// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package webdav
// The XML encoding is covered by Section 14.
// http://www.webdav.org/specs/rfc4918.html#xml.element.definitions
import (
"bytes"
"encoding/xml"
"fmt"
"io"
"net/http"
"time"
// As of https://go-review.googlesource.com/#/c/12772/ which was submitted
// in July 2015, this package uses an internal fork of the standard
// library's encoding/xml package, due to changes in the way namespaces
// were encoded. Such changes were introduced in the Go 1.5 cycle, but were
// rolled back in response to https://github.com/golang/go/issues/11841
//
// However, this package's exported API, specifically the Property and
// DeadPropsHolder types, need to refer to the standard library's version
// of the xml.Name type, as code that imports this package cannot refer to
// the internal version.
//
// This file therefore imports both the internal and external versions, as
// ixml and xml, and converts between them.
//
// In the long term, this package should use the standard library's version
// only, and the internal fork deleted, once
// https://github.com/golang/go/issues/13400 is resolved.
ixml "golang.org/x/net/webdav/internal/xml"
)
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_lockinfo
type lockInfo struct {
XMLName ixml.Name `xml:"lockinfo"`
Exclusive *struct{} `xml:"lockscope>exclusive"`
Shared *struct{} `xml:"lockscope>shared"`
Write *struct{} `xml:"locktype>write"`
Owner owner `xml:"owner"`
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_owner
type owner struct {
InnerXML string `xml:",innerxml"`
}
func readLockInfo(r io.Reader) (li lockInfo, status int, err error) {
c := &countingReader{r: r}
if err = ixml.NewDecoder(c).Decode(&li); err != nil {
if err == io.EOF {
if c.n == 0 {
// An empty body means to refresh the lock.
// http://www.webdav.org/specs/rfc4918.html#refreshing-locks
return lockInfo{}, 0, nil
}
err = errInvalidLockInfo
}
return lockInfo{}, http.StatusBadRequest, err
}
// We only support exclusive (non-shared) write locks. In practice, these are
// the only types of locks that seem to matter.
if li.Exclusive == nil || li.Shared != nil || li.Write == nil {
return lockInfo{}, http.StatusNotImplemented, errUnsupportedLockInfo
}
return li, 0, nil
}
type countingReader struct {
n int
r io.Reader
}
func (c *countingReader) Read(p []byte) (int, error) {
n, err := c.r.Read(p)
c.n += n
return n, err
}
func writeLockInfo(w io.Writer, token string, ld LockDetails) (int, error) {
depth := "infinity"
if ld.ZeroDepth {
depth = "0"
}
timeout := ld.Duration / time.Second
return fmt.Fprintf(w, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"+
"<D:prop xmlns:D=\"DAV:\"><D:lockdiscovery><D:activelock>\n"+
" <D:locktype><D:write/></D:locktype>\n"+
" <D:lockscope><D:exclusive/></D:lockscope>\n"+
" <D:depth>%s</D:depth>\n"+
" <D:owner>%s</D:owner>\n"+
" <D:timeout>Second-%d</D:timeout>\n"+
" <D:locktoken><D:href>%s</D:href></D:locktoken>\n"+
" <D:lockroot><D:href>%s</D:href></D:lockroot>\n"+
"</D:activelock></D:lockdiscovery></D:prop>",
depth, ld.OwnerXML, timeout, escape(token), escape(ld.Root),
)
}
func escape(s string) string {
for i := 0; i < len(s); i++ {
switch s[i] {
case '"', '&', '\'', '<', '>':
b := bytes.NewBuffer(nil)
ixml.EscapeText(b, []byte(s))
return b.String()
}
}
return s
}
// Next returns the next token, if any, in the XML stream of d.
// RFC 4918 requires to ignore comments, processing instructions
// and directives.
// http://www.webdav.org/specs/rfc4918.html#property_values
// http://www.webdav.org/specs/rfc4918.html#xml-extensibility
func next(d *ixml.Decoder) (ixml.Token, error) {
for {
t, err := d.Token()
if err != nil {
return t, err
}
switch t.(type) {
case ixml.Comment, ixml.Directive, ixml.ProcInst:
continue
default:
return t, nil
}
}
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_prop (for propfind)
type propfindProps []xml.Name
// UnmarshalXML appends the property names enclosed within start to pn.
