Python 3.8.5 : PyEphem astronomy library for Python - part 001.

About this python package, you can find it from the official website.
PyEphem provides an ephem Python package for performing high-precision astronomy computations. The underlying numeric routines are coded in C and are the same ones that drive the popular XEphem astronomy application, whose author, Elwood Charles Downey, generously gave permission for their use in PyEphem. The name ephem is short for the word ephemeris, which is the traditional term for a table giving the position of a planet, asteroid, or comet for a series of dates.
Because I like astronomy and lately a lot has happened in this field, I thought I would come up with some simple tutorials for those who are interested.
This tutorial is tested on a Linux distribution called Fedora 32 with Python version 3.8.5.
I installed this python packet with the pip3 tool.

[mythcat@desk ~]$ sudo pip3 install ephem --user
WARNING: Running pip install with root privileges is generally not a good idea. 
Try `pip3 install --user` instead.
Collecting ephem
...
Installing collected packages: ephem
Successfully installed ephem-3.7.7.1

You know that NASA has launched the Mars Perseverance rover, so let's play with this topic a bit.
Let's see current azimuth and elevation for planet Mars.
For this is need the position of the observer and then is compute the position of the planet Mars.
I used the position of the Greenwich for the observer, but you can create your oun observer and use it.

[mythcat@desk ~]$ python3
Python 3.8.5 (default, Jul 20 2020, 00:00:00) 
[GCC 10.1.1 20200507 (Red Hat 10.1.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import ephem
>>> import math
>>> convert = math.pi / 180.
>>> mars = ephem.Mars()
>>> greenwich = ephem.Observer()
>>> greenwich.lat = "51.477928"
>>> greenwich.lon = "-0.001545"
>>> mars.compute(greenwich)
>>> az_deg, alt_deg = mars.az*convert, mars.alt*convert
>>> print(f"Mars' current azimuth and elevation: {az_deg:.2f} {alt_deg:.2f}")
Mars' current azimuth and elevation: 0.11 -0.01

Let's see another example with Mars to take ascension and declination for the epoch specified:

...
>>> import datetime
>>> now = datetime.datetime.now()
>>> print(now)
2020-07-31 19:11:42.312027
>>> mars.compute(now)
>>> print(mars.ra)
1:12:43.64
>>> print(mars.dec)
3:33:22.6

You can get the magnitude, size (diameter in arcseconds) and size (radius as an angle):

>>> print(mars.mag)
-1.11
>>> print(mars.size)
14.555475234985352
>>> print(mars.radius)
0:00:07.3

You can easily see which constellation Mars is on.

>>> ephem.constellation(mars)
('Psc', 'Pisces')

Python 3.6.9 : My colab tutorials - parts 006 - 007.

This tutorial is called: My colab tutorials - parts 006 - 007.
The only reason for synchronization with the source code from my GitHub account on the Colab project.
I like collab more and more because I can quickly test the source code.
The example is taken from here and adapted to work on Colab and the new version of numba
Here is a simple example with the python numba package to creat that Mandelbrot fractal set.

import numba
from numba import jit

@jit
def mandel(x, y, max_iters):
  """
    Given the real and imaginary parts of a complex number,
    determine if it is a candidate for membership in the Mandelbrot
    set given a fixed number of iterations.
  """
  c = complex(x, y)
  z = 0.0j
  for i in range(max_iters):
    z = z*z + c
    if (z.real*z.real + z.imag*z.imag) >= 4:
      return i

  return max_iters

@jit
def create_fractal(min_x, max_x, min_y, max_y, image, iters):
  height = image.shape[0]
  width = image.shape[1]

  pixel_size_x = (max_x - min_x) / width
  pixel_size_y = (max_y - min_y) / height
    
  for x in range(width):
    real = min_x + x * pixel_size_x
    for y in range(height):
      imag = min_y + y * pixel_size_y
      color = mandel(real, imag, iters)
      image[y, x] = color

image = np.zeros((1024, 1536), dtype = np.uint8)
start = timer()
create_fractal(-2.0, 1.0, -1.0, 1.0, image, 20) 
dt = timer() - start

print ("Mandelbrot created in %f s" % dt)
imshow(image)
show() 

Python 3.8.2 : The numba python package - part 001 .

The development of this python package comes with this short intro:
Numba is a just-in-time compiler for Python that works best on code that uses NumPy arrays and functions and loops. The most common way to use Numba is through its collection of decorators that can be applied to your functions to instruct Numba to compile them. When a call is made to a Numba decorated function it is compiled to machine code “just-in-time” for execution and all or part of your code can subsequently run at native machine code speed!
I installed this python package on my folder Python38:

D:\Python38>pip3 install numba
Collecting numba
...
Successfully installed numba-0.50.1
D:\Python38>python.exe
Python 3.8.2 (tags/v3.8.2:7b3ab59, Feb 25 2020, 22:45:29) [MSC v.1916 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import numba
>>> numba.__version__
'0.50.1'

This package did not work with python install on the folder Python38_64:

D:\Python38_64>pip3 install numba
Collecting numba
...
Installing collected packages: numpy, llvmlite, numba
Successfully installed llvmlite-0.33.0 numba-0.50.1 numpy-1.19.1
WARNING: You are using pip version 20.1; however, version 20.1.1 is available.
...
D:\Python38_64>python.exe
Python 3.8.4 (tags/v3.8.4:dfa645a, Jul 13 2020, 16:46:45) [MSC v.1924 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import numba
Traceback (most recent call last):
...
ModuleNotFoundError: No module named 'numba'

You can write standard Python functions and run them on a CUDA-capable GPU.
First, I need to enable this feature:

D:\Python38>SET NUMBA_ENABLE_CUDASIM=1

D:\Python38>python
Python 3.8.2 (tags/v3.8.2:7b3ab59, Feb 25 2020, 22:45:29) [MSC v.1916 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from numba import cuda
>>> print(cuda.gpus)
...Managed Device 0...

