DEV Community: volfcan

How to See Someone’s First Post on Instagram? 🤔

volfcan — Thu, 17 Oct 2024 14:35:17 +0000

Scrolling endlessly through a person’s profile is a pain.
But what if there existed a trick that could help you scroll automatically for as long as you wished? 👾

Open the developer console on the profile page you want to see the first post on

and type enter the following command on the console section

scroll=window.setInterval(function(){window.scrollTo(0,document.body.scrollHeight);},1000);

How git commands works? 👾

volfcan — Sun, 13 Oct 2024 08:37:05 +0000

I've made a infographic that shows how git commands works 👇¡

How to design a URL shortener?

volfcan — Sat, 12 Oct 2024 09:54:32 +0000

Popular System Design Interview Question:
How to design a URL shortener?

Here is how to answer with a step-by-step approach: ↓

Requirements

Functional requirements:

A user enters a URL and gets back a short URL
The short URL redirect to the long URL when accessed
The lifetime of the short URL can be customized
The usage of the short URL can be tracked for analytics

Non Functional requirements:

High availability
Minimal latency for URL redirection
each short URL shall be unique

Design the Data Model

We create three tables:

ShortURL (urlId, creationDate, userID, longURL) -> ~= 500 bytes
User (userId, creationDate, lastUpdate, email) -> ~= 100 bytes
UsageMetric (metricId, url_id, timestamp, metric_type) -> ~= 200 bytes

UsageMetric has a one to many strong relationship with ShortURL.

User has a one to many weak relationship with ShortURL.

Back of the Envelope estimation

10M users / create 3 URL per month -> 30M writes and 2B reads per month -> ~= 12 writes, 770 reads per second

High level system design

There are two main data flows: request a short URL and access a short URL. From the user device, each request hit the Load Balancer before going to a web server. Without the load balancer, the requests would be unevenly distributed to the servers, causing congestions and failures.

The functionalities for requesting and accessing a short URL are encapsulated by two different set of APIs (write and read APIs) handled by separated services.

To avoid single point of failures, the database can be replicated using a single-leader architecture. The write requests go to the leader, the read requests to the replicas. An in-memory cache is also used to reduce latency. Since the requests do not require any complex joins or strong relationships with data a NoSQL database using urlId as primary key fits the requirements.

Analytic Service

A frontend web page sends requests to the analytic service and displays the analytics to the users. If real-time statistics are not required, the service can be implemented by batch jobs running at regular intervals.

h/t: Fernando Franco

how to download single file from a repository? 📁

volfcan — Mon, 07 Oct 2024 16:57:00 +0000

if there are tons of directories in a single github repo and you want to use/download just one of them.

i've got you covered ⚡️

here's a tool for downloading a single directory from a github repo 👇

https://github.com/MinhasKamal/DownGit

⚡️ trick: take a screenshot of a webpage with the dev console ™

volfcan — Mon, 12 Aug 2024 07:26:44 +0000

taking screenshots of a webpage and its components is one of the key steps for proper product design and development.

here is the trick 👇

open the developer console of the web page you want to take screenshot.
choose the element and right click "Capture node screenshot"

you can whether take a screenshot of a full page or individual component/element with this mechanic

⚡️ trick: hide youtube video player hud

volfcan — Sun, 11 Aug 2024 11:33:52 +0000

you can't read what's going on the terminal or shell while watching a youtube tutorial?

If you write document.querySelector(".ytp-chrome-bottom").style.display= 'None'; on the console tab of the developer console, It hides the bottom timeline of the youtube video so you can see much better the content.

like so: