go-webdav/carddav/server.go
Conrad Hoffmann 71bd967b43 carddav: support address book creation/deletion
Now that the handling for multiple address books is in place, this
commit adds initial support for creation and deletion of address books.

These operations obviously require support from the backend, so the
interface gains two new methods. All properties of the address book
passed to `CreateAddressBook()` may be unset (e.g. when a client sends a
MKCOL request without a body), except for the path, which is always set.
It is up to the backend to put any desired default values in place.
2024-02-07 17:20:48 +01:00

756 lines
22 KiB
Go

package carddav
import (
"bytes"
"context"
"encoding/xml"
"fmt"
"io"
"mime"
"net/http"
"path"
"strconv"
"strings"
"github.com/emersion/go-vcard"
"github.com/emersion/go-webdav"
"github.com/emersion/go-webdav/internal"
)
type PutAddressObjectOptions struct {
// IfNoneMatch indicates that the client does not want to overwrite
// an existing resource.
IfNoneMatch webdav.ConditionalMatch
// IfMatch provides the ETag of the resource that the client intends
// to overwrite, can be ""
IfMatch webdav.ConditionalMatch
}
// Backend is a CardDAV server backend.
type Backend interface {
AddressBookHomeSetPath(ctx context.Context) (string, error)
ListAddressBooks(ctx context.Context) ([]AddressBook, error)
GetAddressBook(ctx context.Context, path string) (*AddressBook, error)
CreateAddressBook(ctx context.Context, addressBook AddressBook) error
DeleteAddressBook(ctx context.Context, path string) error
GetAddressObject(ctx context.Context, path string, req *AddressDataRequest) (*AddressObject, error)
ListAddressObjects(ctx context.Context, path string, req *AddressDataRequest) ([]AddressObject, error)
QueryAddressObjects(ctx context.Context, path string, query *AddressBookQuery) ([]AddressObject, error)
PutAddressObject(ctx context.Context, path string, card vcard.Card, opts *PutAddressObjectOptions) (loc string, err error)
DeleteAddressObject(ctx context.Context, path string) error
webdav.UserPrincipalBackend
}
// Handler handles CardDAV HTTP requests. It can be used to create a CardDAV
// server.
type Handler struct {
Backend Backend
Prefix string
}
// ServeHTTP implements http.Handler.
func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if h.Backend == nil {
http.Error(w, "carddav: no backend available", http.StatusInternalServerError)
return
}
if r.URL.Path == "/.well-known/carddav" {
principalPath, err := h.Backend.CurrentUserPrincipal(r.Context())
if err != nil {
http.Error(w, "carddav: failed to determine current user principal", http.StatusInternalServerError)
return
}
http.Redirect(w, r, principalPath, http.StatusPermanentRedirect)
return
}
var err error
switch r.Method {
case "REPORT":
err = h.handleReport(w, r)
default:
b := backend{
Backend: h.Backend,
Prefix: strings.TrimSuffix(h.Prefix, "/"),
}
hh := internal.Handler{&b}
hh.ServeHTTP(w, r)
}
if err != nil {
internal.ServeError(w, err)
}
}
func (h *Handler) handleReport(w http.ResponseWriter, r *http.Request) error {
var report reportReq
if err := internal.DecodeXMLRequest(r, &report); err != nil {
return err
}
if report.Query != nil {
return h.handleQuery(r, w, report.Query)
} else if report.Multiget != nil {
return h.handleMultiget(r.Context(), w, report.Multiget)
}
return internal.HTTPErrorf(http.StatusBadRequest, "carddav: expected addressbook-query or addressbook-multiget element in REPORT request")
}
func decodePropFilter(el *propFilter) (*PropFilter, error) {
pf := &PropFilter{Name: el.Name, Test: FilterTest(el.Test)}
if el.IsNotDefined != nil {
if len(el.TextMatches) > 0 || len(el.Params) > 0 {
