API design & gRPC
REST best practices, protobuf, API versioning, and backward-compatible service contracts.
How to Build Cursor Pagination with Next and Prev Tokens in Python
A minimal cursor pagination implementation that returns next and previous cursor tokens for navigating a dataset.
from pprint import pprint
def make_cursor(page):
return f"page:{page:04d}"
def parse_cursor(cursor):
_, page = cursor.split(":", 1)
return int(page)
def paginate(all_items, page_size, cursor=None):
start = parse_cursor(cursor) if cursor else 0
end = start + page_size
items = all_items[sta…How to Mock OAuth2 Bearer Token Auth Middleware in Python
Create a simple OAuth2 bearer token authentication middleware that verifies signed tokens and enforces scope-based access control.
import hmac
import time
import base64
import json
from functools import wraps
VALID_TOKENS = {"test_token_123": {"user": "alice", "scope": "read:posts"}}
def generate_token(username: str) -> str:
payload = {"user": username, "iat": int(time.time())}
encoded = base64.urlsafe_b64encode(json.dumps(payload).enc…How to Validate a JWT Signature in Python with a Mock Secret
Validates a JWT's signature using a mock secret, decoding and handling expired or invalid tokens gracefully.
import jwt
import time
SECRET = "mock_secret_key_123"
def validate_token(token):
try:
payload = jwt.decode(token, SECRET, algorithms=["HS256"])
return f"Valid token. Payload: {payload}"
except jwt.ExpiredSignatureError:
return "Token expired"
except jwt.InvalidTokenError:
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API design & gRPC — Python code examples
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