From 1389b6b510b33736e873ed0fa4b4589e83af94a4 Mon Sep 17 00:00:00 2001
From: Patrick Jentsch <p.jentsch@uni-bielefeld.de>
Date: Wed, 6 Nov 2019 14:35:33 +0100
Subject: [PATCH] Change logic of how connected sessions are identified.

---
 app/corpora/__init__.py                       |  3 +-
 app/corpora/events.py                         | 30 ++++++++++++++
 app/events.py                                 | 39 +++++++++----------
 app/templates/corpora/corpus_analysis.html.j2 |  5 +++
 4 files changed, 54 insertions(+), 23 deletions(-)
 create mode 100644 app/corpora/events.py

diff --git a/app/corpora/__init__.py b/app/corpora/__init__.py
index 85739bc7..8323ec6a 100644
--- a/app/corpora/__init__.py
+++ b/app/corpora/__init__.py
@@ -2,5 +2,4 @@ from flask import Blueprint
 
 corpora = Blueprint('corpora', __name__)
 
-
-from . import views
+from . import events, views
diff --git a/app/corpora/events.py b/app/corpora/events.py
new file mode 100644
index 00000000..9a7a5af1
--- /dev/null
+++ b/app/corpora/events.py
@@ -0,0 +1,30 @@
+from app import socketio
+from app.events import connected_sessions
+from flask import current_app, request
+from flask_login import login_required
+import logging
+
+
+@socketio.on('init_corpus_analysis')
+@login_required
+def init_corpus_analysis(corpus_id):
+    ''' TODO: Check if current_user is allowed to subscribe to this '''
+    socketio.start_background_task(init_corpus_analysis_,
+                                   current_app._get_current_object(),
+                                   corpus_id,
+                                   request.sid)
+
+
+@socketio.on('query_event')
+def recv_query(message):
+    logger = logging.getLogger(__name__)
+    logger.warning(message)
+
+
+def init_corpus_analysis_(app, corpus_id, session_id):
+    logger = logging.getLogger(__name__)
+    with app.app_context():
+        while session_id in connected_sessions:
+            logger.warning('Run container, run!')
+            socketio.sleep(3)
+    logger.warning('Stop container, stop!')
diff --git a/app/events.py b/app/events.py
index 35474c64..bd628c88 100644
--- a/app/events.py
+++ b/app/events.py
@@ -9,10 +9,10 @@ import logging
 
 
 '''
-' A list containing session ids of disconnected Socket.IO sessions. It is used
-' to signal associated background tasks to stop.
+' A list containing session ids of connected Socket.IO sessions. It is used to
+' determine runtimes of associated background tasks.
 '''
-disconnected = []
+connected_sessions = []
 
 
 @socketio.on('connect')
@@ -24,12 +24,23 @@ def connect():
     ' will be used for further information exchange generated by a background
     ' task associated with the sid.
     '''
+    connected_sessions.append(request.sid)
     socketio.start_background_task(background_task,
                                    current_app._get_current_object(),
                                    current_user.id,
                                    request.sid)
 
 
+@socketio.on('disconnect')
+@login_required
+def disconnect():
+    '''
+    ' On disconnect the session id (sid) of the connection gets placed in the
+    ' disconnected list (see above).
+    '''
+    connected_sessions.remove(request.sid)
+
+
 @socketio.on('inspect_user')
 @login_required
 @admin_required
@@ -48,22 +59,6 @@ def inspect_user(user_id):
                                    True)
 
 
-@socketio.on('disconnect')
-@login_required
-def disconnect():
-    '''
-    ' On disconnect the session id (sid) of the connection gets placed in the
-    ' disconnected list (see above).
-    '''
-    disconnected.append(request.sid)
-
-
-@socketio.on('query_event')
-def recv_query(message):
-    logger = logging.getLogger(__name__)
-    logger.warning(message)
-
-
 def background_task(app, user_id, session_id, foreign=False):
     '''
     ' Sends initial corpus and job lists to the client. Afterwards it checks
@@ -75,6 +70,7 @@ def background_task(app, user_id, session_id, foreign=False):
     '
     '       > where '*' is either 'corpora' or 'jobs'
     '''
+    logger = logging.getLogger(__name__)
     with app.app_context():
         user = db.session.query(User).get_or_404(user_id)
         ''' Get current values from the database. '''
@@ -88,7 +84,8 @@ def background_task(app, user_id, session_id, foreign=False):
                       json.dumps(jobs),
                       room=session_id)
         ''' TODO: Implement maximum runtime for this loop. '''
-        while session_id not in disconnected:
+        while session_id in connected_sessions:
+            logger.warning('Running...')
             ''' Get current values from the database '''
             new_corpora = user.corpora_as_dict()
             new_jobs = user.jobs_as_dict()
@@ -108,4 +105,4 @@ def background_task(app, user_id, session_id, foreign=False):
             corpora = new_corpora
             jobs = new_jobs
             socketio.sleep(3)
-    disconnected.remove(session_id)
+    logger.warning('Stoping!')
diff --git a/app/templates/corpora/corpus_analysis.html.j2 b/app/templates/corpora/corpus_analysis.html.j2
index bd2eb46e..33534038 100644
--- a/app/templates/corpora/corpus_analysis.html.j2
+++ b/app/templates/corpora/corpus_analysis.html.j2
@@ -1,6 +1,11 @@
 {% extends "full_width.html.j2" %}
 
 {% block page_content %}
+<script>
+socket.emit('init_corpus_analysis', {{ corpus.id }});
+</script>
+
+
 
 <div class="col s12 m3 l3 sticky">
   <a class="waves-effect waves-light btn" href="{{ url_for('corpora.corpus', corpus_id=corpus_id) }}"><i class="material-icons left">arrow_back</i>Back to corpus overview</a>