Adds empty queue mode to webhook notification.

nodes/webhook.py

@@ -1,5 +1,6 @@
 import requests
 import json
+from server import PromptServer
 
 from .util import ComfyAnyType
 
@@ -9,7 +10,7 @@ class Webhook:
         return {
             "required": {
                 "any": (ComfyAnyType("*"), {}),
-                # "mode": (["always", "on empty queue"], {}), # TODO: Need a way to get queue status from main.py
+                "mode": (["always", "on empty queue"], {}),
                 "webhook_url": ("STRING", {'default': 'http://localhost:5000/'}),
                 "verify_ssl": ("BOOLEAN", {"default": True}),
                 "notification_text": ('STRING', {'default': 'Your notification has triggered.'}),
@@ -23,8 +24,13 @@ class Webhook:
     RETURN_TYPES = tuple()
     CATEGORY = "notifications"
 
-    def hook(self, any, webhook_url, notification_text, json_format, timeout, verify_ssl):
-
+    def hook(self, any, mode, webhook_url, notification_text, json_format, timeout, verify_ssl):
+        if mode == 'on empty queue':
+            queue = PromptServer.instance.prompt_queue.queue
+            queue_len = len(queue)
+            if queue_len > 0:
+                print(f'[Webhook Notificaton] Not sending notification, queue is not empty (size: {queue_len})')
+                return (0, )
         payload = json_format.replace("<notification_text>", notification_text)
         payload = json.loads(payload)
         res = requests.post(webhook_url, json=payload, timeout=timeout, verify=verify_ssl)