) {
+		// The os.File Readdir docs say that at the end of a directory,
+		// the error is io.EOF if count > 0 and nil if count <= 0.
+		if count > 0 {
+			return nil, io.EOF
+		}
+		return nil, nil
+	}
+	if count > 0 {
+		wdf.dirPos += count
+		if wdf.dirPos > len(wdf.dirContent) {
+			wdf.dirPos = len(wdf.dirContent)
+		}
+	} else {
+		wdf.dirPos = len(wdf.dirContent)
+		old = 0
+	}
+
+	return wdf.dirContent[old:wdf.dirPos], nil
+}
+
+func (wdf *webDAVFile) Stat() (os.FileInfo, error) {
+	return wdf.fi, nil
+}
+
+func (wdf *webDAVFile) Read(p []byte) (int, error) {
+	wdf.mu.Lock()
+	defer wdf.mu.Unlock()
+
+	n, err := wdf.Reader.ReadAt(p, wdf.pos)
+	wdf.pos += int64(n)
+
+	return n, err
+}
+
+func (wdf *webDAVFile) Seek(offset int64, whence int) (int64, error) {
+	wdf.mu.Lock()
+	defer wdf.mu.Unlock()
+
+	switch whence {
+	case io.SeekStart:
+		wdf.pos = offset
+		break
+	case io.SeekCurrent:
+		wdf.pos = wdf.pos + offset
+		break
+	case io.SeekEnd:
+		wdf.pos = wdf.fi.Size() + offset
+		break
+	}
+
+	return wdf.pos, nil
+}
+
+func (wdf *webDAVFile) Write(p []byte) (n int, err error) {
+	return 0, webdav.ErrNotImplemented
+}
+
+type webDAVFileInfo struct {
+	name  string
+	size  int64
+	isDir bool
+}
+
+func newFileInfo(name string, size int64, isDir bool) *webDAVFileInfo {
+	return &webDAVFileInfo{
+		name:  name,
+		size:  size,
+		isDir: isDir,
+	}
+}
+
+func (wdfi *webDAVFileInfo) Name() string {
+	return wdfi.name
+}
+
+func (wdfi *webDAVFileInfo) Size() int64 {
+	return wdfi.size
+}
+
+func (wdfi *webDAVFileInfo) Mode() os.FileMode {
+	if wdfi.isDir {
+		return 0555 | os.ModeDir
+	}
+
+	return 0555
+}
+
+func (wdfi *webDAVFileInfo) ModTime() time.Time {
+	// TODO fix it
+	return time.Now()
+}
+
+func (wdfi *webDAVFileInfo) IsDir() bool {
+	return wdfi.isDir
+}
+
+func (wdfi *webDAVFileInfo) Sys() interface{} {
+	return nil
+}

webdav/handler.go

@@ -0,0 +1,14 @@
+package webdav
+
+import (
+	"github.com/distribyted/distribyted/fs"
+	"golang.org/x/net/webdav"
+)
+
+func newHandler(fss map[string][]fs.Filesystem) *webdav.Handler {
+	return &webdav.Handler{
+		Prefix:     "/",
+		FileSystem: newFS(fss),
+		LockSystem: webdav.NewMemLS(),
+	}
+}

webdav/http.go

@@ -0,0 +1,14 @@
+package webdav
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/distribyted/distribyted/fs"
+	"github.com/sirupsen/logrus"
+)
+
+func NewWebDAVServer(fss map[string][]fs.Filesystem, port int) error {
+	logrus.WithField("host", fmt.Sprintf("0.0.0.0:%d", port)).Info("starting webDAV server")
+	return http.ListenAndServe(fmt.Sprintf("0.0.0.0:%d", port), newHandler(fss))
+}