server.py

import os
import sys
import asyncio
import traceback

import nodes
import folder_paths
import execution
import uuid
import urllib
import json
import glob
import struct
import ssl
from PIL import Image, ImageOps
from PIL.PngImagePlugin import PngInfo
from io import BytesIO

import aiohttp
from aiohttp import web
import logging

import mimetypes
from comfy.cli_args import args
import comfy.utils
import comfy.model_management
import node_helpers
from app.frontend_management import FrontendManager
from app.user_manager import UserManager
from model_filemanager import download_model, DownloadModelStatus
from typing import Optional

class BinaryEventTypes:
    PREVIEW_IMAGE = 1
    UNENCODED_PREVIEW_IMAGE = 2

async def send_socket_catch_exception(function, message):
    try:
        await function(message)
    except (aiohttp.ClientError, aiohttp.ClientPayloadError, ConnectionResetError) as err:
        logging.warning("send error: {}".format(err))

@web.middleware
async def cache_control(request: web.Request, handler):
    response: web.Response = await handler(request)
    if request.path.endswith('.js') or request.path.endswith('.css'):
        response.headers.setdefault('Cache-Control', 'no-cache')
    return response

def create_cors_middleware(allowed_origin: str):
    @web.middleware
    async def cors_middleware(request: web.Request, handler):
        if request.method == "OPTIONS":
            # Pre-flight request. Reply successfully:
            response = web.Response()
        else:
            response = await handler(request)

        response.headers['Access-Control-Allow-Origin'] = allowed_origin
        response.headers['Access-Control-Allow-Methods'] = 'POST, GET, DELETE, PUT, OPTIONS'
        response.headers['Access-Control-Allow-Headers'] = 'Content-Type, Authorization'
        response.headers['Access-Control-Allow-Credentials'] = 'true'
        return response

    return cors_middleware

class PromptServer():
    def __init__(self, loop):
        PromptServer.instance = self

        mimetypes.init()
        mimetypes.types_map['.js'] = 'application/javascript; charset=utf-8'

        self.user_manager = UserManager()
        self.supports = ["custom_nodes_from_web"]
        self.prompt_queue = None
        self.loop = loop
        self.messages = asyncio.Queue()
        self.client_session:Optional[aiohttp.ClientSession] = None
        self.number = 0

        middlewares = [cache_control]
        if args.enable_cors_header:
            middlewares.append(create_cors_middleware(args.enable_cors_header))

        max_upload_size = round(args.max_upload_size * 1024 * 1024)
        self.app = web.Application(client_max_size=max_upload_size, middlewares=middlewares)
        self.sockets = dict()
        self.web_root = (
            FrontendManager.init_frontend(args.front_end_version)
            if args.front_end_root is None
            else args.front_end_root
        )
        logging.info(f"[Prompt Server] web root: {self.web_root}")
        routes = web.RouteTableDef()
        self.routes = routes
        self.last_node_id = None
        self.client_id = None

        self.on_prompt_handlers = []

        @routes.get('/ws')
        async def websocket_handler(request):
            ws = web.WebSocketResponse()
            await ws.prepare(request)
            sid = request.rel_url.query.get('clientId', '')
            if sid:
                # Reusing existing session, remove old
                self.sockets.pop(sid, None)
            else:
                sid = uuid.uuid4().hex

            self.sockets[sid] = ws

            try:
                # Send initial state to the new client
                await self.send("status", { "status": self.get_queue_info(), 'sid': sid }, sid)
                # On reconnect if we are the currently executing client send the current node
                if self.client_id == sid and self.last_node_id is not None:
                    await self.send("executing", { "node": self.last_node_id }, sid)

                async for msg in ws:
                    if msg.type == aiohttp.WSMsgType.ERROR:
                        logging.warning('ws connection closed with exception %s' % ws.exception())
            finally:
                self.sockets.pop(sid, None)
            return ws

        @routes.get("/")
        async def get_root(request):
            response = web.FileResponse(os.path.join(self.web_root, "index.html"))
            response.headers['Cache-Control'] = 'no-cache'
            response.headers["Pragma"] = "no-cache"
            response.headers["Expires"] = "0"
            return response

        @routes.get("/embeddings")
        def get_embeddings(self):
            embeddings = folder_paths.get_filename_list("embeddings")
            return web.json_response(list(map(lambda a: os.path.splitext(a)[0], embeddings)))

