Develop Reference

Multiprocessing In Django Function

Is it possible to use multi processing in Django on a request.
#so if I send a request to http://127.0.0.1:8000/wallet_verify
def wallet_verify(request):
walelts = botactive.objects.all()
#here I check if the user want to be included in the process or not so if they set it to True then i'll include them else ignore.
for active in walelts:
check_active = active.active
if check_active == True:
user_is_active = active.user
#for the ones that want to be included I then go to get their key data.
I need to get both api and secret so then I loop through to get the data from active users.
database = Bybitapidatas.objects.filter(user=user_is_active)
for apikey in database:
apikey = apikey.apikey
for apisecret in database:
apisecret = apisecret.apisecret
#since I am making a request to an exchange endpoint I can only include one API and secret at a time . So for 1 person at a time this is why I want to run in parallel.
for a, b in zip(list(Bybitapidatas.objects.filter(user=user_is_active).values("apikey")), list(Bybitapidatas.objects.filter(user=user_is_active).values("apisecret"))):
session =spot.HTTP(endpoint='https://api-testnet.bybit.com/', api_key=a['apikey'], api_secret=b['apisecret'])
#here I check to see if they have balance to open trades if they have selected to be included.
GET_USDT_BALANCE = session.get_wallet_balance()['result']['balances']
for i in GET_USDT_BALANCE:
if 'USDT' in i.values():
GET_USDT_BALANCE = session.get_wallet_balance()['result']['balances']
idx_USDT = GET_USDT_BALANCE.index(i)
GET_USDTBALANCE = session.get_wallet_balance()['result']['balances'][idx_USDT]['free']
print(round(float(GET_USDTBALANCE),2))
#if they don't have enough balance I skip the user.
if round(float(GET_USDTBALANCE),2) < 11 :
pass
else:
session.place_active_order(
symbol="BTCUSDT",
side="Buy",
type="MARKET",
qty=10,
timeInForce="GTC"
)
How can I run this process in parallel while looping through the database to also get data for each individual user.
I am still new to coding so hope I explained that it makes sense.
I have tried multiprocessing and pools but then I get that the app has not started yet and I have to run it outside of wallet_verify is there a way to do it in wallet_verify
and when I send the Post Request.
Any help appreciated.

Filtering the Database to get Users who have set it to True
Listi - [1,3](these are user ID's Returned
processess = botactive.objects.filter(active=True).values_list('user')
listi = [row[0] for row in processess]
Get the Users from the listi and perform the action.
def wallet_verify(listi):
# print(listi)
database = Bybitapidatas.objects.filter(user = listi)
print("---------------------------------------------------- START")
for apikey in database:
apikey = apikey.apikey
print(apikey)
for apisecret in database:
apisecret = apisecret.apisecret
print(apisecret)
start_time = time.time()
session =spot.HTTP(endpoint='https://api-testnet.bybit.com/', api_key=apikey, api_secret=apisecret)
GET_USDT_BALANCE = session.get_wallet_balance()['result']['balances']
for i in GET_USDT_BALANCE:
if 'USDT' in i.values():
GET_USDT_BALANCE = session.get_wallet_balance()['result']['balances']
idx_USDT = GET_USDT_BALANCE.index(i)
GET_USDTBALANCE = session.get_wallet_balance()['result']['balances'][idx_USDT]['free']
print(round(float(GET_USDTBALANCE),2))
if round(float(GET_USDTBALANCE),2) < 11 :
pass
else:
session.place_active_order(
symbol="BTCUSDT",
side="Buy",
type="MARKET",
qty=10,
timeInForce="GTC"
)
print ("My program took", time.time() - start_time, "to run")
print("---------------------------------------------------- END")
return HttpResponse("Wallets verified")
Verifyt is what I use for the multiprocessing since I don't want it to run without being requested to run. also initialiser starts apps for each loop
def verifyt(request):
with ProcessPoolExecutor(max_workers=4, initializer=django.setup) as executor:
results = executor.map(wallet_verify, listi)
return HttpResponse("done")
```

Why does Python say that I am giving 64 arguments for a function when I am only giving 1 each time with a for loop?

I'm making a dictionary attack with SHA-256 hashes from Violent Python and I have a function which tests the hash and sees if it matches the password. Then I have a main() function.
The program opens a dictionary file and a UNIX-style sheet with users and their hashes passwords.