return nil, fmt.Errorf("carddav: failed to parse prop-filter: if is-not-defined is provided, text-match or param-filter can't be provided")
}
pf.IsNotDefined = true
}
for _, tm := range el.TextMatches {
pf.TextMatches = append(pf.TextMatches, *decodeTextMatch(&tm))
}
for _, paramEl := range el.Params {
param, err := decodeParamFilter(&paramEl)
if err != nil {
return nil, err
}
pf.Params = append(pf.Params, *param)
}
return pf, nil
}
func decodeParamFilter(el *paramFilter) (*ParamFilter, error) {
pf := &ParamFilter{Name: el.Name}
if el.IsNotDefined != nil {
if el.TextMatch != nil {
return nil, fmt.Errorf("carddav: failed to parse param-filter: if is-not-defined is provided, text-match can't be provided")
}
pf.IsNotDefined = true
}
if el.TextMatch != nil {
pf.TextMatch = decodeTextMatch(el.TextMatch)
}
return pf, nil
}
func decodeTextMatch(tm *textMatch) *TextMatch {
return &TextMatch{
Text: tm.Text,
NegateCondition: bool(tm.NegateCondition),
MatchType: MatchType(tm.MatchType),
}
}
func decodeAddressDataReq(addressData *addressDataReq) (*AddressDataRequest, error) {
if addressData.Allprop != nil && len(addressData.Props) > 0 {
return nil, internal.HTTPErrorf(http.StatusBadRequest, "carddav: only one of allprop or prop can be specified in address-data")
}
req := &AddressDataRequest{AllProp: addressData.Allprop != nil}
for _, p := range addressData.Props {
req.Props = append(req.Props, p.Name)
}
return req, nil
}
func (h *Handler) handleQuery(r *http.Request, w http.ResponseWriter, query *addressbookQuery) error {
var q AddressBookQuery
if query.Prop != nil {
var addressData addressDataReq
if err := query.Prop.Decode(&addressData); err != nil && !internal.IsNotFound(err) {
return err
}
req, err := decodeAddressDataReq(&addressData)
if err != nil {
return err
}
q.DataRequest = *req
}
q.FilterTest = FilterTest(query.Filter.Test)
for _, el := range query.Filter.Props {
pf, err := decodePropFilter(&el)
if err != nil {
return &internal.HTTPError{http.StatusBadRequest, err}
}
q.PropFilters = append(q.PropFilters, *pf)
}
if query.Limit != nil {
q.Limit = int(query.Limit.NResults)
if q.Limit <= 0 {
return internal.ServeMultiStatus(w, internal.NewMultiStatus())
}
}
aos, err := h.Backend.QueryAddressObjects(r.Context(), r.URL.Path, &q)
if err != nil {
return err
}
var resps []internal.Response
for _, ao := range aos {
b := backend{
Backend: h.Backend,
Prefix: strings.TrimSuffix(h.Prefix, "/"),
}
propfind := internal.PropFind{
Prop: query.Prop,
AllProp: query.AllProp,
PropName: query.PropName,
}
resp, err := b.propFindAddressObject(r.Context(), &propfind, &ao)
if err != nil {
return err
}
resps = append(resps, *resp)
}
ms := internal.NewMultiStatus(resps...)
return internal.ServeMultiStatus(w, ms)
}
func (h *Handler) handleMultiget(ctx context.Context, w http.ResponseWriter, multiget *addressbookMultiget) error {
var dataReq AddressDataRequest
if multiget.Prop != nil {
var addressData addressDataReq
if err := multiget.Prop.Decode(&addressData); err != nil && !internal.IsNotFound(err) {
return err
}
decoded, err := decodeAddressDataReq(&addressData)
if err != nil {
return err
}
dataReq = *decoded
}
var resps []internal.Response
for _, href := range multiget.Hrefs {
ao, err := h.Backend.GetAddressObject(ctx, href.Path, &dataReq)
if err != nil {
resp := internal.NewErrorResponse(href.Path, err)
resps = append(resps, *resp)
continue
}
b := backend{
Backend: h.Backend,
Prefix: strings.TrimSuffix(h.Prefix, "/"),
}
propfind := internal.PropFind{
Prop: multiget.Prop,
AllProp: multiget.AllProp,
PropName: multiget.PropName,
}
resp, err := b.propFindAddressObject(ctx, &propfind, ao)
if err != nil {
return err
}
resps = append(resps, *resp)
}
ms := internal.NewMultiStatus(resps...)
