3 files changed, 50 insertions, 31 deletions

diff --git a/plugins/carddav/carddav.go b/plugins/carddav/carddav.go
index 55c76b4..0c1a06d 100644
--- a/plugins/carddav/carddav.go
+++ b/plugins/carddav/carddav.go
@@ -21,32 +21,10 @@ func (rt *authRoundTripper) RoundTrip(req *http.Request) (*http.Response, error)
 	return rt.upstream.RoundTrip(req)
 }
 
-func getAddressBook(u *url.URL, session *koushin.Session) (*carddav.Client, *carddav.AddressBook, error) {
+func newClient(u *url.URL, session *koushin.Session) (*carddav.Client, error) {
 	rt := authRoundTripper{
 		upstream: http.DefaultTransport,
 		session:  session,
 	}
-	c, err := carddav.NewClient(&http.Client{Transport: &rt}, u.String())
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to create CardDAV client: %v", err)
-	}
-
-	principal, err := c.FindCurrentUserPrincipal()
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to query CardDAV principal: %v", err)
-	}
-
-	addressBookHomeSet, err := c.FindAddressBookHomeSet(principal)
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to query CardDAV address book home set: %v", err)
-	}
-
-	addressBooks, err := c.FindAddressBooks(addressBookHomeSet)
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to query CardDAV address books: %v", err)
-	}
-	if len(addressBooks) == 0 {
-		return nil, nil, errNoAddressBook
-	}
-	return c, &addressBooks[0], nil
+	return carddav.NewClient(&http.Client{Transport: &rt}, u.String())
 }
diff --git a/plugins/carddav/plugin.go b/plugins/carddav/plugin.go
index 99e5f62..a77762b 100644
--- a/plugins/carddav/plugin.go
+++ b/plugins/carddav/plugin.go
@@ -30,6 +30,44 @@ func sanityCheckURL(u *url.URL) error {
 	return nil
 }
 
+type plugin struct {
+	koushin.GoPlugin
+	url          *url.URL
+	homeSetCache map[string]string
+}
+
+func (p *plugin) clientWithAddressBook(session *koushin.Session) (*carddav.Client, *carddav.AddressBook, error) {
+	c, err := newClient(p.url, session)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to create CardDAV client: %v", err)
+	}
+
+	homeSet, ok := p.homeSetCache[session.Username()]
+	if !ok {
+		principal, err := c.FindCurrentUserPrincipal()
+		if err != nil {
+			return nil, nil, fmt.Errorf("failed to query CardDAV principal: %v", err)
+		}
+
+		homeSet, err = c.FindAddressBookHomeSet(principal)
+		if err != nil {
+			return nil, nil, fmt.Errorf("failed to query CardDAV address book home set: %v", err)
+		}
+
+		p.homeSetCache[session.Username()] = homeSet
+		// TODO: evict entries from the cache if it's getting too big
+	}
+
+	addressBooks, err := c.FindAddressBooks(homeSet)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to query CardDAV address books: %v", err)
+	}
+	if len(addressBooks) == 0 {
+		return nil, nil, errNoAddressBook
+	}
+	return c, &addressBooks[0], nil
+}
+
 func newPlugin(srv *koushin.Server) (koushin.Plugin, error) {
 	u, err := srv.Upstream("carddavs", "carddav+insecure", "https", "http+insecure")
 	if _, ok := err.(*koushin.NoUpstreamError); ok {
@@ -61,14 +99,18 @@ func newPlugin(srv *koushin.Server) (koushin.Plugin, error) {
 
 	srv.Logger().Printf("Configured upstream CardDAV server: %v", u)
 
-	p := koushin.GoPlugin{Name: "carddav"}
+	p := &plugin{
+		GoPlugin:     koushin.GoPlugin{Name: "carddav"},
+		url:          u,
+		homeSetCache: make(map[string]string),
+	}
 
-	registerRoutes(&p, u)
+	registerRoutes(p)
 
 	p.Inject("compose.html", func(ctx *koushin.Context, _data koushin.RenderData) error {
 		data := _data.(*koushinbase.ComposeRenderData)
 
-		c, addressBook, err := getAddressBook(u, ctx.Session)
+		c, addressBook, err := p.clientWithAddressBook(ctx.Session)
 		if err == errNoAddressBook {
 			return nil
 		} else if err != nil {
diff --git a/plugins/carddav/routes.go b/plugins/carddav/routes.go
index 82b729e..2f33852 100644
--- a/plugins/carddav/routes.go
+++ b/plugins/carddav/routes.go
@@ -3,7 +3,6 @@ package koushincarddav
 import (
 	"fmt"
 	"net/http"
-	"net/url"
 
 	"git.sr.ht/~emersion/koushin"
 	"github.com/emersion/go-vcard"
@@ -22,11 +21,11 @@ type AddressObjectRenderData struct {
 	AddressObject *carddav.AddressObject
 }
 
-func registerRoutes(p *koushin.GoPlugin, u *url.URL) {
+func registerRoutes(p *plugin) {
 	p.GET("/contacts", func(ctx *koushin.Context) error {
 		queryText := ctx.QueryParam("query")
 
-		c, addressBook, err := getAddressBook(u, ctx.Session)
+		c, addressBook, err := p.clientWithAddressBook(ctx.Session)
 		if err != nil {
 			return err
 		}
@@ -70,7 +69,7 @@ func registerRoutes(p *koushin.GoPlugin, u *url.URL) {
 	p.GET("/contacts/:uid", func(ctx *koushin.Context) error {
 		uid := ctx.Param("uid")
 
-		c, addressBook, err := getAddressBook(u, ctx.Session)
+		c, addressBook, err := p.clientWithAddressBook(ctx.Session)
 		if err != nil {
 			return err
 		}