Forem: liamlo-dev

Download dood video (+ js -> img)

liamlo-dev — Wed, 02 Aug 2023 04:58:15 +0000

Example:
https://dooood.com/e/kluhm510q8r9
https://asiajjj.com/view1/54691/

Online decoder (may not work later):
https://9xbuddy.com/

Passing the 1st guard (no right click / F12):

View -> Developer

Passing the 2nd guard (Paused in debugger):

Deactivate breakpoints

Passing the 3rd guard (download):

function saveFile(blob, filename) {
if (window.navigator.msSaveOrOpenBlob) {
window.navigator.msSaveOrOpenBlob(blob, filename);
} else {
const a = document.createElement('a');
document.body.appendChild(a);
const url = window.URL.createObjectURL(blob);
a.href = url;
a.download = filename;
a.click();
setTimeout(() => {
window.URL.revokeObjectURL(url);
document.body.removeChild(a);
}, 0)
}
} // copy paste from a stackoverflow
const response = await fetch(videojs.getAllPlayers()[0]["src"]());
const reader = response.body.getReader();
var length = 0;
var total = +response.headers.get("content-length");
var chunks = [];
while(true) {
const {done, value} = await reader.read();
if (done) {
break;
}
chunks.push(value);
length += value.length;
console.log((length/total*100).toFixed(2)+"%");
}
var blob = new Blob(chunks);
saveFile(blob, "video.mp4")

Passing the 4th guard (img src = "xxx.js"):

Download it anyway. Then change the file extension to jpg or png

Source: https://www.reddit.com/r/DataHoarder/comments/11m8eqa/need_help_downloading_videos_from_doodstream/

Keynote high resolution image

liamlo-dev — Tue, 25 Jul 2023 09:34:42 +0000

Use this as an alternative to Canva, which offers low resolution (even for Instagram profile photos) in its free version.

Establish image resolution in Keynote: Inspector (RHS) > Document > Document > Slide Size For IG, 4xxx is recommended
Export to JPEG: File > Export > Images

Source: https://discussions.apple.com/thread/4536285

Auto Join Zoom Meetings with Python

liamlo-dev — Mon, 08 May 2023 02:43:32 +0000

Step 1 Installation:

Installing pip:
https://stackoverflow.com/questions/17271319/how-do-i-install-pip-on-macos-or-os-x

Installing virtualenv:
pip uninstall virtualenv
sudo pip install virtualenv

mkdir zoom_automation
cd zoom_automation
virtualenv env
source env/bin/activate          *** for Mac
.\env\scripts\activate           *** for Windows
pip install schedule

Step 2: Simple code
touch meeting_scheduler.py

import schedule
import time
import webbrowser

def open_link(link):
    webbrowser.open(link)

def demo_meeting():
    open_link('MY ZOOM MEETING URL')

schedule.every().friday.at("12:25").do(demo_meeting)

while 1:
    schedule.run_pending()
    time.sleep(1)

Step 3: Run
python meeting_scheduler.py

Uniswap Deep Dive 1:

liamlo-dev — Mon, 07 Nov 2022 01:38:35 +0000

Before we start

For introduction, please read
Uniswap V2 Overview by Uniswap
Uniswap V2 Contract Walk-through

For source code,
Uniswap V2 Core and Uniswap V2 Peripheral

Overview

Uniswap V2 Core has 3 contracts: Factory, Pair, WETH and Uniswap V2 Periphery has 1 contract: Router.

Factory contract (UniswapV2Factory.sol)

It is responsible for creating trading pairs and saving the addresses of all trading pairs.

Pair contract (UniswapV2Pair.sol)

It saves the pool information of a single trading pair, including the addresses of the two ERC20 tokens in each trading pair, and their respective reserve.
It handles mint, burn and swap operations.
UniswapV2Pair itself is also an unique ERC20 token. Whenever liquidity is deposited into a pool, unique tokens known as liquidity tokens are minted and sent to the provider's address. These tokens represent a given liquidity provider's contribution to a pool. The proportion of the pool's liquidity provided determines the number of liquidity tokens the provider receives. If the provider is minting a new pool, the number of liquidity tokens they will receive will equal sqrt(x * y), where x and y represent the amount of each token provided.
totalSupply of pair token === sqrt(reserve1 * reserve2) [not sure]

WETH contract

This contract is a special ERC20, for the sole purpose to facilitate users to directly trade between ETH and ERC20. Think of WETH as a fully guaranteed bond: the ETH stored in this contract is always equal to the WETH it issued (unless someone sent ETH to it directly using WETH_address.transfer ).
WETH is created because the trading pair of the Pair contract are always ERC20 tokens and it does not support trading between ETH and ERC20.
It has 2 methods, deposit() and withdraw(). The former is to deposit ETH to get WETH, and the latter is to destroy WETH to get ETH. But these two methods are usually called by the Router, such as the swapExactETHForTokens function in the Router

function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
                external
                virtual
                override
                payable
                ensure(deadline)
                returns (uint[] memory amounts)
            {
                require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
                amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
                require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
                IWETH(WETH).deposit{value: amounts[0]}();
                assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
                _swap(amounts, path, to);
            }

Solve one problem a day

liamlo-dev — Thu, 03 Nov 2022 15:02:22 +0000

3 November 2022

Installing `nvm`

Why: Have been using n, which is much easier to install and to use. However, since it is a npm package which may cause a circular dependency-like problem, I guess there is no harm to install nvm too. See more

Problem: Using brew as always, followed the instruction popped up.

Solution: Thanks to this,

Add source $(brew --prefix nvm)/nvm.sh to ~/.zshrc
Restart the terminal or source ~/.zshrc

4 November 2022

Reverting back to `n`

Why: Can't believe I am reverting back to n in only 1 day... CRANQ seems to be only working with n, seemingly because n always stores node in /usr/local/bin when nvm stores it in a user specific path (and with redirection), while CRANQ only recognizes /usr/local/bin

Lack of ETH

Why: Goerli is the only official testnet now after ETH Merge, as Rinkeby is depreciated.

Problem: Due to the above reason, Goerli gas fee 10x in 2 months causing contract deployment to be very "expensive". Talked to some devs, 2 months ago the average gas is 6Gwei * 6m for 1 contract. Now it is 60Gwei.

Solution:

useDApp setup

Problem: I run into opensslErrorStack: [ 'error:03000086:digital envelope routines::initialization error' ]