Let's test with a simple example to create a data and use it:

D:\Python38>python
Python 3.8.2 (tags/v3.8.2:7b3ab59, Feb 25 2020, 22:45:29) [MSC v.1916 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import time
>>> import numpy as np
>>> from numba import cuda
>>>
>>> @cuda.jit
... def create(data):
...     data[cuda.blockIdx.x, cuda.threadIdx.x] = cuda.blockIdx.x
...
>>> numBlocks = 4
>>> threadsPerBlock = 6
>>>
>>> data = np.ones((numBlocks, threadsPerBlock), dtype=np.uint8)
>>> create[numBlocks, threadsPerBlock](data)
>>> print(data)
[[0 0 0 0 0 0]
 [1 1 1 1 1 1]
 [2 2 2 2 2 2]
 [3 3 3 3 3 3]]

Python Qt5 : Create a simple web browser.

This python package named PyQtWebEngine, see the official webpage for more infos:
The team development comes with this intro:
PyQtWebEngine is a set of Python bindings for The Qt Company’s Qt WebEngine framework. The framework provides the ability to embed web content in applications and is based on the Chrome browser. The bindings sit on top of PyQt5 and are implemented as three separate modules corresponding to the different libraries that make up the framework.
I used my python version: Python 3.8.3rc1 (tags/v3.8.3rc1:802eb67, Apr 29 2020, 21:39:14) [MSC v.1924 64 bit (AMD64)] on win32
... and PyQt5 version PyQt version: 5.15.0:

>>> from PyQt5.Qt import PYQT_VERSION_STR        
>>> print("PyQt version:", PYQT_VERSION_STR)  
PyQt version: 5.15.0

First, let's install this python package:

pip3 install PyQtWebEngine --user
Collecting PyQtWebEngine
  Using cached PyQtWebEngine-5.15.0-5.15.0-cp35.cp36.cp37.cp38-none-win_amd64.whl (57.9 MB)
Collecting PyQt5-sip<13>=12.8
  Using cached PyQt5_sip-12.8.0-cp38-cp38-win_amd64.whl (63 kB)
Collecting PyQt5>=5.15
  Using cached PyQt5-5.15.0-5.15.0-cp35.cp36.cp37.cp38-none-win_amd64.whl (64.5 MB)
Installing collected packages: PyQt5-sip, PyQt5, PyQtWebEngine
  WARNING: The scripts pylupdate5.exe, pyrcc5.exe and pyuic5.exe are installed in 
'C:\Users\catal\AppData\Roaming\Python\Python38\Scripts' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, 
use --no-warn-script-location.
Successfully installed PyQt5-5.15.0 PyQt5-sip-12.8.0 PyQtWebEngine-5.15.0

The WARNING reflects the path for this tool, but you can find on user folder, see:

C:\Users\catal>pylupdate5.exe
Usage:
    pylupdate5 [options] project-file
    pylupdate5 [options] source-files -ts ts-files

Options:
    -help  Display this information and exit
    -version
           Display the version of pylupdate5 and exit
    -verbose
           Explain what is being done
    -noobsolete
           Drop all obsolete strings
    -tr-function name
           name() may be used instead of tr()
    -translate-function name
           name() may be used instead of translate()

C:\Users\catal>

This is a simple source code with an browser example:

import sys
from PyQt5.Qt import *
from PyQt5 import QtCore, QtWidgets
from PyQt5.QtWidgets import QMainWindow, QWidget, QLabel, QLineEdit
from PyQt5.QtWidgets import QPushButton
from PyQt5.QtCore import QSize, QUrl
from PyQt5.QtWebEngineWidgets import *
from PyQt5.QtWebEngineWidgets import QWebEnginePage, QWebEngineView
class MainWindow(QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()

        self.setWindowTitle('catafest browser')

        self.browser_toolbar = QToolBar()
        self.addToolBar(self.browser_toolbar)
        self.back_button = QPushButton()
        #self.back_button.setIcon(QIcon('left.png'))
        self.back_button.clicked.connect(self.back_page)
        self.browser_toolbar.addWidget(self.back_button)
        self.forward_button = QPushButton()
        #self.forward_button.setIcon(QIcon('right.png'))
        self.forward_button.clicked.connect(self.forward_page)
        self.browser_toolbar.addWidget(self.forward_button)

        self.web_address = QLineEdit()
        self.web_address.returnPressed.connect(self.load_page)
        self.browser_toolbar.addWidget(self.web_address)

        self.web_browser = QWebEngineView()
        self.setCentralWidget(self.web_browser)
        first_url = "https://pypi.org/project/PyQt5/"

        self.web_address.setText(first_url)
        self.web_browser.load(QUrl(first_url))
        self.web_browser.page().titleChanged.connect(self.setWindowTitle)
        self.web_browser.page().urlChanged.connect(self.changed_page)
        
    def load_page(self):
        url = QUrl.fromUserInput(self.web_address.text())
        if url.isValid():
            self.web_browser.load(url)

    def back_page(self):
        self.web_browser.page().triggerAction(QWebEnginePage.Back)

    def forward_page(self):
        self.web_browser.page().triggerAction(QWebEnginePage.Forward)

    def changed_page(self, url):
        self.web_address.setText(url.toString())
        
if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    mainWin = MainWindow()
    availableGeometry = app.desktop().availableGeometry(mainWin)
    mainWin.resize(availableGeometry.width(), availableGeometry.height())
    mainWin.show()
    sys.exit( app.exec_() )

Python 3.8.3 : Lists in Python 3 - part 001.