        @routes.get("/extensions")
        async def get_extensions(request):
            files = glob.glob(os.path.join(
                glob.escape(self.web_root), 'extensions/**/*.js'), recursive=True)

            extensions = list(map(lambda f: "/" + os.path.relpath(f, self.web_root).replace("\\", "/"), files))

            for name, dir in nodes.EXTENSION_WEB_DIRS.items():
                files = glob.glob(os.path.join(glob.escape(dir), '**/*.js'), recursive=True)
                extensions.extend(list(map(lambda f: "/extensions/" + urllib.parse.quote(
                    name) + "/" + os.path.relpath(f, dir).replace("\\", "/"), files)))

            return web.json_response(extensions)

        def get_dir_by_type(dir_type):
            if dir_type is None:
                dir_type = "input"

            if dir_type == "input":
                type_dir = folder_paths.get_input_directory()
            elif dir_type == "temp":
                type_dir = folder_paths.get_temp_directory()
            elif dir_type == "output":
                type_dir = folder_paths.get_output_directory()

            return type_dir, dir_type

        def compare_image_hash(filepath, image):
            hasher = node_helpers.hasher()
            
            # function to compare hashes of two images to see if it already exists, fix to #3465
            if os.path.exists(filepath):
                a = hasher()
                b = hasher()
                with open(filepath, "rb") as f:
                    a.update(f.read())
                    b.update(image.file.read())
                    image.file.seek(0)
                    f.close()
                return a.hexdigest() == b.hexdigest()
            return False

        def image_upload(post, image_save_function=None):
            image = post.get("image")
            overwrite = post.get("overwrite")
            image_is_duplicate = False

            image_upload_type = post.get("type")
            upload_dir, image_upload_type = get_dir_by_type(image_upload_type)

            if image and image.file:
                filename = image.filename
                if not filename:
                    return web.Response(status=400)

                subfolder = post.get("subfolder", "")
                full_output_folder = os.path.join(upload_dir, os.path.normpath(subfolder))
                filepath = os.path.abspath(os.path.join(full_output_folder, filename))

                if os.path.commonpath((upload_dir, filepath)) != upload_dir:
                    return web.Response(status=400)

                if not os.path.exists(full_output_folder):
                    os.makedirs(full_output_folder)

                split = os.path.splitext(filename)

                if overwrite is not None and (overwrite == "true" or overwrite == "1"):
                    pass
                else:
                    i = 1
                    while os.path.exists(filepath):
                        if compare_image_hash(filepath, image): #compare hash to prevent saving of duplicates with same name, fix for #3465
                            image_is_duplicate = True
                            break
                        filename = f"{split[0]} ({i}){split[1]}"
                        filepath = os.path.join(full_output_folder, filename)
                        i += 1

                if not image_is_duplicate:
                    if image_save_function is not None:
                        image_save_function(image, post, filepath)
                    else:
                        with open(filepath, "wb") as f:
                            f.write(image.file.read())

                return web.json_response({"name" : filename, "subfolder": subfolder, "type": image_upload_type})
            else:
                return web.Response(status=400)

        @routes.post("/upload/image")
        async def upload_image(request):
            post = await request.post()
            return image_upload(post)


        @routes.post("/upload/mask")
        async def upload_mask(request):
            post = await request.post()

            def image_save_function(image, post, filepath):
                original_ref = json.loads(post.get("original_ref"))
                filename, output_dir = folder_paths.annotated_filepath(original_ref['filename'])

                # validation for security: prevent accessing arbitrary path
                if filename[0] == '/' or '..' in filename:
                    return web.Response(status=400)

                if output_dir is None:
                    type = original_ref.get("type", "output")
                    output_dir = folder_paths.get_directory_by_type(type)

                if output_dir is None:
                    return web.Response(status=400)

                if original_ref.get("subfolder", "") != "":
                    full_output_dir = os.path.join(output_dir, original_ref["subfolder"])
                    if os.path.commonpath((os.path.abspath(full_output_dir), output_dir)) != output_dir:
                        return web.Response(status=403)
                    output_dir = full_output_dir

                file = os.path.join(output_dir, filename)

                if os.path.isfile(file):
                    with Image.open(file) as original_pil:
                        metadata = PngInfo()
                        if hasattr(original_pil,'text'):
                            for key in original_pil.text:
                                metadata.add_text(key, original_pil.text[key])
                        original_pil = original_pil.convert('RGBA')
                        mask_pil = Image.open(image.file).convert('RGBA')

