Pause the main thread during the execute callback function Question: I am trying to use page.on to listening certain event, and once it is triggered I want to use callback function to handle it and pause the main thread operation till the callback finished. How can I achieve that? So far it is what I …
WebSockets in FastAPI – ConnectionClosedOK: received 1000 (OK) Question: I have 3 clients, who periodically send data to my server. I use the example from FastAPI’s documentation. This is my server code: class ConnectionManager: def __init__(self): self.active_connections: list[WebSocket] = [] async def connect(self, websocket: WebSocket): await websocket.accept() self.active_connections.append(websocket) def disconnect(self, websocket: WebSocket): self.active_connections.remove(websocket) async def …
Can't get Telegram bot to send messages to user and run polling loop at the same time (python-telegram-bot) Question: I m trying to build a telegram bot usin the telegram.ext.Application class of python-telegram-bot and I need the bot to send periodic messages to a specific user while also running its polling loop to receive incoming …
How does sync_to_async convert sync functions to async Question: I know that asgiref.sync.sync_to_async is for running sync code in an async context and cannot magically convert them to async code. I have also seen this question and the examples in the answer. But I came up with an unexpected case that I can’t wrap my …
In Python, what is the difference between `async for x in async_iterator` and `for x in await async_iterator`? Question: The subject contains the whole idea. I came accross code sample where it shows something like: async for item in getItems(): await item.process() And others where the code is: for item in await getItems(): await item.process() …
Is there a way to take a key from one dictionary and add it to another? Question: My goal is to take a key from one dictionary which holds lots of keys and values, and add the key to an empty dictionary. The key is stored in a variable name called "bossname" all of the …
Convert Blocking python function to async function Question: So currently I have 4 api requests which are called in synchronous method using a third_party lib which is synchronous. What i want is to run them in parallel. So that my total time to call all 4 apis is reduced. I am using fastapi as micro …
Background task with asyncio Question: I have one class produceMessages that keeps feeding messages to its attribute message_logs. I want to process these messages in the other class processMessages. However, the code in processMessages won’t execute until produceMessages is done – which is never, as I want these messages to come forever. Looking at documentation, …
How to continously wait on any of multiple concurrent tasks to complete? Question: Let’s say there are multiple sources of events I want to monitor and respond to in an orderly fashion – for instance multiple connected sockets. What’s the best way to continuously await until any of them has data available to be read? …
Sqlalchemy does not return an model object with `session.scalars` on mapped objects Question: from attrs import define from sqlalchemy.orm import ( registry, ) from sqlalchemy.sql import ( schema, sqltypes, ) @define(slots=False) class Cat(): id: int name: str mapper_registry = registry() cat_table = schema.Table( "cat", mapper_registry.metadata, schema.Column("id", sqltypes.Integer, primary_key=True), schema.Column("name", sqltypes.String, nullable=False), ) mapper_registry.map_imperatively(models.Cat, cat_table) async …