I am currently working on a project that involves the use of complex data structures and lists and my time is limited.
This led me to start a new series of python tutorials on python lists.
I realized that the lists had no substantial changes in the evolution of the python programming language, see the official documentation.
You will find on the internet a lot of questions related to lists, algorithms, and problems involving lists.
If you are not a beginner then it will seem boring at first but over time I will try to draw attention to really significant elements in python programming with lists.
Let's start taking significant steps in using lists.
Before using the methods of list objects, let's create some lists:

# create a empty list 
my_list_001 = []
# fill the list with 4 consecutive numbers from 0 to 3 
my_list_001 = list(range(0,4))
# show the list 
my_list_001
[0, 1, 2, 3]
# set the variable n with value 4
n = 4
# create a list with 4 zeroes 
list_of_zeros = [0] * n
# show the list
listofzeros
[0, 0, 0, 0]
# import string python package 
import string
# create a string with all ascii letters
my_letters = string.ascii_letters
# use list to create a list with all letters
list(my_letters)
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
# create a nested list is a list can also have another list as an item
my_list = ["catafest", [1,9,7,6], ["!"]]
# show the list
my_list
['catafest', [1, 9, 7, 6], ['!']]
# access elements from a list with index operator pozitive and negative [] 
my_list[0]
'catafest'
my_list[-1]
['!']
my_list[-2]
[1, 9, 7, 6]
my_list[-3]
'catafest'
# test conditions boolean
my_list[-3] == my_list[0]
True
my_list[-3] != my_list[0]
False
my_list_001[1] > listofzeros[1]
True
# sum an list element with another
sum_of_list_elemenet = my_list_001[1] + listofzeros[1]
# show result
sum_of_list_elemenet
1
# iterating through a list
for list_element in my_list:
...     print(list_element)
...
catafest
[1, 9, 7, 6]
['!']
# iterating each list  
for list_element in my_list:
...     for e in list_element:
...             print(e)
...
c
a
t
a
f
e
s
t
1
9
7
6
!
# create a list with all letters using chr and ord built-in functions
[chr(i) for i in range(ord('a'),ord('z')+1)]
# the result is
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
 'u', 'v', 'w', 'x', 'y', 'z']
# create a binary list from a integer
output = [int(x) for x in '{:08b}'.format(1976)]
# show the result of the list
output
[1, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0]
# show the result just for on element of the list
output[3]
1
# convert a binary list to integer named result and set first with value 0
# using the bitwise left shift operator
result = 0
for digits in output:
    result = (result << 1) | digits
# show result of conversion from binary to integer
result
1976
# create a hexadecimal list from a list
hex_list = [hex(x) for x in my_list_001]
# show the hexadecimal list using the hex built-in function
hex_list
['0x0', '0x1', '0x2', '0x3']
# convert hexadecimal list to int list using the int 
int_list = [int(x,0) for x in hex_list]
# show the result
int_list
[0, 1, 2, 3]
# convert hexadecimal list to float list using the float.fromhex
float_list = [float.fromhex(x) for x in hex_list]
# show the result
float_list
[0.0, 1.0, 2.0, 3.0]
# create list using math python module 
import math
[2*x for x in my_list_001]
[0, 2, 4, 6]
[math.sin(x) for x in my_list_001]
[0.0, 0.8414709848078965, 0.9092974268256817, 0.1411200080598672]
# create sized list
sized_list = [1] * 4
# show the result
sized_list
[1, 1, 1, 1]
# list from 
>>> chars = ''.join(map(chr, range(32, 1048)))
>>> list(chars)
[' ', '!', '"', '#', '$', '%', '&', "'", '(', ')', '*', '+', ',', '-', '.', '/', '0', '1', '2', '3', '4', '5',
 '6', '7', '8', '9', ':', ';', '<', '=', '>', '?', '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K',
 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '[', '\\', ']', '^', '_', '`', 'a',
 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
 'x', 'y', 'z', '{', '|', '}', '~', '\x7f', '\x80', '\x81', '\x82', '\x83', '\x84', '\x85', '\x86', '\x87', 
'\x88', '\x89', '\x8a', '\x8b', '\x8c', '\x8d', '\x8e', '\x8f', '\x90', '\x91', '\x92', '\x93', '\x94', '\x95',
 '\x96', '\x97', '\x98', '\x99', '\x9a', '\x9b', '\x9c', '\x9d', '\x9e', '\x9f', '\xa0', '¡', '¢', '£', '¤', '¥',
 '¦', '§', '¨', '©', 'ª', '«', '¬', '\xad', '®', '¯', '°', '±', '²', '³', '´', 'µ', '¶', '·', '¸', '¹', 'º', '»',
 '¼', '½', '¾', '¿', 'À', 'Á', 'Â', 'Ã', 'Ä', 'Å', 'Æ', 'Ç', 'È', 'É', 'Ê', 'Ë', 'Ì', 'Í', 'Î', 'Ï', 'Ð', 'Ñ', 'Ò',
 'Ó', 'Ô', 'Õ', 'Ö', '×', 'Ø', 'Ù', 'Ú', 'Û', 'Ü', 'Ý', 'Þ', 'ß', 'à', 'á', 'â', 'ã', 'ä', 'å', 'æ', 'ç', 'è', 'é',
 'ê', 'ë', 'ì', 'í', 'î', 'ï', 'ð', 'ñ', 'ò', 'ó', 'ô', 'õ', 'ö', '÷', 'ø', 'ù', 'ú', 'û', 'ü', 'ý', 'þ', 'ÿ', 'Ā',
 'ā', 'Ă', 'ă', 'Ą', 'ą', 'Ć', 'ć', 'Ĉ', 'ĉ', 'Ċ', 'ċ', 'Č', 'č', 'Ď', 'ď', 'Đ', 'đ', 'Ē', 'ē', 'Ĕ', 'ĕ', 'Ė', 'ė',
 'Ę', 'ę', 'Ě', 'ě', 'Ĝ', 'ĝ', 'Ğ', 'ğ', 'Ġ', 'ġ', 'Ģ', 'ģ', 'Ĥ', 'ĥ', 'Ħ', 'ħ', 'Ĩ', 'ĩ', 'Ī', 'ī', 'Ĭ', 'ĭ', 'Į',
 'į', 'İ', 'ı', 'IJ', 'ij', 'Ĵ', 'ĵ', 'Ķ', 'ķ', 'ĸ', 'Ĺ', 'ĺ', 'Ļ', 'ļ', 'Ľ', 'ľ', 'Ŀ', 'ŀ', 'Ł', 'ł', 'Ń', 'ń', 'Ņ',
 'ņ', 'Ň', 'ň', 'ʼn', 'Ŋ', 'ŋ', 'Ō', 'ō', 'Ŏ', 'ŏ', 'Ő', 'ő', 'Œ', 'œ', 'Ŕ', 'ŕ', 'Ŗ', 'ŗ', 'Ř', 'ř', 'Ś', 'ś', 'Ŝ',
 'ŝ', 'Ş', 'ş', 'Š', 'š', 'Ţ', 'ţ', 'Ť', 'ť', 'Ŧ', 'ŧ', 'Ũ', 'ũ', 'Ū', 'ū', 'Ŭ', 'ŭ', 'Ů', 'ů', 'Ű', 'ű', 'Ų', 'ų', 
'Ŵ', 'ŵ', 'Ŷ', 'ŷ', 'Ÿ', 'Ź', 'ź', 'Ż', 'ż', 'Ž', 'ž', 'ſ', 'ƀ', 'Ɓ', 'Ƃ', 'ƃ', 'Ƅ', 'ƅ', 'Ɔ', 'Ƈ', 'ƈ', 'Ɖ', 'Ɗ', 'Ƌ', 'ƌ',
 'ƍ', 'Ǝ', 'Ə', 'Ɛ', 'Ƒ', 'ƒ', 'Ɠ', 'Ɣ', 'ƕ', 'Ɩ', 'Ɨ', 'Ƙ', 'ƙ', 'ƚ', 'ƛ', 'Ɯ', 'Ɲ', 'ƞ', 'Ɵ', 'Ơ', 'ơ', 'Ƣ', 'ƣ',
...
...
 'ϗ', 'Ϙ', 'ϙ', 'Ϛ', 'ϛ', 'Ϝ', 'ϝ', 'Ϟ', 'ϟ', 'Ϡ', 'ϡ', 'Ϣ', 'ϣ', 'Ϥ', 'ϥ', 'Ϧ', 'ϧ', 'Ϩ', 'ϩ', 'Ϫ', 'ϫ', 'Ϭ', 'ϭ',
 'Ϯ', 'ϯ', 'ϰ', 'ϱ', 'ϲ', 'ϳ', 'ϴ', 'ϵ', '϶', 'Ϸ', 'ϸ', 'Ϲ', 'Ϻ', 'ϻ', 'ϼ', 'Ͻ', 'Ͼ', 'Ͽ', 'Ѐ', 'Ё', 'Ђ', 'Ѓ', 'Є',
 'Ѕ', 'І', 'Ї', 'Ј', 'Љ', 'Њ', 'Ћ', 'Ќ', 'Ѝ', 'Ў', 'Џ', 'А', 'Б', 'В', 'Г', 'Д', 'Е', 'Ж', 'З']

