Add error returning for missing error output paths

Co-Authored-By: Captain ALM <captainalm@captainalm.com>

.gitignore

@@ -12,3 +12,4 @@
 
 # Project-local glide cache, RE: https://github.com/Masterminds/glide/issues/736
 .glide/
+.idea/

README.md

@@ -1,7 +1,6 @@
 # go-webdav
 
 [![Go Reference](https://pkg.go.dev/badge/github.com/emersion/go-webdav.svg)](https://pkg.go.dev/github.com/emersion/go-webdav)
-[![builds.sr.ht status](https://builds.sr.ht/~emersion/go-webdav/commits/master.svg)](https://builds.sr.ht/~emersion/go-webdav/commits/master?)
 
 A Go library for [WebDAV], [CalDAV] and [CardDAV].
 

caldav/server.go

@@ -465,12 +465,10 @@ func (b *backend) propFindRoot(ctx context.Context, propfind *internal.PropFind)
 	}
 
 	props := map[xml.Name]internal.PropFindFunc{
-		internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: principalPath}}, nil
-		},
-		internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return internal.NewResourceType(internal.CollectionName), nil
-		},
+		internal.CurrentUserPrincipalName: internal.PropFindValue(&internal.CurrentUserPrincipal{
+			Href: internal.Href{Path: principalPath},
+		}),
+		internal.ResourceTypeName: internal.PropFindValue(internal.NewResourceType(internal.CollectionName)),
 	}
 	return internal.NewPropFindResponse(principalPath, propfind, props)
 }
@@ -486,15 +484,13 @@ func (b *backend) propFindUserPrincipal(ctx context.Context, propfind *internal.
 	}
 
 	props := map[xml.Name]internal.PropFindFunc{
-		internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: principalPath}}, nil
-		},
-		calendarHomeSetName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &calendarHomeSet{Href: internal.Href{Path: homeSetPath}}, nil
-		},
-		internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return internal.NewResourceType(internal.CollectionName), nil
-		},
+		internal.CurrentUserPrincipalName: internal.PropFindValue(&internal.CurrentUserPrincipal{
+			Href: internal.Href{Path: principalPath},
+		}),
+		calendarHomeSetName: internal.PropFindValue(&calendarHomeSet{
+			Href: internal.Href{Path: homeSetPath},
+		}),
+		internal.ResourceTypeName: internal.PropFindValue(internal.NewResourceType(internal.CollectionName)),
 	}
 	return internal.NewPropFindResponse(principalPath, propfind, props)
 }
@@ -511,12 +507,10 @@ func (b *backend) propFindHomeSet(ctx context.Context, propfind *internal.PropFi
 
 	// TODO anything else to return here?
 	props := map[xml.Name]internal.PropFindFunc{
-		internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: principalPath}}, nil
-		},
-		internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return internal.NewResourceType(internal.CollectionName), nil
-		},
+		internal.CurrentUserPrincipalName: internal.PropFindValue(&internal.CurrentUserPrincipal{
+			Href: internal.Href{Path: principalPath},
+		}),
+		internal.ResourceTypeName: internal.PropFindValue(internal.NewResourceType(internal.CollectionName)),
 	}
 	return internal.NewPropFindResponse(homeSetPath, propfind, props)
 }
@@ -530,19 +524,15 @@ func (b *backend) propFindCalendar(ctx context.Context, propfind *internal.PropF
 			}
 			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: path}}, nil
 		},
-		internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return internal.NewResourceType(internal.CollectionName, calendarName), nil
-		},
-		calendarDescriptionName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &calendarDescription{Description: cal.Description}, nil
-		},
-		supportedCalendarDataName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &supportedCalendarData{
-				Types: []calendarDataType{
-					{ContentType: ical.MIMEType, Version: "2.0"},
-				},
-			}, nil
-		},
+		internal.ResourceTypeName: internal.PropFindValue(internal.NewResourceType(internal.CollectionName, calendarName)),
+		calendarDescriptionName: internal.PropFindValue(&calendarDescription{
+			Description: cal.Description,
+		}),
+		supportedCalendarDataName: internal.PropFindValue(&supportedCalendarData{
+			Types: []calendarDataType{
+				{ContentType: ical.MIMEType, Version: "2.0"},
+			},
+		}),
 		supportedCalendarComponentSetName: func(*internal.RawXMLValue) (interface{}, error) {
 			components := []comp{}
 			if cal.SupportedComponentSet != nil {
@@ -559,19 +549,22 @@ func (b *backend) propFindCalendar(ctx context.Context, propfind *internal.PropF
 	}
 
