[evolution] I#39 - Extend Mail autoconfig to check in server's autoconfiguration too

[Milan Crha <mcrha src gnome org>]

commit 600351ef67482e725308f145bb714a4a507af07a
Author: Milan Crha <mcrha redhat com>
Date:   Tue Jul 10 20:01:29 2018 +0200

    I#39 - Extend Mail autoconfig to check in server's autoconfiguration too
    
    Closes https://gitlab.gnome.org/GNOME/evolution/issues/39

 src/mail/e-mail-autoconfig.c | 185 +++++++++++++++++++++++++++++--------------
 1 file changed, 127 insertions(+), 58 deletions(-)
---
diff --git a/src/mail/e-mail-autoconfig.c b/src/mail/e-mail-autoconfig.c
index 3464936974..b0e414fa74 100644
--- a/src/mail/e-mail-autoconfig.c
+++ b/src/mail/e-mail-autoconfig.c
@@ -77,6 +77,8 @@
 
 #define AUTOCONFIG_BASE_URI "https://autoconfig.thunderbird.net/v1.1/";
 
+#define FAKE_EVOLUTION_USER_STRING "EVOLUTIONUSER"
+
 #define ERROR_IS_NOT_FOUND(error) \
        (g_error_matches ((error), SOUP_HTTP_ERROR, SOUP_STATUS_NOT_FOUND))
 
@@ -185,16 +187,54 @@ mail_autoconfig_parse_end_element (GMarkupParseContext *context,
                closure->result = NULL;
 }
 
+/* Returns NULL when not being there */
+static gchar *
+mail_autoconfig_replace_case_insensitive (const gchar *text,
+                                         const gchar *before,
+                                         const gchar *after)
+{
+       const gchar *p, *next;
+       GString *str;
+       gint find_len;
+
+       if (!text)
+               return NULL;
+
+       find_len = strlen (before);
+       str = g_string_new ("");
+
+       p = text;
+       while (next = camel_strstrcase (p, before), next) {
+               if (p < next)
+                       g_string_append_len (str, p, next - p);
+
+               if (after && *after)
+                       g_string_append (str, after);
+
+               p = next + find_len;
+       }
+
+       if (p == text) {
+               g_string_free (str, TRUE);
+               return NULL;
+       }
+
+       g_string_append (str, p);
+
+       return g_string_free (str, FALSE);
+}
+
 static void
 mail_autoconfig_parse_text (GMarkupParseContext *context,
-                            const gchar *text,
-                            gsize text_length,
+                            const gchar *in_text,
+                            gsize in_text_length,
                             gpointer user_data,
                             GError **error)
 {
        ParserClosure *closure = user_data;
        EMailAutoconfigPrivate *priv;
-       const gchar *element_name;
+       const gchar *element_name, *text;
+       gchar *to_free;
        GString *string;
 
        priv = closure->autoconfig->priv;
@@ -202,6 +242,9 @@ mail_autoconfig_parse_text (GMarkupParseContext *context,
        if (closure->result == NULL)
                return;
 
+       to_free = mail_autoconfig_replace_case_insensitive (in_text, FAKE_EVOLUTION_USER_STRING, 
priv->email_local_part);
+       text = to_free ? to_free : in_text;
+
        /* Perform the following text substitutions:
         *
         * %EMAILADDRESS%    :  closure->email_address
@@ -332,6 +375,7 @@ mail_autoconfig_parse_text (GMarkupParseContext *context,
        }
 
        g_string_free (string, TRUE);
+       g_free (to_free);
 }
 
 static GMarkupParser mail_autoconfig_parser = {
@@ -374,22 +418,78 @@ mail_autoconfig_abort_soup_session_cb (GCancellable *cancellable,
        soup_session_abort (soup_session);
 }
 
+static gboolean
+mail_autoconfig_lookup_uri_sync (EMailAutoconfig *autoconfig,
+                                const gchar *uri,
+                                SoupSession *soup_session,
+                                GCancellable *cancellable,
+                                GError **error)
+{
+       SoupMessage *soup_message;
+       gboolean success;
+       guint status;
+
+       soup_message = soup_message_new (SOUP_METHOD_GET, uri);
+
+       if (!soup_message) {
+               g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
+                       _("Invalid URI: “%s”"), uri);
+               return FALSE;
+       }
+
+       soup_message_headers_append (
+               soup_message->request_headers,
+               "User-Agent", "Evolution/" VERSION VERSION_SUBSTRING " " VERSION_COMMENT);
+
+       status = soup_session_send_message (soup_session, soup_message);
+
+       success = SOUP_STATUS_IS_SUCCESSFUL (status);
+
+       if (success) {
+               GMarkupParseContext *context;
+               ParserClosure closure;
+
+               closure.autoconfig = autoconfig;
+               closure.result = NULL;
+
+               context = g_markup_parse_context_new (
+                       &mail_autoconfig_parser, 0,
+                       &closure, (GDestroyNotify) NULL);
+
+               success = g_markup_parse_context_parse (
+                       context,
+                       soup_message->response_body->data,
+                       soup_message->response_body->length,
+                       error);
+
+               if (success)
+                       success = g_markup_parse_context_end_parse (context, error);
+
+               g_markup_parse_context_free (context);
+       } else {
+               g_set_error_literal (
+                       error, SOUP_HTTP_ERROR,
+                       soup_message->status_code,
+                       soup_message->reason_phrase);
+       }
+
+       g_object_unref (soup_message);
+
+       return success;
+}
+
 static gboolean
 mail_autoconfig_lookup (EMailAutoconfig *autoconfig,
                         const gchar *domain,
                         GCancellable *cancellable,
                         GError **error)
 {
-       GMarkupParseContext *context;
        ESourceRegistry *registry;
        ESource *proxy_source;
-       SoupMessage *soup_message;
        SoupSession *soup_session;
-       ParserClosure closure;
        gulong cancel_id = 0;
-       gboolean success;
-       guint status;
        gchar *uri;
+       gboolean success = FALSE;
 
