From 3268102d5a6d450fe92b6565a616a04b453ba3c2 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Wed, 22 Jan 2020 11:43:36 +0100
Subject: [PATCH] webdav: add MOVE support to server

---
 carddav/server.go  |  4 ++++
 fs_local.go        | 32 ++++++++++++++++++++++++++++++++
 internal/server.go | 42 ++++++++++++++++++++++++++++++++++++++++++
 server.go          |  9 +++++++++
 4 files changed, 87 insertions(+)

diff --git a/carddav/server.go b/carddav/server.go
index 38adee5..d6e26f6 100644
--- a/carddav/server.go
+++ b/carddav/server.go
@@ -276,3 +276,7 @@ func (b *backend) Delete(r *http.Request) error {
 func (b *backend) Mkcol(r *http.Request) error {
 	return internal.HTTPErrorf(http.StatusForbidden, "carddav: address book creation unsupported")
 }
+
+func (b *backend) Move(r *http.Request, dest *internal.Href, overwrite bool) (created bool, err error) {
+	panic("TODO")
+}
diff --git a/fs_local.go b/fs_local.go
index 08f50f0..73c5dc8 100644
--- a/fs_local.go
+++ b/fs_local.go
@@ -122,4 +122,36 @@ func (fs LocalFileSystem) Mkdir(name string) error {
 	return os.Mkdir(p, 0755)
 }
 
+func (fs LocalFileSystem) MoveAll(src, dst string, overwrite bool) (created bool, err error) {
+	srcPath, err := fs.localPath(src)
+	if err != nil {
+		return false, err
+	}
+	dstPath, err := fs.localPath(dst)
+	if err != nil {
+		return false, err
+	}
+
+	if _, err := os.Stat(dstPath); err != nil {
+		if !os.IsNotExist(err) {
+			return false, err
+		}
+		created = true
+	} else {
+		if overwrite {
+			if err := os.RemoveAll(dstPath); err != nil {
+				return false, err
+			}
+		} else {
+			return false, os.ErrExist
+		}
+	}
+
+	if err := os.Rename(srcPath, dstPath); err != nil {
+		return false, err
+	}
+
+	return created, nil
+}
+
 var _ FileSystem = LocalFileSystem("")
diff --git a/internal/server.go b/internal/server.go
index 039e1bf..6ed6502 100644
--- a/internal/server.go
+++ b/internal/server.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"mime"
 	"net/http"
+	"net/url"
 	"strings"
 )
 
@@ -81,6 +82,7 @@ type Backend interface {
 	Put(r *http.Request) error
 	Delete(r *http.Request) error
 	Mkcol(r *http.Request) error
+	Move(r *http.Request, dest *Href, overwrite bool) (created bool, err error)
 }
 
 type Handler struct {
@@ -120,6 +122,8 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			if err == nil {
 				w.WriteHeader(http.StatusCreated)
 			}
+		case "MOVE":
+			err = h.handleMove(w, r)
 		default:
 			err = HTTPErrorf(http.StatusMethodNotAllowed, "webdav: unsupported method")
 		}
@@ -254,3 +258,41 @@ func (h *Handler) handleProppatch(w http.ResponseWriter, r *http.Request) error
 	ms := NewMultistatus(*resp)
 	return ServeMultistatus(w, ms)
 }
+
+func parseDestination(h http.Header) (*Href, error) {
+	destHref := h.Get("Destination")
+	if destHref == "" {
+		return nil, HTTPErrorf(http.StatusBadRequest, "webdav: missing Destination header in MOVE request")
+	}
+	dest, err := url.Parse(destHref)
+	if err != nil {
+		return nil, HTTPErrorf(http.StatusBadRequest, "webdav: marlformed Destination header in MOVE request: %v", err)
+	}
+	return (*Href)(dest), nil
+}
+
+func (h *Handler) handleMove(w http.ResponseWriter, r *http.Request) error {
+	dest, err := parseDestination(r.Header)
+	if err != nil {
+		return err
+	}
+
+	overwrite := true
+	if s := r.Header.Get("Overwrite"); s != "" {
+		overwrite, err = ParseOverwrite(s)
+		if err != nil {
+			return err
+		}
+	}
+
+	created, err := h.Backend.Move(r, dest, overwrite)
+	if err != nil {
+		return err
+	}
+	if created {
+		w.WriteHeader(http.StatusCreated)
+	} else {
+		w.WriteHeader(http.StatusNoContent)
+	}
+	return nil
+}
diff --git a/server.go b/server.go
index 1995b2f..693dda2 100644
--- a/server.go
+++ b/server.go
@@ -18,6 +18,7 @@ type FileSystem interface {
 	Create(name string) (io.WriteCloser, error)
 	RemoveAll(name string) error
 	Mkdir(name string) error
+	MoveAll(name, dest string, overwrite bool) (created bool, err error)
 }
 
 // Handler handles WebDAV HTTP requests. It can be used to create a WebDAV
@@ -213,3 +214,11 @@ func (b *backend) Mkcol(r *http.Request) error {
 	}
 	return err
 }
+
+func (b *backend) Move(r *http.Request, dest *internal.Href, overwrite bool) (created bool, err error) {
+	created, err = b.FileSystem.MoveAll(r.URL.Path, dest.Path, overwrite)
+	if os.IsExist(err) {
+		return false, &internal.HTTPError{http.StatusPreconditionFailed, err}
+	}
+	return created, err
+}