Implement error handling and default node creation for mindmap routes; initialize database on first request to ensure root node exists.

website/app.py

@@ -116,7 +116,16 @@ def index():
 # Route for the mindmap page
 @app.route('/mindmap')
 def mindmap():
-    return render_template('mindmap.html')
+    try:
+        root_node = MindMapNode.query.filter_by(parent_id=None).first()
+        if not root_node:
+            root_node = MindMapNode(name="Wissenschaft")
+            db.session.add(root_node)
+            db.session.commit()
+        return render_template('mindmap.html')
+    except Exception as e:
+        app.logger.error(f"Error loading mindmap: {str(e)}")
+        return render_template('mindmap.html', error="Fehler beim Laden der Mindmap. Bitte versuchen Sie es erneut.")
 
 # Route for user profile
 @app.route('/profile')
@@ -128,17 +137,28 @@ def profile():
 # API routes for mindmap and thoughts
 @app.route('/api/mindmap')
 def get_mindmap():
-    root_nodes = MindMapNode.query.filter_by(parent_id=None).all()
+    try:
+        root_nodes = MindMapNode.query.filter_by(parent_id=None).all()
         
-    def build_tree(node):
-        return {
-            'id': node.id,
-            'name': node.name,
-            'children': [build_tree(child) for child in node.children]
-        }
+        def build_tree(node):
+            return {
+                'id': node.id,
+                'name': node.name,
+                'children': [build_tree(child) for child in node.children]
+            }
         
-    result = [build_tree(node) for node in root_nodes]
-    return jsonify(result)
+        result = [build_tree(node) for node in root_nodes]
+        if not result:
+            # Create default root if no nodes exist
+            root = MindMapNode(name="Wissenschaft")
+            db.session.add(root)
+            db.session.commit()
+            result = [build_tree(root)]
+            
+        return jsonify(result)
+    except Exception as e:
+        app.logger.error(f"Error in get_mindmap: {str(e)}")
+        return jsonify({'error': 'Fehler beim Laden der Mindmap'}), 500
 
 @app.route('/api/thoughts/<int:node_id>', methods=['GET'])
 def get_thoughts(node_id):
@@ -256,9 +276,27 @@ def admin():
     
     return render_template('admin.html', users=users, nodes=nodes, thoughts=thoughts)
 
+@app.before_first_request
+def initialize_database():
+    db.create_all()
+    # Create root node if it doesn't exist
+    if not MindMapNode.query.first():
+        root = MindMapNode(name="Wissenschaft")
+        db.session.add(root)
+        db.session.commit()
+
 # Flask starten
 if __name__ == '__main__':
     with app.app_context():
-        # Make sure tables exist
+        # Initialize database and create root node
         db.create_all()
+        try:
+            root = MindMapNode.query.filter_by(parent_id=None).first()
+            if not root:
+                root = MindMapNode(name="Wissenschaft")
+                db.session.add(root)
+                db.session.commit()
+        except Exception as e:
+            print(f"Error initializing database: {str(e)}")
+    
     app.run(host="0.0.0.0", debug=True)