                        # alpha copy
                        new_alpha = mask_pil.getchannel('A')
                        original_pil.putalpha(new_alpha)
                        original_pil.save(filepath, compress_level=4, pnginfo=metadata)

            return image_upload(post, image_save_function)

        @routes.get("/view")
        async def view_image(request):
            if "filename" in request.rel_url.query:
                filename = request.rel_url.query["filename"]
                filename,output_dir = folder_paths.annotated_filepath(filename)

                # validation for security: prevent accessing arbitrary path
                if filename[0] == '/' or '..' in filename:
                    return web.Response(status=400)

                if output_dir is None:
                    type = request.rel_url.query.get("type", "output")
                    output_dir = folder_paths.get_directory_by_type(type)

                if output_dir is None:
                    return web.Response(status=400)

                if "subfolder" in request.rel_url.query:
                    full_output_dir = os.path.join(output_dir, request.rel_url.query["subfolder"])
                    if os.path.commonpath((os.path.abspath(full_output_dir), output_dir)) != output_dir:
                        return web.Response(status=403)
                    output_dir = full_output_dir

                filename = os.path.basename(filename)
                file = os.path.join(output_dir, filename)

                if os.path.isfile(file):
                    if 'preview' in request.rel_url.query:
                        with Image.open(file) as img:
                            preview_info = request.rel_url.query['preview'].split(';')
                            image_format = preview_info[0]
                            if image_format not in ['webp', 'jpeg'] or 'a' in request.rel_url.query.get('channel', ''):
                                image_format = 'webp'

                            quality = 90
                            if preview_info[-1].isdigit():
                                quality = int(preview_info[-1])

                            buffer = BytesIO()
                            if image_format in ['jpeg'] or request.rel_url.query.get('channel', '') == 'rgb':
                                img = img.convert("RGB")
                            img.save(buffer, format=image_format, quality=quality)
                            buffer.seek(0)

                            return web.Response(body=buffer.read(), content_type=f'image/{image_format}',
                                                headers={"Content-Disposition": f"filename=\"{filename}\""})

                    if 'channel' not in request.rel_url.query:
                        channel = 'rgba'
                    else:
                        channel = request.rel_url.query["channel"]

                    if channel == 'rgb':
                        with Image.open(file) as img:
                            if img.mode == "RGBA":
                                r, g, b, a = img.split()
                                new_img = Image.merge('RGB', (r, g, b))
                            else:
                                new_img = img.convert("RGB")

                            buffer = BytesIO()
                            new_img.save(buffer, format='PNG')
                            buffer.seek(0)

                            return web.Response(body=buffer.read(), content_type='image/png',
                                                headers={"Content-Disposition": f"filename=\"{filename}\""})

                    elif channel == 'a':
                        with Image.open(file) as img:
                            if img.mode == "RGBA":
                                _, _, _, a = img.split()
                            else:
                                a = Image.new('L', img.size, 255)

                            # alpha img
                            alpha_img = Image.new('RGBA', img.size)
                            alpha_img.putalpha(a)
                            alpha_buffer = BytesIO()
                            alpha_img.save(alpha_buffer, format='PNG')
                            alpha_buffer.seek(0)

                            return web.Response(body=alpha_buffer.read(), content_type='image/png',
                                                headers={"Content-Disposition": f"filename=\"{filename}\""})
                    else:
                        return web.FileResponse(file, headers={"Content-Disposition": f"filename=\"{filename}\""})

            return web.Response(status=404)

        @routes.get("/view_metadata/{folder_name}")
        async def view_metadata(request):
            folder_name = request.match_info.get("folder_name", None)
            if folder_name is None:
                return web.Response(status=404)
            if not "filename" in request.rel_url.query:
                return web.Response(status=404)

            filename = request.rel_url.query["filename"]
            if not filename.endswith(".safetensors"):
                return web.Response(status=404)

            safetensors_path = folder_paths.get_full_path(folder_name, filename)
            if safetensors_path is None:
                return web.Response(status=404)
            out = comfy.utils.safetensors_header(safetensors_path, max_size=1024*1024)
            if out is None:
                return web.Response(status=404)
            dt = json.loads(out)
            if not "__metadata__" in dt:
                return web.Response(status=404)
            return web.json_response(dt["__metadata__"])