This is not all about create and convert list, but it is quite close to the reality of the lists.
This tutorial remains open due to the complex issue and maybe I will complete it in the future.

Python 3.8.3 : Short intro to Appium-Python-Client python package.

This is a short intro of the Appium-Python-Client python package and Appium based on Client-Server Architecture.
The Appium Server can be installed using two ways: using NPM or using Appium Desktop.
I download and run the desktop version from here.

Appium-windows-1.18.0-beta.1>Appium.exe

The latest version of Java, needed for Android Studio ( you can use the installation of Android Studio with SDK) and mobile phone set on USB debugging.
The next step is to set all settings for android into Appium interface:

Using appium server, you can send commands to the Appium Server which translates it to platform-specific commands and executes on the devices.
The Appium-Python-Client python package is an extension library for use with the mobile testing framework Appium, see the official webpage.
Install Appium-Python-Client python package with pip3 tool.

pip3 install Appium-Python-Client
Collecting Appium-Python-Client
...
Successfully built Appium-Python-Client
Installing collected packages: Appium-Python-Client
Successfully installed Appium-Python-Client-1.0.1

Now you can test this python package with Appium and simple examples.

Python 3.8.3 : About aiohttp python package.

This python package can help you to writing single-threaded concurrent code using coroutines, multiplexing I/O access over sockets and other resources, running network clients and servers, and other related primitives, see the official documentation.
In this simple tutorial, I will show you in a few simple steps how to use it.
It is a complex module and there are multiple ways to use it.
First, on the Windows operating system users can install easily with:

pip3 install aiohttp
Collecting aiohttp
...
Installing collected packages: attrs, multidict, yarl, async-timeout, aiohttp
Successfully installed aiohttp-3.6.2 async-timeout-3.0.1 attrs-19.3.0 multidict-4.7.6 yarl-1.4.2

If you use a Linus operating system then you can use this command:

[mythcat@desk ~]$ pip3 install aiohttp --user 
...
Successfully installed aiohttp-3.6.2 async-timeout-3.0.1 multidict-4.7.5 yarl-1.4.2

This python package can be used as client or server.
The aiohttp.web implements a basic CLI for quickly serving an Application in development over TCP/IP.
You can find some example on this webpage.
These simple examples show how you can use handlers for web and servers and a request handler with a coroutine.

