codesnips

idempotency

python 
from django.conf import settings
from django.db.models.signals import post_save
from django.dispatch import receiver

from .models import EmailOutbox

Sending Welcome Emails via a Django post_save Signal and Outbox Worker

django signals email
by codesnips 4 tabs
ruby 
class WebhookSignature
  class VerificationError < StandardError; end

  TOLERANCE = 300 # seconds

  def initialize(payload:, header:, secrets:)

Robust Webhook Verification (HMAC + Timestamp)

rails security webhooks
by codesnips 3 tabs
ruby 
class EmailDedupService
  DEFAULT_TTL = 5.minutes.to_i

  def self.claim(fingerprint, ttl: DEFAULT_TTL)
    key = "email_dedup:#{fingerprint}"
    # Atomic set-if-absent with expiry; returns true only for the first caller.

Throttle Duplicate Emails in Rails with a Mailer Interceptor and Redis Dedup Service

rails actionmailer redis
by codesnips 3 tabs
sql 
CREATE TABLE country (
    code       CHAR(2)      PRIMARY KEY,
    name       VARCHAR(128) NOT NULL,
    currency   CHAR(3)      NOT NULL,
    updated_at TIMESTAMPTZ  NOT NULL DEFAULT now()
);

Seeding Reference Data After a Flyway Migration with a Java Callback

flyway spring-boot migrations
by codesnips 3 tabs
sql 
CREATE TYPE outbox_status AS ENUM ('pending', 'retry', 'processing', 'done', 'dead');

CREATE TABLE outbox_events (
    id           BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    dedupe_key   TEXT        NOT NULL,
    topic        TEXT        NOT NULL,

Atomic “Read + Mark Processed” with UPDATE … RETURNING

postgres concurrency reliability
by codesnips 3 tabs
ruby 
class AddSlugToPosts < ActiveRecord::Migration[7.1]
  def change
    add_column :posts, :slug, :string, null: false
    add_index :posts, :slug, unique: true
  end
end

Database-Backed Unique Slugs with Retry

rails postgres slugs
by codesnips 4 tabs
ruby 
namespace :cleanup do
  desc "Enqueue a job to purge expired sessions"
  task expired_sessions: :environment do
    job = ExpiredSessionCleanupJob.perform_later
    Rails.logger.info("[cleanup:expired_sessions] enqueued job #{job.job_id}")
  end

Recurring Cleanup with a Rake Task and an Idempotent Active Job in Rails

rails background-jobs active-job
by codesnips 4 tabs
ruby 
require "securerandom"

class RedisMutex
  class LockError < StandardError; end

  UNLOCK_SCRIPT = <<~LUA.freeze

Redis-Based Distributed Mutex (with TTL)

rails redis concurrency
by codesnips 2 tabs
php 
<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

Idempotent Stripe Webhook Processing With a Processed-Events Table in Laravel

laravel webhooks idempotency
by codesnips 3 tabs
ruby 
class ExportWriter
  def initialize(export)
    @export = export
  end

  def append(rows)

Chaining Dependent GoodJob Jobs with a Callback-Scheduled Continuation

rails good-job background-jobs
by codesnips 3 tabs
java 
@Entity
@Table(name = "idempotency_records",
       uniqueConstraints = @UniqueConstraint(columnNames = "idempotency_key"))
public class IdempotencyRecord {

    public enum Status { IN_PROGRESS, COMPLETED }

Idempotent POST Handling in Spring Boot with a Stored Idempotency-Key

spring-boot idempotency rest-api
by codesnips 3 tabs
php 
<?php

namespace App\Jobs;

use App\Models\Invoice;
use App\Services\StripeGateway;

Preventing Double-Charges in Laravel with WithoutOverlapping Job Middleware

laravel queues background-jobs
by codesnips 3 tabs