Change logs:

1. Revise trkd_wsstreaming.py to let shorter variable names
2. Add comment for trkd_wsstreaming.py
3. Update README.md file
4. Add LICENSE.md file

Author: Wasin Waeosri

LICENSE.md

@@ -0,0 +1,13 @@
+Copyright 2018 Refinitiv
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

README.md

@@ -14,9 +14,10 @@ This is an example project that shows how to implement TRKD HTTP JSON client and
 - trkd_onlinereport.py: An example application that shows how to subscribe the Online Report data from TRKD service
 - trkd_chart.py: An example application that shows how to subscribe and download the Chart image data from TRKD service
 - trkd_wsstreaming.py: An example application that show how to subscribe the Quote data from TRKD Streming service via a WebSocket connection
-- requestments.txt: A requirement file contains a list of required libraries. 
+- requestments.txt: A requirement file contains a list of required libraries for HTTP JSON and WebSocket connections. 
 - docs\TRKD_REST_with_Python.docx: A document that describes the trkd_authen.py and trkd_quote.py applications
 
+All source code and scripts are provided under the Apache 2.0 license. Thye are provided AS IS with no warranty or guarantee of fit for purpose. See the project's LICENSE.md for details. 
 
 ## Prerequisite
 The following softwares are required to use this script
@@ -46,7 +47,13 @@ The best way is via the pip package management tool
 	$>pip install -r requestments.txt
 	```
 
-*Note*: If you aim to use only TRKD HTTP JSON services, you can just install requests library via ```pip install requests``` command.
+*Note*: If you aim to use only TRKD HTTP JSON services, you can just install requests library via a ```pip install requests``` command.
+
+## References
+For further details, please check out the following resources:
+* [Thomson Reuters Knowledge Direct API page](https://developers.thomsonreuters.com/thomson-reuters-knowledge-direct-trkd) on the [Thomson Reuters Developer Community](https://developers.thomsonreuters.com/) web site.
+* [Thomson Reuters Knowledge Direct API Catalog](https://www.trkd.thomsonreuters.com/SupportSite/RequestBuilder/requestbuilder.aspx) web site.
+* [Elektron WebSocket API](https://developers.thomsonreuters.com/websocket-api) page on the [Thomson Reuters Developer Community](https://developers.thomsonreuters.com/) web site.
 
 ## Release Note
 - Version 1: 6 Sep 2016
@@ -85,3 +92,4 @@ The best way is via the pip package management tool
 	- remove all ```is not None``` statements and make them a bit more **Pythonic**.
 - version 1.0.11: January 2019
 	- Add trkd_wsstreaming.py application for TRKD Streaming service.
+	- Add License.md file

trkd_wsstreaming.py

@@ -41,8 +41,8 @@
 
 ric_name = 'EUR='
 
-expire_time_in_seconds = None
-time_before_expire_in_seconds = 15 * 60 # 15 Minutes to Seconds
+expire_time = 0
+time_to_relogin = 15 * 60 # 15 Minutes to Seconds
 
 ## ------------------------------------------ TRKD HTTP REST functions ------------------------------------------ ##
 
@@ -85,15 +85,16 @@ def CreateAuthorization(username, password, appid):
 
         ## Calcuate Expiration time
         expire_datetime_utc = dateutil.parser.parse(expiration) ## Parse incoming Expiration to Python datetime object (UTC)
-        utc_time_now = datetime.now(timezone.utc) ## Get current machine datetime in UTC 
+        now_datetime_utc = datetime.now(timezone.utc) ## Get current machine datetime object in UTC 
 
-        time_difference = expire_datetime_utc - utc_time_now ## Get time different between now and expiration time value 
-        time_difference_in_seconds = int(round(time_difference / timedelta(seconds=1))) ## convert it to second as a round int
+        expire_time = expire_datetime_utc - now_datetime_utc ## Get time different between now and expiration time value 
+        expire_time = int(round(expire_time / timedelta(seconds=1))) ## convert it to second as a round int
 
-    return token, expiration, time_difference_in_seconds
+    return token, expiration, expire_time
 
 ## ------------------------------------------ TRKD WebSocket functions ------------------------------------------ ##
 
+# Process incoming messages from TRKD Elektron WebSocket Server
 def process_message(message_json):
     """ Parse at high level and output JSON of message """
     message_type = message_json['Type']
@@ -103,21 +104,22 @@ def process_message(message_json):
             message_domain = message_json['Domain']
             if message_domain == "Login":
                 process_login_response(message_json)
