Python 3.7.4 : Test the DHCP handshakes.

First, the DHCP is based on the earlier BOOTP protocol which uses well-known port numbers for both server and client instead of an ephemeral port. The server and the client communicate via broadcast and the server broadcasts the offered IP address to the client on UDP port 68.
This python example has a learning purpose and does not harm anyone.

import subprocess as sub
import re

def find_word(w):
    return re.compile(r'\b({0})\b'.format(w), flags=re.IGNORECASE).search

p = sub.Popen(('sudo', 'tcpdump', '-l', '-s 0', '-vvv', '-n', '((udp port 67) and (udp[8:1] = 0x1))'),
 stdout=sub.PIPE)
for row in iter(p.stdout.readline, b''):
    if find_word(row):
        print (row.split(' ')[-1])
    elif find_word(row):
        print (row.split(' ')[-1])

The result of my script ( I don't have inputs on this port).

[mythcat@desk scripts]$ python3 dhcpreq.py 
tcpdump: listening on ___, link-type EN10MB (Ethernet), capture size 262144 bytes
^CTraceback (most recent call last):
  File "dhcpreq.py", line 10, in 
    for row in iter(p.stdout.readline, b''):
KeyboardInterrupt
0 packets captured
0 packets received by filter
0 packets dropped by kernel
[mythcat@desk scripts]$ vim dhcpreq.py 

Python 3.8.0 : New release of python development.

Good news from the python development area with the new release of python development:
Python 3.7.5 Oct. 15, 2019 and Python 3.8.0 Oct. 14, 2019

Now you can use the new python version 3.8.0 from the official webpage.

Major new features of the 3.8 series, compared to 3.7 - release Date: Oct. 14, 2019:

• PEP 572, Assignment expressions
• PEP 570, Positional-only arguments
• PEP 587, Python Initialization Configuration (improved embedding)
• PEP 590, Vectorcall: a fast calling protocol for CPython
• PEP 578, Runtime audit hooks
• PEP 574, Pickle protocol 5 with out-of-band data
• Typing-related: PEP 591 (Final qualifier), PEP 586 (Literal types), and PEP 589 (TypedDict)
• Parallel filesystem cache for compiled bytecode
• Debug builds share ABI as release builds
• f-strings support a handy = specifier for debugging
• continue is now legal in finally: blocks
• on Windows, the default asyncio event loop is now ProactorEventLoop
• on macOS, the spawn start method is now used by default in multiprocessing
• multiprocessing can now use shared memory segments to avoid pickling costs between processes
• typed_ast is merged back to CPython
• LOAD_GLOBAL is now 40% faster
• pickle now uses Protocol 4 by default, improving performance

Let's install on Fedora 30 Linux distro:

[mythcat@desk ~]$ cd Python-3.8.0/
[mythcat@desk Python-3.8.0]$ ls
aclocal.m4          Doc         m4               Parser         README.rst
CODE_OF_CONDUCT.md  Grammar     Mac              PC             setup.py
config.guess        Include     Makefile.pre.in  PCbuild        Tools
config.sub          install-sh  Misc             Programs
configure           Lib         Modules          pyconfig.h.in
configure.ac        LICENSE     Objects          Python
[mythcat@desk Python-3.8.0]$ ./configure 
checking build system type... x86_64-pc-linux-gnu
checking host system type... x86_64-pc-linux-gnu
checking for python3.8... no
...
creating Makefile

If you want a release build with all stable optimizations active (PGO, etc),
please run ./configure --enable-optimizations

If you want then you can run the tool to prepare the build with optimizations:

[mythcat@desk Python-3.8.0]$ ./configure --enable-optimizations --with-ensurepip=install
...
creating Modules/Setup.local
creating Makefile

Use the make with the -j option to use building into parallel steps to speed up the compilation.

[mythcat@desk Python-3.8.0]$ make -j 2
...
make[1]: Leaving directory '/home/mythcat/Python-3.8.0'

Since you’re installing Python into /usr/bin, you’ll need to run as root:

[mythcat@desk Python-3.8.0]$ sudo make altinstall
...
Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Successfully installed pip-19.2.3 setuptools-41.2.0

Let's test it in this folder and with new python3.8 :

[mythcat@desk Python-3.8.0]$ ./python 
Python 3.8.0 (default, Oct 15 2019, 23:45:20) 
[GCC 9.2.1 20190827 (Red Hat 9.2.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()
[mythcat@desk Python-3.8.0]$ python3.8
Python 3.8.0 (default, Oct 15 2019, 23:45:20) 
[GCC 9.2.1 20190827 (Red Hat 9.2.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 

Python 3.7.4 : Testing python source code with streamlit tool.

