DEV Community: Giuseppe Zileni

whitelistcors

Giuseppe Zileni — Fri, 15 Jan 2021 11:56:42 +0000

CORS ( Cross-Origin Resource Sharing) is a mechanism that allows you to control the sources of requests on a Web page, which is particularly useful for defining security policies on your server, so that a browser and server interact to determine whether it is safe to allow cross-origin request.

The whitelistcors module helps developers configure CORS with a NodeJS and ExpressJS server and is very easy to use:

npm install --save whitelistcors
yarn add whitelistcors

To enable a resource to a specific request from an HTTP source, you must implement only an array of addresses:

var whitelist = require('whitelistcors');

// lists of origin domains
var origins = ['http://localhost', 'http://mysite.com'];

app.post('/myapi', whitelist(origins), function(req, res, next) {
    res.send('CORS OK!');
})

GitHub Projects: https://gzileni.github.io/whitelistcors/

Flask Bootstrap

Giuseppe Zileni — Mon, 11 Jan 2021 14:37:53 +0000

Flask is very simple to use to create REST APIs with Python even with a single file. The repository flask-bootstrap is a template to start developing more complex applications with Flask.

Let's start with the configuration file config.py:

class Config(object):
  pass

class ProdConfig(Config):
  pass

class DevConfig(Config):
  DEBUG = True

The root file main.py with ENDPOINT:

from flask import Flask
from config import DevConfig

app = Flask(__name__)
app.config.from_object(DevConfig)

@app.route('/')
def home():
  return '<h1>Hello World!</h1>'

if __name__ == '__main__':
  app.run()

The template is a simple REST API Server with an ENDPOINT '/' to display the classic "Hello World!" in the browser at the address to http://127.0.0.1:5000.

The project is structured as follows:

Dockerfile: Instructions for applying with Flask in a docker container
requirements.txt: Application dependencies
/venv: Developmental python environment
.gitignore: Files to exclude in commits for Git
main.py: The main file
config.py: Application configuration

To run the first flask project:

git clone https://github.com/gzileni/flask-bootstrap.git
cd flask-bootstrap

pip install -r requirements.txt
export FLASK_APP=main.py
flask run

An easy way to run and share the application with the team and send it to production is by using Docker:

docker build -t flask-bootstrap .
docker run -p 5000:5000 flask-bootstrap
docker container list

GitHub Projects: https://gzileni.github.io/flask-bootstrap/

logbootstrap

Giuseppe Zileni — Fri, 08 Jan 2021 16:39:33 +0000

During a developer's work on a nodejs application are often used console.log to visualize the progress of code at critical points, for quick debugging, or to display any warnings and errors in your code.

The logbootstrap module is very simple because it allows you to use colored log messages. The colors available are the same as in the BootStrap tool kit:

green : successful message
yellow: for a warning
cyan: a simple piece of information
gray: a secondary message
blue: a very important primary message
red: error message

Let's create a simple nodejs application:

$ mkdir ~/helloworld
$ cd ~/helloword
$ npm init
$ npm install logbootstrap
$ nano index.js

the index file.js will be a simple Endpoint API with the most classic "Hello World!"

const http = require('http');
const log = require('logbootstrap);

const hostname = '127.0.0.1';
const port = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello, World!\n');
});

server.listen(port, hostname, () => {
  log('info', 'Server running at http://' + hostname + ':' + port + '/');
  log('success', 'Success log information');
  log('warning', 'Warning log information');
  log('secondary', 'Secondary log information');
  log('primary', 'Primary log information');
  log('danger', 'Danger log information');
});

We run the code:

Good Colorful Code !

GitHub Projects: https://gzileni.github.io/logbootstrap/