[mythcat@desk ~]$ python3 
Python 3.7.6 (default, Jan 30 2020, 09:44:41) 
[GCC 9.2.1 20190827 (Red Hat 9.2.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from aiohttp import web 
>>> def handler_req(request):
...     return web.Response(text='Handler')
... 
>>> handler_req
<function 0x7fc8a76aab00="" at="" handler_req="">
>>> async def handler_req_async(request):
...     return web.Response(text='async Handler')
... 
>>> handler_req_async
<function+0x7fc8a574edd0...
>>> import aiohttp
>>> from aiohttp import web
>>> from aiohttp.client import _RequestContextManager
>>> async def test_await(test_server, loop):
...  
...     async def handler(request):
...         return web.HTTPOk()
...
...     app = web.Application(loop=loop)
...     app.router.add_route('GET', '/', handler)
...     server = await test_server(app)
...     resp = await aiohttp.get(server.make_url('/'), loop=loop)
...     assert resp.status == 200
...     assert resp.connection is not None
...     await resp.release()
...     assert resp.connection is None
>>> test_await('htthttp://localhost:8080/',1000)   
<coroutine object test_await at 0x00000261FB96EA40>

Let's see the output of the dir:

dir(aiohttp)
['AsyncIterablePayload', 'AsyncResolver', 'BadContentDispositionHeader', 'BadContentDispositionParam', 
'BaseConnector', 'BasicAuth', 'BodyPartReader', 'BufferedReaderPayload', 'BytesIOPayload', 'BytesPayload',
 'ChainMapProxy', 'ClientConnectionError', 'ClientConnectorCertificateError', 'ClientConnectorError', 
'ClientConnectorSSLError', 'ClientError', 'ClientHttpProxyError', 'ClientOSError', 'ClientPayloadError', 
'ClientProxyConnectionError', 'ClientRequest', 'ClientResponse', 'ClientResponseError', 'ClientSSLError', 
'ClientSession', 'ClientTimeout', 'ClientWebSocketResponse', 'ContentTypeError', 'CookieJar', 'DataQueue', 
'DefaultResolver', 'DummyCookieJar', 'EMPTY_PAYLOAD', 'EofStream', 'Fingerprint', 'FlowControlDataQueue', 
'FormData', 'HttpVersion', 'HttpVersion10', 'HttpVersion11', 'IOBasePayload', 'InvalidURL', 'JsonPayload', 
'MultipartReader', 'MultipartWriter', 'NamedPipeConnector', 'PAYLOAD_REGISTRY', 'Payload', 'RequestInfo', 
'ServerConnectionError', 'ServerDisconnectedError', 'ServerFingerprintMismatch', 'ServerTimeoutError', 
'Signal', 'StreamReader', 'StringIOPayload', 'StringPayload', 'TCPConnector', 'TextIOPayload', 
'ThreadedResolver', 'TooManyRedirects', 'TraceConfig', 'TraceConnectionCreateEndParams', 
'TraceConnectionCreateStartParams', 'TraceConnectionQueuedEndParams', 'TraceConnectionQueuedStartParams', 
'TraceConnectionReuseconnParams', 'TraceDnsCacheHitParams', 'TraceDnsCacheMissParams', 
'TraceDnsResolveHostEndParams', 'TraceDnsResolveHostStartParams', 'TraceRequestChunkSentParams', 
'TraceRequestEndParams', 'TraceRequestExceptionParams', 'TraceRequestRedirectParams', 'TraceRequestStartParams',
 'TraceResponseChunkReceivedParams', 'Tuple', 'UnixConnector', 'WSCloseCode', 'WSMessage', 'WSMsgType', 
'WSServerHandshakeError', 'WebSocketError', '__all__', '__builtins__', '__cached__', '__doc__', '__file__',
 '__loader__', '__name__', '__package__', '__path__', '__spec__', '__version__', 'abc', 'base_protocol', 
'client', 'client_exceptions', 'client_proto', 'client_reqrep', 'client_ws', 'connector', 
'content_disposition_filename', 'cookiejar', 'formdata', 'frozenlist', 'get_payload', 'hdrs', 'helpers', 
'http', 'http_exceptions', 'http_parser', 'http_websocket', 'http_writer', 'locks', 'log', 'multipart', 
'parse_content_disposition', 'payload', 'payload_streamer', 'payload_type', 'request', 'resolver', 'signals', 
'streamer', 'streams', 'tcp_helpers', 'tracing', 'typedefs']

Python 3.8.3 : PyCryptodome python package - part 001.

In the last tutorial, I wrote on Sunday, June 16, 2019, you can see a simple example of this python package with KDF with PBKDF2 function.

I guess it should be interesting for visitors to this blog to read more about this package because it is very useful and interesting.

Today I come up with another tutorial covering how to use A.E.S. standard encryption and decrypting text in a binary file.

The A.E.S. is a standard?

The Federal Information Processing Standards Publications (FIPS PUBS) announcing the A.E.S. on November 26, 2001, on the Federal Information Processing Standards Publication 197.

A.E.S. known as Advanced Encryption Standard is a symmetric block cipher standardized by NIST.

The N.I.S.T is an abbreviation National Institute of Standards and Technology.

This python package named PyCryptodome is a self-contained Python package of low-level cryptographic primitives, see the readthedocs.io webpage.

First, you need to see if this python package is not on conflict with another one named PyCrypto.

