1 files changed, 71 insertions, 0 deletions
diff --git a/plugins/caldav/plugin.go b/plugins/caldav/plugin.go
new file mode 100644
index 0000000..1915646
--- /dev/null
+++ b/plugins/caldav/plugin.go
@@ -0,0 +1,71 @@
+package koushincaldav
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"git.sr.ht/~emersion/koushin"
+)
+
+func sanityCheckURL(u *url.URL) error {
+	req, err := http.NewRequest(http.MethodOptions, u.String(), nil)
+	if err != nil {
+		return err
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return err
+	}
+	resp.Body.Close()
+
+	// Servers might require authentication to perform an OPTIONS request
+	if resp.StatusCode/100 != 2 && resp.StatusCode != http.StatusUnauthorized {
+		return fmt.Errorf("HTTP request failed: %v %v", resp.StatusCode, resp.Status)
+	}
+	return nil
+}
+
+func newPlugin(srv *koushin.Server) (koushin.Plugin, error) {
+	u, err := srv.Upstream("caldavs", "caldav+insecure", "https", "http+insecure")
+	if _, ok := err.(*koushin.NoUpstreamError); ok {
+		return nil, nil
+	} else if err != nil {
+		return nil, fmt.Errorf("caldav: failed to parse upstream caldav server: %v", err)
+	}
+	switch u.Scheme {
+	case "caldavs":
+		u.Scheme = "https"
+	case "caldav+insecure", "http+insecure":
+		u.Scheme = "http"
+	}
+	if u.Scheme == "" {
+		return nil, fmt.Errorf("caldav: discovery not yet implemented") // TODO
+	}
+
+	if err := sanityCheckURL(u); err != nil {
+		return nil, fmt.Errorf("caldav: failed to connect to CalDAV server %q: %v", u, err)
+	}
+
+	srv.Logger().Printf("Configured upstream CalDAV server: %v", u)
+
+	p := koushin.GoPlugin{Name: "caldav"}
+
+	registerRoutes(&p, u)
+
+	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
+	})
+}