        @routes.get("/system_stats")
        async def get_queue(request):
            device = comfy.model_management.get_torch_device()
            device_name = comfy.model_management.get_torch_device_name(device)
            vram_total, torch_vram_total = comfy.model_management.get_total_memory(device, torch_total_too=True)
            vram_free, torch_vram_free = comfy.model_management.get_free_memory(device, torch_free_too=True)
            system_stats = {
                "system": {
                    "os": os.name,
                    "python_version": sys.version,
                    "embedded_python": os.path.split(os.path.split(sys.executable)[0])[1] == "python_embeded"
                },
                "devices": [
                    {
                        "name": device_name,
                        "type": device.type,
                        "index": device.index,
                        "vram_total": vram_total,
                        "vram_free": vram_free,
                        "torch_vram_total": torch_vram_total,
                        "torch_vram_free": torch_vram_free,
                    }
                ]
            }
            return web.json_response(system_stats)

        @routes.get("/prompt")
        async def get_prompt(request):
            return web.json_response(self.get_queue_info())

        def node_info(node_class):
            obj_class = nodes.NODE_CLASS_MAPPINGS[node_class]
            info = {}
            info['input'] = obj_class.INPUT_TYPES()
            info['input_order'] = {key: list(value.keys()) for (key, value) in obj_class.INPUT_TYPES().items()}
            info['output'] = obj_class.RETURN_TYPES
            info['output_is_list'] = obj_class.OUTPUT_IS_LIST if hasattr(obj_class, 'OUTPUT_IS_LIST') else [False] * len(obj_class.RETURN_TYPES)
            info['output_name'] = obj_class.RETURN_NAMES if hasattr(obj_class, 'RETURN_NAMES') else info['output']
            info['name'] = node_class
            info['display_name'] = nodes.NODE_DISPLAY_NAME_MAPPINGS[node_class] if node_class in nodes.NODE_DISPLAY_NAME_MAPPINGS.keys() else node_class
            info['description'] = obj_class.DESCRIPTION if hasattr(obj_class,'DESCRIPTION') else ''
            info['python_module'] = getattr(obj_class, "RELATIVE_PYTHON_MODULE", "nodes")
            info['category'] = 'sd'
            if hasattr(obj_class, 'OUTPUT_NODE') and obj_class.OUTPUT_NODE == True:
                info['output_node'] = True
            else:
                info['output_node'] = False

            if hasattr(obj_class, 'CATEGORY'):
                info['category'] = obj_class.CATEGORY

            if hasattr(obj_class, 'OUTPUT_TOOLTIPS'):
                info['output_tooltips'] = obj_class.OUTPUT_TOOLTIPS

            if getattr(obj_class, "DEPRECATED", False):
                info['deprecated'] = True
            if getattr(obj_class, "EXPERIMENTAL", False):
                info['experimental'] = True
            return info

        @routes.get("/object_info")
        async def get_object_info(request):
            out = {}
            for x in nodes.NODE_CLASS_MAPPINGS:
                try:
                    out[x] = node_info(x)
                except Exception as e:
                    logging.error(f"[ERROR] An error occurred while retrieving information for the '{x}' node.")
                    logging.error(traceback.format_exc())
            return web.json_response(out)

        @routes.get("/object_info/{node_class}")
        async def get_object_info_node(request):
            node_class = request.match_info.get("node_class", None)
            out = {}
            if (node_class is not None) and (node_class in nodes.NODE_CLASS_MAPPINGS):
                out[node_class] = node_info(node_class)
            return web.json_response(out)

        @routes.get("/history")
        async def get_history(request):
            max_items = request.rel_url.query.get("max_items", None)
            if max_items is not None:
                max_items = int(max_items)
            return web.json_response(self.prompt_queue.get_history(max_items=max_items))

        @routes.get("/history/{prompt_id}")
        async def get_history(request):
            prompt_id = request.match_info.get("prompt_id", None)
            return web.json_response(self.prompt_queue.get_history(prompt_id=prompt_id))

        @routes.get("/queue")
        async def get_queue(request):
            queue_info = {}
            current_queue = self.prompt_queue.get_current_queue()
            queue_info['queue_running'] = current_queue[0]
            queue_info['queue_pending'] = current_queue[1]
            return web.json_response(queue_info)