 	if cal.Name != "" {
-		props[internal.DisplayNameName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.DisplayName{Name: cal.Name}, nil
-		}
+		props[internal.DisplayNameName] = internal.PropFindValue(&internal.DisplayName{
+			Name: cal.Name,
+		})
 	}
 	if cal.Description != "" {
-		props[calendarDescriptionName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &calendarDescription{Description: cal.Description}, nil
-		}
+		props[calendarDescriptionName] = internal.PropFindValue(&calendarDescription{
+			Description: cal.Description,
+		})
 	}
 	if cal.MaxResourceSize > 0 {
-		props[maxResourceSizeName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &maxResourceSize{Size: cal.MaxResourceSize}, nil
-		}
+		props[maxResourceSizeName] = internal.PropFindValue(&maxResourceSize{
+			Size: cal.MaxResourceSize,
+		})
+	}
+	props[internal.CurrentUserPrivilegeSetName] = func(*internal.RawXMLValue) (interface{}, error) {
+		return &internal.CurrentUserPrivilegeSet{Privilege: internal.NewAllPrivileges()}, nil
 	}
 
 	// TODO: CALDAV:calendar-timezone, CALDAV:supported-calendar-component-set, CALDAV:min-date-time, CALDAV:max-date-time, CALDAV:max-instances, CALDAV:max-attendees-per-instance
@@ -612,9 +605,9 @@ func (b *backend) propFindCalendarObject(ctx context.Context, propfind *internal
 			}
 			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: path}}, nil
 		},
-		internal.GetContentTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetContentType{Type: ical.MIMEType}, nil
-		},
+		internal.GetContentTypeName: internal.PropFindValue(&internal.GetContentType{
+			Type: ical.MIMEType,
+		}),
 		// TODO: calendar-data can only be used in REPORT requests
 		calendarDataName: func(*internal.RawXMLValue) (interface{}, error) {
 			var buf bytes.Buffer
@@ -627,20 +620,20 @@ func (b *backend) propFindCalendarObject(ctx context.Context, propfind *internal
 	}
 
 	if co.ContentLength > 0 {
-		props[internal.GetContentLengthName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetContentLength{Length: co.ContentLength}, nil
-		}
+		props[internal.GetContentLengthName] = internal.PropFindValue(&internal.GetContentLength{
+			Length: co.ContentLength,
+		})
 	}
 	if !co.ModTime.IsZero() {
-		props[internal.GetLastModifiedName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetLastModified{LastModified: internal.Time(co.ModTime)}, nil
-		}
+		props[internal.GetLastModifiedName] = internal.PropFindValue(&internal.GetLastModified{
+			LastModified: internal.Time(co.ModTime),
+		})
 	}
 
 	if co.ETag != "" {
-		props[internal.GetETagName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetETag{ETag: internal.ETag(co.ETag)}, nil
-		}
+		props[internal.GetETagName] = internal.PropFindValue(&internal.GetETag{
+			ETag: internal.ETag(co.ETag),
+		})
 	}
 
 	return internal.NewPropFindResponse(co.Path, propfind, props)

carddav/server.go

@@ -431,12 +431,10 @@ func (b *backend) propFindRoot(ctx context.Context, propfind *internal.PropFind)
 	}
 
 	props := map[xml.Name]internal.PropFindFunc{
-		internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: principalPath}}, nil
-		},
-		internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return internal.NewResourceType(internal.CollectionName), nil
-		},
+		internal.CurrentUserPrincipalName: internal.PropFindValue(&internal.CurrentUserPrincipal{
+			Href: internal.Href{Path: principalPath},
+		}),
+		internal.ResourceTypeName: internal.PropFindValue(internal.NewResourceType(internal.CollectionName)),
 	}
 	return internal.NewPropFindResponse(principalPath, propfind, props)
 }
@@ -446,30 +444,24 @@ func (b *backend) propFindUserPrincipal(ctx context.Context, propfind *internal.
 	if err != nil {
 		return nil, err
 	}
-	homeSetPath, err := b.Backend.AddressBookHomeSetPath(ctx)
-	if err != nil {
-		return nil, err
-	}
 