//
// It returns an error if start does not contain any properties or if
// properties contain values. Character data between properties is ignored.
func (pn *propfindProps) UnmarshalXML(d *ixml.Decoder, start ixml.StartElement) error {
for {
t, err := next(d)
if err != nil {
return err
}
switch t.(type) {
case ixml.EndElement:
if len(*pn) == 0 {
return fmt.Errorf("%s must not be empty", start.Name.Local)
}
return nil
case ixml.StartElement:
name := t.(ixml.StartElement).Name
t, err = next(d)
if err != nil {
return err
}
if _, ok := t.(ixml.EndElement); !ok {
return fmt.Errorf("unexpected token %T", t)
}
*pn = append(*pn, xml.Name(name))
}
}
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_propfind
type propfind struct {
XMLName ixml.Name `xml:"DAV: propfind"`
Allprop *struct{} `xml:"DAV: allprop"`
Propname *struct{} `xml:"DAV: propname"`
Prop propfindProps `xml:"DAV: prop"`
Include propfindProps `xml:"DAV: include"`
}
func readPropfind(r io.Reader) (pf propfind, status int, err error) {
c := countingReader{r: r}
if err = ixml.NewDecoder(&c).Decode(&pf); err != nil {
if err == io.EOF {
if c.n == 0 {
// An empty body means to propfind allprop.
// http://www.webdav.org/specs/rfc4918.html#METHOD_PROPFIND
return propfind{Allprop: new(struct{})}, 0, nil
}
err = errInvalidPropfind
}
return propfind{}, http.StatusBadRequest, err
}
if pf.Allprop == nil && pf.Include != nil {
return propfind{}, http.StatusBadRequest, errInvalidPropfind
}
if pf.Allprop != nil && (pf.Prop != nil || pf.Propname != nil) {
return propfind{}, http.StatusBadRequest, errInvalidPropfind
}
if pf.Prop != nil && pf.Propname != nil {
return propfind{}, http.StatusBadRequest, errInvalidPropfind
}
if pf.Propname == nil && pf.Allprop == nil && pf.Prop == nil {
return propfind{}, http.StatusBadRequest, errInvalidPropfind
}
return pf, 0, nil
}
// Property represents a single DAV resource property as defined in RFC 4918.
// See http://www.webdav.org/specs/rfc4918.html#data.model.for.resource.properties
type Property struct {
// XMLName is the fully qualified name that identifies this property.
XMLName xml.Name
// Lang is an optional xml:lang attribute.
Lang string `xml:"xml:lang,attr,omitempty"`
// InnerXML contains the XML representation of the property value.
// See http://www.webdav.org/specs/rfc4918.html#property_values
//
// Property values of complex type or mixed-content must have fully
// expanded XML namespaces or be self-contained with according
// XML namespace declarations. They must not rely on any XML
// namespace declarations within the scope of the XML document,
// even including the DAV: namespace.
InnerXML []byte `xml:",innerxml"`
}
// ixmlProperty is the same as the Property type except it holds an ixml.Name
// instead of an xml.Name.
type ixmlProperty struct {
XMLName ixml.Name
Lang string `xml:"xml:lang,attr,omitempty"`
InnerXML []byte `xml:",innerxml"`
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_error
// See multistatusWriter for the "D:" namespace prefix.
type xmlError struct {
XMLName ixml.Name `xml:"D:error"`
InnerXML []byte `xml:",innerxml"`
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_propstat
// See multistatusWriter for the "D:" namespace prefix.
type propstat struct {
Prop []Property `xml:"D:prop>_ignored_"`
Status string `xml:"D:status"`
Error *xmlError `xml:"D:error"`
ResponseDescription string `xml:"D:responsedescription,omitempty"`
}
// ixmlPropstat is the same as the propstat type except it holds an ixml.Name
// instead of an xml.Name.
type ixmlPropstat struct {
Prop []ixmlProperty `xml:"D:prop>_ignored_"`
Status string `xml:"D:status"`
Error *xmlError `xml:"D:error"`
ResponseDescription string `xml:"D:responsedescription,omitempty"`
}
// MarshalXML prepends the "D:" namespace prefix on properties in the DAV: namespace
// before encoding. See multistatusWriter.