        @routes.post("/prompt")
        async def post_prompt(request):
            logging.info("got prompt")
            resp_code = 200
            out_string = ""
            json_data =  await request.json()
            json_data = self.trigger_on_prompt(json_data)

            if "number" in json_data:
                number = float(json_data['number'])
            else:
                number = self.number
                if "front" in json_data:
                    if json_data['front']:
                        number = -number

                self.number += 1

            if "prompt" in json_data:
                prompt = json_data["prompt"]
                valid = execution.validate_prompt(prompt)
                extra_data = {}
                if "extra_data" in json_data:
                    extra_data = json_data["extra_data"]

                if "client_id" in json_data:
                    extra_data["client_id"] = json_data["client_id"]
                if valid[0]:
                    prompt_id = str(uuid.uuid4())
                    outputs_to_execute = valid[2]
                    self.prompt_queue.put((number, prompt_id, prompt, extra_data, outputs_to_execute))
                    response = {"prompt_id": prompt_id, "number": number, "node_errors": valid[3]}
                    return web.json_response(response)
                else:
                    logging.warning("invalid prompt: {}".format(valid[1]))
                    return web.json_response({"error": valid[1], "node_errors": valid[3]}, status=400)
            else:
                return web.json_response({"error": "no prompt", "node_errors": []}, status=400)

        @routes.post("/queue")
        async def post_queue(request):
            json_data =  await request.json()
            if "clear" in json_data:
                if json_data["clear"]:
                    self.prompt_queue.wipe_queue()
            if "delete" in json_data:
                to_delete = json_data['delete']
                for id_to_delete in to_delete:
                    delete_func = lambda a: a[1] == id_to_delete
                    self.prompt_queue.delete_queue_item(delete_func)

            return web.Response(status=200)

        @routes.post("/interrupt")
        async def post_interrupt(request):
            nodes.interrupt_processing()
            return web.Response(status=200)

        @routes.post("/free")
        async def post_free(request):
            json_data = await request.json()
            unload_models = json_data.get("unload_models", False)
            free_memory = json_data.get("free_memory", False)
            if unload_models:
                self.prompt_queue.set_flag("unload_models", unload_models)
            if free_memory:
                self.prompt_queue.set_flag("free_memory", free_memory)
            return web.Response(status=200)

        @routes.post("/history")
        async def post_history(request):
            json_data =  await request.json()
            if "clear" in json_data:
                if json_data["clear"]:
                    self.prompt_queue.wipe_history()
            if "delete" in json_data:
                to_delete = json_data['delete']
                for id_to_delete in to_delete:
                    self.prompt_queue.delete_history_item(id_to_delete)

            return web.Response(status=200)
        
        # Internal route. Should not be depended upon and is subject to change at any time.
        # TODO(robinhuang): Move to internal route table class once we refactor PromptServer to pass around Websocket.
        @routes.post("/internal/models/download")
        async def download_handler(request):
            async def report_progress(filename: str, status: DownloadModelStatus):
                await self.send_json("download_progress", status.to_dict())

            data = await request.json()
            url = data.get('url')
            model_directory = data.get('model_directory')
            model_filename = data.get('model_filename')
            progress_interval = data.get('progress_interval', 1.0) # In seconds, how often to report download progress.

            if not url or not model_directory or not model_filename:
                return web.json_response({"status": "error", "message": "Missing URL or folder path or filename"}, status=400)

            session = self.client_session
            if session is None:
                logging.error("Client session is not initialized")
                return web.Response(status=500)
            
            task = asyncio.create_task(download_model(lambda url: session.get(url), model_filename, url, model_directory, report_progress, progress_interval))
            await task

            return web.json_response(task.result().to_dict())

    async def setup(self):
        timeout = aiohttp.ClientTimeout(total=None) # no timeout
        self.client_session = aiohttp.ClientSession(timeout=timeout)

    def add_routes(self):
        self.user_manager.add_routes(self.routes)