I am using threads to test the words all at once, and using a for loop to test them:
from hashlib import *
from os import chdir
from pathlib import Path
from threading import Thread
from time import sleep
chdir(Path.home() / 'Downloads')
dict = open('dictionary.txt')
def test(encrypted):
for word in dict.readlines():
hash = sha256()
word = word.strip('\n')
hash.update(bytes(word))
if hash.hexdigest() == encrypted:
print('Match!:' + word)
else:
return null
def main():
users = open('users.txt')
for line in users.readlines():
user = line.split(':')[0]
encrypted = line.split(':')[1].strip(' ')
print('cracking for' + user + '...')
t = Thread(target = test, args = encrypted)
t.start()
main()
sleep(200)
Python gives me this error though:
TypeError: test() takes 1 positional argument but 64 were given
I think Python thinks I am trying to test all the dictionary words at once, but that is impossible because there are not 64 words in my dictionary, yet I can't find anything else wrong with the code.
apple
orange
egg
lemon
grapes
secret
strawberry
password
Here is the users.txt:
victim: 34707c3f40dfa20c3902b807b627d420d6d474d9d98066ba637953d1cfd6b914: 503:100:Iama Victim:/home/victim:/bin/sh
root: 3a7bd3e2360a3d29eea436fcfb7e44c735d117c42d1c1835420b6b9942dd4f1b: 504:100: Markus Hess:/root:/bin/bash

The args keyword of a Thread accepts a tuple
This might work :
t = Thread(target = test, args = (encrypted,))
Also there's nothing like null in python but none

How to send a message to process zero, from all other processes?

How to send a message to process zero, from all other processes?
I'm using mpi4py, with Python 2, and was following this example Parallel programming Research
Why does this line fail, and what fixes it?
searchResult = comm.recv(source=tempRank)
My code below (appears to) works fine until it reaches the line above. I put print statements above and below this line, so I pretty sure this is the problem.
My expectation was ... processor zero will receive a message from each processor, but it does not. The program seems to just hang and do nothing. Here is the program.
import time
from random import randint
from random import shuffle
from mpi4py import MPI
import sys
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
size = MPI.COMM_WORLD.Get_size()
name = MPI.Get_processor_name()
if rank == 0:
starttime=time.time()
searchResult=False
someNumber = 0
data = list(range(1,8))
chunks = [ [] for _ in range(size) ]
for i,chunk in enumerate(data):
chunks[i % size].append(chunk)
else:
data=None
chunks=None
someNumber=None
# scatter data to all processors
data=comm.scatter(chunks,root=0)
# give another variable to each processor
someNumber = comm.bcast(someNumber,root=0)
print('im rank=',rank,', my data=', data, ' searching for someNumber = ',someNumber)
searchResult=False
for num in data:
if someNumber == num:
print('found the someNumber')
searchResult=True
break
if searchResult == False:
print('someNumber not found')
searchResult=False
# Now, at this point, I want all processors (including processor 0)
# to send processor 0 a message
tempRank=rank
# attempting to send process 0 a message from all other processes
# (does/can processor 0 send itself a message?)
if rank == 0:
print('this line prints one time, and program hangs')
searchResult = comm.recv(source=tempRank)
print('this line never prints, so whats wrong with previous line?')
else:
comm.send(searchResult,dest=0)
if rank == 0:
if searchResult == True:
print('found the someNumber, everyone stop searching .. how to make all processes stop?')
print('elapsedtime = {}'.format(time.time()-starttime))
else:
print('no one found the someNumber')
print('elapsedtime = {}'.format(time.time()-starttime))

Python refresh file from disk

I have a python script that calls a system program and reads the output from a file out.txt, acts on that output, and loops. However, it doesn't work, and a close investigation showed that the python script just opens out.txt once and then keeps on reading from that old copy. How can I make the python script reread the file on each iteration? I saw a similar question here on SO but it was about a python script running alongside a program, not calling it, and the solution doesn't work. I tried closing the file before looping back but it didn't do anything.
EDIT:
I already tried closing and opening, it didn't work. Here's the code:
import subprocess, os, sys
filename = sys.argv[1]
file = open(filename,'r')
foo = open('foo','w')
foo.write(file.read().rstrip())
foo = open('foo','a')
crap = open(os.devnull,'wb')
numSolutions = 0
while True:
subprocess.call(["minisat", "foo", "out"], stdout=crap,stderr=crap)
out = open('out','r')
if out.readline().rstrip() == "SAT":
numSolutions += 1
clause = out.readline().rstrip()
clause = clause.split(" ")
print clause
clause = map(int,clause)
clause = map(lambda x: -x,clause)
output = ' '.join(map(lambda x: str(x),clause))
print output
foo.write('\n'+output)
out.close()
else:
break
print "There are ", numSolutions, " solutions."

