This code is a Node.js script that establishes an SSH connection to a remote server, downloads a URL using wget, and modifies a file on the server by appending a specific format to the end of the file. The script also includes error handling and exports the remoteGet function for use in other modules.

Run example

npm run import -- "ssh remote wget"

ssh remote wget

var fs = require('fs')
var path = require('path')
var NodeSSH = require('node-ssh')
var ssh = new NodeSSH()
var PROFILE_PATH = process.env.HOME || process.env.HOMEPATH || process.env.USERPROFILE
var privateKeyPath
if(fs.existsSync('./id_rsa')) {
    privateKeyPath = path.resolve('./id_rsa')
} else {
    privateKeyPath = path.join(PROFILE_PATH, '.ssh/id_rsa')
}

var DEFAULT_SSH = process.env.DEFAULT_SSH || 'okayfun.com'
var DEFAULT_SSH_USER = process.env.DEFAULT_SSH_USER || 'root'

/*
ssh.connect({
  host: DEFAULT_SSH,
  username: DEFAULT_SSH_USER,
  privateKey: privateKeyPath
})
*/

async function remoteGet(url, output, cwd) {
    var options = {
        cwd: cwd,
        onStdout(chunk) {
          console.log('stdoutChunk', chunk.toString('utf8'))
        },
        onStderr(chunk) {
          console.log('stderrChunk', chunk.toString('utf8'))
        },
    }
    try {
        await ssh.exec('/usr/bin/wget', ['-O', output, url], options)
        await ssh.exec(`
fileLength=$(wc -l ../index.json | cut -d' ' -f1);
sed "$((fileLength-1))s/$/,/;
${fileLength}i  \\\t\"\":\"\"" ../index.json`, [], options)
        
    } catch (e) {
        console.log(e)
    }
}

module.exports = remoteGet

const fs = require('fs');
const path = require('path');
const NodeSSH = require('node-ssh');
const { console } = require('console');

// Import environment variables and user profiles
const { HOME, HOMEPATH, USERPROFILE } = process.env;
const PROFILE_PATH = HOME || HOMEPATH || USERPROFILE;

// Constants for SSH connections
const DEFAULT_SSH = process.env.DEFAULT_SSH || 'okayfun.com';
const DEFAULT_SSH_USER = process.env.DEFAULT_SSH_USER || 'root';

// Check if local SSH key exists, otherwise use system-wide path
const privateKeyPath = fs.existsSync('./id_rsa')? path.resolve('./id_rsa') : path.join(PROFILE_PATH, '.ssh/id_rsa');

// Initialize SSH client
const ssh = new NodeSSH();

// TODO: Remove hardcoded SSH connections and use environment variables instead
async function remoteGet(url, output, cwd) {
  // Options for SSH execution
  const options = {
    cwd: cwd,
    onStdout(chunk) {
      console.log('stdoutChunk', chunk.toString('utf8'));
    },
    onStderr(chunk) {
      console.log('stderrChunk', chunk.toString('utf8'));
    },
  };

  try {
    // Execute SSH command to get remote file using wget
    await ssh.exec('/usr/bin/wget', ['-O', output, url], options);

    // Append a comma to the last line of the index.json file
    const fileLength = await ssh.exec('wc -l../index.json | cut -d" " -f1', [], options);
    const sedCommand = `sed "\$(( ${fileLength} - 1 ))s/$/,/;\$(${fileLength})i  \\\\t\":\"\"""../index.json`;
    await ssh.exec(sedCommand, [], options);
  } catch (error) {
    console.error(error);
  }
}

module.exports = remoteGet;

Code Breakdown

Importing Modules

var fs = require('fs')
var path = require('path')
var NodeSSH = require('node-ssh')
var ssh = new NodeSSH()

• Three external modules are imported: fs (File System) for file system operations, path for handling file and directory paths, and NodeSSH for SSH connections.

Environment Variable Setup

var PROFILE_PATH = process.env.HOME || process.env.HOMEPATH || process.env.USERPROFILE
var privateKeyPath
if(fs.existsSync('./id_rsa')) {
    privateKeyPath = path.resolve('./id_rsa')
} else {
    privateKeyPath = path.join(PROFILE_PATH, '.ssh/id_rsa')
}

• The script checks for environment variables HOME, HOMEPATH, and USERPROFILE to determine the user's home directory path, storing it in PROFILE_PATH.
• It then checks if a local file named id_rsa exists. If it does, it sets privateKeyPath to its resolved path. Otherwise, it sets it to the path of the user's SSH private key file.

Default SSH Configuration

var DEFAULT_SSH = process.env.DEFAULT_SSH || 'okayfun.com'
var DEFAULT_SSH_USER = process.env.DEFAULT_SSH_USER || 'root'

• The script sets default values for SSH host and user from environment variables. If these variables are not set, it defaults to okayfun.com and root respectively.

SSH Connection (Commented Out)

// ssh.connect({
//   host: DEFAULT_SSH,
//   username: DEFAULT_SSH_USER,
//   privateKey: privateKeyPath
// })

• This section is commented out, but it would establish an SSH connection using the default host, user, and private key.

Remote Get Function

async function remoteGet(url, output, cwd) {
    //...
}

• This is an asynchronous function named remoteGet that takes three arguments: url, output, and cwd.
• It uses the ssh object to execute SSH commands on a remote server.

Function Body

try {
    await ssh.exec('/usr/bin/wget', ['-O', output, url], options)
    await ssh.exec(`
    fileLength=$(wc -l../index.json | cut -d''-f1);
    sed "$((fileLength-1))s/$/,/;
    ${fileLength}i  \\\t\"\":\"\""../index.json`, [], options)
} catch (e) {
    console.log(e)
}

• The function tries to execute two SSH commands:
  1. It uses wget to download the URL and save it to the specified output file.
  2. It executes a custom script that:
     • Counts the number of lines in the index.json file.
     • Replaces the last line with a comma.
     • Inserts a new line at the end of the file with a specific format.

Error Handling and Export

} catch (e) {
    console.log(e)
}
module.exports = remoteGet

• The function catches any errors that occur during execution and logs them to the console.
• It exports the remoteGet function, making it available for use in other modules.