Ever wondered how the middlewares in popular web frameworks, e.g. Express or Koa, work?

Article Basic Middleware Pattern in JavaScript
-- Published on October 4, 2020

Implementation

function Pipeline(...middlewares) {
  const stack = middlewares

  const push = (...middlewares) => {
    stack.push(...middlewares)
  }

  const execute = async (context) => {
    let prevIndex = -1

    const runner = async (index) => {
      if (index === prevIndex) {
        throw new Error('next() called multiple times')
      }

      prevIndex = index

      const middleware = stack[index]

      if (middleware) {
        await middleware(context, () => {
          return runner(index + 1)
        })
      }
    }

    await runner(0)
  }

  return { push, execute }
}

Usage

// create a middleware pipeline
const pipeline = Pipeline(
  // with an initial middleware
  (ctx, next) => {
    console.log(ctx)
    next()
  }
)

// add some more middlewares
pipeline.push(
  (ctx, next) => {
    ctx.value = ctx.value + 21
    next()
  },
  (ctx, next) => {
    ctx.value = ctx.value * 2
    next()
  }
)

// add the terminating middleware
pipeline.push((ctx, next) => {
  console.log(ctx)
  // not calling `next()`
})

// add another one for fun ¯\_(ツ)_/¯
pipeline.push((ctx, next) => {
  console.log('this will not be logged')
})

// execute the pipeline with initial value of `ctx`
pipeline.execute({ value: 0 })

Galleries:

Article top-10 ..picked from the list:

1. Grid Gallery. A lightweight, responsive photo grid gallery with lightbox integrated that allows the user to switch between images in a popup by clicking on any thumbnail.
   • grid-gallery
   • github
2. Light Gallery. The Vanilla JavaScript Version of the lightGallery jQuery plugin. Light Gallery is a modular, responsive, touch-enabled, dependency-free JavaScript lightbox gallery library that enables you to present various types of media (images, videos, etc) in a fullscreen, scalable, navigatable, shareable, downloadable, and CSS3 animated gallery popup. And the beast off all it's modular.
   • lightGallery
   • github

A really good article for PHP caching & structuring.

What are the approaches?

There are many approaches to caching. You can check the list of PHP-compatible tools on the php-cache page. However, the most common ones are:

• APCu
• Array
• Memcached

• Redis

• article
• partials.php

Repositories

• Gamestarter

askubuntu