The official webpage for this python package can be found at streamlit.io.
Let's install it with pip3 tool:

[mythcat@desk proiecte_github]$ mkdir streamlit_examples
[mythcat@desk proiecte_github]$ cd streamlit_examples/
[mythcat@desk streamlit_examples]$ pip3 install streamlit --user

Let's try some examples.
Create a file named 001.py
This simple example will show a map with randoms spots:

import pandas as pd
import numpy as np
import streamlit as st    
df = pd.DataFrame(
    np.random.randn(100, 2) / [50, 50] + [47.45, 26.3],
    columns=['lat', 'lon'])
st.map(df)

Let's run it with this command:

[mythcat@desk streamlit_examples]$ streamlit run 001.py 

  You can now view your Streamlit app in your browser.

  Local URL: http://localhost:8501
...

The next source code will show just the map because the df variable is empty:

import streamlit as st
df = []
st.deck_gl_chart(
    viewport={
        'latitude': 47.45,
        'longitude': 26.3,
        'zoom': 13,
        'pitch': 50,
    },
    layers=[{
        'type': 'HexagonLayer',
        'data': df,
        'radius': 200,
        'elevationScale': 4,
        'elevationRange': [0, 1000],
        'pickable': True,
        'extruded': True,
    }, {
        'type': 'ScatterplotLayer',
        'data': df,
    }])

The source code is added into another file named 002.py and can be run with this command:

[mythcat@desk streamlit_examples]$ streamlit run 002.py 

  You can now view your Streamlit app in your browser.

  Local URL: http://localhost:8501
...

You can see more about this tool at the official youtube channel:

Python 3.7.4 : Testing the PyUSB python module.

This python module named PyUSB can be found at pypi website.

[mythcat@desk scripts]$ pip3 install pyusb --user
Collecting pyusb
...
Successfully installed pyusb-1.0.2

Let' see some usb device with lsusb command:

[mythcat@desk scripts]$ lsusb
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 003: ID 093a:2510 Pixart Imaging, Inc. Optical Mouse
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

First you need to set this to avoid the error: Access denied (insufficient permissions.

[mythcat@desk scripts]$ ll  /dev/bus/usb/001/004
crw-rw-r--. 1 root root 189, 3 Oct 10 20:34 /dev/bus/usb/001/004
[mythcat@desk scripts]$ chmod a+rw /dev/bus/usb/001/004
chmod: changing permissions of '/dev/bus/usb/001/004': Operation not permitted
[mythcat@desk scripts]$ sudo chmod a+rw /dev/bus/usb/001/004
[sudo] password for mythcat: 
[mythcat@desk scripts]$ ll  /dev/bus/usb/001/004
crw-rw-rw-. 1 root root 189, 3 Oct 10 20:34 /dev/bus/usb/001/004

The script is simple:

import sys
  
import usb.core
import usb.util
print(usb.__version__)
busses = usb.busses()
for bus in busses:
    devices = bus.devices
    for dev in devices:
        if dev != None:
            try:
                usd_dev = usb.core.find(idVendor=dev.idVendor, idProduct=dev.idProduct)
                print(usb_dev)
            except:
                pass
# 1a40:0101
dev  = usb.core.find(idVendor=0x1a40, idProduct=0x0101)
print ("The 8087:0024 is : ", dev)
if dev is None:
    raise ValueError("Device not found!")
else:

    if dev.is_kernel_driver_active(0):
        try:
                dev.detach_kernel_driver(0)
                print ("kernel driver detached")
        except usb.core.USBError as e:
                sys.exit("Could not detach kernel driver: %s" % str(e))
    else:
        print ("no kernel driver attached")
    try:
        usb.util.claim_interface(dev, 0)
        print ("claimed device")
    except:
        sys.exit("Could not claim the device: %s" % str(e))
    try:
        dev.set_configuration()
        dev.reset()
    except usb.core.USBError as e:
        sys.exit("Could not set configuration: %s" % str(e))

usb.util.release_interface(dev,interface)
dev.attach_kernel(interface

The result of this python script is this:

