Merge pull request #693 from NextCenturyCorporation/restrictToOneTab

MCS-1945 [Webenabled] Restrict to one tab

webenabled/mcsweb.py

@@ -47,7 +47,7 @@ def clean_request_data(request, is_json=False):
     return data
 
 
-def get_mcs_interface(request, label):
+def get_mcs_interface(request, label, on_exit=False):
     # Do we know who this is?
     uniq_id_str = request.cookies.get("uniq_id")
 
@@ -63,14 +63,17 @@ def get_mcs_interface(request, label):
         else:
             app.logger.info("MCS interface is unavailable")
 
-    letters = string.ascii_lowercase
-    uniq_id_str = ''.join(random.choice(letters) for i in range(10))
-    app.logger.info(f"{label}: new user: {uniq_id_str}")
+    # skip for exit_unity route, since in that case, we don't
+    # need to start a new interface/controller if one isn't found
+    if (on_exit is False):
+        letters = string.ascii_lowercase
+        uniq_id_str = ''.join(random.choice(letters) for i in range(10))
+        app.logger.info(f"{label}: new user: {uniq_id_str}")
 
-    # Don't recognize, create new mcs interface
-    mcs_interface = MCSInterface(uniq_id_str)
-    mcs_interface.start_mcs()
-    session[uniq_id_str] = mcs_interface
+        # Don't recognize, create new mcs interface
+        mcs_interface = MCSInterface(uniq_id_str)
+        mcs_interface.start_mcs()
+        session[uniq_id_str] = mcs_interface
 
     return mcs_interface, uniq_id_str
 
@@ -135,10 +138,18 @@ def handle_keypress():
 @app.route("/exit_unity", methods=["POST"])
 def exit_unity():
     app.logger.info("=" * 30)
-    mcs_interface, unique_id = get_mcs_interface(request, "Exit Unity")
+    mcs_interface, unique_id = get_mcs_interface(
+        request, "Exit Unity", on_exit=True)
     if mcs_interface is None:
-        app.logger.warn("Cannot load MCS interface")
-        return
+        error_msg = ("Cannot find MCS interface to exit. If you attempted "
+                     "to quit on startup/initial page load, you will "
+                     "likely have to kill the MCS controller process "
+                     "manually.")
+        app.logger.warn(error_msg)
+        resp = jsonify(
+            error_msg=error_msg
+        )
+        return resp
 
     controller_pid = mcs_interface.get_controller_pid()
 

webenabled/templates/mcs_page.html

@@ -20,6 +20,11 @@
             flex-direction: row;
         }
 
+        #another-tab-err {
+            display: none;
+            flex-direction: column;
+        }
+
         div#header h1 {
             height: 80px;
             line-height: 80px;
@@ -232,7 +237,13 @@
     <div id="header">
         <h1>Machine Common Sense</h1>
     </div>
+    <div id="another-tab-err">
+        <div class="section">
+            <p>Error: It looks like MCS is already running in a separate tab. Please close this tab.</p>
+        </div>
+    </div>
     <div id="content-wrapper">
+
         <div class="left-panel column">
             <div id="scene-nav-info" class="section">
                 <p><strong>Scenes</strong>
@@ -367,10 +378,25 @@ <h1>Machine Common Sense</h1>
         "objectImageCoordsY": 200
     }
     var hasValidInput = true
+    var isMainWindow = true;
     loadingSpinner(false)
-    loadController()
+    checkForExistingTab()
 
-    sceneSelect.addEventListener('change', select_scene, false);
+    function checkForExistingTab() {
+        let doesTabExist = localStorage.getItem("mainMcsTabIsOpen")
+
+        if(doesTabExist === null) {
+            localStorage.setItem("mainMcsTabIsOpen", true)
+
+            loadController()
+
+            sceneSelect.addEventListener('change', select_scene, false);
+        } else {
+            isMainWindow = false;
+            document.getElementById("another-tab-err").style.display = "flex"
+            document.getElementById("content-wrapper").style.display = "none"
+        }
+    }
 
     function eventHandleScenes() {
         sceneSelect = document.getElementById("scenes-dropdown");
@@ -654,9 +680,13 @@ <h1>Machine Common Sense</h1>
 
 
     function cleanup(e) {
-        resp = fetch("{{url_for('exit_unity')}}",
+        let mainTabOpened = localStorage.getItem("mainMcsTabIsOpen")
+        if(mainTabOpened && isMainWindow) {
+            localStorage.clear()
+            resp = fetch("{{url_for('exit_unity')}}",
             {method: 'POST', body: JSON.stringify(this.innerHTML)})
             .then(parseJsonResponse)
+        }
     }
 
     window.addEventListener('beforeunload', this.cleanup, false);