 	props := map[xml.Name]internal.PropFindFunc{
-		internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: principalPath}}, nil
-		},
+		internal.CurrentUserPrincipalName: internal.PropFindValue(&internal.CurrentUserPrincipal{
+			Href: internal.Href{Path: principalPath},
+		}),
 		addressBookHomeSetName: func(*internal.RawXMLValue) (interface{}, error) {
+			homeSetPath, err := b.Backend.AddressBookHomeSetPath(ctx)
+			if err != nil {
+				return nil, err
+			}
 			return &addressbookHomeSet{Href: internal.Href{Path: homeSetPath}}, nil
 		},
-		internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return internal.NewResourceType(internal.CollectionName), nil
-		},
+		internal.ResourceTypeName: internal.PropFindValue(internal.NewResourceType(internal.CollectionName)),
 	}
 	return internal.NewPropFindResponse(principalPath, propfind, props)
 }
 
 func (b *backend) propFindHomeSet(ctx context.Context, propfind *internal.PropFind) (*internal.Response, error) {
-	principalPath, err := b.Backend.CurrentUserPrincipal(ctx)
-	if err != nil {
-		return nil, err
-	}
 	homeSetPath, err := b.Backend.AddressBookHomeSetPath(ctx)
 	if err != nil {
 		return nil, err
@@ -478,11 +470,13 @@ func (b *backend) propFindHomeSet(ctx context.Context, propfind *internal.PropFi
 	// TODO anything else to return here?
 	props := map[xml.Name]internal.PropFindFunc{
 		internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
+			principalPath, err := b.Backend.CurrentUserPrincipal(ctx)
+			if err != nil {
+				return nil, err
+			}
 			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: principalPath}}, nil
 		},
-		internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return internal.NewResourceType(internal.CollectionName), nil
-		},
+		internal.ResourceTypeName: internal.PropFindValue(internal.NewResourceType(internal.CollectionName)),
 	}
 	return internal.NewPropFindResponse(homeSetPath, propfind, props)
 }
@@ -496,33 +490,32 @@ func (b *backend) propFindAddressBook(ctx context.Context, propfind *internal.Pr
 			}
 			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: path}}, nil
 		},
-		internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return internal.NewResourceType(internal.CollectionName, addressBookName), nil
-		},
-		supportedAddressDataName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &supportedAddressData{
-				Types: []addressDataType{
-					{ContentType: vcard.MIMEType, Version: "3.0"},
-					{ContentType: vcard.MIMEType, Version: "4.0"},
-				},
-			}, nil
-		},
+		internal.ResourceTypeName: internal.PropFindValue(internal.NewResourceType(internal.CollectionName, addressBookName)),
+		supportedAddressDataName: internal.PropFindValue(&supportedAddressData{
+			Types: []addressDataType{
+				{ContentType: vcard.MIMEType, Version: "3.0"},
+				{ContentType: vcard.MIMEType, Version: "4.0"},
+			},
+		}),
 	}
 
 	if ab.Name != "" {
-		props[internal.DisplayNameName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.DisplayName{Name: ab.Name}, nil
-		}
+		props[internal.DisplayNameName] = internal.PropFindValue(&internal.DisplayName{
+			Name: ab.Name,
+		})
 	}
 	if ab.Description != "" {
-		props[addressBookDescriptionName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &addressbookDescription{Description: ab.Description}, nil
-		}
+		props[addressBookDescriptionName] = internal.PropFindValue(&addressbookDescription{
+			Description: ab.Description,
+		})
 	}
 	if ab.MaxResourceSize > 0 {
-		props[maxResourceSizeName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &maxResourceSize{Size: ab.MaxResourceSize}, nil
-		}
+		props[maxResourceSizeName] = internal.PropFindValue(&maxResourceSize{
+			Size: ab.MaxResourceSize,
+		})
+	}
+	props[internal.CurrentUserPrivilegeSetName] = func(*internal.RawXMLValue) (interface{}, error) {
+		return &internal.CurrentUserPrivilegeSet{Privilege: internal.NewAllPrivileges()}, nil
 	}
 