[mythcat@desk scripts]$ python3 usb_test.py 
1.0.2
The 8087:0024 is :  DEVICE ID 1a40:0101 on Bus 001 Address 004 =================
 bLength                :   0x12 (18 bytes)
 bDescriptorType        :    0x1 Device
 bcdUSB                 :  0x200 USB 2.0
 bDeviceClass           :    0x9 Hub
 bDeviceSubClass        :    0x0
 bDeviceProtocol        :    0x1
 bMaxPacketSize0        :   0x40 (64 bytes)
 idVendor               : 0x1a40
 idProduct              : 0x0101
 bcdDevice              :  0x111 Device 1.11
 iManufacturer          :    0x0 
 iProduct               :    0x1 USB 2.0 Hub
 iSerialNumber          :    0x0 
 bNumConfigurations     :    0x1
  CONFIGURATION 1: 100 mA ==================================
   bLength              :    0x9 (9 bytes)
   bDescriptorType      :    0x2 Configuration
   wTotalLength         :   0x19 (25 bytes)
   bNumInterfaces       :    0x1
   bConfigurationValue  :    0x1
   iConfiguration       :    0x0 
   bmAttributes         :   0xe0 Self Powered, Remote Wakeup
   bMaxPower            :   0x32 (100 mA)
    INTERFACE 0: Hub =======================================
     bLength            :    0x9 (9 bytes)
     bDescriptorType    :    0x4 Interface
     bInterfaceNumber   :    0x0
     bAlternateSetting  :    0x0
     bNumEndpoints      :    0x1
     bInterfaceClass    :    0x9 Hub
     bInterfaceSubClass :    0x0
     bInterfaceProtocol :    0x0
     iInterface         :    0x0 
      ENDPOINT 0x81: Interrupt IN ==========================
       bLength          :    0x7 (7 bytes)
       bDescriptorType  :    0x5 Endpoint
       bEndpointAddress :   0x81 IN
       bmAttributes     :    0x3 Interrupt
       wMaxPacketSize   :    0x1 (1 bytes)
       bInterval        :    0xc
kernel driver detached
claimed device
Could not set configuration: [Errno 16] Resource busy

Set permisions for next usb:

[mythcat@desk scripts]$ ll /dev/bus/usb/001/003
crw-rw-rw-. 1 root root 189, 2 Oct 10 20:34 /dev/bus/usb/001/003

Te next source code will read the mouse device:

#!/usr/bin/python
import sys
import usb.core
import usb.util
# decimal vendor and product values
#dev = usb.core.find(idVendor=1118, idProduct=1917)
# or, uncomment the next line to search instead by the hexidecimal equivalent
# 093a:2510
dev = usb.core.find(idVendor=0x093a, idProduct=0x2510)
# first endpoint
interface = 0
endpoint = dev[0][(0,0)][0]
# if the OS kernel already claimed the device, which is most likely true
# thanks to http://stackoverflow.com/questions/8218683/pyusb-cannot-set-configuration
if dev.is_kernel_driver_active(interface) is True:
  # tell the kernel to detach
  dev.detach_kernel_driver(interface)
  # claim the device
  usb.util.claim_interface(dev, interface)
collected = 0
attempts = 50
while collected < attempts :
    try:
        data = dev.read(endpoint.bEndpointAddress,endpoint.wMaxPacketSize)
        collected += 1
        print (data)
    except usb.core.USBError as e:
        data = None
        if e.args == ('Operation timed out',):
            continue
# release the device
usb.util.release_interface(dev, interface)
# reattach the device to the OS kernel
dev.attach_kernel_driver(interface)

The output of mouse moves is this:

[mythcat@desk scripts]$ python3 usb_mouse.py 
[mythcat@desk scripts]$ python3 usb_mouse.py 
array('B', [0, 254, 255, 0])
array('B', [0, 253, 2, 0])
array('B', [0, 252, 3, 0])
array('B', [0, 251, 3, 0])
array('B', [0, 252, 3, 0])
array('B', [0, 254, 1, 0])
array('B', [0, 253, 2, 0])
array('B', [0, 255, 1, 0])
array('B', [0, 255, 4, 0])
array('B', [0, 0, 3, 0])
array('B', [0, 0, 3, 0])
array('B', [0, 0, 2, 0])
array('B', [0, 0, 2, 0])
array('B', [0, 2, 1, 0])
array('B', [0, 4, 1, 0])
array('B', [0, 3, 0, 0])
array('B', [0, 3, 0, 0])
array('B', [0, 1, 0, 0])

Python 3.7.4 : Example with subprocess - part 001.

