Server launch script improvements:

Added command line options for help and to set the working root directory for the server.
Improved the directory location and selection code to work on different environments.

launch_arduino.py

@@ -3,10 +3,13 @@
 # The comment above works if the Python Launcher for Windows path included
 # in Python>3.3 does not conflict with the py.exe file added to "C:\Windows"
 # Currently this application should work in Python >2.6 and 3.x, although 
-# python 2 is prefered, as it is the main development platform. 
+# python 2 is preferred, as it is the main development platform.
 ###############################################################################
 from __future__ import unicode_literals, absolute_import
 import os
+import re
+import sys
+import getopt
 import platform
 import threading
 import webbrowser
@@ -14,35 +17,102 @@ import ArduinoServerCompiler.ServerCompilerSettings
 import ArduinoServerCompiler.BlocklyHTTPServer
 
 
-def open_browser(filetoload):
-    """ Start a browser after waiting for half a second. """
-
+def open_browser(open_file):
+    """
+    Start a browser in a separate thread after waiting for half a second.
+    """
     def _open_browser():
         webbrowser.open('http://%s:%s/%s' %
                         (ArduinoServerCompiler.BlocklyHTTPServer.ADDRESS,
                         ArduinoServerCompiler.BlocklyHTTPServer.PORT,
-                        filetoload))
+                        open_file))
 
     thread = threading.Timer(0.5, _open_browser)
     thread.start()
 
 
-def main():
+def parsing_args(argv):
+    """
+    Processes the command line arguments. Arguments supported:
+    -h / --help
+    -s / --serverroot <working directory>
+    :return: dictionary with available options(keys) and value(value)
+    """
+    option_dict = {}
+    try:
+        opts, args = getopt.getopt(argv, "hs:", ["help", "serverroot="])
+    except getopt.GetoptError as e:
+        print('There was a problem parsing the command line arguments:')
+        print('\t%s' % e)
+        sys.exit(1)
+
+    for opt, arg in opts:
+        if opt in ("-h", "--help"):
+            print('Include a server working directory using the flag:')
+            print('\t -s <folder>')
+            sys.exit(0)
+        if opt in ("-s", "--serverroot"):
+            # Windows only issue: In BlocklyRequestHandler, if chdir is fed
+            # an 'incorrect' path like 'C:' instead of 'C:\' or C:/' it
+            # fails silently maintaining the current working directory.
+            # Use regular expressions to catch this corner case.
+            if re.match("^[a-zA-Z]:$", arg):
+                print('The windows drive letter needs to end in a slash, ' +
+                      'eg. %s\\' % arg)
+                sys.exit(1)
+            # Check if the value is a valid directory
+            if os.path.isdir(arg):
+                option_dict['serverroot'] = arg
+                print ('Parsed "' + opt + '" flag with "' + arg + '" value.')
+            else:
+                print('Invalid directory "' + arg + '".')
+                sys.exit(1)
+        else:
+            print('Flag ' + opt + ' not recognised.')
+    return option_dict
+
+
+def main(argv):
     """
     Initialises the Settings singleton and starts the HTTP Server
     """
     print('Running Python version ' + platform.python_version())
+
+    # Checking command line arguments
+    if len(argv) > 0:
+        print("\n======= Parsing Command line arguments =======")
+        arguments = parsing_args(argv)
+        if 'serverroot' in arguments:
+            # Overwrite server working directory if valid
+            server_root = arguments['serverroot']
+
+    # Loading the settings
     print("\n======= Loading Settings =======")
     ArduinoServerCompiler.ServerCompilerSettings.ServerCompilerSettings()
-    current_dir = os.getcwd()
-    app_index = os.path.basename(os.path.normpath(current_dir))
-    app_index = os.path.join(app_index, 'apps', 'arduino_material')
-    open_browser(app_index)
+
+    # Loading the server with the argument working root directory, or by default
+    # with the parent folder of where this script is executed, done to be able
+    # to find the closure lib directory on the same level as the project folder
     print("\n======= Starting Server =======")
-    #parent directory as working directory due to closure requirements
-    parent_dir = os.path.dirname(os.getcwd())
-    ArduinoServerCompiler.BlocklyHTTPServer.start_server(parent_dir)
+    this_file_dir = os.path.dirname(os.path.realpath(sys.argv[0]))
+    try:
+        server_root
+    except NameError:
+        server_root = os.path.dirname(this_file_dir)
+    # Opening the browser to the web-app
+    paths = [server_root, this_file_dir]
+    common_path = os.path.commonprefix(paths)
+    if not common_path:
+        print('The server working directory and Ardublockly project need to ' +
+              'be in the same root directory!')
+        sys.exit(1)
+    relative_path = [os.path.relpath(this_file_dir, common_path)]
+    app_index = os.path.join(relative_path[0], 'apps', 'arduino_material')
+    #print('Root & this file: %s\nCommon & relative path: %s; %s\nIndex: %s' %
+    #      (paths, common_path, relative_path, app_index))
+    open_browser(app_index)
+    ArduinoServerCompiler.BlocklyHTTPServer.start_server(server_root)
 
 
 if __name__ == "__main__":
-    main()
+    main(sys.argv[1:])