Then use pip3 tool to install.

pip3 uninstall PyCrypto
WARNING: Skipping PyCrypto as it is not installed.
...
pip3 install pycryptodome
Collecting pycryptodome
...
Installing collected packages: pycryptodome
Successfully installed pycryptodome-3.9.8

Here is the source code commented for a better understanding of the encryption and decryption steps.

from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes

# the data input needs to be encoded, else you will receive this error
# python TypeError: Object type  cannot be passed to C code

data = "Hello World! by catafest!".encode("utf8")
# first step - prepare for encrypt
key = get_random_bytes(16)
print("print key is: ", key)
cipher = AES.new(key, AES.MODE_EAX)
print("print cipher is: ", cipher)
ciphertext, tag = cipher.encrypt_and_digest(data)
print("print ciphertext is: ", ciphertext)

# open the binary file 
file_out = open("AES_encrypted.bin", "wb")
# write to binary file 
[ file_out.write(x) for x in (cipher.nonce, tag, ciphertext) ]

# the file is close 
file_out.close()

# next step - prepare for decrypt
new_cipher = AES.new(key, AES.MODE_EAX, cipher.nonce)

# open again the binary file 
file_in = open("AES_encrypted.bin", "rb")
# read all data from file
nonce, tag, ciphertext = [file_in.read(x) for x in (16, 16, -1) ]
# the file is close 
file_out.close()

# show data from file
print("print nonce is: ", nonce)
print("print tag is: ", tag)
print("print ciphertext is: ", ciphertext)

# create a new cipher
cipher = AES.new(key, AES.MODE_EAX, nonce)

# use this to decrypt
data = cipher.decrypt_and_verify(ciphertext, tag)
# show the result 
print(data)

The result of running the python script is this:

python.exe .\pycryptodome_AES_001.py
print key is:  b'\xbdEX\xf8\x1d!\xc5\xceI\x87\x81\xf1\xd5\xba\x8c\r'
print cipher is:  <Crypto.Cipher._mode_eax.EaxMode object at 0x000001D5F32DE100>
print cipher is:  <Crypto.Cipher._mode_eax.EaxMode object at 0x000001E062AFE100>
print ciphertext is:  b'ON\x1d\xb9\xb7\xa8\xf5\xd6\x0c\x91\xc5`B\xf4\x95u\xe1D\xb5\x88&I\x15\xc5\xc5'
print nonce is:  b'3\xa6R8\xbb\n \x9cimp$\xe4\xee\xf5-'
print tag is:  b'\xb8)\xe4\xe7\x08uE~\x84s]\xedX\xf5\xf9\xea'
print ciphertext is:  b'ON\x1d\xb9\xb7\xa8\xf5\xd6\x0c\x91\xc5`B\xf4\x95u\xe1D\xb5\x88&I\x15\xc5\xc5'
b'Hello World! by catafest!'

You can read about this process on this website.

Python 2.7.10 : IronPython and C# with Dynamic Language Runtime.

This is a simple tutorial about python and C# using the Dynamic Language Runtime with IronPython.

I use Visual Studio 2019 and .NET Framework 4.7.2 with my Console C# project named DynamicLanguageRuntime_001.

Let's install the package with Visual Studio by open the console using the main menu: Tools - NuGet Package Manager - Package Manager Console command.

PM> Install-Package DynamicLanguageRuntime
Package 'DynamicLanguageRuntime.1.2.3' already exists in project 'DynamicLanguageRuntime_001'
Time Elapsed: 00:00:01.2208674

Use Solution Explorer use right-click on References item from your project and use Add Reference ...

Into the new window dialog named Reference Manager on the Assemblies - Framework uses the edit box to search IronPython.

Then use the checkbox to select these two options: IronPython and IronPython.Modules.

See the screenshot from Visual Studio I.D.E.:

This is the source code I used:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using IronPython.Hosting;
using IronPython.Runtime;
using IronPython;
using Microsoft.Scripting.Hosting;
using Microsoft.Scripting;

namespace DynamicLanguageRuntime_001
{
    class Program
    {
        static void Main(string[] args)
        {
            // create python engine 
            ScriptEngine engine = Python.CreateEngine();
            // get and add paths to enfine
            var python_search_paths = engine.GetSearchPaths();
            python_search_paths.Add(@"C:\Program Files\IronPython 2.7\Lib");
            engine.SetSearchPaths(python_search_paths);
            // create a scope 
            ScriptScope scope = engine.CreateScope();
            // using CreateScriptSourceFromString
            engine.CreateScriptSourceFromString("print '... simple example with ironpython and C#'").Execute();
            // using Execute
            engine.Execute("print '                             by catafest!'", scope);
            // using ExecuteFile
            engine.ExecuteFile(@"D:\Projects\Python\testing\test_webpage_001.py", scope);
            dynamic testFunction = scope.GetVariable("GetFriends");
            var result = testFunction();
        }
    }
} 

Python 3.6.9 : My colab tutorials - part 005.

Today I tested google colab python features with google authentification and google.colab drive and files.
The first part of google colab code comes with authentification and you need to add the verification code for google account.
The google colab use the same version of python:

3.6.9 (default, Apr 18 2020, 01:56:04) [GCC 8.4.0]

You can see all source code on my GitHub account.
The notebook can be found here.

Python 3.8.3 : Using twitter application with python-twitter - part 002.

This is the second part of tutorials series with python-twitter.

Today I will show you how to get pieces of information about friends, users and save into a binary file with pickle known as cPickle.

