From 6308aeedf5f83a26763de3c33f10ce0c770eda04 Mon Sep 17 00:00:00 2001
From: Rob Norris <rw_norris@hotmail.com>
Date: Sun, 15 Jan 2017 15:44:46 +0000
Subject: [PATCH] Allow specifying an alternative URL base location for
 acquiring DEM SRTM files.

Advanced configuration setting only in viking.ini.
No GUI method provided ATM, as it's unlikely this setting needs changing.
---
 help/C/viking.xml |  5 +++++
 src/vikdemlayer.c | 20 ++++++++++++++++----
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/help/C/viking.xml b/help/C/viking.xml
index 4de9f4b9..159c1909 100644
--- a/help/C/viking.xml
+++ b/help/C/viking.xml
@@ -3457,6 +3457,11 @@ Accept: */*
 	  <listitem>
 	    <para>maps_scale_smaller_zoom_first=true</para>
 	  </listitem>
+	  <listitem>
+	    <para>srtm_http_base_url=https://dds.cr.usgs.gov/srtm/version2_1/SRTM3</para>
+	    <para>Allows using an alternative service for acquiring DEM SRTM files.
+	    Note that the layout on the server needs to be split into Continent directories.</para>
+	  </listitem>
 	  <listitem>
 	    <para>mapnik_buffer_size=128 (in pixels)</para>
 	  </listitem>
diff --git a/src/vikdemlayer.c b/src/vikdemlayer.c
index d554f673..934a7559 100644
--- a/src/vikdemlayer.c
+++ b/src/vikdemlayer.c
@@ -47,9 +47,11 @@
 #include "icons/icons.h"
 
 #define MAPS_CACHE_DIR maps_layer_default_dir()
-
 #define SRTM_CACHE_TEMPLATE "%ssrtm3-%s%s%c%02d%c%03d.hgt.zip"
+
 #define SRTM_HTTP_BASE_URL "https://dds.cr.usgs.gov/srtm/version2_1/SRTM3"
+static gchar *base_url = NULL;
+#define VIK_SETTINGS_SRTM_HTTP_BASE_URL "srtm_http_base_url"
 
 #ifdef VIK_CONFIG_DEM24K
 #define DEM24K_DOWNLOAD_SCRIPT "dem24k.pl"
@@ -259,6 +261,16 @@ struct _VikDEMLayer {
   GtkMenu *right_click_menu;
 };
 
+// NB Only performed once per program run
+static void vik_dem_class_init ( VikDEMLayerClass *klass )
+{
+  // Note if suppling your own base URL - the site must still follow the Continent directory layout
+  if ( ! a_settings_get_string ( VIK_SETTINGS_SRTM_HTTP_BASE_URL, &base_url ) ) {
+    // Otherwise use the default
+    base_url = g_strdup ( SRTM_HTTP_BASE_URL );
+  }
+}
+
 GType vik_dem_layer_get_type ()
 {
   static GType vdl_type = 0;
@@ -270,7 +282,7 @@ GType vik_dem_layer_get_type ()
       sizeof (VikDEMLayerClass),
       NULL, /* base_init */
       NULL, /* base_finalize */
-      NULL, /* class init */
+      (GClassInitFunc) vik_dem_class_init, /* class init */
       NULL, /* class_finalize */
       NULL, /* class_data */
       sizeof (VikDEMLayer),
@@ -949,7 +961,7 @@ static void srtm_dem_download_thread ( DEMDownloadParams *p, gpointer threaddata
   }
 
   gchar *src_url = g_strdup_printf("%s/%s/%c%02d%c%03d.hgt.zip",
-                SRTM_HTTP_BASE_URL,
+                base_url,
                 continent_dir,
 		(intlat >= 0) ? 'N' : 'S',
 		ABS(intlat),
@@ -1209,7 +1221,7 @@ static void dem_layer_file_info ( GtkWidget *widget, struct LatLon *ll )
   gchar *source = NULL;
   if ( continent_dir )
     source = g_strdup_printf ( "%s/%s/%c%02d%c%03d.hgt.zip",
-                               SRTM_HTTP_BASE_URL,
+                               base_url,
                                continent_dir,
                                (intlat >= 0) ? 'N' : 'S',
                                ABS(intlat),
-- 
2.39.5