fastapi-walletauth 0.1.0

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FastAPI Wallet Authentication

fastapi-walletauth provides a simple way to authenticate users in FastAPI applications using a wallet. It currently supports Ethereum and Solana wallets/signatures.

Installation

pip install fastapi-walletauth

Usage

Adding the authentication endpoints is as simple as importing the fastapi_walletauth.magic module after the FastAPI application has been created:

from fastapi import FastAPI

app = FastAPI()

import fastapi_walletauth.magic

or if you prefer, you can add the endpoints manually:

from fastapi import FastAPI
from fastapi_walletauth.router import authorization

app = FastAPI()

app.include_router(authorization)

This will add the following endpoints to your application:

• POST /authentication/challenge: Returns a challenge for the user to sign
• POST /authentication/solve: Returns a Bearer token if the signature is valid
• POST /authentication/logout: Invalidates the current token
• POST /authentication/refresh: Returns a new token if the current token is valid

You can then use WalletAuthDep to protect your endpoints:

from fastapi import FastAPI
from fastapi_walletauth import WalletAuth, WalletAuthDep

app = FastAPI()

import fastapi_walletauth.magic

@app.get("/protected")
def protected(wa: WalletAuth = WalletAuthDep()):
    return wa.address

Signing the challenge

The challenge is a JSON object (similar to Aleph messages) containing the following fields:

message = {
    "chain": "ETH",
    "address": "0x...",
    "type": "authorization_challenge",
    "item_hash": "0x...",
}

• chain: The chain ID (e.g. ETH for Ethereum mainnet)
• address: The address of the user
• type: The type of message to be signed (authorization_challenge)
• item_hash: A random hash

Currently, it requires to be preprocessed into a Verification Buffer like this:

"{chain}\n{sender}\n{type}\n{item_hash}".format(**message).encode("utf-8")

before being signed with the user's private key. This signature is then sent to the /authentication/solve endpoint.