return internal.ServeMultiStatus(w, ms)
}
type backend struct {
Backend Backend
Prefix string
}
type resourceType int
const (
resourceTypeRoot resourceType = iota
resourceTypeUserPrincipal
resourceTypeAddressBookHomeSet
resourceTypeAddressBook
resourceTypeAddressObject
)
func (b *backend) resourceTypeAtPath(reqPath string) resourceType {
p := path.Clean(reqPath)
p = strings.TrimPrefix(p, b.Prefix)
if !strings.HasPrefix(p, "/") {
p = "/" + p
}
if p == "/" {
return resourceTypeRoot
}
return resourceType(len(strings.Split(p, "/")) - 1)
}
func (b *backend) Options(r *http.Request) (caps []string, allow []string, err error) {
caps = []string{"addressbook"}
if b.resourceTypeAtPath(r.URL.Path) != resourceTypeAddressObject {
// Note: some clients assume the address book is read-only when
// DELETE/MKCOL are missing
return caps, []string{http.MethodOptions, "PROPFIND", "REPORT", "DELETE", "MKCOL"}, nil
}
var dataReq AddressDataRequest
_, err = b.Backend.GetAddressObject(r.Context(), r.URL.Path, &dataReq)
if httpErr, ok := err.(*internal.HTTPError); ok && httpErr.Code == http.StatusNotFound {
return caps, []string{http.MethodOptions, http.MethodPut}, nil
} else if err != nil {
return nil, nil, err
}
return caps, []string{
http.MethodOptions,
http.MethodHead,
http.MethodGet,
http.MethodPut,
http.MethodDelete,
"PROPFIND",
}, nil
}
func (b *backend) HeadGet(w http.ResponseWriter, r *http.Request) error {
var dataReq AddressDataRequest
if r.Method != http.MethodHead {
dataReq.AllProp = true
}
ao, err := b.Backend.GetAddressObject(r.Context(), r.URL.Path, &dataReq)
if err != nil {
return err
}
w.Header().Set("Content-Type", vcard.MIMEType)
if ao.ContentLength > 0 {
w.Header().Set("Content-Length", strconv.FormatInt(ao.ContentLength, 10))
}
if ao.ETag != "" {
w.Header().Set("ETag", internal.ETag(ao.ETag).String())
}
if !ao.ModTime.IsZero() {
w.Header().Set("Last-Modified", ao.ModTime.UTC().Format(http.TimeFormat))
}
if r.Method != http.MethodHead {
return vcard.NewEncoder(w).Encode(ao.Card)
}
return nil
}
func (b *backend) PropFind(r *http.Request, propfind *internal.PropFind, depth internal.Depth) (*internal.MultiStatus, error) {
resType := b.resourceTypeAtPath(r.URL.Path)
var dataReq AddressDataRequest
var resps []internal.Response
switch resType {
case resourceTypeRoot:
resp, err := b.propFindRoot(r.Context(), propfind)
if err != nil {
return nil, err
}
resps = append(resps, *resp)
case resourceTypeUserPrincipal:
principalPath, err := b.Backend.CurrentUserPrincipal(r.Context())
if err != nil {
return nil, err
}
if r.URL.Path == principalPath {
resp, err := b.propFindUserPrincipal(r.Context(), propfind)
if err != nil {
return nil, err
}
resps = append(resps, *resp)
if depth != internal.DepthZero {
resp, err := b.propFindHomeSet(r.Context(), propfind)
if err != nil {
return nil, err
}
resps = append(resps, *resp)
if depth == internal.DepthInfinity {
resps_, err := b.propFindAllAddressBooks(r.Context(), propfind, true)
if err != nil {
return nil, err
}
resps = append(resps, resps_...)
