[evolution] I#240 - Make SRV config lookup check also TXT records for CalDAV/CardDAV

[Milan Crha <mcrha src gnome org>]

commit ca723a1886315926b0bfbc76efc89a45b65bc24f
Author: Дилян Палаузов <git-dpa aegee org>
Date:   Thu Apr 25 09:02:30 2019 +0200

    I#240 - Make SRV config lookup check also TXT records for CalDAV/CardDAV
    
    Closes https://gitlab.gnome.org/GNOME/evolution/issues/240

 src/modules/config-lookup/e-srv-config-lookup.c | 43 +++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 3 deletions(-)
---
diff --git a/src/modules/config-lookup/e-srv-config-lookup.c b/src/modules/config-lookup/e-srv-config-lookup.c
index fe4c11407d..a290ac6e6f 100644
--- a/src/modules/config-lookup/e-srv-config-lookup.c
+++ b/src/modules/config-lookup/e-srv-config-lookup.c
@@ -183,12 +183,49 @@ srv_config_lookup_domain_sync (EConfigLookup *config_lookup,
                                        gboolean is_calendar = g_str_equal (known_services[ii].evo_protocol, 
"caldav");
                                        gboolean is_secure = g_str_has_suffix 
(known_services[ii].gio_protocol, "s");
                                        guint16 port = g_srv_target_get_port (target);
-                                       gchar *url;
+                                       const gchar *txt_path = is_calendar ? ".well-known/caldav" : 
".well-known/carddav";
+                                       GList *txt_records;
+                                       gchar *url, *tmp;
+
+                                       tmp = g_strconcat (is_calendar ? "_caldav" : "_carddav", is_secure ? 
"s" : "", "._tcp.", domain, NULL);
+                                       txt_records = g_resolver_lookup_records (resolver, tmp, 
G_RESOLVER_RECORD_TXT, cancellable, NULL);
+                                       g_clear_pointer (&tmp, g_free);
+
+                                       if (txt_records) {
+                                               GList *txt_record;
+
+                                               for (txt_record = txt_records; txt_record; txt_record = 
g_list_next (txt_record)) {
+                                                       gchar **contents = NULL;
+                                                       gint jj;
+
+                                                       g_variant_get (txt_record->data, "(^a&s)", &contents);
+
+                                                       for (jj = 0; contents && contents[jj]; jj++) {
+                                                               const gchar *txt_value = contents[jj];
+
+                                                               /* Compare case-insensitively, according to 
section 6.4 of RFC 6763 */
+                                                               if (!g_ascii_strncasecmp ("path=/", 
txt_value, 6)) {
+                                                                       tmp = g_strdup (txt_value + 6);
+                                                                       txt_path = tmp;
+                                                                       break;
+                                                               }
+                                                       }
+
+                                                       g_free (contents);
+
+                                                       if (tmp)
+                                                               break;
+                                               }
+
+                                               g_list_free_full (txt_records, (GDestroyNotify) 
g_variant_unref);
+                                       }
 
                                        if ((!is_secure && port == 80) || (is_secure && port == 443))
-                                               url = g_strdup_printf ("http%s://%s", is_secure ? "s" : "", 
hostname);
+                                               url = g_strdup_printf ("http%s://%s/%s", is_secure ? "s" : 
"", hostname, txt_path);
                                        else
-                                               url = g_strdup_printf ("http%s://%s:%d", is_secure ? "s" : 
"", hostname, port);
+                                               url = g_strdup_printf ("http%s://%s:%d/%s", is_secure ? "s" : 
"", hostname, port, txt_path);
+
+                                       g_free (tmp);
 
                                        e_config_lookup_result_simple_add_string (lookup_result, 
E_SOURCE_EXTENSION_COLLECTION,
                                                "backend-name", "webdav");