-    elif message_type == "Ping":
-        pong_json = { 'Type':'Pong' }
+    # Ping and Pong messages are exchanged between endpoints of a connection to verify that the remote endpoint is still alive.
+    elif message_type == "Ping": 
+        pong_json = { 'Type':'Pong' } # when either endpoint receives a Ping message, it should send a Pong message in response.
         web_socket_app.send(json.dumps(pong_json))
         print("SENT:")
         print(json.dumps(pong_json, sort_keys=True, indent=2, separators=(',', ':')))
 
-
+# Process incoming Login Refresh message from TRKD Elektron WebSocket Server
 def process_login_response(message_json):
     """ Send item request """
     global logged_in
 
     logged_in = True
     send_market_price_request(ric_name)
 
-
+# Send JSON OMM Market Price Request message to TRKD Elektron WebSocket Server
 def send_market_price_request(ric_name):
     """ Create and send simple Market Price request """
     mp_req_json = {
@@ -130,7 +132,7 @@ def send_market_price_request(ric_name):
     print("SENT:")
     print(json.dumps(mp_req_json, sort_keys=True, indent=2, separators=(',', ':')))
 
-
+# Send JSON OMM Login Request message to TRKD Elektron WebSocket Server to initiate the OMM connection
 def send_login_request(is_refresh_token=False):
     """ Generate a login request from command line data (or defaults) and send """
     login_json = {
@@ -160,7 +162,7 @@ def send_login_request(is_refresh_token=False):
     print("SENT:")
     print(json.dumps(login_json, sort_keys=True, indent=2, separators=(',', ':')))
 
-
+# Receive every messages from TRKD Elektron WebSocket Server
 def on_message(_, message):
     """ Called when message received, parse message into JSON for processing """
     print("RECEIVED: ")
@@ -182,7 +184,7 @@ def on_close(_):
     print("WebSocket Closed")
     web_socket_open = False
 
-
+# Establish a WebSocket connection success
 def on_open(_):
     """ Called when handshake is complete and websocket is open, send login """
 
@@ -200,10 +202,10 @@ def on_open(_):
     password = getpass.getpass(prompt='Please input password: ')
     appid = input('Please input appid: ')
 
-    token, expiration, expire_time_in_seconds = CreateAuthorization(username,password,appid)
+    token, expiration, expire_time = CreateAuthorization(username,password,appid)
     print('Token = %s'%(token))
     print('Expiration  = %s'%(expiration))
-    print('Expiration in next = %d seconds'%(expire_time_in_seconds))
+    print('Expiration in next = %d seconds'%(expire_time))
     ## if authentiacation success, continue subscribing Quote
     if token and expiration:
         print('Do WS here')
@@ -215,30 +217,26 @@ def on_open(_):
             on_close=on_close,
             subprotocols=[ws_protocol])
         web_socket_app.on_open = on_open
-        # for test
 
-        # expire_time_in_seconds = 120
-        # time_before_expire_in_seconds = 15
         # Event loop
         wst = threading.Thread(target=web_socket_app.run_forever)
         wst.start()
 
         try:
             while True:
-                #time.sleep(1)
-                if (expire_time_in_seconds > time_before_expire_in_seconds):
-                    time.sleep(expire_time_in_seconds-time_before_expire_in_seconds)
+                if (expire_time > time_to_relogin):
+                    time.sleep(expire_time - time_to_relogin) # Sleep Thread until 15 minutes before expiration
                 else:
                     # failt the refresh sine value too small
                     sys.exit(1)
-                token, expiration, expire_time_in_seconds = CreateAuthorization(username,password,appid)
-                print('new Token = %s'%(token))
-                print('new Expiration  = %s'%(expiration))
-                print('new Expiration in next = %d seconds'%(expire_time_in_seconds))
+                
+                # Re-issue login request before token expiration to keep session open. 
+                token, expiration, expire_time = CreateAuthorization(username,password,appid)
                 if not token:
                     sys.exit(1)
                 if logged_in:
                     print('############### Re-new Authentication to TRKD ###############')
-                    send_login_request(is_refresh_token=True)
+                    # Resend JSON OMM Login Request message with Refresh: false to TRKD Elektron WebSocket Server
+                    send_login_request(is_refresh_token=True) 
         except KeyboardInterrupt:
             web_socket_app.close()