Code Explainers

Code explainers tagged #request-lifecycle

rust 
use axum::{
    body::Body,
    extract::Request,
    http::{header::SET_COOKIE, HeaderValue},

Flash messages via Axum middleware

middleware shared-state cookies
Intermediate 8 steps
ruby 
class Current < ActiveSupport::CurrentAttributes
  attribute :user, :request_id, :user_agent, :ip_address
 
  resets { Time.zone = nil }

Per-request audit trails with Current in Rails

thread-local-state auditing concerns
Intermediate 8 steps
python 
from flask import Flask, g, current_app
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
 

Scoped SQLAlchemy sessions in Flask

database session-management connection-pooling
Intermediate 6 steps
python 
from flask import Flask, request, Response
from prometheus_client import Counter, Histogram, generate_latest, CONTENT_TYPE_LATEST
import time
 

Instrumenting a Flask app with Prometheus

metrics observability middleware
Intermediate 6 steps
typescript 
import {
  MiddlewareConsumer,
  Module,
  NestModule,

How middleware binds to routes in NestJS

middleware routing modules
Intermediate 6 steps
python 
import logging
import uuid
from flask import Flask, request, g
 

Adding correlation IDs to Flask logs

logging request-lifecycle observability
Intermediate 7 steps
python 
from flask import Flask, request, g, jsonify
from flask_babel import Babel, gettext as _, format_datetime
from datetime import datetime
 

Per-request localization in Flask with Babel

i18n content-negotiation request-lifecycle
Intermediate 8 steps
java 
@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class TenantResolutionFilter extends OncePerRequestFilter {
 

How a tenant-resolution filter works in Spring

multi-tenancy servlet-filter thread-local
Intermediate 8 steps
typescript 
import { Injectable, NestInterceptor, ExecutionContext, CallHandler } from '@nestjs/common';
import { Observable, catchError, concatMap, finalize } from 'rxjs';
import { DataSource, QueryRunner } from 'typeorm';
 

Wrapping requests in a transaction with NestJS

interceptors transactions rxjs
Advanced 7 steps
php 
<?php
 
namespace App\Http\Middleware;
 

Resolving the current team in Laravel middleware

middleware multi-tenancy cookies
Intermediate 8 steps
python 
import time
 
from flask import Flask, g, request
 

Timing requests with Flask hooks

middleware request-lifecycle instrumentation
Intermediate 5 steps
java 
@Component
public class RequestTimingInterceptor implements HandlerInterceptor {
 
    private static final Logger log = LoggerFactory.getLogger(RequestTimingInterceptor.class);

How a Spring HandlerInterceptor times requests

interceptor request-lifecycle logging
Intermediate 6 steps