From 557972089c22a6bc0ee832e0061f86f97c6dad2e Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Fri, 17 Jan 2020 16:59:29 +0100
Subject: [PATCH] carddav: add very basic server implementation

---
 carddav/server.go | 134 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 carddav/server.go

diff --git a/carddav/server.go b/carddav/server.go
new file mode 100644
index 0000000..4bc6773
--- /dev/null
+++ b/carddav/server.go
@@ -0,0 +1,134 @@
+package carddav
+
+import (
+	"encoding/xml"
+	"net/http"
+
+	"github.com/emersion/go-vcard"
+	"github.com/emersion/go-webdav/internal"
+)
+
+// TODO: add support for multiple address books
+
+type Backend interface {
+	GetAddressObject(href string) (*AddressObject, error)
+	ListAddressObjects() ([]AddressObject, error)
+}
+
+type Handler struct {
+	Backend Backend
+}
+
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if h.Backend == nil {
+		http.Error(w, "carddav: no backend available", http.StatusInternalServerError)
+		return
+	}
+
+	b := backend{h.Backend}
+	hh := internal.Handler{&b}
+	hh.ServeHTTP(w, r)
+}
+
+type backend struct {
+	Backend Backend
+}
+
+func (b *backend) Options(r *http.Request) ([]string, error) {
+	// TODO: add DAV: addressbook
+
+	if r.URL.Path == "/" {
+		return []string{http.MethodOptions, "PROPFIND"}, nil
+	}
+
+	_, err := b.Backend.GetAddressObject(r.URL.Path)
+	if httpErr, ok := err.(*internal.HTTPError); ok && httpErr.Code == http.StatusNotFound {
+		return []string{http.MethodOptions}, nil
+	} else if err != nil {
+		return nil, err
+	}
+
+	return []string{http.MethodOptions, http.MethodHead, http.MethodGet, "PROPFIND"}, nil
+}
+
+func (b *backend) HeadGet(w http.ResponseWriter, r *http.Request) error {
+	if r.URL.Path == "/" {
+		return &internal.HTTPError{Code: http.StatusMethodNotAllowed}
+	}
+
+	ao, err := b.Backend.GetAddressObject(r.URL.Path)
+	if err != nil {
+		return err
+	}
+
+	w.Header().Set("Content-Type", vcard.MIMEType)
+	// TODO: set ETag, Last-Modified
+
+	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) {
+	var resps []internal.Response
+	if r.URL.Path == "/" {
+		resp, err := b.propfindAddressBook(propfind)
+		if err != nil {
+			return nil, err
+		}
+		resps = append(resps, *resp)
+
+		if depth != internal.DepthZero {
+			aos, err := b.Backend.ListAddressObjects()
+			if err != nil {
+				return nil, err
+			}
+
+			for _, ao := range aos {
+				resp, err := b.propfindAddressObject(propfind, &ao)
+				if err != nil {
+					return nil, err
+				}
+				resps = append(resps, *resp)
+			}
+		}
+	} else {
+		ao, err := b.Backend.GetAddressObject(r.URL.Path)
+		if err != nil {
+			return nil, err
+		}
+
+		resp, err := b.propfindAddressObject(propfind, ao)
+		if err != nil {
+			return nil, err
+		}
+		resps = append(resps, *resp)
+	}
+
+	return internal.NewMultistatus(resps...), nil
+}
+
+func (b *backend) propfindAddressBook(propfind *internal.Propfind) (*internal.Response, error) {
+	props := map[xml.Name]internal.PropfindFunc{
+		{"DAV:", "resourcetype"}: func(*internal.RawXMLValue) (interface{}, error) {
+			return internal.NewResourceType(internal.CollectionName, addressBookName), nil
+		},
+	}
+
+	return internal.NewPropfindResponse("/", propfind, props)
+}
+
+func (b *backend) propfindAddressObject(propfind *internal.Propfind, ao *AddressObject) (*internal.Response, error) {
+	props := map[xml.Name]internal.PropfindFunc{
+		{"DAV:", "resourcetype"}: func(*internal.RawXMLValue) (interface{}, error) {
+			return internal.NewResourceType(), nil
+		},
+		{"DAV:", "getcontenttype"}: func(*internal.RawXMLValue) (interface{}, error) {
+			return &internal.GetContentType{Type: vcard.MIMEType}, nil
+		},
+		// TODO getlastmodified, getetag
+	}
+
+	return internal.NewPropfindResponse(ao.Href, propfind, props)
+}