Update app.py

app.py

@@ -16,18 +16,31 @@ if uploaded_file is not None:
         # Load JSON data
         graph_data = json.load(uploaded_file)
         
+        # Validate JSON structure
+        if "nodes" not in graph_data or "edges" not in graph_data:
+            raise ValueError("The JSON file must contain 'nodes' and 'edges' keys.")
+        
+        if not isinstance(graph_data["nodes"], list) or not isinstance(graph_data["edges"], list):
+            raise ValueError("'nodes' and 'edges' must be lists.")
+        
         # Function to create a NetworkX graph from data
         def create_graph(data):
             G = nx.DiGraph()
-            for node in data.get("nodes", []):
+            for node in data["nodes"]:
                 G.add_node(node["id"], label=node.get("label", node["id"]))
-            for edge in data.get("edges", []):
+            for edge in data["edges"]:
                 G.add_edge(edge["source"], edge["target"], label=edge.get("label", ""))
             return G
         
         # Generate the graph
         graph = create_graph(graph_data)
         
+        # Check if the graph has any nodes or edges
+        if graph.number_of_nodes() == 0:
+            raise ValueError("The graph has no nodes.")
+        if graph.number_of_edges() == 0:
+            raise ValueError("The graph has no edges.")
+        
         # Function to create a pyvis network from NetworkX graph
         def create_pyvis_graph(G):
             net = Network(height="600px", width="100%", directed=True)
@@ -45,7 +58,8 @@ if uploaded_file is not None:
         pyvis_graph.show(output_file)
         
         # Display the graph in Streamlit
-        st.components.v1.html(open(output_file, "r").read(), height=600, width=800)
+        with open(output_file, "r") as file:
+            st.components.v1.html(file.read(), height=600, width=800)
         
         # Clean up the temporary file
         if os.path.exists(output_file):