initial commit for a python based terrasync client

diff --git a/utils/TerraSync/terrasync.py b/utils/TerraSync/terrasync.py
new file mode 100755 (executable)
index 0000000..8f01be5
--- /dev/null
+++ b/utils/TerraSync/terrasync.py
@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2016  Torsten Dreyer
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# terrasync.py - synchronize terrascenery data to your local disk
+#
+# this is a terrible stub, please improve
+
+import os 
+import hashlib
+import urllib.request
+
+dirindex = ".dirindex"
+DIRINDEXVERSION = 1
+
+#TODO: use DNS to resolve list of mirrors
+# - lookup terrasync.flightgear.org, type=NAPTR, service="ws20", flags="U"
+# - sort by order,preference ascending
+# - pick entries with lowest order and preference
+# - randomly pick one of those
+# - use regexp fields URL
+URL="http://flightgear.sourceforge.net/scenery"
+
+########################################################################
+
+def fn_hash_of_file(fname):
+    hash = hashlib.sha1()
+    try:
+        with open(fname, "rb") as f:
+            for chunk in iter(lambda: f.read(4096), b""):
+                hash.update(chunk)
+    except:
+        pass
+
+    return hash.hexdigest()
+
+########################################################################
+def do_download_file( _url, _path, _localfile, _hash ):
+  if os.path.exists( _localfile ):
+    h = fn_hash_of_file(_localfile)
+    if h == _hash:
+      print("hash match for ", _localfile)
+      return
+
+  r = urllib.request.urlopen( _url + _path )
+  f = open(_localfile, 'wb')
+  f.write( r.read() )
+  f.close()
+  print("downloaded ", _localfile, " from ", _url + _path )
+
+########################################################################
+def do_terrasync( _url, _path, _localdir ):
+  url = _url + _path
+  print("syncing ",url)
+
+  if not os.path.exists( _localdir ):
+    os.makedirs( _localdir )
+
+  for line in urllib.request.urlopen(url + "/.dirindex").readlines():
+    tokens = line.decode("utf-8").rstrip().split(':')
+    if( len(tokens) == 0 ):
+      continue
+
+    # TODO: check version number, should be equal to DIRINDEXVERSION
+    #       otherwise complain and terminate
+    if( tokens[0] == "version" ):
+      continue
+
+    if( tokens[0] == "path" ):
+      continue
+
+    if( tokens[0] == "d" ):
+      do_terrasync( url,  "/" + tokens[1], os.path.join(_localdir,tokens[1] ) )
+
+    if( tokens[0] == "f" ):
+      do_download_file( url, "/" + tokens[1], os.path.join(_localdir,tokens[1]), tokens[2] )
+
+########################################################################
+
+# TODO: parse command line args
+# --url=automatic for automatic detection of server URL
+# --url=http://flightgear.sourceforge.net/scenery to use explicit server
+# --path=/Models sync only the /Models path from the server
+# --destination=/some/path write files to destination instead of pwd
+# TODO: sanitize user provided data
+
+do_terrasync( URL, "", "." )
+
+########################################################################