Node.js在child_process域和错误冒泡及捕获实践

const { spawn } = require('child_process');
const ls = spawn('ls', ['-lh', '/usr']);
ls.stdout.on('data', (data) => {
  console.log(`输出：${data}`);
});
ls.stderr.on('data', (data) => {
  console.log(`错误：${data}`);
});
ls.on('close', (code) => {
  console.log(`子进程退出码：$[code]`);
});

const { exec } = require('child_process');
exec('my.bat', (err, stdout, stderr) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log(stdout);
});
// 文件名带有空格的脚本：
const bat = spawn('"my script.cmd"', ['a', 'b'], { shell: true });
// 或：
exec('"my script.cmd" a b', (err, stdout, stderr) => {
  // ...
});

const { spawn } = require('child_process');
const grep = spawn('grep', ['ssh']);
grep.on('close', (code, signal) => {
  console.log(`子进程收到信号 ${signal} 而终止`);
});
// 发送 SIGHUP 到进程
grep.kill('SIGHUP');

const fs = require('fs');
const { spawn } = require('child_process');
const out = fs.openSync('./out.log', 'a');
const err = fs.openSync('./out.log', 'a');
const subprocess = spawn('prg', [], {
  detached: true,
  stdio: [ 'ignore', out, err ]
});
subprocess.unref();

const { spawn } = require('child_process');
const subprocess = spawn(process.argv[0], ['child_program.js'], {
  detached: true,
  stdio: 'ignore'
});
subprocess.unref();

'use strict';
const { spawn } = require('child_process');
const subprocess = spawn(
  'sh',
  [
    '-c',
    `node -e "setInterval(() => {
      console.log(process.pid, 'is alive')
    }, 500);"`
  ], {
    stdio: ['inherit', 'inherit', 'inherit']
  }
);
setTimeout(() => {
  subprocess.kill(); // 不会终止 shell 中的 node 进程
}, 2000);

const crypto = require('crypto');
const decipher = crypto.createDecipher('aes192', 'a password');
let decrypted = '';
decipher.on('readable', () => {
  const data = decipher.read();
  if (data)
    decrypted += data.toString('utf8');
});
decipher.on('end', () => {
  console.log(decrypted);
  // Prints: some clear text data
});
const encrypted =
    'ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504';
decipher.write(encrypted, 'hex');
decipher.end();

const crypto = require('crypto');
const fs = require('fs');
const decipher = crypto.createDecipher('aes192', 'a password');
const input = fs.createReadStream('test.enc');
const output = fs.createWriteStream('test.js');
input.pipe(decipher).pipe(output);

const crypto = require('crypto');
const assert = require('assert');
// Generate Alice's keys...
const alice = crypto.createDiffieHellman(2048);
const aliceKey = alice.generateKeys();
// Generate Bob's keys...
const bob = crypto.createDiffieHellman(alice.getPrime(), alice.getGenerator());
const bobKey = bob.generateKeys();
// Exchange and generate the secret...
const aliceSecret = alice.computeSecret(bobKey);
const bobSecret = bob.computeSecret(aliceKey);
// OK
assert.strictEqual(aliceSecret.toString('hex'), bobSecret.toString('hex'));

try {
  const m = 1;
  const n = m + z;
} catch (err) {
  // 在这里处理错误。
}