X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/165993fac96251ec0ec2e881fab40a5db113a282..3455707de557c596b9a17dd3c367264febb63dce:/services/keep-web/webdav.go

diff --git a/services/keep-web/webdav.go b/services/keep-web/webdav.go
index 0a7b7822b2..501c355a73 100644
--- a/services/keep-web/webdav.go
+++ b/services/keep-web/webdav.go
@@ -2,18 +2,22 @@
 //
 // SPDX-License-Identifier: AGPL-3.0
 
-package main
+package keepweb
 
 import (
 	"crypto/rand"
 	"errors"
 	"fmt"
+	"io"
 	prand "math/rand"
-	"net/http"
 	"os"
+	"path"
+	"strings"
 	"sync/atomic"
 	"time"
 
+	"git.arvados.org/arvados.git/sdk/go/arvados"
+
 	"golang.org/x/net/context"
 	"golang.org/x/net/webdav"
 )
@@ -24,50 +28,118 @@ var (
 	errReadOnly           = errors.New("read-only filesystem")
 )
 
-// webdavFS implements a read-only webdav.FileSystem by wrapping
-// http.Filesystem.
+// webdavFS implements a webdav.FileSystem by wrapping an
+// arvados.CollectionFilesystem.
+//
+// Collections don't preserve empty directories, so Mkdir is
+// effectively a no-op, and we need to make parent dirs spring into
+// existence automatically so sequences like "mkcol foo; put foo/bar"
+// work as expected.
 type webdavFS struct {
-	httpfs http.FileSystem
+	collfs  arvados.FileSystem
+	writing bool
+	// webdav PROPFIND reads the first few bytes of each file
+	// whose filename extension isn't recognized, which is
+	// prohibitively expensive: we end up fetching multiple 64MiB
+	// blocks. Avoid this by returning EOF on all reads when
+	// handling a PROPFIND.
+	alwaysReadEOF bool
 }
 
-var _ webdav.FileSystem = &webdavFS{}
+func (fs *webdavFS) makeparents(name string) {
+	if !fs.writing {
+		return
+	}
+	dir, _ := path.Split(name)
+	if dir == "" || dir == "/" {
+		return
+	}
+	dir = dir[:len(dir)-1]
+	fs.makeparents(dir)
+	fs.collfs.Mkdir(dir, 0755)
+}
 
 func (fs *webdavFS) Mkdir(ctx context.Context, name string, perm os.FileMode) error {
-	return errReadOnly
+	if !fs.writing {
+		return errReadOnly
+	}
+	name = strings.TrimRight(name, "/")
+	fs.makeparents(name)
+	return fs.collfs.Mkdir(name, 0755)
 }
 
-func (fs *webdavFS) OpenFile(ctx context.Context, name string, flag int, perm os.FileMode) (webdav.File, error) {
-	f, err := fs.httpfs.Open(name)
-	if err != nil {
-		return nil, err
+func (fs *webdavFS) OpenFile(ctx context.Context, name string, flag int, perm os.FileMode) (f webdav.File, err error) {
+	writing := flag&(os.O_WRONLY|os.O_RDWR|os.O_TRUNC) != 0
+	if writing {
+		fs.makeparents(name)
+	}
+	f, err = fs.collfs.OpenFile(name, flag, perm)
+	if !fs.writing {
+		// webdav module returns 404 on all OpenFile errors,
+		// but returns 405 Method Not Allowed if OpenFile()
+		// succeeds but Write() or Close() fails. We'd rather
+		// have 405. writeFailer ensures Close() fails if the
+		// file is opened for writing *or* Write() is called.
+		var err error
+		if writing {
+			err = errReadOnly
+		}
+		f = writeFailer{File: f, err: err}
 	}
-	return &webdavFile{File: f}, nil
+	if fs.alwaysReadEOF {
+		f = readEOF{File: f}
+	}
+	return
 }
 
 func (fs *webdavFS) RemoveAll(ctx context.Context, name string) error {
-	return errReadOnly
+	return fs.collfs.RemoveAll(name)
 }
 
 func (fs *webdavFS) Rename(ctx context.Context, oldName, newName string) error {
-	return errReadOnly
+	if !fs.writing {
+		return errReadOnly
+	}
+	if strings.HasSuffix(oldName, "/") {
+		// WebDAV "MOVE foo/ bar/" means rename foo to bar.
+		oldName = oldName[:len(oldName)-1]
+		newName = strings.TrimSuffix(newName, "/")
+	}
+	fs.makeparents(newName)
+	return fs.collfs.Rename(oldName, newName)
 }
 
 func (fs *webdavFS) Stat(ctx context.Context, name string) (os.FileInfo, error) {
-	if f, err := fs.httpfs.Open(name); err != nil {
-		return nil, err
-	} else {
-		return f.Stat()
+	if fs.writing {
+		fs.makeparents(name)
+	}
+	return fs.collfs.Stat(name)
+}
+
+type writeFailer struct {
+	webdav.File
+	err error
+}
+
+func (wf writeFailer) Write([]byte) (int, error) {
+	wf.err = errReadOnly
+	return 0, wf.err
+}
+
+func (wf writeFailer) Close() error {
+	err := wf.File.Close()
+	if err != nil {
+		wf.err = err
 	}
+	return wf.err
 }
 
-// webdavFile implements a read-only webdav.File by wrapping
-// http.File. Writes fail.
-type webdavFile struct {
-	http.File
+type readEOF struct {
+	webdav.File
 }
 
-func (f *webdavFile) Write([]byte) (int, error) {
-	return 0, errReadOnly
+func (readEOF) Read(p []byte) (int, error) {
+	return 0, io.EOF
 }
 
 // noLockSystem implements webdav.LockSystem by returning success for