}
}
}
case resourceTypeAddressBookHomeSet:
homeSetPath, err := b.Backend.AddressBookHomeSetPath(r.Context())
if err != nil {
return nil, err
}
if r.URL.Path == homeSetPath {
resp, err := b.propFindHomeSet(r.Context(), propfind)
if err != nil {
return nil, err
}
resps = append(resps, *resp)
if depth != internal.DepthZero {
recurse := depth == internal.DepthInfinity
resps_, err := b.propFindAllAddressBooks(r.Context(), propfind, recurse)
if err != nil {
return nil, err
}
resps = append(resps, resps_...)
}
}
case resourceTypeAddressBook:
ab, err := b.Backend.GetAddressBook(r.Context(), r.URL.Path)
if err != nil {
return nil, err
}
resp, err := b.propFindAddressBook(r.Context(), propfind, ab)
if err != nil {
return nil, err
}
resps = append(resps, *resp)
if depth != internal.DepthZero {
resps_, err := b.propFindAllAddressObjects(r.Context(), propfind, ab)
if err != nil {
return nil, err
}
resps = append(resps, resps_...)
}
case resourceTypeAddressObject:
ao, err := b.Backend.GetAddressObject(r.Context(), r.URL.Path, &dataReq)
if err != nil {
return nil, err
}
resp, err := b.propFindAddressObject(r.Context(), propfind, ao)
if err != nil {
return nil, err
}
resps = append(resps, *resp)
}
return internal.NewMultiStatus(resps...), nil
}
func (b *backend) propFindRoot(ctx context.Context, propfind *internal.PropFind) (*internal.Response, error) {
principalPath, err := b.Backend.CurrentUserPrincipal(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.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
return internal.NewResourceType(internal.CollectionName), nil
},
}
return internal.NewPropFindResponse(principalPath, propfind, props)
}
func (b *backend) propFindUserPrincipal(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
}
props := map[xml.Name]internal.PropFindFunc{
internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
return &internal.CurrentUserPrincipal{Href: internal.Href{Path: principalPath}}, nil
},
addressBookHomeSetName: func(*internal.RawXMLValue) (interface{}, error) {
return &addressbookHomeSet{Href: internal.Href{Path: homeSetPath}}, nil
},
internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
return internal.NewResourceType(internal.CollectionName), nil
},
}
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
}
// 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
},
}
return internal.NewPropFindResponse(homeSetPath, propfind, props)
}
func (b *backend) propFindAddressBook(ctx context.Context, propfind *internal.PropFind, ab *AddressBook) (*internal.Response, error) {
props := map[xml.Name]internal.PropFindFunc{
internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
path, err := b.Backend.CurrentUserPrincipal(ctx)
if err != nil {
return nil, err
}
return &internal.CurrentUserPrincipal{Href: internal.Href{Path: path}}, nil
},
internal.ResourceTypeName: func(*internal.RawXMLValue) (interface{}, error) {
return internal.NewResourceType(internal.CollectionName, addressBookName), nil
},
internal.DisplayNameName: func(*internal.RawXMLValue) (interface{}, error) {
return &internal.DisplayName{Name: ab.Name}, nil
},
addressBookDescriptionName: func(*internal.RawXMLValue) (interface{}, error) {
return &addressbookDescription{Description: ab.Description}, nil
},
supportedAddressDataName: func(*internal.RawXMLValue) (interface{}, error) {
return &supportedAddressData{
Types: []addressDataType{
{ContentType: vcard.MIMEType, Version: "3.0"},
{ContentType: vcard.MIMEType, Version: "4.0"},
},
}, nil
},
}
if ab.MaxResourceSize > 0 {
props[maxResourceSizeName] = func(*internal.RawXMLValue) (interface{}, error) {
return &maxResourceSize{Size: ab.MaxResourceSize}, nil
}
}
return internal.NewPropFindResponse(ab.Path, propfind, props)
}
func (b *backend) propFindAllAddressBooks(ctx context.Context, propfind *internal.PropFind, recurse bool) ([]internal.Response, error) {
abs, err := b.Backend.ListAddressBooks(ctx)
if err != nil {
return nil, err
}
var resps []internal.Response
for _, ab := range abs {
resp, err := b.propFindAddressBook(ctx, propfind, &ab)
if err != nil {
return nil, err
}
resps = append(resps, *resp)
if recurse {
resps_, err := b.propFindAllAddressObjects(ctx, propfind, &ab)
if err != nil {
return nil, err
}
resps = append(resps, resps_...)