func (ps propstat) MarshalXML(e *ixml.Encoder, start ixml.StartElement) error {
// Convert from a propstat to an ixmlPropstat.
ixmlPs := ixmlPropstat{
Prop: make([]ixmlProperty, len(ps.Prop)),
Status: ps.Status,
Error: ps.Error,
ResponseDescription: ps.ResponseDescription,
}
for k, prop := range ps.Prop {
ixmlPs.Prop[k] = ixmlProperty{
XMLName: ixml.Name(prop.XMLName),
Lang: prop.Lang,
InnerXML: prop.InnerXML,
}
}
for k, prop := range ixmlPs.Prop {
if prop.XMLName.Space == "DAV:" {
prop.XMLName = ixml.Name{Space: "", Local: "D:" + prop.XMLName.Local}
ixmlPs.Prop[k] = prop
}
}
// Distinct type to avoid infinite recursion of MarshalXML.
type newpropstat ixmlPropstat
return e.EncodeElement(newpropstat(ixmlPs), start)
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_response
// See multistatusWriter for the "D:" namespace prefix.
type response struct {
XMLName ixml.Name `xml:"D:response"`
Href []string `xml:"D:href"`
Propstat []propstat `xml:"D:propstat"`
Status string `xml:"D:status,omitempty"`
Error *xmlError `xml:"D:error"`
ResponseDescription string `xml:"D:responsedescription,omitempty"`
}
// MultistatusWriter marshals one or more Responses into a XML
// multistatus response.
// See http://www.webdav.org/specs/rfc4918.html#ELEMENT_multistatus
// TODO(rsto, mpl): As a workaround, the "D:" namespace prefix, defined as
// "DAV:" on this element, is prepended on the nested response, as well as on all
// its nested elements. All property names in the DAV: namespace are prefixed as
// well. This is because some versions of Mini-Redirector (on windows 7) ignore
// elements with a default namespace (no prefixed namespace). A less intrusive fix
// should be possible after golang.org/cl/11074. See https://golang.org/issue/11177
type multistatusWriter struct {
// ResponseDescription contains the optional responsedescription
// of the multistatus XML element. Only the latest content before
// close will be emitted. Empty response descriptions are not
// written.
responseDescription string
w http.ResponseWriter
enc *ixml.Encoder
}
// Write validates and emits a DAV response as part of a multistatus response
// element.
//
// It sets the HTTP status code of its underlying http.ResponseWriter to 207
// (Multi-Status) and populates the Content-Type header. If r is the
// first, valid response to be written, Write prepends the XML representation
// of r with a multistatus tag. Callers must call close after the last response
// has been written.
func (w *multistatusWriter) write(r *response) error {
switch len(r.Href) {
case 0:
return errInvalidResponse
case 1:
if len(r.Propstat) > 0 != (r.Status == "") {
return errInvalidResponse
}
default:
if len(r.Propstat) > 0 || r.Status == "" {
return errInvalidResponse
}
}
err := w.writeHeader()
if err != nil {
return err
}
return w.enc.Encode(r)
}
// writeHeader writes a XML multistatus start element on w's underlying
// http.ResponseWriter and returns the result of the write operation.
// After the first write attempt, writeHeader becomes a no-op.
func (w *multistatusWriter) writeHeader() error {
if w.enc != nil {
return nil
}
w.w.Header().Add("Content-Type", "text/xml; charset=utf-8")
w.w.WriteHeader(StatusMulti)
_, err := fmt.Fprintf(w.w, `<?xml version="1.0" encoding="UTF-8"?>`)
if err != nil {
return err
}
w.enc = ixml.NewEncoder(w.w)
return w.enc.EncodeToken(ixml.StartElement{
Name: ixml.Name{
Space: "DAV:",
Local: "multistatus",
},
Attr: []ixml.Attr{{
Name: ixml.Name{Space: "xmlns", Local: "D"},
Value: "DAV:",
}},
})
}
// Close completes the marshalling of the multistatus response. It returns
// an error if the multistatus response could not be completed. If both the
// return value and field enc of w are nil, then no multistatus response has
// been written.
