From f8b08e0b33ca31124c2773f47a624eeb0a4f302f Mon Sep 17 00:00:00 2001
From: Marco Perini <perinim.98@gmail.com>
Date: Tue, 4 Jun 2024 23:34:43 +0200
Subject: [PATCH] feat(append_node): append node to existing graph

---
 scrapegraphai/graphs/abstract_graph.py | 10 ++++++++++
 scrapegraphai/graphs/base_graph.py     | 24 +++++++++++++++++++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/scrapegraphai/graphs/abstract_graph.py b/scrapegraphai/graphs/abstract_graph.py
index 380def19..4227db79 100644
--- a/scrapegraphai/graphs/abstract_graph.py
+++ b/scrapegraphai/graphs/abstract_graph.py
@@ -378,6 +378,16 @@ class AbstractGraph(ABC):
             return self.final_state[key]
         return self.final_state
 
+    def append_node(self, node):
+        """
+        Add a node to the graph.
+
+        Args:
+            node (BaseNode): The node to add to the graph.
+        """
+
+        self.graph.append_node(node)
+
     def get_execution_info(self):
         """
         Returns the execution information of the graph.
diff --git a/scrapegraphai/graphs/base_graph.py b/scrapegraphai/graphs/base_graph.py
index 625e8f12..1b2cb4da 100644
--- a/scrapegraphai/graphs/base_graph.py
+++ b/scrapegraphai/graphs/base_graph.py
@@ -49,6 +49,7 @@ class BaseGraph:
     def __init__(self, nodes: list, edges: list, entry_point: str, use_burr: bool = False, burr_config: dict = None):
 
         self.nodes = nodes
+        self.raw_edges = edges
         self.edges = self._create_edges({e for e in edges})
         self.entry_point = entry_point.node_name
         self.initial_state = {}
@@ -168,4 +169,25 @@ class BaseGraph:
             result = bridge.execute(initial_state)
             return (result["_state"], [])
         else:
-            return self._execute_standard(initial_state)
\ No newline at end of file
+            return self._execute_standard(initial_state)
+    
+    def append_node(self, node):
+        """
+        Adds a node to the graph.
+
+        Args:
+            node (BaseNode): The node instance to add to the graph.
+        """
+        
+        # if node name already exists in the graph, raise an exception
+        if node.node_name in {n.node_name for n in self.nodes}:
+            raise ValueError(f"Node with name '{node.node_name}' already exists in the graph. You can change it by setting the 'node_name' attribute.")
+        
+        # get the last node in the list
+        last_node = self.nodes[-1]
+        # add the edge connecting the last node to the new node
+        self.raw_edges.append((last_node, node))
+        # add the node to the list of nodes
+        self.nodes.append(node)
+        # update the edges connecting the last node to the new node
+        self.edges = self._create_edges({e for e in self.raw_edges})
\ No newline at end of file