        registry = e_mail_autoconfig_get_registry (autoconfig);
        proxy_source = e_source_registry_ref_builtin_proxy (registry);
@@ -401,26 +501,6 @@ mail_autoconfig_lookup (EMailAutoconfig *autoconfig,
 
        g_object_unref (proxy_source);
 
-       uri = g_strconcat (AUTOCONFIG_BASE_URI, domain, NULL);
-
-       soup_message = soup_message_new (SOUP_METHOD_GET, uri);
-
-       if (!soup_message) {
-               g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
-                       _("Invalid URI: “%s”"), uri);
-
-               g_object_unref (soup_session);
-               g_free (uri);
-
-               return FALSE;
-       }
-
-       g_free (uri);
-
-       soup_message_headers_append (
-               soup_message->request_headers,
-               "User-Agent", "Evolution/" VERSION VERSION_SUBSTRING " " VERSION_COMMENT);
-
        if (G_IS_CANCELLABLE (cancellable))
                cancel_id = g_cancellable_connect (
                        cancellable,
@@ -428,41 +508,30 @@ mail_autoconfig_lookup (EMailAutoconfig *autoconfig,
                        g_object_ref (soup_session),
                        (GDestroyNotify) g_object_unref);
 
-       status = soup_session_send_message (soup_session, soup_message);
-
-       if (cancel_id > 0)
-               g_cancellable_disconnect (cancellable, cancel_id);
-
-       success = SOUP_STATUS_IS_SUCCESSFUL (status);
-
-       if (!success) {
-               g_set_error_literal (
-                       error, SOUP_HTTP_ERROR,
-                       soup_message->status_code,
-                       soup_message->reason_phrase);
-               goto exit;
+       /* First try user configuration in autoconfig.$DOMAIN URL and ignore error */
+       if (!success && !g_cancellable_is_cancelled (cancellable)) {
+               uri = g_strconcat ("http://autoconfig.";, domain, "/mail/config-v1.1.xml?emailaddress=" 
FAKE_EVOLUTION_USER_STRING "%40", domain, NULL);
+               success = mail_autoconfig_lookup_uri_sync (autoconfig, uri, soup_session, cancellable, NULL);
+               g_free (uri);
        }
 
-       closure.autoconfig = autoconfig;
-       closure.result = NULL;
-
-       context = g_markup_parse_context_new (
-               &mail_autoconfig_parser, 0,
-               &closure, (GDestroyNotify) NULL);
-
-       success = g_markup_parse_context_parse (
-               context,
-               soup_message->response_body->data,
-               soup_message->response_body->length,
-               error);
+       /* Then with $DOMAIN/.well-known/autoconfig/ and ignore error */
+       if (!success && !g_cancellable_is_cancelled (cancellable)) {
+               uri = g_strconcat ("http://";, domain, 
"/.well-known/autoconfig/mail/config-v1.1.xml?emailaddress=" FAKE_EVOLUTION_USER_STRING "%40", domain, NULL);
+               success = mail_autoconfig_lookup_uri_sync (autoconfig, uri, soup_session, cancellable, NULL);
+               g_free (uri);
+       }
 
-       if (success)
-               success = g_markup_parse_context_end_parse (context, error);
+       /* Final, try the upstream ISPDB and propagate error */
+       if (!success && !g_cancellable_is_cancelled (cancellable)) {
+               uri = g_strconcat (AUTOCONFIG_BASE_URI, domain, NULL);
+               success = mail_autoconfig_lookup_uri_sync (autoconfig, uri, soup_session, cancellable, error);
+               g_free (uri);
+       }
 
-       g_markup_parse_context_free (context);
+       if (cancel_id > 0)
+               g_cancellable_disconnect (cancellable, cancel_id);
 
-exit:
-       g_object_unref (soup_message);
        g_object_unref (soup_session);
 
        return success;