 	return internal.NewPropFindResponse(ab.Path, propfind, props)
@@ -561,9 +554,9 @@ func (b *backend) propFindAddressObject(ctx context.Context, propfind *internal.
 			}
 			return &internal.CurrentUserPrincipal{Href: internal.Href{Path: path}}, nil
 		},
-		internal.GetContentTypeName: func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetContentType{Type: vcard.MIMEType}, nil
-		},
+		internal.GetContentTypeName: internal.PropFindValue(&internal.GetContentType{
+			Type: vcard.MIMEType,
+		}),
 		// TODO: address-data can only be used in REPORT requests
 		addressDataName: func(*internal.RawXMLValue) (interface{}, error) {
 			var buf bytes.Buffer
@@ -576,20 +569,20 @@ func (b *backend) propFindAddressObject(ctx context.Context, propfind *internal.
 	}
 
 	if ao.ContentLength > 0 {
-		props[internal.GetContentLengthName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetContentLength{Length: ao.ContentLength}, nil
-		}
+		props[internal.GetContentLengthName] = internal.PropFindValue(&internal.GetContentLength{
+			Length: ao.ContentLength,
+		})
 	}
 	if !ao.ModTime.IsZero() {
-		props[internal.GetLastModifiedName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetLastModified{LastModified: internal.Time(ao.ModTime)}, nil
-		}
+		props[internal.GetLastModifiedName] = internal.PropFindValue(&internal.GetLastModified{
+			LastModified: internal.Time(ao.ModTime),
+		})
 	}
 
 	if ao.ETag != "" {
-		props[internal.GetETagName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetETag{ETag: internal.ETag(ao.ETag)}, nil
-		}
+		props[internal.GetETagName] = internal.PropFindValue(&internal.GetETag{
+			ETag: internal.ETag(ao.ETag),
+		})
 	}
 
 	return internal.NewPropFindResponse(ao.Path, propfind, props)

fs_local.go

@@ -114,15 +114,31 @@ func (fs LocalFileSystem) ReadDir(ctx context.Context, name string, recursive bo
 	return l, errFromOS(err)
 }
 
-func (fs LocalFileSystem) Create(ctx context.Context, name string, body io.ReadCloser) (*FileInfo, bool, error) {
+func (fs LocalFileSystem) Create(ctx context.Context, name string, body io.ReadCloser, opts *CreateOptions) (fi *FileInfo, created bool, err error) {
 	p, err := fs.localPath(name)
 	if err != nil {
 		return nil, false, err
 	}
-	created := false
-	fi, _ := fs.Stat(ctx, name)
-	if fi == nil {
-		created = true
+	fi, _ = fs.Stat(ctx, name)
+	created = fi == nil
+	etag := ""
+	if fi != nil {
+		etag = fi.ETag
+	}
+
+	if opts.IfMatch.IsSet() {
+		if ok, err := opts.IfMatch.MatchETag(etag); err != nil {
+			return nil, false, NewHTTPError(http.StatusBadRequest, err)
+		} else if !ok {
+			return nil, false, NewHTTPError(http.StatusPreconditionFailed, fmt.Errorf("If-Match condition failed"))
+		}
+	}
+	if opts.IfNoneMatch.IsSet() {
+		if ok, err := opts.IfNoneMatch.MatchETag(etag); err != nil {
+			return nil, false, NewHTTPError(http.StatusBadRequest, err)
+		} else if ok {
+			return nil, false, NewHTTPError(http.StatusPreconditionFailed, fmt.Errorf("If-None-Match condition failed"))
+		}
 	}
 
 	wc, err := os.Create(p)
@@ -132,9 +148,11 @@ func (fs LocalFileSystem) Create(ctx context.Context, name string, body io.ReadC
 	defer wc.Close()
 
 	if _, err := io.Copy(wc, body); err != nil {
+		os.Remove(p)
 		return nil, false, err
 	}
 	if err := wc.Close(); err != nil {
+		os.Remove(p)
 		return nil, false, err
 	}
 

internal/elements.go

@@ -1,6 +1,7 @@
 package internal
 
 import (
+	"encoding/base64"
 	"encoding/xml"
 	"errors"
 	"fmt"
@@ -22,6 +23,8 @@ var (
 	GetETagName          = xml.Name{Namespace, "getetag"}
 
 	CurrentUserPrincipalName = xml.Name{Namespace, "current-user-principal"}
+
+	CurrentUserPrivilegeSetName = xml.Name{Namespace, "current-user-privilege-set"}
 )
 
 type Status struct {
@@ -351,7 +354,7 @@ type Time time.Time
 func (t *Time) UnmarshalText(b []byte) error {
 	tt, err := http.ParseTime(string(b))
 	if err != nil {
-		return err
+		return errors.New(err.Error() + " : time_data : " + base64.StdEncoding.EncodeToString(b))
 	}
 	*t = Time(tt)
 	return nil
@@ -417,6 +420,30 @@ type CurrentUserPrincipal struct {
 	Unauthenticated *struct{} `xml:"unauthenticated,omitempty"`
 }
 
