Solidity get interface id and ERC165
To get interface id, use Remember interfaceId = xor of all selectors (methods) name, don’t care to return type, just name For example: Return zero with empty interface Return same…
About Smart Contract
If you are a smart contract developer, you will need to consider something about the contract: Clean: No unused code, nonsense comment, Well document: Comment to all functions Formatted: Reformat,…
About dividend token
I have some exp with this kind of topic “Dividend Token”. Just share some thoughts What is “Dividend Token”? You should search for more detail. =]] But you can go…
Host your own PancakeSwap Testnet
https://github.com/nhancv/pancake-swap-testnet#readme Preparing source Clone pancake-swap-core Clone pancake-swap-periphery Clone pancake-swap-interface-v1 Setup Install contract merger: https://www.npmjs.com/package/sol-merger Prepare PancakeFactory and PancakeRouter Deploy PancakeFactory and PancakeRouter Access: https://remix.ethereum.org/#optimize=false&runs=200&evmVersion=null&version=soljson-v0.5.16+commit.9c3226ce.js Deploy WBNB New File: WBNB.sol => Copy source from https://gist.github.com/nhancv/b0b35f16472e4998d0fd17b7a1e4f707 Compiler tab => Select compiler: v0.8.3+commit.8d00100c Deploy tab…
Install Zabbix – Server Monitor
Config Server Install here: https://www.zabbix.com/download?zabbix=5.4&os_distribution=ubuntu&os_version=20.04_focal&db=postgresql&ws=nginx Config server: Config frontend web Restart server Setup Agent Access to vps agent -> Install zabbix-agent Public agent Restart agent Add host to Server Access…
Smart contract pagination for list
A contract has an infinite internal storage There are 2 limits to practicality: gas costs and the block gas limit. Example Create 5k5 players, read one time https://testnet.bscscan.com/address/0x721ff9e58831b698efd26b9ac744cf8f0aaecbc2#readContract Max Gas Limit is 28,500,000 at…
MongoDB Replica Setup
Setup MongoDB Controls Config replica Option 1: Use separate 3 vps – 3 instances mongod Option 2: (For test) Use 1 vps and create 3 instances mongod with difference db…
Node App with PM2 Cluster
https://pm2.keymetrics.io/docs/usage/cluster-mode/ Make sure your application is stateless: share database/cache, cronjob Create ecosystem.config.js at root
Nginx HTTP load balancer
Config Simple config: nginx.conf Health check: https://docs.nginx.com/nginx/admin-guide/load-balancer/http-health-check/ Monitoring: https://docs.nginx.com/nginx/admin-guide/monitoring/live-activity-monitoring/
Web stress test with jmeter
Download https://jmeter.apache.org/download_jmeter.cgi Get started https://jmeter.apache.org/usermanual/get-started.html INSTRUCTION Download jmeter -> extract PREPARE TEST PLAN open terminal run GUI ./bin/jmeter Create new Test Plan Right click on “Test Plan” -> Add -> Threads -> Thread…