Develop Reference

python sockets, trying to make a log in interaction betwen server and client

Hello so i have my server with a database (dictironay) and another passworddatabase
import socket
import sys
from _thread import *
host = ""
port = 8000
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print("Socket Created")
try:
serversocket.bind((host, port))
except socket.error as e:
print(str(e))
sys.exit()
database = {"name1" :{"hair" : "red", "size" : 1.50}}
password_database = {"name1": "1234",
"name2": "4321"}
def client_thread(conn): #threader client
welcome = "Welcome to the server. Type something and hit enter \n"
conn.send(welcome.encode("UTF-8"))
login(conn)
while True: # NOT IMPORTANT KEEP READING
data = conn.recv(24)
reply = data.decode("UTF-8")
if reply == "1":
menu1 = "Menu 1: Buy \n"
conn.send(menu1.encode("UTF-8"))
else:
wrong = "wrong option \n"
conn.send(wrong.encode("UTF-8"))
def login(conn): #MY LOGIC PROBLEM IS HERE
log = "Log in MENU: \n"
logi = log.encode("UTF-8")
conn.send(logi)
us = "Username: \n"
use = us.encode("UTF-8")
conn.send(use)
userr = conn.recv(24)
user = userr.decode("UTF-8")
pa = "Password: \n"
pasw = pa.encode("UTF-8")
conn.send(pasw)
passr = conn.recv(24)
passw = passr.decode("UTF-8")
tries = 0
while tries < 3:
if user in passwordDictionary and passwordDictionary[user] == passw:
print("Logged in")
menu()
else:
print("Wrong Username Or Password \n")
tries += 1
print("You failed the login too many times, blocking you out")
conn.close()
while 1: # NOT IMPORTANT
conn, addr = serversocket.accept()
print("Connected with " + addr[0] + ":" + str(addr[1]))
start_new_thread(client_thread, (conn, ))
serversocket.close()
Whats working:
The server is working fine, i'm having troubles doing the login on the client side.
client.py ==> client DOESNT go into the if data == Log in menu
is there a better way to do this?
#! /usr/bin/python3
import socket
clientsocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
clientsocket.connect(('localhost', 8000))
print("Connected")
datae = clientsocket.recv(24)
data = datae.decode("UTF-8")
clientsocket.send(datae)
while data != "!q":
if data == "Log in MENU: \n":
usere = input()
user = usere.encode("UTF-8")
clientsocket.send(user)
What would be the best way to create an log in interaction with the server?
the server has the usernames and passwords, i need to log in and then i need to edit the database depending on what user was chossen, but i'm having a hard time doing the algorithm

theres problems with the code you provided... however ill assume it actually works for you somehow and rather than copy paste you manually typed it
you are recieveing the first message here
datae = clientsocket.recv(24)
data = datae.decode("UTF-8") # GOT A MESSAGE
You then have the message datae = b'Welcome to the server. '
which does not match "Log in MENU: \n", and data != "!q" so it goes back into your loop and checks if data == "Log in MENU: \n" it doesnt so it repeats ... but you never get the next message instead try something like this second message
data = ""
while data != "!q":
if data == "Log in MENU: \n":
usere = input()
user = usere.encode("UTF-8")
clientsocket.send(user)
data = clientsocket.recv(24).decode("UTF-8") # GET THE NEXT MESSAGE!
but even then you are going to have problems because your server continues to write so you will get something like "Log in MENU: \nUsername" or something .... basically you need to work out a better message passing scheme than recv(24)

To avoid Errors try using a header with something like 64 Bytes wich always is the first message send. This Header is then used to send the actual length of the following message to the server. For example:
def send_response(conn, msg):
message = msg.encode(FORMAT)
send_length = len(str(len(message)).encode(FORMAT))
res_len = bytes(len(message)) + (b' ' * (HEADER - send_length))
print(f"[SENDING MESSAGE] {msg}")
conn.send(res_len)
conn.send(response)