}
}
return resps, nil
}
func (b *backend) propFindAddressObject(ctx context.Context, propfind *internal.PropFind, ao *AddressObject) (*internal.Response, error) {
props := map[xml.Name]internal.PropFindFunc{
internal.CurrentUserPrincipalName: func(*internal.RawXMLValue) (interface{}, error) {
path, err := b.Backend.CurrentUserPrincipal(ctx)
if err != nil {
return nil, err
}
return &internal.CurrentUserPrincipal{Href: internal.Href{Path: path}}, nil
},
internal.GetContentTypeName: func(*internal.RawXMLValue) (interface{}, error) {
return &internal.GetContentType{Type: vcard.MIMEType}, nil
},
// TODO: address-data can only be used in REPORT requests
addressDataName: func(*internal.RawXMLValue) (interface{}, error) {
var buf bytes.Buffer
if err := vcard.NewEncoder(&buf).Encode(ao.Card); err != nil {
return nil, err
}
return &addressDataResp{Data: buf.Bytes()}, nil
},
}
if ao.ContentLength > 0 {
props[internal.GetContentLengthName] = func(*internal.RawXMLValue) (interface{}, error) {
return &internal.GetContentLength{Length: ao.ContentLength}, nil
}
}
if !ao.ModTime.IsZero() {
props[internal.GetLastModifiedName] = func(*internal.RawXMLValue) (interface{}, error) {
return &internal.GetLastModified{LastModified: internal.Time(ao.ModTime)}, nil
}
}
if ao.ETag != "" {
props[internal.GetETagName] = func(*internal.RawXMLValue) (interface{}, error) {
return &internal.GetETag{ETag: internal.ETag(ao.ETag)}, nil
}
}
return internal.NewPropFindResponse(ao.Path, propfind, props)
}
func (b *backend) propFindAllAddressObjects(ctx context.Context, propfind *internal.PropFind, ab *AddressBook) ([]internal.Response, error) {
var dataReq AddressDataRequest
aos, err := b.Backend.ListAddressObjects(ctx, ab.Path, &dataReq)
if err != nil {
return nil, err
}
var resps []internal.Response
for _, ao := range aos {
resp, err := b.propFindAddressObject(ctx, propfind, &ao)
if err != nil {
return nil, err
}
resps = append(resps, *resp)
}
return resps, nil
}
func (b *backend) PropPatch(r *http.Request, update *internal.PropertyUpdate) (*internal.Response, error) {
homeSetPath, err := b.Backend.AddressBookHomeSetPath(r.Context())
if err != nil {
return nil, err
}
resp := internal.NewOKResponse(r.URL.Path)
if r.URL.Path == homeSetPath {
// TODO: support PROPPATCH for address books
for _, prop := range update.Remove {
emptyVal := internal.NewRawXMLElement(prop.Prop.XMLName, nil, nil)
if err := resp.EncodeProp(http.StatusNotImplemented, emptyVal); err != nil {
return nil, err
}
}
for _, prop := range update.Set {
emptyVal := internal.NewRawXMLElement(prop.Prop.XMLName, nil, nil)
if err := resp.EncodeProp(http.StatusNotImplemented, emptyVal); err != nil {
return nil, err
}
}
} else {
for _, prop := range update.Remove {
emptyVal := internal.NewRawXMLElement(prop.Prop.XMLName, nil, nil)
if err := resp.EncodeProp(http.StatusMethodNotAllowed, emptyVal); err != nil {
return nil, err
}
}
for _, prop := range update.Set {
emptyVal := internal.NewRawXMLElement(prop.Prop.XMLName, nil, nil)
if err := resp.EncodeProp(http.StatusMethodNotAllowed, emptyVal); err != nil {
return nil, err
}
}
}
return resp, nil
}
func (b *backend) Put(r *http.Request) (*internal.Href, error) {
