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.

carddav/carddav_test.go

@@ -68,6 +68,14 @@ func (b *testBackend) GetAddressBook(ctx context.Context, path string) (*Address
 	return nil, webdav.NewHTTPError(404, fmt.Errorf("Not found"))
 }
 
+func (*testBackend) CreateAddressBook(ctx context.Context, ab AddressBook) error {
+	panic("TODO: implement")
+}
+
+func (*testBackend) DeleteAddressBook(ctx context.Context, path string) error {
+	panic("TODO: implement")
+}
+
 func (*testBackend) GetAddressObject(ctx context.Context, path string, req *AddressDataRequest) (*AddressObject, error) {
 	if path == alicePath {
 		card, err := vcard.NewDecoder(strings.NewReader(aliceData)).Decode()

carddav/elements.go

@@ -211,3 +211,11 @@ func (r *reportReq) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
 
 	return d.DecodeElement(v, &start)
 }
+
+type mkcolReq struct {
+	XMLName      xml.Name               `xml:"DAV: mkcol"`
+	ResourceType internal.ResourceType  `xml:"set>prop>resourcetype"`
+	DisplayName  string                 `xml:"set>prop>displayname"`
+	Description  addressbookDescription `xml:"set>prop>addressbook-description"`
+	// TODO this could theoretically contain all addressbook properties?
+}

carddav/server.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/xml"
 	"fmt"
+	"io"
 	"mime"
 	"net/http"
 	"path"
@@ -30,6 +31,8 @@ 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)
@@ -682,11 +685,44 @@ func (b *backend) Put(r *http.Request) (*internal.Href, error) {
 }
 
 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 {
-	return internal.HTTPErrorf(http.StatusForbidden, "carddav: address book creation unsupported")
+	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) {