func (w *multistatusWriter) close() error {
if w.enc == nil {
return nil
}
var end []ixml.Token
if w.responseDescription != "" {
name := ixml.Name{Space: "DAV:", Local: "responsedescription"}
end = append(end,
ixml.StartElement{Name: name},
ixml.CharData(w.responseDescription),
ixml.EndElement{Name: name},
)
}
end = append(end, ixml.EndElement{
Name: ixml.Name{Space: "DAV:", Local: "multistatus"},
})
for _, t := range end {
err := w.enc.EncodeToken(t)
if err != nil {
return err
}
}
return w.enc.Flush()
}
var xmlLangName = ixml.Name{Space: "http://www.w3.org/XML/1998/namespace", Local: "lang"}
func xmlLang(s ixml.StartElement, d string) string {
for _, attr := range s.Attr {
if attr.Name == xmlLangName {
return attr.Value
}
}
return d
}
type xmlValue []byte
func (v *xmlValue) UnmarshalXML(d *ixml.Decoder, start ixml.StartElement) error {
// The XML value of a property can be arbitrary, mixed-content XML.
// To make sure that the unmarshalled value contains all required
// namespaces, we encode all the property value XML tokens into a
// buffer. This forces the encoder to redeclare any used namespaces.
var b bytes.Buffer
e := ixml.NewEncoder(&b)
for {
t, err := next(d)
if err != nil {
return err
}
if e, ok := t.(ixml.EndElement); ok && e.Name == start.Name {
break
}
if err = e.EncodeToken(t); err != nil {
return err
}
}
err := e.Flush()
if err != nil {
return err
}
*v = b.Bytes()
return nil
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_prop (for proppatch)
type proppatchProps []Property
// UnmarshalXML appends the property names and values enclosed within start
// to ps.
//
// An xml:lang attribute that is defined either on the DAV:prop or property
// name XML element is propagated to the property's Lang field.
//
// UnmarshalXML returns an error if start does not contain any properties or if
// property values contain syntactically incorrect XML.
func (ps *proppatchProps) UnmarshalXML(d *ixml.Decoder, start ixml.StartElement) error {
lang := xmlLang(start, "")
for {
t, err := next(d)
if err != nil {
return err
}
switch elem := t.(type) {
case ixml.EndElement:
if len(*ps) == 0 {
return fmt.Errorf("%s must not be empty", start.Name.Local)
}
return nil
case ixml.StartElement:
p := Property{
XMLName: xml.Name(t.(ixml.StartElement).Name),
Lang: xmlLang(t.(ixml.StartElement), lang),
}
err = d.DecodeElement(((*xmlValue)(&p.InnerXML)), &elem)
if err != nil {
return err
}
*ps = append(*ps, p)
}
}
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_set
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_remove
type setRemove struct {
XMLName ixml.Name
Lang string `xml:"xml:lang,attr,omitempty"`
Prop proppatchProps `xml:"DAV: prop"`
}
// http://www.webdav.org/specs/rfc4918.html#ELEMENT_propertyupdate
type propertyupdate struct {
XMLName ixml.Name `xml:"DAV: propertyupdate"`
Lang string `xml:"xml:lang,attr,omitempty"`
SetRemove []setRemove `xml:",any"`
}
func readProppatch(r io.Reader) (patches []Proppatch, status int, err error) {
var pu propertyupdate
if err = ixml.NewDecoder(r).Decode(&pu); err != nil {
return nil, http.StatusBadRequest, err
}
for _, op := range pu.SetRemove {
remove := false
switch op.XMLName {
case ixml.Name{Space: "DAV:", Local: "set"}:
// No-op.
case ixml.Name{Space: "DAV:", Local: "remove"}:
for _, p := range op.Prop {
if len(p.InnerXML) > 0 {
return nil, http.StatusBadRequest, errInvalidProppatch
}
}
remove = true
default:
return nil, http.StatusBadRequest, errInvalidProppatch
}
patches = append(patches, Proppatch{Remove: remove, Props: op.Prop})
}
return patches, 0, nil
}