Assign new tasks on the fly

The old logic assigned a task when the user finished the
demo, logged in, or finished an annotation. This was not
optimal as it could lead to race conditions where some
datasets were annotated unnecessarily. With this change
we select the dataset to annotate at the exact moment the
user wants to do another one.

1 files changed, 26 insertions, 11 deletions

diff --git a/app/main/routes.py b/app/main/routes.py
index 13fe3f8..8a0e83e 100644
--- a/app/main/routes.py
+++ b/app/main/routes.py
@@ -46,6 +46,32 @@ def index():
     return render_template("index.html", title="Home")
 
 
+@bp.route("/assign")
+@login_required
+def assign():
+    # Intermediate page that assigns a task to a user if needed and then
+    # redirects to /annotate/task.id
+    user_tasks = Task.query.filter_by(annotator_id=current_user.id).all()
+    user_tasks = [t for t in user_tasks if not t.dataset.is_demo]
+    user_tasks = [t for t in user_tasks if not t.done]
+
+    # if the user has, for some reason, a unfinished assigned task, redirect to
+    # that
+    if len(user_tasks) > 0:
+        task = user_tasks[0]
+        return redirect(url_for("main.annotate", task_id=task.id))
+
+    task = generate_user_task(current_user)
+    if task is None:
+        flash(
+            "There are no more datasets to annotate at the moment, thanks for all your help!",
+            "info",
+        )
+        return redirect(url_for("main.index"))
+    db.session.add(task)
+    db.session.commit()
+    return redirect(url_for("main.annotate", task_id=task.id))
+
 @bp.route("/annotate/<int:task_id>", methods=("GET", "POST"))
 @login_required
 def annotate(task_id):
@@ -94,17 +120,6 @@ def annotate(task_id):
             "annotations_raw": annotation,
         }
         send_annotation_backup(record)
-
-        # assign a new task if necessary
-        task = generate_user_task(current_user)
-        if task is None:
-            return url_for("main.index")
-        db.session.add(task)
-        db.session.commit()
-        flash(
-            "A new dataset has been assigned for you to annotate. Thanks for your help!",
-            "info",
-        )
         return url_for("main.index")
 
     task = Task.query.filter_by(id=task_id).first()