Update local_file_upload.py

Add simplify the script, add explanatory comments, and make the script structure consistent with the other example scripts.

Author: cmlccie

examples/local_file_upload.py

@@ -1,16 +1,73 @@
+#!/usr/bin/env python
+#  -*- coding: utf-8 -*-
+"""Demo script showing how to upload a local file.
+
+A simple script showing how to upload a local file when creating a message in
+a Webex Teams space.
+
+You upload a file by using the `files=` parameter of the
+`WebexTeamsAPI.messages.create()` method, which expects to receive a list
+containing a single string with the path to file to be attached to the created
+message (Example: `files=["./image.png"]`).  The files parameter receives a
+list to allow for future expansion; however today, only one file may be
+included when creating a message via the Webex Teams APIs.
+
+The WebexTeamsSDK natively retrieves your Webex Teams access token from the
+WEBEX_TEAMS_ACCESS_TOKEN environment variable.  You must have this environment
+variable set to run this script.
+
+
+Copyright (c) 2016-2019 Cisco and/or its affiliates.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+"""
+
+
+from __future__ import print_function
+
 import os
-import sys
-from webexteamssdk import WebexTeamsAPI, ApiError
 
-cwd  = os.path.abspath(os.path.dirname('.'))
-sys.path.append(cwd)
-testfile = '/'+cwd+'/test.png' #expected format: '//Users/userid/dir/test.png'
+from webexteamssdk import WebexTeamsAPI
+
+
+ROOM_ID = "<your_room_id>"
+FILE_PATH = "<the_path_to_the_local_file>"
+
+
+# Create a WebexTeamsAPI connection object; uses your WEBEX_TEAMS_ACCESS_TOKEN
+api = WebexTeamsAPI()
+
+
+# Let's make sure the file exists
+if not os.path.isfile(FILE_PATH):
+    print("ERROR: File {} does not exist.".format(FILE_PATH))
+
+
+# Not a requirement but to be completely clear let's make sure we are using
+# an absolute path.
+abs_path = os.path.abspath(FILE_PATH)
+
 
-file_list = []
-file_list.append(testfile)
+# The files parameter expects to receive a list containing a single string with
+# the path to the file to be uploaded.
+file_list = [abs_path]
 
-token = 'your_bot_token'
-api = WebexTeamsAPI(access_token=token)
-headers = {'Authorization': 'Bearer '+token}
 
-api.messages.create(roomId='your_room_id', files=file_list)
+# It takes just a single statement to upload the file and create the message
+api.messages.create(roomId=ROOM_ID, files=file_list)