Exception in ASGI application error

[bajirama]

Question

I am getting this error when I execute it from Command line but when I run that from Pycharm in debug mode the code is working fine. Only thing I did is updated the nicegui framework Please help

python main.py
NiceGUI ready to go on http://localhost:8080,...........
Type is not JSON serializable: WindowsPath
TypeError: Object of type WindowsPath is not JSON serializable

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Python311\Lib\site-packages\starlette\middleware\errors.py", line 162, in __call__
    await self.app(scope, receive, _send)
  File "C:\Python311\Lib\site-packages\starlette\middleware\base.py", line 108, in __call__
    response = await self.dispatch_func(request, call_next)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\nicegui\middlewares.py", line 10, in dispatch
    response = await call_next(request)
               ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\starlette\middleware\base.py", line 84, in call_next
    raise app_exc
  File "C:\Python311\Lib\site-packages\starlette\middleware\base.py", line 70, in coro
    await self.app(scope, receive_or_disconnect, send_no_error)
  File "C:\Python311\Lib\site-packages\starlette\middleware\gzip.py", line 24, in __call__
    await responder(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\middleware\gzip.py", line 44, in __call__
    await self.app(scope, receive, self.send_with_gzip)
  File "C:\Python311\Lib\site-packages\starlette\middleware\exceptions.py", line 79, in __call__
    raise exc
  File "C:\Python311\Lib\site-packages\starlette\middleware\exceptions.py", line 68, in __call__
    await self.app(scope, receive, sender)
  File "C:\Python311\Lib\site-packages\fastapi\middleware\asyncexitstack.py", line 20, in __call__
    raise e
  File "C:\Python311\Lib\site-packages\fastapi\middleware\asyncexitstack.py", line 17, in __call__
    await self.app(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\routing.py", line 718, in __call__
    await route.handle(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\routing.py", line 276, in handle
    await self.app(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\routing.py", line 66, in app
    response = await func(request)
               ^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\fastapi\routing.py", line 274, in app
    raw_response = await run_endpoint_function(
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\fastapi\routing.py", line 191, in run_endpoint_function
    return await dependant.call(**values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\nicegui\page.py", line 112, in decorated
    return client.build_response(request)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\nicegui\client.py", line 97, in build_response
    elements = json.dumps({
               ^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\nicegui\json\orjson_wrapper.py", line 36, in dumps
    return orjson.dumps(obj, option=opts, default=_orjson_converter).decode('utf-8')
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: Type is not JSON serializable: WindowsPath
ERROR:    Exception in ASGI application
TypeError: Object of type WindowsPath is not JSON serializable

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Python311\Lib\site-packages\uvicorn\protocols\http\httptools_impl.py", line 435, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\uvicorn\middleware\proxy_headers.py", line 78, in __call__
    return await self.app(scope, receive, send)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\fastapi\applications.py", line 1106, in __call__
    await super().__call__(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\applications.py", line 122, in __call__
    await self.middleware_stack(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\middleware\errors.py", line 184, in __call__
    raise exc
  File "C:\Python311\Lib\site-packages\starlette\middleware\errors.py", line 162, in __call__
    await self.app(scope, receive, _send)
  File "C:\Python311\Lib\site-packages\starlette\middleware\base.py", line 108, in __call__
    response = await self.dispatch_func(request, call_next)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\nicegui\middlewares.py", line 10, in dispatch
    response = await call_next(request)
               ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\starlette\middleware\base.py", line 84, in call_next
    raise app_exc
  File "C:\Python311\Lib\site-packages\starlette\middleware\base.py", line 70, in coro
    await self.app(scope, receive_or_disconnect, send_no_error)
  File "C:\Python311\Lib\site-packages\starlette\middleware\gzip.py", line 24, in __call__
    await responder(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\middleware\gzip.py", line 44, in __call__
    await self.app(scope, receive, self.send_with_gzip)
  File "C:\Python311\Lib\site-packages\starlette\middleware\exceptions.py", line 79, in __call__
    raise exc
  File "C:\Python311\Lib\site-packages\starlette\middleware\exceptions.py", line 68, in __call__
    await self.app(scope, receive, sender)
  File "C:\Python311\Lib\site-packages\fastapi\middleware\asyncexitstack.py", line 20, in __call__
    raise e
  File "C:\Python311\Lib\site-packages\fastapi\middleware\asyncexitstack.py", line 17, in __call__
    await self.app(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\routing.py", line 718, in __call__
    await route.handle(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\routing.py", line 276, in handle
    await self.app(scope, receive, send)
  File "C:\Python311\Lib\site-packages\starlette\routing.py", line 66, in app
    response = await func(request)
               ^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\fastapi\routing.py", line 274, in app
    raw_response = await run_endpoint_function(
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\fastapi\routing.py", line 191, in run_endpoint_function
    return await dependant.call(**values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\nicegui\page.py", line 112, in decorated
    return client.build_response(request)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\nicegui\client.py", line 97, in build_response
    elements = json.dumps({
               ^^^^^^^^^^^^
  File "C:\Python311\Lib\site-packages\nicegui\json\orjson_wrapper.py", line 36, in dumps
    return orjson.dumps(obj, option=opts, default=_orjson_converter).decode('utf-8')
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: Type is not JSON serializable: WindowsPath

