Python

Helpers

Virtual environment

needs rewriting [ https://dev.to/codemouse92/dead-simple-python-virtual-environments-and-pip-5b56 venv] dev.to Part of "Dead Simple Python" series.

The venv module provides support for creating lightweight “virtual environments” with their own site directories, optionally isolated from system site directories.

Install venv, requires python3.3+

python3 -V
sudo apt-get install build-essential libssl-dev libffi-dev python-dev
sudo apt-get install -y python3-pip
sudo apt install python3-venv
python3 -m venv my_env             #create virtual environment
source my_env/bin/activate         #activate env
(my_env) piotr@ubuntu ~/scripts $  #prompt change to acknowledge activated environment

Note: Within the virtual environment, you can use the command python instead of python3, and pip instead of pip3 if you would prefer. If you use Python 3 on your machine outside of an environment, you will need to use the python3 and pip3 commands exclusively.

Syntax, semantics and functions

print()

Print in v3 is a function, it uses arguments with variables like below:

%s - String (or any object with a string representation, like numbers)
%d - Integers
%f - Floating point numbers
%.<number of digits>f - Floating point numbers with a fixed amount of digits to the right of the dot.
%x/%X - Integers in hex representation (lowercase/uppercase)

Eaxmple:

print("%s is %d years old." % (name, age))

Simple HTTP Server

It provides the local files browser over http protocol and access logs

sudo python  -m SimpleHTTPServer 80 #python 2
sudo python3 -m http.server      80 #python 3

Install Selenium lib on Ubuntu

$ which python python3
/usr/bin/python
/usr/bin/python3
sudo apt-get install python3-pip        # install pip for python3
sudo python3 -m pip install -U selenium # install selenium for python3
sudo python3 -m pip install -U pip      # upgrade pip

Install geckodriver on Ubuntu

It's required if you use Selenium in Python, webdriver function:

default_browser = webdriver.Firefox()

Install

## Geckodriver (verified on Ubuntu 16.04 running on Vagrant)
wget https://github.com/mozilla/geckodriver/releases/download/v0.21.0/geckodriver-v0.21.0-linux64.tar.gz
sudo sh -c 'tar -x geckodriver -zf geckodriver-v0.21.0-linux64.tar.gz -O > /usr/bin/geckodriver'
sudo chmod +x /usr/bin/geckodriver
rm geckodriver-v0.21.0-linux64.tar.gz

## Chromedriver
wget https://chromedriver.storage.googleapis.com/2.29/chromedriver_linux64.zip
unzip chromedriver_linux64.zip
sudo chmod +x chromedriver
sudo mv chromedriver /usr/bin/
rm chromedriver_linux64.zip

Selenium - Website automation test to mimic human interaction - page login

Script below demonstrate usage of Selenium automation through Mozilla Geckodriver. It will open Firefox, navigate to a give URL, fill in a form, click a login button and take a screenshot.

Credentials file

cat creds.yaml
wpUser: user
wpPass: pass123

Main script

#!/usr/bin/python3
from selenium import webdriver
import yaml
driver = webdriver.Firefox()
creds = yaml.safe_load(open('creds.yaml','r'))
driver.get('http://wiki.ciscolinux.co.uk/index.php?title=Special:UserLogin&returnto=Main+Page')

user_field = driver.find_element_by_name("wpName")
pass_field = driver.find_element_by_name("wpPassword")
user_field.send_keys(creds['wpUser'])
pass_field.send_keys(creds['wpPass'])
# find login button and click on it
driver.find_element_by_name('wploginattempt').click()
driver.save_screenshot('screenshot.png')
driver.close

References

• A Beginner's Python Tutorial Wikibooks
• List of free Python learning resources
• VIM and Python - a Match Made in Heaven Vim as Python IDE
• Vundle Vim bundle/plugins manager