From 43b9a8d0fee519857484cf548d7a87bf26ad811a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Louis=20V=C3=A9zina?=
 <5130500+morpheus65535@users.noreply.github.com>
Date: Tue, 17 Dec 2019 23:37:38 -0500
Subject: [PATCH] Added server side events (SSE) to update client datatables.

---
 bazarr/SSE.py              | 33 +++++++++++++++++++++++++++++++++
 bazarr/api.py              | 16 +++++++++++++++-
 bazarr/templates/test.html |  7 ++++++-
 3 files changed, 54 insertions(+), 2 deletions(-)
 create mode 100644 bazarr/SSE.py

diff --git a/bazarr/SSE.py b/bazarr/SSE.py
new file mode 100644
index 000000000..9c9c03183
--- /dev/null
+++ b/bazarr/SSE.py
@@ -0,0 +1,33 @@
+from __future__ import absolute_import
+from collections import deque
+import json
+import time
+
+
+class EventStream:
+    """
+    This class is used to read or write items to the notifications deque.
+    """
+    
+    def __init__(self):
+        self.queue = deque(maxlen=10)
+    
+    def write(self, msg):
+        """
+            :param msg: The message to display.
+            :type msg: str
+        """
+        
+        self.queue.append("data:" + msg + "\n\n")
+    
+    def read(self):
+        """
+            :return: Return the oldest notification available.
+            :rtype: str
+        """
+
+        if self.queue or (len(self.queue) > 0):
+            return self.queue.popleft()
+
+
+event_stream = EventStream()
diff --git a/bazarr/api.py b/bazarr/api.py
index 6e94b8932..0f093fa09 100644
--- a/bazarr/api.py
+++ b/bazarr/api.py
@@ -14,11 +14,14 @@ from database import database
 from helper import path_replace, path_replace_reverse, path_replace_movie, path_replace_reverse_movie
 from get_languages import load_language_in_db, alpha2_from_language, alpha3_from_language, language_from_alpha2, \
     alpha3_from_alpha2
+from SSE import event_stream
 
 from flask import Flask, jsonify, request, render_template
+import flask
 from flask_restful import Resource, Api
 
 app = Flask(__name__)
+app.debug = True
 api = Api(app)
 
 load_language_in_db()
@@ -28,6 +31,17 @@ def test():
     return render_template('test.html')
 
 
+@app.route('/event')
+def event():
+    return flask.Response(event_stream.read(), mimetype="text/event-stream")
+
+
+@app.route('/write')
+def write():
+    event_stream.write('fake message')
+    return "", 200
+
+
 class Badges(Resource):
     def get(self):
         result = {
@@ -438,4 +452,4 @@ api.add_resource(WantedSeries, '/api/wanted_series')
 api.add_resource(WantedMovies, '/api/wanted_movies')
 
 if __name__ == '__main__':
-    app.run(port=6767, debug=True)
+    app.run(port=6767, threaded=True)
diff --git a/bazarr/templates/test.html b/bazarr/templates/test.html
index 50fc7eff0..a0519eb94 100644
--- a/bazarr/templates/test.html
+++ b/bazarr/templates/test.html
@@ -23,7 +23,7 @@
 
 <script type="text/javascript">
     $(document).ready(function() {
-        $('#example').DataTable( {
+        var table = $('#example').DataTable( {
             "processing": true,
             "serverSide": true,
             "ajax": "http://localhost:6767/api/history_movies",
@@ -34,6 +34,11 @@
             { "data": "description" }
             ]
         } );
+
+        var source = new EventSource('/event');
+        source.onmessage = function (event) {
+             table.ajax.reload(null, false);
+        };
     } );
 </script>
 </html>
\ No newline at end of file