+type CurrentUserPrivilegeSet struct {
+	XMLName   xml.Name    `xml:"DAV: current-user-privilege-set"`
+	Privilege []Privilege `xml:"privilege"`
+}
+
+type Privilege struct {
+	XMLName         xml.Name  `xml:"DAV: privilege"`
+	Read            *struct{} `xml:"DAV: read,omitempty"`
+	All             *struct{} `xml:"DAV: all,omitempty"`
+	Write           *struct{} `xml:"DAV: write,omitempty"`
+	WriteProperties *struct{} `xml:"DAV: write-properties,omitempty"`
+	WriteContent    *struct{} `xml:"DAV: write-content,omitempty"`
+}
+
+func NewAllPrivileges() []Privilege {
+	return []Privilege{
+		{Read: &struct{}{}},
+		{All: &struct{}{}},
+		{Write: &struct{}{}},
+		{WriteProperties: &struct{}{}},
+		{WriteContent: &struct{}{}},
+	}
+}
+
 // https://tools.ietf.org/html/rfc4918#section-14.19
 type PropertyUpdate struct {
 	XMLName xml.Name `xml:"DAV: propertyupdate"`

internal/server.go

@@ -125,7 +125,7 @@ func (h *Handler) handleOptions(w http.ResponseWriter, r *http.Request) error {
 
 	w.Header().Add("DAV", strings.Join(caps, ", "))
 	w.Header().Add("Allow", strings.Join(allow, ", "))
-	w.WriteHeader(http.StatusNoContent)
+	w.WriteHeader(http.StatusOK)
 	return nil
 }
 
@@ -162,13 +162,17 @@ func (h *Handler) handlePropfind(w http.ResponseWriter, r *http.Request) error {
 
 type PropFindFunc func(raw *RawXMLValue) (interface{}, error)
 
+func PropFindValue(value interface{}) PropFindFunc {
+	return func(raw *RawXMLValue) (interface{}, error) {
+		return value, nil
+	}
+}
+
 func NewPropFindResponse(path string, propfind *PropFind, props map[xml.Name]PropFindFunc) (*Response, error) {
 	resp := &Response{Hrefs: []Href{Href{Path: path}}}
 
 	if _, ok := props[ResourceTypeName]; !ok {
-		props[ResourceTypeName] = func(*RawXMLValue) (interface{}, error) {
-			return NewResourceType(), nil
-		}
+		props[ResourceTypeName] = PropFindValue(NewResourceType())
 	}
 
 	if propfind.PropName != nil {
@@ -187,9 +191,8 @@ func NewPropFindResponse(path string, propfind *PropFind, props map[xml.Name]Pro
 
 			code := http.StatusOK
 			if err != nil {
-				// TODO: don't throw away error message here
 				code = HTTPErrorFromError(err).Code
-				val = emptyVal
+				val = NewRawXMLElement(xmlName, []xml.Attr{{Name: xml.Name{Space: "ERR", Local: "Error"}, Value: err.Error()}}, nil)
 			}
 
 			if err := resp.EncodeProp(code, val); err != nil {
@@ -210,8 +213,8 @@ func NewPropFindResponse(path string, propfind *PropFind, props map[xml.Name]Pro
 			f, ok := props[xmlName]
 			if ok {
 				if v, err := f(&raw); err != nil {
-					// TODO: don't throw away error message here
 					code = HTTPErrorFromError(err).Code
+					val = NewRawXMLElement(xmlName, []xml.Attr{{Name: xml.Name{Space: "ERR", Local: "Error"}, Value: err.Error()}}, nil)
 				} else {
 					code = http.StatusOK
 					val = v