Python telnet client

Everyone, hello!
I'm currently trying to use Telnetlib (https://docs.python.org/2/library/telnetlib.html) for Python 2.7 to communicate with some external devices.
I have the basics set up:
import sys
import telnetlib
tn_ip = xxxx
tn_port = xxxx
tn_username = xxxxx
tn_password = xxxx
searchfor = "Specificdata"
def telnet():
try:
tn = telnetlib.Telnet(tn, tn, 15)
tn.set_debuglevel(100)
tn.read_until("login: ")
tn.write(tn_username + "\n")
tn.read_until("Password: ")
tn.write(tn_password + "\n")
tn.read_until(searchfor)
print "Found it!"
except:
print "Unable to connect to Telnet server: " + tn_ip
telnet()
And I'm trying to go through all of the data it's outputting (which is quite a lot) until I catch what I need. Although it is logging in quite fine, and even finds the data I'm looking for, and prints my found it message, I'm trying for a way to keep the connection with telnet open as there might be other data (or repeated data) i would be missing if I logged off and logged back in.
Does anyone know how to do this?

Seems like you want to connect to external device once and print a message each time you see a specific string.
import sys
import telnetlib
tn_ip = "0.0.0.0"
tn_port = "23"
tn_username = "xxxxx"
tn_password = "xxxx"
searchfor = "Specificdata"
def telnet():
try:
tn = telnetlib.Telnet(tn_ip, tn_port, 15)
except:
print "Unable to connect to Telnet server: " + tn_ip
return
tn.set_debuglevel(100)
tn.read_until("login: ")
tn.write(tn_username + "\n")
tn.read_until("Password: ")
tn.write(tn_password + "\n")
while True:
tn.read_until(searchfor)
print "Found it"
telnet()

Using Python 3.4 to Ping a network then report address, dns name, etc.

I wanted to create a Python program that does several things. Ping all addresses in a predefined network, gather the DNS information, write a file with IP address, DNS name, ping fail or pass, date. Then run and email the resulting file to myself once a week, every Friday. I have created this program and will post my own answer. I am new to Python and was able to get this written with the help from other answers posted on this site. Thanks to all those who contributed answers on this site. Hope the answer I post will help someone else.

#!/usr/bin/python3.4
#Above statement makes sure you are using version 3.4
#when multiple versions are installed. has to be the 1st line.
# Import modules
import subprocess
import socket
import errno
import time
import datetime
import ipaddress
today = datetime.date.today()
# define DNS lookup and error handling
# return none,none,none needed otherwise if no DNS record
# the routine errors out and the program stops
def lookup(addr):
try:
return socket.gethostbyaddr(addr)
except socket.herror:
return None, None, None
# Prompt the user to input a network address
# commented out the prompt for input so it can run unattended
# net_addr = input("Enter a network address in CIDR
format(ex.192.168.1.0/24): ")
net_addr = ('192.168.1.0/24')
# Create the network
ip_net = ipaddress.ip_network(net_addr)
# Get all hosts on that network
all_hosts = list(ip_net.hosts())
# Configure subprocess to hide the console window
# removed code due to errors not windows linux
# setup online and offline count variables
offCnt = 0
onCnt = 0
# Open file and or create if it doesn't exist.
# file to be overwritten each time the program is run.
file = open("lab-ip.doc","w")
# For each IP address in the subnet,
# run the ping command with subprocess.popen interface
# Grab the DNS information for each IP address
# Print to console add counters and write to file.
for i in range(len(all_hosts)):
output = subprocess.Popen(['ping', '-c', '2', str(all_hosts[i])],
stdout=subprocess.PIPE).communicate()[0]
name,alias,addresslist = lookup(str(all_hosts[i]))
if "Destination Host Unreachable" in output.decode('utf-8'):
print(str(all_hosts[i]), " Ping Fail", str(name), today)
file.write(str(all_hosts[i]) + " Ping Fail - " + str(name) + " " + str(today) + "\n")
offCnt = offCnt + 1
elif "Request timed out" in output.decode('utf-8'):
print(str(all_hosts[i]), " Ping Fail", str(name), today)
file.write(str(all_hosts[i]) + " Ping Fail - " + str(name) + " " + str(today) + "\n")
offCnt = offCnt + 1
else:
print(str(all_hosts[i]), " Ping Pass", str(name), today)
file.write(str(all_hosts[i]) + " Ping Pass - " + str(name) + " " + str(today) + "\n")
onCnt = onCnt + 1
print ("Pass count = ", str(onCnt))
file.write("Pass count = " + str(onCnt))
print ("Fail count = ", str(offCnt))
file.write(" Fail count = " + str(offCnt))
file.close()
# Import yagmail for the actual sending function
import yagmail
yag = yagmail.SMTP('Gmail-id', 'gmail-pswd')
yag.send('email#email.com', subject = "Lab-ip List",contents = 'lab-ip.doc')
yag.send('email2#email2.com', subject = "Lab-ip List",contents = 'lab-ip.doc')
#end