I will use my old source code from the last tutorial.

import os
import twitter
# for save to file import by python version
try:
   import cPickle as pickle
except:
   import pickle

consumer_key=' '
consumer_secret=' '
token_key=' '
token_secret=' '

if __name__ == "__main__":
    api = twitter.Api(consumer_key=consumer_key,
                  consumer_secret=consumer_secret,
                  access_token_key=token_key,
                  access_token_secret=token_secret) 
    
    screen_name = 'catafest'
       
    # print all users of this account authentificated 
    # you can use GetFriends(screen_name=screen_name) 
    users = api.GetFriends()
    
    print([u.screen_name for u in users])
    # get followers 
    followers = api.GetFollowers(screen_name=screen_name)
    # print followers 
    print([f.screen_name for f in followers])
    
    # ... and save into a binary file 
    followers_file = "followers_file.bin"
    
    if not os.path.exists(followers_file):
        pickle.dump(followers, open(followers_file, "wb"), protocol=pickle.HIGHEST_PROTOCOL)
        
    # load binary file     
    if os.path.exists(followers_file):
        followers_read = pickle.load(open(followers_file, "rb"))
        print(followers_read)

The result is similar with this:

python.exe .\test_webpage_001.py
['SnapChick', 'NASA', 'andor_saga', 'blendermarket', 'Minehut', 'Aternos', 'axnro', 'Flexi23',
...
['PStackoverflow', 'SamLeac86078418', 'Sohanurr559', 'jasonalba', 'avkorablev', 'dotnetfiddle',
...
[User(ID=1260415029855256583, ScreenName=PStackoverflow), 
...

Python 3.8.3 : Using twitter application with python-twitter - part 001.

You need to create a application for your twitter user developer on this webpage.

The next step is to get all keys and tokens from your application.

I used the python-twitter see the official webpage documentation.

Let's install this python module using the pip tool

pip install python-twitter
Collecting python-twitter
...
Installing collected packages: oauthlib, requests-oauthlib, python-twitter
Successfully installed oauthlib-3.1.0 python-twitter-3.5 requests-oauthlib-1.3.0

Let's see a simple source code:

import os
import matplotlib
import matplotlib.pyplot as plt
import numpy as np
import twitter
import datetime
from datetime import *

consumer_key=' '
consumer_secret=' '
token_key=' '
token_secret=' '

def get_tweets(api=None, screen_name=None):
    timeline = api.GetUserTimeline(screen_name=screen_name, count=200)
    earliest_tweet = min(timeline, key=lambda x: x.id).id
    print("getting tweets before:", earliest_tweet)

    while True:
        tweets = api.GetUserTimeline(
            screen_name=screen_name, max_id=earliest_tweet, count=200
        )
        new_earliest = min(tweets, key=lambda x: x.id).id

        if not tweets or new_earliest == earliest_tweet:
            break
        else:
            earliest_tweet = new_earliest
            print("getting tweets before:", earliest_tweet)
            timeline += tweets

    return timeline

if __name__ == "__main__":
    api = twitter.Api(consumer_key=consumer_key,
                  consumer_secret=consumer_secret,
                  access_token_key=token_key,
                  access_token_secret=token_secret) 
    # print api 
    #print(dir(api))
    
    # print all users of this account authentificated 
    #users = api.GetFriends()
    #print([u.screen_name for u in users])
    
    # print all tweets of my user catafest 
    screen_name = "catafest"
    timeline = get_tweets(api=api, screen_name=screen_name)
    dates = []
    for x in timeline:
        created = x.created_at
        dates.append(created)
        
    print(dates)
    dat = [datetime.strptime(d, "%a %b %d %H:%M:%S +0000 %Y") for d in dates]

    levels = np.tile([-8, 8, -4, 4, -1, 1],int(np.ceil(len(dat)/3)))[:len(dat)]
    print(levels)
    fig, ax = plt.subplots(figsize=(7.6, 5), constrained_layout=True)
    ax.set(title="Twitter dates")
    markerline, stemline, baseline = ax.stem(dat, levels,linefmt="C3-", basefmt="k-",use_line_collection=True)
    markerline.set_ydata(np.zeros(len(dat)))
    plt.setp(markerline, mec="k", mfc="w", zorder=1)
    plt.show()

The result of this script comes with this output:

python .\test_webpage_001.py
getting tweets before: 1123237192422367234
['Mon May 18 13:52:09 +0000 2020', 'Sat May 09 11:14:43 +0000 2020', 'Fri May 08 10:42:18 +0000 2020', 
'Fri May 08 10:41:37 +0000 2020', 'Sat May 02 17:41:07 +0000 2020', 'Sat May 02 17:39:15 +0000 2020', 
'Thu Apr 30 12:53:48 +0000 2020', 'Tue Apr 28 20:00:38 +0000 2020', 'Mon Apr 27 21:12:07 +0000 2020', 
'Fri Apr 24 16:39:58 +0000 2020', 'Fri Apr 24 16:09:26 +0000 2020', 'Sat Apr 11 16:56:40 +0000 2020', 
'Sun Mar 22 19:11:16 +0000 2020', 'Sat Mar 21 09:03:30 +0000 2020', 'Sat Mar 21 09:02:48 +0000 2020', 
'Sat Mar 21 08:59:18 +0000 2020', 'Mon Mar 16 06:29:34 +0000 2020', 'Fri Jan 24 19:59:38 +0000 2020', 
'Sat Jan 18 12:14:07 +0000 2020', 'Fri Jan 17 20:58:18 +0000 2020', 'Thu Jan 16 20:50:47 +0000 2020', 
'Thu Jan 16 20:49:16 +0000 2020', 'Fri Jan 03 17:57:33 +0000 2020', 'Sat Dec 28 10:14:11 +0000 2019', 
'Tue Apr 30 14:46:30 +0000 2019']
[-8  8 -4  4 -1  1 -8  8 -4  4 -1  1 -8  8 -4  4 -1  1 -8  8 -4  4 -1  1 -8]

The image show with matplotlib is this:

Python 3.7.5 : Django on Fedora distro.

[mythcat@desk django]$ source env/bin/activate
(env) [mythcat@desk django]$ python3 
Python 3.7.6 (default, Dec 19 2019, 22:52:49) 
[GCC 9.2.1 20190827 (Red Hat 9.2.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import django
>>> django.VERSION
(3, 0, 1, 'final', 1) 

Static files are those files that can not be processed, generated or modified by the server.
Static files improve the performance of the website with the template inheritance method.
Static file management is an important factor in web development.
I will show you how static file works on Django project.
The new static files folder is set on settings.py file:

...
# Static files (CSS, JavaScript, Images)

STATIC_URL = '/static/'

STATIC_ROOT = os.path.join(BASE_DIR, '/home/mythcat/projects/django/mysite/test001/')
STATICFILES_DIRS = [
   os.path.join(BASE_DIR, 'static'),
 ]
...

