7,321 questions
0
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24
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Testing LangGraph functional API entrypoint with injected checkpointer raises RuntimeError: checkpointer not set
I'm building a FastAPI application that uses LangGraph's functional API (@entrypoint) for defining workflows. Each entrypoint requires a checkpointer, and I want to use PostgresSaver in production but ...
- 95
Best practices
0
votes
1
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71
views
Looking for feedback on my FastAPI project
I'm fairly new to programming and just finished my first backend project. I'm using FastAPI with PostgreSQL and JWT authentication.
I know the functionality is basic, but I'd really appreciate ...
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2
votes
1
answer
40
views
escape circular imports with fastapi
i am learning fastapi and i structure an app like this
app in FastAPI:
models.py file to hold database and other python important methods
routes.py file to hold the routes (URLs)
schemas.py file to ...
- 41
-1
votes
1
answer
76
views
FastAPI + Pydantic not parsing List[int] query parameters (multiple values not working)
I am trying to accept multiple query parameters as a list using FastAPI and Pydantic, but it is not working as expected.
Example request:
GET /api/v1/items/guest?industries=4&industries=5&...
- 633
Best practices
1
vote
3
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114
views
FastAPI high-load login: how to handle bcrypt/argon2 hashing without blocking and scaling limits?
I’m working on a high-load async web application using FastAPI and I have a question about implementing login/registration logic with password hashing.
Problem
As we know, password hashing (e.g. with ...
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-4
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0
answers
107
views
How to speed up FastAPI StreamingResponse
I am downloading file from S3 and the returning the file content via fastapi.responses.StreamingResponse
For 500Mb file it takse 5-10 minutes to return file. How to increase speed of function?
...
- 1,692
Best practices
0
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38
views
Should frontend render figures with data calculated in backend , or to receive PNG from backend?
context : I want to render the efficient frontier figure on the frontend- figure that shows many portfolios risks and returns-
in my backend- FastAPI-, I have two design choices:
1- calculate all the ...
Best practices
0
votes
2
replies
77
views
FastAPI int model field
I have been trying to learn FastAPI, with a small project and now I need to add a database table with an auto generated int id as a field.
I want to know how to write this id field in Python models ...
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-2
votes
1
answer
88
views
Backend question with CSRF (FastAPI, AuthX, SQLalchemy, Pydantic...) [closed]
I'm trying to create simple API with login system and roles. I have a problem with my code:
from fastapi import FastAPI, Response, HTTPException, Request, Depends
from fastapi.responses import ...
- 11
0
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0
answers
74
views
Way to edit inline message after web app submit?
I'm sending inline markup in private chat (or group chat) with button launching web app form. Data from form collected by FastApi POST-processor (save to db, report etc).
I'm wondering how to disable ...
-1
votes
1
answer
46
views
fastapi mounted on flask on Digital Ocean App Platform issues
I have a flask app that I have mounted a fastapi app on so that my flask app is at / and the api is at /api/v1. Locally I serve this up on my windows machine using waitress and it works great. I ...
- 11
0
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0
answers
48
views
boto3 presigned PUT URL for Backblaze B2 S3 returns SignatureDoesNotMatch
I’m trying to generate presigned PUT URLs for Backblaze B2 (S3-compatible API) using boto3, but even a minimal curl PUT fails with SignatureDoesNotMatch.
This happens without any extra headers, so it ...
Best practices
2
votes
4
replies
81
views
How to solve import problem in Microservice Architecture?
As part of learning I'm trying to switch monolithic project to microservice architecture and encountered import problems.
GitHub Project
Project's tree looks like:
users/
pyproject.toml
src/
...
0
votes
1
answer
58
views
FastAPI websocket implementation with subprotocols
I'm trying to implement WebSocket‑based communication in a web app with a FastAPI backend and a Next.js front end. The app already has JWT‑based authentication, and to use the token to secure the ...
- 3
0
votes
1
answer
76
views
Websocket closes without asking
I open websocket to send client balance updates, but after {'message': 'accepted'} websocket closes and I can't send any data.
def get_contract_listener(access_token: str, callback: Callable[[int | ...
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