https web server with ubuntu, letsencript and nodejs

sudo apt-get install letsencrypt

letsencrypt certonly --standalone -d example.com

Note: this will generate the following files in folder /etc/letsencrypt/live/example.com: cert.pem chain.pem fullchain.pem privkey.pem

Now you are ready to implement and execute your nodejs https server. Run the following program and then open https://example.com and it should be working without any browser warning, ready for production.

const https = require('https');
const fs = require('fs');

// cert.pem  chain.pem  fullchain.pem  privkey.pem

const options = {
  key: fs.readFileSync('/etc/letsencrypt/live/example.com/privkey.pem'),
  cert: fs.readFileSync('/etc/letsencrypt/live/example.com/cert.pem')
};

https.createServer(options, (req, res) => {
  res.writeHead(200);
  res.end('hello world\n');
}).listen(443);

Or using http-server command line utility:

http-server . -p 443 --ssl --cert "/etc/letsencrypt/live/example.com/cert.pem" --key "/etc/letsencrypt/live/example.com/privkey.pem"

writing selenium in javascript node with webdriverio - instructions for impatients

The following is what you need to do in order to write a javascript program that will command your browser through selenium using webdriver.io node library.

 First is about installing and running the selenium server. Second is a little webdriverio example. 

Installing the selenium server

The following instructions are give in a shell script that was tested on mac:

#install java

# download selenium server: 

curl -O http://selenium-release.storage.googleapis.com/2.53/selenium-server-standalone-2.53.0.jar

#download googlechrome selenium drivers: 

curl -O http://chromedriver.storage.googleapis.com/2.22/chromedriver_mac32.zip
unzip chromedriver_mac32.zip


#Execute selenium server: 

java -Dwebdriver.chrome.driver=./chromedriver -jar selenium-server-standalone-2.53.0.jar

The Program

From here the instructions are the same as in http://webdriver.io/guide.html - just execute ```npm install webdriverio``` in your node project and execute the following file. In this simple program that will navigate to google and when is ready print the document title in the console:

var webdriverio = require('webdriverio');
var options = {
    desiredCapabilities: {
        browserName: 'chrome'
    }
};
webdriverio
    .remote(options)
    .init()
    .url('http://www.google.com')
    .getTitle().then(function(title) {
        console.log('Title was: ' + title);
    })
    .end();

Appendix: Technologies used

• http://www.seleniumhq.org/ - the infrastructure that talks to browsers (java) 
• http://webdriver.io/guide.html - the selenium javascript api 
• http://chromedriver.storage.googleapis.com/index.html - selenium driver to manage chrome browser.
• java and node

Minify JavaScript code with esprima and escodegen

var esprima = require('esprima'), 
escodegen = require('escodegen');

function doUglify(s)
{
 try
 {
  var ast = esprima.parse(s);
  s = escodegen.generate(ast, {format: escodegen.FORMAT_MINIFY}) || s;
 }
 catch(ex)
 {
  console.log(ex);
 }
 return s;
}

first steps with postgresql for inpatients

The following is a bash script that show easy steps for getting started with postgresql and verified in a arch linux distribution. There are also some comments for explaining, ideal for inpatients:

DATA_FOLDER=.data
mkdir myproject
cd myproject

initdb -D $DATA_FOLDER

#TODO DONT DO THIS IN PRODUCTION
sudo chmod -R a+wr /run/postgresql/ 

postgres -D $DATA_FOLDER >logfile 2>&1 &

createdb mydb