server.go

@@ -17,7 +17,7 @@ type FileSystem interface {
 	Open(ctx context.Context, name string) (io.ReadCloser, error)
 	Stat(ctx context.Context, name string) (*FileInfo, error)
 	ReadDir(ctx context.Context, name string, recursive bool) ([]FileInfo, error)
-	Create(ctx context.Context, name string, body io.ReadCloser) (fileInfo *FileInfo, created bool, err error)
+	Create(ctx context.Context, name string, body io.ReadCloser, opts *CreateOptions) (fileInfo *FileInfo, created bool, err error)
 	RemoveAll(ctx context.Context, name string) error
 	Mkdir(ctx context.Context, name string) error
 	Copy(ctx context.Context, name, dest string, options *CopyOptions) (created bool, err error)
@@ -162,26 +162,26 @@ func (b *backend) propFindFile(propfind *internal.PropFind, fi *FileInfo) (*inte
 	}
 
 	if !fi.IsDir {
-		props[internal.GetContentLengthName] = func(*internal.RawXMLValue) (interface{}, error) {
-			return &internal.GetContentLength{Length: fi.Size}, nil
-		}
+		props[internal.GetContentLengthName] = internal.PropFindValue(&internal.GetContentLength{
+			Length: fi.Size,
+		})
 
 		if !fi.ModTime.IsZero() {
-			props[internal.GetLastModifiedName] = func(*internal.RawXMLValue) (interface{}, error) {
-				return &internal.GetLastModified{LastModified: internal.Time(fi.ModTime)}, nil
-			}
+			props[internal.GetLastModifiedName] = internal.PropFindValue(&internal.GetLastModified{
+				LastModified: internal.Time(fi.ModTime),
+			})
 		}
 
 		if fi.MIMEType != "" {
-			props[internal.GetContentTypeName] = func(*internal.RawXMLValue) (interface{}, error) {
-				return &internal.GetContentType{Type: fi.MIMEType}, nil
-			}
+			props[internal.GetContentTypeName] = internal.PropFindValue(&internal.GetContentType{
+				Type: fi.MIMEType,
+			})
 		}
 
 		if fi.ETag != "" {
-			props[internal.GetETagName] = func(*internal.RawXMLValue) (interface{}, error) {
-				return &internal.GetETag{ETag: internal.ETag(fi.ETag)}, nil
-			}
+			props[internal.GetETagName] = internal.PropFindValue(&internal.GetETag{
+				ETag: internal.ETag(fi.ETag),
+			})
 		}
 	}
 
@@ -194,12 +194,18 @@ func (b *backend) PropPatch(r *http.Request, update *internal.PropertyUpdate) (*
 }
 
 func (b *backend) Put(w http.ResponseWriter, r *http.Request) error {
-	fi, created, err := b.FileSystem.Create(r.Context(), r.URL.Path, r.Body)
+	ifNoneMatch := ConditionalMatch(r.Header.Get("If-None-Match"))
+	ifMatch := ConditionalMatch(r.Header.Get("If-Match"))
+
+	opts := CreateOptions{
+		IfNoneMatch: ifNoneMatch,
+		IfMatch:     ifMatch,
+	}
+	fi, created, err := b.FileSystem.Create(r.Context(), r.URL.Path, r.Body, &opts)
 	if err != nil {
 		return err
 	}
 
-	w.Header().Set("Content-Length", strconv.FormatInt(fi.Size, 10))
 	if fi.MIMEType != "" {
 		w.Header().Set("Content-Type", fi.MIMEType)
 	}
@@ -293,7 +299,7 @@ func ServePrincipal(w http.ResponseWriter, r *http.Request, options *ServePrinci
 		allow := []string{http.MethodOptions, "PROPFIND", "REPORT", "DELETE", "MKCOL"}
 		w.Header().Add("DAV", strings.Join(caps, ", "))
 		w.Header().Add("Allow", strings.Join(allow, ", "))
-		w.WriteHeader(http.StatusNoContent)
+		w.WriteHeader(http.StatusOK)
 	case "PROPFIND":
 		if err := servePrincipalPropfind(w, r, options); err != nil {
 			internal.ServeError(w, err)

webdav.go

@@ -19,6 +19,11 @@ type FileInfo struct {
 	ETag     string
 }
 
+type CreateOptions struct {
+	IfMatch     ConditionalMatch
+	IfNoneMatch ConditionalMatch
+}
+
 type CopyOptions struct {
 	NoRecursive bool
 	NoOverwrite bool
@@ -48,3 +53,11 @@ func (val ConditionalMatch) ETag() (string, error) {
 	}
 	return string(e), nil
 }
+
+func (val ConditionalMatch) MatchETag(etag string) (bool, error) {
+	if val.IsWildcard() {
+		return true, nil
+	}
+	t, err := val.ETag()
+	return t == etag, err
+}