This is a simple example with the python 3 subprocess package.
The source code is simple to understand.
The execute_proceess_with_communicate let run the ls command with the sudo user permissions:

import os
import sys
import string
import subprocess
import codecs

inp = ''
cmd = 'ls'
password = ''

def execute_proceess_with_communicate(inp):
    """Return a list of hops from traceroute command."""
    p = subprocess.Popen(
            ['sudo', cmd, inp],
            stdin=subprocess.PIPE,
            stdout=subprocess.PIPE,
            shell=False)
    text, _ = p.communicate(password)
    #print(type(text))
    outp = codecs.decode(text,'utf8')
    out_split=outp.split('\n')
    return out_split

def normalize_out(list_outp):
    """Extract information from traceroute line per line."""

    normalized_out = []
    for op in list_outp:
        # filer out if an empty line
        if len(op) is 0:
            continue
        op_split = op.split()
        normalized_out.append(op_split)
    return normalized_out

if __name__ == '__main__':
    inp = sys.argv[1]

    out = execute_proceess_with_communicate(inp)
    n_out = normalize_out(out)
    print(n_out)

The result is this:

[mythcat@desk scripts]$ python3 subprocess_001.py '/' 
[['bin'], ['boot'], ['dev'], ['etc'], ['home'], ['lib'], ['lib64'], ['media'], ['mnt'], ['opt'], ['proc'],
 ['root'], ['run'], ['sbin'], ['srv'], ['sys'], ['tmp'], ['usr'], ['var']]

Python Qt5 : the drag and drop feature.

Today I tested drag and drop feature with PyQt5.

Python 3.7.4 (default, Jul  9 2019, 16:32:37) 
[GCC 9.1.1 20190503 (Red Hat 9.1.1-1)] on linux

This is a simple example using setAcceptDrops and setDragEnabled:

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QListWidget, QHBoxLayout,QListWidgetItem
from PyQt5.QtGui import QIcon

class Window(QWidget):
    def __init__(self):
        super().__init__()

        self.myListWidget1 = QListWidget()
        self.myListWidget2 = QListWidget()
        self.myListWidget2.setViewMode(QListWidget.IconMode)
        self.myListWidget1.setAcceptDrops(True)
        self.myListWidget1.setDragEnabled(True)
        self.myListWidget2.setAcceptDrops(True)
        self.myListWidget2.setDragEnabled(True)
        self.setGeometry(480, 400, 640, 480)
        self.myLayout = QHBoxLayout()
        self.myLayout.addWidget(self.myListWidget1)
        self.myLayout.addWidget(self.myListWidget2)

        l1 = QListWidgetItem(QIcon('house.png'), "House")
        l2 = QListWidgetItem(QIcon('cloud.png'), "Clouds ")
        l3 = QListWidgetItem(QIcon('user.png'), "User")
        l4 = QListWidgetItem(QIcon('save.png'), "Save")

        self.myListWidget1.insertItem(1, l1)
        self.myListWidget1.insertItem(2, l2)
        self.myListWidget1.insertItem(3, l3)
        self.myListWidget1.insertItem(4, l4)

        QListWidgetItem(QIcon('house.png'), "House", self.
                        myListWidget2)
        QListWidgetItem(QIcon('cloud.png'), "Clouds", self.
                        myListWidget2)
        QListWidgetItem(QIcon('save.png'), "Save", self.
                        myListWidget2)

        self.setWindowTitle('Example: Drag and Drop');
        self.setLayout(self.myLayout)

        self.show()

App = QApplication(sys.argv)
window = Window()
sys.exit(App.exec())

The result is a windows with two QListWidget with an drag and drop feature.