codesnips

postgres

go 
package httpstream

import (
	"bufio"
	"database/sql"
	"fmt"

Streaming Large SQL Query Results as a JSON Array in Go

go database sql
by codesnips 2 tabs
sql 
CREATE TABLE idempotency_keys (
    id              BIGSERIAL PRIMARY KEY,
    idempotency_key TEXT        NOT NULL,
    request_path    TEXT        NOT NULL,
    request_fingerprint TEXT    NOT NULL,
    status          TEXT        NOT NULL DEFAULT 'in_progress',

Idempotent POST Requests with an Idempotency-Key Middleware in Express

express idempotency middleware
by codesnips 3 tabs
python 
import base64
import json
from datetime import datetime
from typing import Optional, Tuple

Opaque Cursor Pagination for FastAPI Endpoints with SQLAlchemy

fastapi sqlalchemy pagination
by codesnips 3 tabs
python 
import uuid
from django.db import models


class Cart(models.Model):
    OPEN = "open"

Prevent Duplicate Order Submissions in Django with select_for_update Row Locking

django postgres concurrency
by codesnips 3 tabs
sql 
CREATE TABLE daily_metrics (
    id          BIGGENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    tenant_id   BIGINT      NOT NULL,
    metric      TEXT        NOT NULL,
    day         DATE        NOT NULL,
    count       BIGINT      NOT NULL DEFAULT 0,

SQL upsert for counters (ON CONFLICT DO UPDATE)

postgres sql concurrency
by codesnips 3 tabs
ruby 
module StatementTimeout
  extend ActiveSupport::Concern

  class TimeoutExceeded < StandardError; end

  def with_statement_timeout(milliseconds)

Guard Against Slow Queries with statement_timeout

rails postgres performance
by codesnips 3 tabs
python 
from sqlalchemy import select

from .models import Order, db


def stream_orders(batch_size=1000):

Stream a Large CSV Export in Flask With a Generator Response

flask streaming csv
by codesnips 3 tabs
java 
package com.example.feed;

import java.nio.charset.StandardCharsets;
import java.time.Instant;
import java.util.Base64;

Keyset (Cursor) Pagination with Spring Data JPA and Base64 Cursors

spring spring-data jpa
by codesnips 3 tabs
ruby 
class CounterFlushJob
  include Sidekiq::Job
  sidekiq_options queue: :counters, retry: 3

  def perform
    CounterBuffer.flush_all.each do |field, delta|

Coalesced Counter Cache with Redis Buffering and Nightly Reconciliation in Rails

rails counter-cache redis
by codesnips 4 tabs
ruby 
class DiscountCode < ApplicationRecord
  has_many :redemptions, dependent: :destroy

  enum discount_type: { percentage: 0, fixed: 1 }

  validates :code, presence: true, uniqueness: { case_sensitive: false }

Redeem Discount Codes in Rails with a Locking Service and Row-Level Guards

rails activerecord discounts
by codesnips 4 tabs
javascript 
const { AsyncLocalStorage } = require('async_hooks');

const storage = new AsyncLocalStorage();

function runWithTenant(tenantId, userId, callback) {
  return storage.run({ tenantId, userId }, callback);

Per-Tenant Request Context in Express With AsyncLocalStorage and a Scoped Repository

express multi-tenancy middleware
by codesnips 4 tabs
typescript 
import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

export async function getFeedNaive(limit = 20) {
  const posts = await prisma.post.findMany({

Prisma: avoid N+1 with include/select

prisma performance typescript
by codesnips 3 tabs