[falkoschindler]

Hi @bajirama, is main.py the one from the NiceGUI repository, or your own app?

[bajirama]

I own that app , this was working fine I did a update on the framework and it is failing - thanks for your help

[falkoschindler]

@bajirama Can you, please, provide a minimal reproducible example? Without seeing the code that is causing the issue it's hard to tell what is wrong. Thanks!

[bajirama]

Sorry for the late response - due to holidays . I did not change any code but 1.3.12 is working where else higher version is not working and failing in the framework level at this function
in
fastapi\routing.py line 274
if errors: raise RequestValidationError(_normalize_errors(errors), body=body) else: raw_response = await run_endpoint_function( dependant=dependant, values=values, is_coroutine=is_coroutine

asyncexitstack.py
class AsyncExitStackMiddleware: def __init__(self, app: ASGIApp, context_name: str = "fastapi_astack") -> None: self.app = app self.context_name = context_name

async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
    dependency_exception: Optional[Exception] = None
    async with AsyncExitStack() as stack:
        scope[self.context_name] = stack
        try:
            await self.app(scope, receive, send)
        except Exception as e:
            **dependency_exception = e**
            raise e
    if dependency_exception:
        # This exception was possibly handled by the dependency but it should
        # still bubble up so that the ServerErrorMiddleware can return a 500
        # or the ExceptionMiddleware can catch and handle any other exceptions
        raise dependency_exception`

Here is the Scope value
scope {'type': 'http', 'asgi': {'version': '3.0', 'spec_version': '2.3'}, 'http_version': '1.1', 'server': ('127.0.0.1', 8080), 'client': ('127.0.0.1', 59760), 'scheme': 'http', 'root_path': '', 'headers': [(b'host', b'127.0.0.1:8080'), (b'connection', b'keep-alive'), (b'cache-control', b'max-age=0'), (b'sec-ch-ua', b'"Microsoft Edge";v="119", "Chromium";v="119", "Not?A_Brand";v="24"'), (b'sec-ch-ua-mobile', b'?0'), (b'sec-ch-ua-platform', b'"Windows"'), (b'upgrade-insecure-requests', b'1'), (b'user-agent', b'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36 Edg/119.0.0.0'), (b'accept', b'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,/;q=0.8,application/signed-exchange;v=b3;q=0.7'), (b'sec-fetch-site', b'same-origin'), (b'sec-fetch-mode', b'navigate'), (b'sec-fetch-dest', b'document'), (b'referer', b'http://127.0.0.1:8080/'), (b'accept-encoding', b'gzip, deflate, br'), (b'accept-language', b'en-US,en;q=0.9')], 'state': {}, 'method': 'GET', 'path': '/', 'raw_path': b'/', 'query_string': b'', 'app': <nicegui.app.app.App object at 0x000001BF9CA29C40>, 'fastapi_astack': <contextlib.AsyncExitStack object at 0x000001BF9D119160>, 'router': <fastapi.routing.APIRouter object at 0x000001BF9CD2E490>, 'endpoint': <function page.call..decorated at 0x000001BF9CD6A430>, 'path_params': {}, 'route': APIRoute(path='/', name='decorated', methods=['GET'])}

[falkoschindler]

Sorry, I don't see how this answers my request for an MRE. Seeing some code that is causing the error would really help a lot.

[bajirama]

Sorry got into other priorities , but found answers to my error , I was not using the the correct method to get my path for my json file got that fixed here is the my code

def getJson(fileName:str):

    file_path = Path(__file__).parent / 'config' / f"{fileName}.json"

    #file_path = f".\config\{fileName}.json"  - old way of calling the json file 

    with open(file_path) as file:

        data = json.load(file)

    return data

[sudarshanbairagi-taggbox]

try running it with gunicorn if you are using fastapi through uvicorn