plugins/carddav: new plugin

A new minimal CardDAV plugin is introduced. It injects a list of e-mail
addresses in the e-mail compose view.

References: https://todo.sr.ht/~sircmpwn/koushin/7

1 files changed, 116 insertions, 0 deletions

diff --git a/plugins/carddav/plugin.go b/plugins/carddav/plugin.go
new file mode 100644
index 0000000..45e447e
--- /dev/null
+++ b/plugins/carddav/plugin.go
@@ -0,0 +1,116 @@
+package koushincarddav
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"git.sr.ht/~emersion/koushin"
+	koushinbase "git.sr.ht/~emersion/koushin/plugins/base"
+	"github.com/emersion/go-vcard"
+	"github.com/emersion/go-webdav/carddav"
+)
+
+type authRoundTripper struct {
+	upstream http.RoundTripper
+	session  *koushin.Session
+}
+
+func (rt *authRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	rt.session.SetHTTPBasicAuth(req)
+	return rt.upstream.RoundTrip(req)
+}
+
+func newPlugin(srv *koushin.Server) (koushin.Plugin, error) {
+	u, err := srv.Upstream("https", "http+insecure")
+	if _, ok := err.(*koushin.NoUpstreamError); ok {
+		srv.Logger().Print("carddav: no upstream server provided")
+		return nil, nil
+	} else if err != nil {
+		return nil, fmt.Errorf("carddav: failed to parse upstream CardDAV server: %v", err)
+	}
+	if u.Scheme == "http+insecure" {
+		u.Scheme = "http"
+	}
+	if u.Scheme == "" {
+		s, err := carddav.Discover(u.Host)
+		if err != nil {
+			srv.Logger().Printf("carddav: failed to discover CardDAV server: %v", err)
+			return nil, nil
+		}
+		u, err = url.Parse(s)
+		if err != nil {
+			return nil, fmt.Errorf("carddav: Discover returned an invalid URL: %v", err)
+		}
+	}
+	srv.Logger().Printf("Configured upstream CardDAV server: %v", u)
+
+	p := koushin.GoPlugin{Name: "carddav"}
+
+	p.Inject("compose.html", func(ctx *koushin.Context, _data koushin.RenderData) error {
+		data := _data.(*koushinbase.ComposeRenderData)
+
+		rt := authRoundTripper{
+			upstream: http.DefaultTransport,
+			session:  ctx.Session,
+		}
+		c, err := carddav.NewClient(&http.Client{Transport: &rt}, u.String())
+		if err != nil {
+			return fmt.Errorf("failed to create CardDAV client: %v", err)
+		}
+
+		principal, err := c.FindCurrentUserPrincipal()
+		if err != nil {
+			return fmt.Errorf("failed to query CardDAV principal: %v", err)
+		}
+
+		addressBookHomeSet, err := c.FindAddressBookHomeSet(principal)
+		if err != nil {
+			return fmt.Errorf("failed to query CardDAV address book home set: %v", err)
+		}
+
+		addressBooks, err := c.FindAddressBooks(addressBookHomeSet)
+		if err != nil {
+			return fmt.Errorf("failed to query CardDAV address books: %v", err)
+		}
+		if len(addressBooks) == 0 {
+			return nil
+		}
+		addressBook := addressBooks[0]
+
+		query := carddav.AddressBookQuery{
+			DataRequest: carddav.AddressDataRequest{
+				Props: []string{vcard.FieldFormattedName, vcard.FieldEmail},
+			},
+		}
+		addrs, err := c.QueryAddressBook(addressBook.Path, &query)
+		if err != nil {
+			return fmt.Errorf("failed to query CardDAV addresses: %v", err)
+		}
+
+		// TODO: cache the results
+		emails := make([]string, 0, len(addrs))
+		for _, addr := range addrs {
+			cardEmails := addr.Card.Values(vcard.FieldEmail)
+			emails = append(emails, cardEmails...)
+		}
+
+		data.Extra["EmailSuggestions"] = emails
+		return nil
+	})
+
+	return p.Plugin(), nil
+}
+
+func init() {
+	koushin.RegisterPluginLoader(func(s *koushin.Server) ([]koushin.Plugin, error) {
+		p, err := newPlugin(s)
+		if err != nil {
+			return nil, err
+		}
+		if p == nil {
+			return nil, nil
+		}
+		return []koushin.Plugin{p}, err
+	})
+}