Python script too much cpu usage

I'm not an expert in programming so i googled a lot to get this script to work. It listens on the serial interface ans is searching for 3 values (temperature, humidity and battery level). If it finds one of zhem it saves it to a text file and checks if the value is above or under a certain level. I f this is the case it sends an e-mail to warn.
My problem is that it uses constatntly about 99% of cpu power...
Can you help me to limit the CPU usage to a minimum.
Thanks
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import serial
import time
import sys
import smtplib
from time import sleep
def mail(kind, how, value, unit):
fromaddr = 'sender#domain.com'
toaddrs = 'recipient#domain.com'
msg = "\r\n".join([
"From: sender",
"To: recipient",
"Subject: Warning",
"",
"The " + str(kind) + " is too " + str(how) + ". It is " + str(value) + str(unit)
])
username = 'user'
password = 'password'
server = smtplib.SMTP('server:port')
server.ehlo()
server.starttls()
server.login(username,password)
server.sendmail(fromaddr, toaddrs, msg)
server.quit()
def main():
port = '/dev/ttyAMA0'
baud = 9600
ser = serial.Serial(port=port, baudrate=baud)
sleep(0.2)
while True:
while ser.inWaiting():
# read a single character
char = ser.read()
# check we have the start of a LLAP message
if char == 'a':
# start building the full llap message by adding the 'a' we have
llapMsg = 'a'
# read in the next 11 characters form the serial buffer
# into the llap message
llapMsg += ser.read(11)
if "TMPB" in llapMsg:
TMPB = llapMsg[7:]
with open("TMPB.txt", "w") as text_file:
text_file.write(TMPB)
if float(TMPB) >= 19:
mail("temperature", "high", TMPB, "°C")
elif float(TMPB) <= 15:
mail("temperature", "low", TMPB, "°C")
else:
pass
elif "HUMB" in llapMsg:
HUMB = llapMsg[7:]
with open("HUMB.txt", "w") as text_file:
text_file.write(HUMB)
if float(HUMB) >= 80:
mail("humidity", "high", HUMB, "%")
elif float(HUMB) <= 70:
mail("humidity", "low", HUMB, "%")
else:
pass
elif "BATT" in llapMsg:
BATT = llapMsg[7:11]
with open("BATT.txt", "w") as text_file:
text_file.write(BATT)
if float(BATT) < 1:
mail("battery level", "low", BATT, "V")
else:
pass
sleep(0.2)
if __name__ == "__main__":
main()

I solved the question myself.
The while ser.inWaiting(): loop was causing the heavy cpu load.
I removed it and corrected the indentation and it works great with a few % cpu load.
Thanks for your hints, it helped me solving the problem.

Checking email with Python

I am interested to trigger a certain action upon receiving an email from specific
address with specific subject. In order to be able to do so I need to implement
monitoring of my mailbox, checking every incoming mail (in particular, i use gmail).
what is the easiest way to do that?

