diff -r a8e48c62ec03 -r 71127797ca73 plover-gtk/transactionhelper.c
--- a/plover-gtk/transactionhelper.c	Fri Mar 08 12:05:41 2019 +0000
+++ b/plover-gtk/transactionhelper.c	Wed Jul 15 16:04:47 2020 +0100
@@ -68,6 +68,7 @@
     g_free(priv->default_prefix);
     g_free(helper->error_primary_text);
     g_free(helper->base);
+    g_free(helper->base_uri);
     g_free(helper->unsatisfied);
     if (helper->comps)
 	plover_comps_free(helper->comps);
@@ -583,12 +584,12 @@
   plover_transaction_helper_get_upstream(PloverTransactionHelper *helper,
   GError **error)
 {
-    const char *base;
+    const char *base_uri;
     g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);
     if (!helper->upstream)
     {
-	base=plover_transaction_helper_get_base(helper);
-	helper->upstream=plover_repository_new_from_yum(base,error);
+	base_uri=plover_transaction_helper_get_base_uri(helper);
+	helper->upstream=plover_repository_new_from_yum_uri(base_uri,error);
     }
     return helper->upstream;
 }
@@ -602,18 +603,53 @@
     helper->upstream=g_object_ref(upstream);
 }
 
+const char *
+  plover_transaction_helper_get_base_uri(PloverTransactionHelper *helper)
+{
+    g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);
+    return helper->base_uri;
+}
+
+static gboolean plover_gtk__uri_validate(const char *uri)
+{
+    char *s;
+    s=razor_path_relative_to_uri(uri,".",NULL);
+    free(s);
+    return !!s;
+}
+
+void plover_transaction_helper_set_base_uri(PloverTransactionHelper *helper,
+  const char *base_uri)
+{
+    g_return_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper));
+    g_return_if_fail(helper->transactions == NULL);
+    g_return_if_fail(plover_gtk__uri_validate(base_uri));
+    g_free(helper->base_uri);
+    helper->base_uri=g_strdup(base_uri);
+    g_free(helper->base);
+    helper->base=NULL;
+}
+
 const char *plover_transaction_helper_get_base(PloverTransactionHelper *helper)
 {
     g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);
+    if (helper->base_uri && !helper->base)
+	helper->base=razor_path_from_uri(helper->base_uri,NULL);
     return helper->base;
 }
 
 void plover_transaction_helper_set_base(PloverTransactionHelper *helper,
   const char *base)
 {
+    gchar *base_uri;
     g_return_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper));
     g_return_if_fail(helper->transactions == NULL);
-    g_free(helper->base);
+    if (base)
+	base_uri=razor_path_to_uri(base);
+    else
+	base_uri=NULL;
+    plover_transaction_helper_set_base_uri(helper,base_uri);
+    g_free(base_uri);
     helper->base=g_strdup(base);
 }
 
@@ -623,13 +659,10 @@
 {
     gchar *s;
     g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);
-    if (!helper->comps && helper->base)
+    if (!helper->comps && helper->base_uri)
     {
-	s=g_strconcat(helper->base,"/repodata/comps.xml",NULL);
-	helper->comps=plover_comps_new_from_file(s);
-	if (!helper->comps)
-	    g_set_error(error,PLOVER_GENERAL_ERROR,
-	      PLOVER_GENERAL_ERROR_FAILED,"%s: %s",s,g_strerror(errno));
+	s=g_strconcat(helper->base_uri,"/repodata/comps.xml",NULL);
+	helper->comps=plover_comps_new_from_uri(s,error);
 	g_free(s);
     }
     return helper->comps;
@@ -643,9 +676,9 @@
     struct comps *comps;
     PloverTransactionHelperPrivate *priv;
     g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);
-    g_return_val_if_fail(helper->base != NULL || plover_transaction_helper_get_installed(helper) != NULL,NULL);
+    g_return_val_if_fail(helper->base_uri != NULL || plover_transaction_helper_get_installed(helper) != NULL,NULL);
     priv=PLOVER_TRANSACTION_HELPER_GET_PRIVATE(helper);
-    if (helper->base)
+    if (helper->base_uri)
     {
 	comps=plover_transaction_helper_get_comps(helper,error);
 	if (!comps)
@@ -951,7 +984,7 @@
   GError **error)
 {
     gboolean ok;
-    const char *base,*prefix;
+    const char *base_uri,*prefix;
     GError *tmp_error=NULL;
     PloverTransaction *transaction;
     g_return_val_if_fail(PLOVER_IS_TRANSACTION_HELPER(helper),NULL);
@@ -969,8 +1002,9 @@
 	ok=plover_transaction_set_upstream(transaction,helper->upstream,error);
     else
     {
-	base=plover_transaction_helper_get_base(helper);
-	ok=plover_transaction_set_upstream_from_yum(transaction,base,error);
+	base_uri=plover_transaction_helper_get_base_uri(helper);
+	ok=plover_transaction_set_upstream_from_yum_uri(transaction,base_uri,
+	  error);
     }
     if (!ok)
     {