app.py

import gradio as gr
import networkx as nx
import matplotlib.pyplot as plt
from neo4j import GraphDatabase
import io
import base64

class Neo4jGraphVisualizer:
    def __init__(self, uri, username, password):
        """
        Initialize the Neo4j graph database connection
        
        Args:
            uri (str): Neo4j database URI
            username (str): Neo4j username
            password (str): Neo4j password
        """
        self.driver = GraphDatabase.driver(uri, auth=(username, password))

    def fetch_graph_data(self):
        """
        Fetch graph data from Neo4j database
        
        Returns:
            dict: A dictionary containing nodes and relationships
        """
        with self.driver.session() as session:
            # Fetch all nodes with elementId instead of deprecated ID()
            nodes_result = session.run("""
                MATCH (n) 
                RETURN elementId(n) as id, 
                       labels(n) as labels, 
                       properties(n) as properties
            """)
            
            # Fetch all relationships using elementId
            relationships_result = session.run("""
                MATCH (a)-[r]->(b) 
                RETURN 
                    elementId(a) as source_id, 
                    elementId(b) as target_id, 
                    type(r) as relationship_type,
                    properties(r) as relationship_properties
            """)
            
            # Process nodes
            nodes = [
                {
                    'id': record['id'], 
                    'label': record['labels'][0] if record['labels'] else 'Unknown',
                    'properties': dict(record['properties'])
                } 
                for record in nodes_result
            ]
            
            # Process relationships
            relationships = [
                {
                    'source': record['source_id'], 
                    'target': record['target_id'], 
                    'type': record['relationship_type'],
                    'properties': dict(record.get('relationship_properties', {}))
                } 
                for record in relationships_result
            ]
            
            return {'nodes': nodes, 'relationships': relationships}

    def visualize_graph(self):
        """
        Visualize the graph using NetworkX and Matplotlib
        
        Returns:
            str: Base64 encoded image of the graph
        """
        try:
            # Fetch graph data
            graph_data = self.fetch_graph_data()
            
            # Create NetworkX graph
            G = nx.DiGraph()
            
            # Add nodes
            for node in graph_data['nodes']:
                # Use node's label or properties for display
                label = node.get('properties', {}).get('name', str(node['id']))
                G.add_node(node['id'], 
                           label=label, 
                           properties=node['properties'])
            
            # Add edges
            for rel in graph_data['relationships']:
                G.add_edge(rel['source'], rel['target'], 
                           type=rel['type'], 
                           properties=rel['properties'])
            
            # Visualization
            plt.figure(figsize=(16, 12))
            pos = nx.spring_layout(G, k=0.9, iterations=50)  # Improved layout
            
            # Draw nodes with color and size based on properties
            node_sizes = [300 + len(str(G.nodes[node]['properties'])) * 10 for node in G.nodes()]
            node_colors = ['lightblue' if idx % 2 == 0 else 'lightgreen' for idx in range(len(G.nodes()))]
            
            nx.draw_networkx_nodes(G, pos, 
                                    node_color=node_colors, 
                                    node_size=node_sizes, 
                                    alpha=0.8)
            
            # Draw edges
            nx.draw_networkx_edges(G, pos, 
                                    edge_color='gray', 
                                    arrows=True,
                                    width=1.5)
            
            # Draw labels
            nx.draw_networkx_labels(G, pos, 
                                     labels={node: G.nodes[node]['label'] for node in G.nodes()},
                                     font_size=8)
            
            plt.title("Neo4j Graph Visualization")
            plt.axis('off')
            
            # Save to buffer
            buffer = io.BytesIO()
            plt.savefig(buffer, format='png', dpi=300, bbox_inches='tight')
            buffer.seek(0)
            image_png = buffer.getvalue()
            buffer.close()
            plt.close()  # Close the plot to free memory
            
            # Encode
            graphic = base64.b64encode(image_png).decode('utf-8')
            return f"data:image/png;base64,{graphic}"
        
        except Exception as e:
            print(f"Error in graph visualization: {e}")
            return f"Error visualizing graph: {e}"

    def close(self):
        """Close the Neo4j driver connection"""
        self.driver.close()

def create_gradio_interface(uri, username, password):
    """
    Create a Gradio interface for Neo4j graph visualization
    
    Args:
        uri (str): Neo4j database URI
        username (str): Neo4j username
        password (str): Neo4j password
    """
    visualizer = Neo4jGraphVisualizer(uri, username, password)
    
    def visualize_graph():
        try:
            graph_image = visualizer.visualize_graph()
            return graph_image
        except Exception as e:
            return f"Error: {str(e)}"
    
    # Create Gradio interface
    iface = gr.Interface(
        fn=visualize_graph,
        inputs=[],
        outputs=gr.Image(type="filepath"),
        title="Neo4j Graph Visualization",
        description="Visualize graph data from Neo4j database"
    )
    
    return iface, visualizer

# Configuration (replace with your actual Neo4j credentials)
NEO4J_URI="neo4j+s://b96332bd.databases.neo4j.io"
NEO4J_USERNAME="neo4j"
NEO4J_PASSWORD="qviTdN6cw66AjIv6lu7kXcsN4keYPdXc2gAWuIoB8T4"
AURA_INSTANCEID="b96332bd"
AURA_INSTANCENAME="Instance01"

def main():
    # Create Gradio interface
    interface, visualizer = create_gradio_interface(
        NEO4J_URI, 
        NEO4J_USERNAME, 
        NEO4J_PASSWORD
    )
    
    try:
        # Launch the interface
        interface.launch(server_name='0.0.0.0', server_port=7860)
    except Exception as e:
        print(f"Error launching interface: {e}")
    finally:
        # Ensure driver is closed
        visualizer.close()

if __name__ == "__main__":
    main()