Gmail provides the ability to connect over POP, which you can turn on in the gmail settings panel. Python can make connections over POP pretty easily:
import poplib
from email import parser
pop_conn = poplib.POP3_SSL('pop.gmail.com')
pop_conn.user('username')
pop_conn.pass_('password')
#Get messages from server:
messages = [pop_conn.retr(i) for i in range(1, len(pop_conn.list()[1]) + 1)]
# Concat message pieces:
messages = ["\n".join(mssg[1]) for mssg in messages]
#Parse message intom an email object:
messages = [parser.Parser().parsestr(mssg) for mssg in messages]
for message in messages:
print message['subject']
pop_conn.quit()
You would just need to run this script as a cron job. Not sure what platform you're on so YMMV as to how that's done.

Gmail provides an atom feed for new email messages. You should be able to monitor this by authenticating with py cURL (or some other net library) and pulling down the feed. Making a GET request for each new message should mark it as read, so you won't have to keep track of which emails you've read.

While not Python-specific, I've always loved procmail wherever I could install it...!
Just use as some of your action lines for conditions of your choice | pathtoyourscript (vertical bar AKA pipe followed by the script you want to execute in those cases) and your mail gets piped, under the conditions of your choice, to the script of your choice, for it to do whatever it wants -- hard to think of a more general approach to "trigger actions of your choice upon receipt of mails that meet your specific conditions!! Of course there are no limits to how many conditions you can check, how many action lines a single condition can trigger (just enclose all the action lines you want in { } braces), etc, etc.

People seem to be pumped up about Lamson:
https://github.com/zedshaw/lamson
It's an SMTP server written entirely in Python. I'm sure you could leverage that to do everything you need - just forward the gmail messages to that SMTP server and then do what you will.
However, I think it's probably easiest to do the ATOM feed recommendation above.
EDIT: Lamson has been abandoned

I found a pretty good snippet when I wanted to do this same thing (and the example uses gmail). Also check out the google search results on this.

I recently solved this problem by using procmail and python
Read the documentation for procmail. You can tell it to send all incoming email to a python script like this in a special procmail config file
:0:
| ./scripts/ppm_processor.py
Python has an "email" package available that can do anything you could possibly want to do with email. Read up on the following ones....
from email.generator import Generator
from email import Message
from email.MIMEBase import MIMEBase
from email.MIMEText import MIMEText
from email.mime.multipart import MIMEMultipart