        # Prefix every route with /api for easier matching for delegation.
        # This is very useful for frontend dev server, which need to forward
        # everything except serving of static files.
        # Currently both the old endpoints without prefix and new endpoints with
        # prefix are supported.
        api_routes = web.RouteTableDef()
        for route in self.routes:
            # Custom nodes might add extra static routes. Only process non-static
            # routes to add /api prefix.
            if isinstance(route, web.RouteDef):
                api_routes.route(route.method, "/api" + route.path)(route.handler, **route.kwargs)
        self.app.add_routes(api_routes)
        self.app.add_routes(self.routes)

        for name, dir in nodes.EXTENSION_WEB_DIRS.items():
            self.app.add_routes([
                web.static('/extensions/' + urllib.parse.quote(name), dir),
            ])

        self.app.add_routes([
            web.static('/', self.web_root),
        ])

    def get_queue_info(self):
        prompt_info = {}
        exec_info = {}
        exec_info['queue_remaining'] = self.prompt_queue.get_tasks_remaining()
        prompt_info['exec_info'] = exec_info
        return prompt_info

    async def send(self, event, data, sid=None):
        if event == BinaryEventTypes.UNENCODED_PREVIEW_IMAGE:
            await self.send_image(data, sid=sid)
        elif isinstance(data, (bytes, bytearray)):
            await self.send_bytes(event, data, sid)
        else:
            await self.send_json(event, data, sid)

    def encode_bytes(self, event, data):
        if not isinstance(event, int):
            raise RuntimeError(f"Binary event types must be integers, got {event}")

        packed = struct.pack(">I", event)
        message = bytearray(packed)
        message.extend(data)
        return message

    async def send_image(self, image_data, sid=None):
        image_type = image_data[0]
        image = image_data[1]
        max_size = image_data[2]
        if max_size is not None:
            if hasattr(Image, 'Resampling'):
                resampling = Image.Resampling.BILINEAR
            else:
                resampling = Image.ANTIALIAS

            image = ImageOps.contain(image, (max_size, max_size), resampling)
        type_num = 1
        if image_type == "JPEG":
            type_num = 1
        elif image_type == "PNG":
            type_num = 2

        bytesIO = BytesIO()
        header = struct.pack(">I", type_num)
        bytesIO.write(header)
        image.save(bytesIO, format=image_type, quality=95, compress_level=1)
        preview_bytes = bytesIO.getvalue()
        await self.send_bytes(BinaryEventTypes.PREVIEW_IMAGE, preview_bytes, sid=sid)

    async def send_bytes(self, event, data, sid=None):
        message = self.encode_bytes(event, data)

        if sid is None:
            sockets = list(self.sockets.values())
            for ws in sockets:
                await send_socket_catch_exception(ws.send_bytes, message)
        elif sid in self.sockets:
            await send_socket_catch_exception(self.sockets[sid].send_bytes, message)

    async def send_json(self, event, data, sid=None):
        message = {"type": event, "data": data}

        if sid is None:
            sockets = list(self.sockets.values())
            for ws in sockets:
                await send_socket_catch_exception(ws.send_json, message)
        elif sid in self.sockets:
            await send_socket_catch_exception(self.sockets[sid].send_json, message)

    def send_sync(self, event, data, sid=None):
        self.loop.call_soon_threadsafe(
            self.messages.put_nowait, (event, data, sid))

    def queue_updated(self):
        self.send_sync("status", { "status": self.get_queue_info() })

    async def publish_loop(self):
        while True:
            msg = await self.messages.get()
            await self.send(*msg)

    async def start(self, address, port, verbose=True, call_on_start=None):
        runner = web.AppRunner(self.app, access_log=None)
        await runner.setup()
        ssl_ctx = None
        scheme = "http"
        if args.tls_keyfile and args.tls_certfile:
                ssl_ctx = ssl.SSLContext(protocol=ssl.PROTOCOL_TLS_SERVER, verify_mode=ssl.CERT_NONE)
                ssl_ctx.load_cert_chain(certfile=args.tls_certfile,
                                keyfile=args.tls_keyfile)
                scheme = "https"

        site = web.TCPSite(runner, address, port, ssl_context=ssl_ctx)
        await site.start()

        self.address = address
        self.port = port

        if verbose:
            logging.info("Starting server\n")
            logging.info("To see the GUI go to: {}://{}:{}".format(scheme, address, port))
        if call_on_start is not None:
            call_on_start(scheme, address, port)

    def add_on_prompt_handler(self, handler):
        self.on_prompt_handlers.append(handler)

    def trigger_on_prompt(self, json_data):
        for handler in self.on_prompt_handlers:
            try:
                json_data = handler(json_data)
            except Exception as e:
                logging.warning(f"[ERROR] An error occurred during the on_prompt_handler processing")
                logging.warning(traceback.format_exc())

        return json_data