jimmychu0807

打工每月有4/5 萬人工。收入較穩定，工時較穩定。少些煩心，憂心事。

點解要攞苦來辛，自己搞 startup？

• 我其中一個最大價值在於靈活性，自覺是複合型人才，會走位，有權變。打工講專才。做工程師，很多時就只有寫 code. 商務人就要吹水交際去 conf，不同社交場合。好少見到複合型人才，可在工作崗位允許隨機應變，隨所遇而施之。要到這境界，要遇到好老闆，並且他相信你。今時今日，難。

• 唔想被蠢過自己的上司指東指西，執行一些無聊頂透的指令。也不想和只拿薪金，無擔當的人一起工作。職場上遇到他們，如在打工，我只能消極避開。自己開公司，可選擇和一流的人才工作。

• 唔想俾人用 4/5萬月薪豢養起來。唔通我就係咁要安全感？就咁唔敢冒險？不時想起秦末起義，聯軍在黃河一邊，無人敢進攻秦國。項羽等到不耐煩，終於等了47天，見自己上司也無意進攻，早上起來進營中殺了上司宋義，奪兵權，然後帶領楚軍，破釜沉舟，只帶三天糧食過河，與秦軍決一死戰。然後楚軍以一當十。最後楚軍大敗秦軍，史稱 鉅鹿之戰。當其時，其他諸侯還只敢作壁上觀，不敢參與其中。遙想當年項羽真英雄也。說到㡳，我還想用自己雙手打出一片天。

jimmychu0807

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

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Common OpenSSL Commands with Keys and Certificates

SSL Info

Generate RSA private key with certificate in a single command

openssl req -x509 -newkey rsa:4096 -sha256 -keyout example.key -out example.crt -subj "/CN=example.com" -days 3650 -passout pass:foobar

Generate Certificate Signing Request (CSR) from private key with passphrase

openssl x509 -x509toreq -in example.crt -out example.csr -signkey example.key -passin pass:foobar

jimmychu0807

use std::str;

fn main() {
  // -- FROM: vec of chars --
  let src1: Vec<char> = vec!['j','{','"','i','m','m','y','"','}'];
  // to String
  let string1: String = src1.iter().collect::<String>();
  // to str
  let str1: &str = &src1.iter().collect::<String>();
  // to vec of byte

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General Instructions

Most workshops at Sub0 will require that you have set up your computer to compile Substrate.

You can use this one-liner to do many of these steps for you automatically:

curl https://getsubstrate.io -sSf | bash -s -- --fast

jimmychu0807

// babe 組件內的常量
console.log(api.consts.babe.epochDuration.toNumber());

// balances 組件內的常量
console.log(api.consts.balances.creationFee.toNumber());
console.log(api.consts.balances.transferFee.toNumber());

jimmychu0807

// 從 mnemonic 來生成，建議方法：
const PHRASE = 'entire material egg meadow latin bargain dutch coral blood melt acoustic thought';
const newPair = keyring.addFromUri(PHRASE);

// 只限開發時使用，即運行 Substrate 節點時加了 `--dev` 參數：
const alice = keyring.addFromUri('//Alice', { name: 'Alice default' });

// 用 32 位的 16 進制數字生成
const hexPair = keyring.addFromUri('0x1234567890123456789012345678901234567890123456789012345678901234');

jimmychu0807

const unsub = await api.queryMulti([
  // 一個 getter function
  api.query.timestamp.now,
  // 另一個 getter function，及所需參數
  [api.query.balances.freeBalance, ADDR],
  [api.query.system.accountNonce, ADDR],
], ([now, balance, nonce]) => { // 回調函數
  console.log(`${now}: balance of ${balance} and a nonce of ${nonce}`);
});

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// 訂閱著該數值
const unsub = await api.query.balances.freeBalance(ADDR, balance => {
  console.log(`balance of ${balance}`);
});

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// 創建 api
// const api = await ...;

api.query.system.events(events => {
  events.forEach(record => {
    // 遍歷所有事件記錄
    const { event, phase } = record;
    const types = event.typeDef;

    // 過濾掉我們不關注的事件