https://developers.google.com/gmail/gmail_inbox_feed
Says you have to have a corporate Gmail, but I have come to find that you can read Gmail free versions without issues. I use this code to get my blood pressure results I email or text to a gmail address.
from email.header import decode_header
from datetime import datetime
import os
import pandas as pd
import plotly.graph_objs as go
import plotly
now = datetime.now()
dt_string = now.strftime("%Y.%m.%d %H:%M:%S")
print("date_time:", dt_string)
email_account = '13123#gmail.com'
email_password = '131231231231231231312313F'
email_server = 'imap.gmail.com'
email_port = 993
accept_emails_from = {'j1231312#gmail.com', '1312312#chase.com', '13131231313131#msg.fi.google.com'}
verbose = True
def get_emails():
email_number = 0
local_csv_data = ''
t_date = None
t_date = None
t_systolic = None
t_diastolic = None
t_pulse = None
t_weight = None
try:
mail = imaplib.IMAP4_SSL(email_server)
email_code, email_auth_status = mail.login(email_account, email_password)
if verbose:
print('[DEBUG] email_code: ', email_code)
print('[DEBUG] email_auth_status: ', email_auth_status)
mail.list()
mail.select('inbox')
# (email_code, messages) = mail.search(None, 'ALL')
(email_code, messages) = mail.search(None, '(UNSEEN)') # only get unread emails to process.
subject = None
email_from = None
for email_id in messages[0].split():
email_number += 1
email_code, email_data = mail.fetch(email_id, '(RFC822)')
for response in email_data:
if isinstance(response, tuple): # we only want the tuple ,the bytes is just b .
msg = email.message_from_bytes(response[1])
content_type = msg.get_content_type()
subject, encoding = decode_header(msg["Subject"])[0]
subject = str(subject.replace("\r\n", ""))
if isinstance(subject, bytes):
subject = subject.decode(encoding)
email_from, encoding = decode_header(msg.get("From"))[0]
if isinstance(email_from, bytes):
email_from = email_from.decode(encoding)
if content_type == "text/plain":
body = msg.get_payload(decode=True).decode()
parse_data = body
else:
parse_data = subject
if '>' in email_from:
email_from = email_from.lower().split('<')[1].split('>')[0]
if email_from in accept_emails_from:
parse_data = parse_data.replace(',', ' ')
key = 0
for value in parse_data.split(' '):
if key == 0:
t_date = value
t_date = t_date.replace('-', '.')
if key == 1:
t_time = value
if ':' not in t_time:
numbers = list(t_time)
t_time = numbers[0] + numbers[1] + ':' + numbers[2] + numbers[3]
if key == 2:
t_systolic = value
if key == 3:
t_diastolic = value
if key == 4:
t_pulse = value
if key == 5:
t_weight = value
key += 1
t_eval = t_date + ' ' + t_time
if verbose:
print()
print('--------------------------------------------------------------------------------')
print('[DEBUG] t_eval:'.ljust(30), t_eval)
date_stamp = datetime.strptime(t_eval, '%Y.%m.%d %H:%M')
if verbose:
print('[DEBUG] date_stamp:'.ljust(30), date_stamp)
print('[DEBUG] t_systolic:'.ljust(30), t_systolic)
print('[DEBUG] t_diastolic:'.ljust(30), t_diastolic)
print('[DEBUG] t_pulse:'.ljust(30), t_pulse)
print('[DEBUG] t_weight:'.ljust(30), t_weight)
new_data = str(date_stamp) + ',' + \
t_systolic + ',' + \
t_diastolic + ',' + \
t_pulse + ',' + \
t_weight + '\n'
local_csv_data += new_data
except Exception as e:
traceback.print_exc()
print(str(e))
return False, email_number, local_csv_data
return True, email_number, local_csv_data
def update_csv(local_data):
""" updates csv and sorts it if there is changes made. """
uniq_rows = 0
if os.name == 'posix':
file_path = '/home/blood_pressure_results.txt'
elif os.name == 'nt':
file_path = '\\\\uncpath\\blood_pressure_results.txt'
else:
print('[ERROR] os not supported:'.ljust(30), os.name)
exit(911)
if verbose:
print('[DEBUG] file_path:'.ljust(30), file_path)
column_names = ['00DateTime', 'Systolic', 'Diastolic', 'Pulse', 'Weight']
if not os.path.exists(file_path):
with open(file_path, 'w') as file:
for col in column_names:
file.write(col + ',')
file.write('\n')
# append the new data to file.
with open(file_path, 'a+') as file:
file.write(local_data)
# sort the file.
df = pd.read_csv(file_path, usecols=column_names)
df_sorted = df.sort_values(by=["00DateTime"], ascending=True)
df_sorted.to_csv(file_path, index=False)
# remove duplicates.
file_contents = ''
with open(file_path, 'r') as file:
for row in file:
if row not in file_contents:
uniq_rows += 1
print('Adding: '.ljust(30), row, end='')
file_contents += row
else:
print('Duplicate:'.ljust(30), row, end='')
with open(file_path, 'w') as file:
file.write(file_contents)
return uniq_rows
# run the main code to get emails.
status, emails, my_data = get_emails()
print('status:'.ljust(30), status)
print('emails:'.ljust(30), emails)
# if the new emails received then sort the files.
csv_rows = update_csv(my_data)
print('csv_rows:'.ljust(30), csv_rows)
exit(0)