ifNoneMatch := webdav.ConditionalMatch(r.Header.Get("If-None-Match"))
ifMatch := webdav.ConditionalMatch(r.Header.Get("If-Match"))
opts := PutAddressObjectOptions{
IfNoneMatch: ifNoneMatch,
IfMatch: ifMatch,
}
t, _, err := mime.ParseMediaType(r.Header.Get("Content-Type"))
if err != nil {
return nil, internal.HTTPErrorf(http.StatusBadRequest, "carddav: malformed Content-Type: %v", err)
}
if t != vcard.MIMEType {
// TODO: send CARDDAV:supported-address-data error
return nil, internal.HTTPErrorf(http.StatusBadRequest, "carddav: unsupporetd Content-Type %q", t)
}
// TODO: check CARDDAV:max-resource-size precondition
card, err := vcard.NewDecoder(r.Body).Decode()
if err != nil {
// TODO: send CARDDAV:valid-address-data error
return nil, internal.HTTPErrorf(http.StatusBadRequest, "carddav: failed to parse vCard: %v", err)
}
// TODO: add support for the CARDDAV:no-uid-conflict error
loc, err := b.Backend.PutAddressObject(r.Context(), r.URL.Path, card, &opts)
if err != nil {
return nil, err
}
return &internal.Href{Path: loc}, nil
}
func (b *backend) Delete(r *http.Request) error {
switch b.resourceTypeAtPath(r.URL.Path) {
case resourceTypeAddressBook:
return b.Backend.DeleteAddressBook(r.Context(), r.URL.Path)
case resourceTypeAddressObject:
return b.Backend.DeleteAddressObject(r.Context(), r.URL.Path)
}
return internal.HTTPErrorf(http.StatusForbidden, "carddav: cannot delete resource at given location")
}
func (b *backend) Mkcol(r *http.Request) error {
if b.resourceTypeAtPath(r.URL.Path) != resourceTypeAddressBook {
return internal.HTTPErrorf(http.StatusForbidden, "carddav: address book creation not allowed at given location")
}
ab := AddressBook{
Path: r.URL.Path,
}
// Check if a request body was sent
_, err := r.Body.Read(nil)
if err != nil && err != io.EOF {
return err
}
if err == nil {
// Not EOF, body is present
var m mkcolReq
if err := internal.DecodeXMLRequest(r, &m); err != nil {
return internal.HTTPErrorf(http.StatusBadRequest, "carddav: error parsing mkcol request: %s", err.Error())
}
if !m.ResourceType.Is(internal.CollectionName) || !m.ResourceType.Is(addressBookName) {
return internal.HTTPErrorf(http.StatusBadRequest, "carddav: unexpected resource type")
}
ab.Name = m.DisplayName
ab.Description = m.Description.Description
// TODO ...
}
return b.Backend.CreateAddressBook(r.Context(), ab)
}
func (b *backend) Copy(r *http.Request, dest *internal.Href, recursive, overwrite bool) (created bool, err error) {
panic("TODO")
}
func (b *backend) Move(r *http.Request, dest *internal.Href, overwrite bool) (created bool, err error) {
panic("TODO")
}
// https://tools.ietf.org/rfcmarkup?doc=6352#section-6.3.2.1
type PreconditionType string
const (
PreconditionNoUIDConflict PreconditionType = "no-uid-conflict"
PreconditionSupportedAddressData PreconditionType = "supported-address-data"
PreconditionValidAddressData PreconditionType = "valid-address-data"
PreconditionMaxResourceSize PreconditionType = "max-resource-size"
)
func NewPreconditionError(err PreconditionType) error {
name := xml.Name{"urn:ietf:params:xml:ns:carddav", string(err)}
elem := internal.NewRawXMLElement(name, nil, nil)
return &internal.HTTPError{
Code: 409,
Err: &internal.Error{
Raw: []internal.RawXMLValue{*elem},
},
}
}