Let's run the server:

(env) [mythcat@desk mysite]$ python3 manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
January 26, 2020 - 09:01:10
Django version 3.0.1, using settings 'mysite.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C. 

If I try to use the admin area then we can see the bad result for static files. 
...

[26/Jan/2020 09:10:02] "GET /admin/test001/post/ HTTP/1.1" 200 5935
[26/Jan/2020 09:10:02] "GET /static/admin/css/changelists.css HTTP/1.1" 200 6190
[26/Jan/2020 09:10:02] "GET /admin/jsi18n/ HTTP/1.1" 200 3223
[26/Jan/2020 09:10:02] "GET /static/admin/js/jquery.init.js HTTP/1.1" 200 363
[26/Jan/2020 09:10:02] "GET /static/admin/js/urlify.js HTTP/1.1" 200 8941
[26/Jan/2020 09:10:02] "GET /static/admin/js/actions.js HTTP/1.1" 200 6766
[26/Jan/2020 09:10:02] "GET /static/admin/js/prepopulate.js HTTP/1.1" 200 1530
[26/Jan/2020 09:10:02] "GET /static/admin/js/core.js HTTP/1.1" 200 5723
[26/Jan/2020 09:10:02] "GET /static/admin/js/admin/RelatedObjectLookups.js HTTP/1.1" 200 6918
[26/Jan/2020 09:10:02] "GET /static/admin/css/fonts.css HTTP/1.1" 200 423
[26/Jan/2020 09:10:02] "GET /static/admin/js/vendor/jquery/jquery.js HTTP/1.1" 200 280364
[26/Jan/2020 09:10:02] "GET /static/admin/js/vendor/xregexp/xregexp.js HTTP/1.1" 200 128820
[26/Jan/2020 09:10:02] "GET /static/admin/img/tooltag-add.svg HTTP/1.1" 200 331
[26/Jan/2020 09:10:02] "GET /static/admin/img/sorting-icons.svg HTTP/1.1" 200 1097
Not Found: /favicon.ico
... 

Now I can try to run the command collectstatic.
When this command is executed, Django performs these operations:

• it looks for static files in all the directories listed in STATICFILES_DIRS;
• the static-files are then copied and saved in STATIC_ROOT directory;
• when the server is requested for static content, it will fetch a file from STATIC_ROOT;
• that file will have its URL modified with STATIC_URL.

These errors show us many informations about this process:

 (env) [mythcat@desk mysite]$ python3 manage.py collectstatic

You have requested to collect static files at the destination
location as specified in your settings:

    /home/mythcat/projects/django/mysite

This will overwrite existing files!
Are you sure you want to do this?

Type 'yes' to continue, or 'no' to cancel: yes
Found another file with the destination path 'admin/js/urlify.js'. It will be ignored since only the first 
encountered file is collected. If this is not what you want, make sure every static file has a unique path.
...
Found another file with the destination path 'django.png'. It will be ignored since only the first 
encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'favicon.ico'. It will be ignored since only the first 
encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/urlify.js'. It will be ignored since only the first 
encountered file is collected. If this is not what you want, make sure every static file has a unique path.
...

Found another file with the destination path 'rest_framework/js/prettify-min.js'. 
It will be ignored since only the first encountered file is collected. If this is not what you want, make
 sure every static file has a unique path.
...
166 static files copied to '/home/mythcat/projects/django/mysite'. 

But, Django respects the order of your applications in settings.py file the INSTALLED_APPS area, when running collectstatic command.
If you have two installed apps that write the same static files then Django collectstatic command will write the static files for the app appearing first in the list.
In my case: django.contrib.admin , test001 and ... .
Also, is need to set this code source on urls.py to return the proper URL pattern for serving static files to your already defined pattern list.

from django.contrib.staticfiles.urls import staticfiles_urlpatterns
...
urlpatterns += staticfiles_urlpatterns()

Let's run the runserver:

 (env) [mythcat@desk mysite]$ python3 manage.py runserver
...
[26/Jan/2020 09:29:18] "GET /static/admin/css/fonts.css HTTP/1.1" 200 423
Not Found: /favicon.ico 

You can see the /favicon.ico is not found in the default path and need to move it at /home/mythcat/projects/django/mysite/test001.
After these changes let's fix all the problems I created with these learning steps on static issues.
Let's move the static folder into mysite folder.
Change the settings.py file for the static issue with this source of code:

# Static files (CSS, JavaScript, Images)

STATIC_URL = '/static/'

STATIC_ROOT = os.path.join(BASE_DIR, 'static')
STATICFILES_DIRS = [
   os.path.join(BASE_DIR, 'static'),
 ]

Run the (env) [mythcat@desk mysite]$ python3 manage.py collectstatic

(env) [mythcat@desk mysite]$ python3 manage.py collectstatic

You have requested to collect static files at the destination
location as specified in your settings:

    /home/mythcat/projects/django/mysite/static

This will overwrite existing files!
Are you sure you want to do this?

Type 'yes' to continue, or 'no' to cancel: yes

163 static files copied to '/home/mythcat/projects/django/mysite/static', 2 unmodified.
(env) [mythcat@desk mysite]$ ls
db.sqlite3  favicon.ico  manage.py  mysite  rest_framework  static  test001
(env) [mythcat@desk mysite]$ cd static/
(env) [mythcat@desk static]$ ls
admin  django.png  favicon.ico  rest_framework

This is a simple base tutorial.
In this point you can select the way of your Django project.