You need to flush foo so that the external program can see its latest changes. When you write to a file, the data is buffered in the local process and sent to the system in larger blocks. This is done because updating the system file is relatively expensive. In your case, you need to force a flush of the data so that minisat can see it.
foo.write('\n'+output)
foo.flush()

I rewrote it to hopefully be a bit easier to understand:
import os
from shutil import copyfile
import subprocess
import sys
TEMP_CNF = "tmp.in"
TEMP_SOL = "tmp.out"
NULL = open(os.devnull, "wb")
def all_solutions(cnf_fname):
"""
Given a file containing a set of constraints,
generate all possible solutions.
"""
# make a copy of original input file
copyfile(cnf_fname, TEMP_CNF)
while True:
# run minisat to solve the constraint problem
subprocess.call(["minisat", TEMP_CNF, TEMP_SOL], stdout=NULL,stderr=NULL)
# look at the result
with open(TEMP_SOL) as result:
line = next(result)
if line.startswith("SAT"):
# Success - return solution
line = next(result)
solution = [int(i) for i in line.split()]
yield solution
else:
# Failure - no more solutions possible
break
# disqualify found solution
with open(TEMP_CNF, "a") as constraints:
new_constraint = " ".join(str(-i) for i in sol)
constraints.write("\n")
constraints.write(new_constraint)
def main(cnf_fname):
"""
Given a file containing a set of constraints,
count the possible solutions.
"""
count = sum(1 for i in all_solutions(cnf_fname))
print("There are {} solutions.".format(count))
if __name__=="__main__":
if len(sys.argv) == 2:
main(sys.argv[1])
else:
print("Usage: {} cnf.in".format(sys.argv[0]))

You take your file_var and end the loop with file_var.close().
for ... :
ga_file = open(out.txt, 'r')
... do stuff
ga_file.close()
Demo of an implementation below (as simple as possible, this is all of the Jython code needed)...
__author__ = ''
import time
var = 'false'
while var == 'false':
out = open('out.txt', 'r')
content = out.read()
time.sleep(3)
print content
out.close()
generates this output:
2015-01-09, 'stuff added'
2015-01-09, 'stuff added' # <-- this is when i just saved my update
2015-01-10, 'stuff added again :)' # <-- my new output from file reads
I strongly recommend reading the error messages. They hold quite a lot of information.
I think the full file name should be written for debug purposes.

XMODEM for python

I am writing a program that requires the use of XMODEM to transfer data from a sensor device. I'd like to avoid having to write my own XMODEM code, so I was wondering if anyone knew if there was a python XMODEM module available anywhere?

def xmodem_send(serial, file):
t, anim = 0, '|/-\\'
serial.setTimeout(1)
while 1:
if serial.read(1) != NAK:
t = t + 1
print anim[t%len(anim)],'\r',
if t == 60 : return False
else:
break
p = 1
s = file.read(128)
while s:
s = s + '\xFF'*(128 - len(s))
chk = 0
for c in s:
chk+=ord(c)
while 1:
serial.write(SOH)
serial.write(chr(p))
serial.write(chr(255 - p))
serial.write(s)
serial.write(chr(chk%256))
serial.flush()
answer = serial.read(1)
if answer == NAK: continue
if answer == ACK: break
return False
s = file.read(128)
p = (p + 1)%256
print '.',
serial.write(EOT)
return True

There is XMODEM module on PyPi. It handles both sending and receiving of data with XModem. Below is sample of its usage:
import serial
try:
from cStringIO import StringIO
except:
from StringIO import StringIO
from xmodem import XMODEM, NAK
from time import sleep
def readUntil(char = None):
def serialPortReader():
while True:
tmp = port.read(1)
if not tmp or (char and char == tmp):
break
yield tmp
return ''.join(serialPortReader())
def getc(size, timeout=1):
return port.read(size)
def putc(data, timeout=1):
port.write(data)
sleep(0.001) # give device time to prepare new buffer and start sending it
port = serial.Serial(port='COM5',parity=serial.PARITY_NONE,bytesize=serial.EIGHTBITS,stopbits=serial.STOPBITS_ONE,timeout=0,xonxoff=0,rtscts=0,dsrdtr=0,baudrate=115200)
port.write("command that initiates xmodem send from device\r\n")
sleep(0.02) # give device time to handle command and start sending response
readUntil(NAK)
buffer = StringIO()
XMODEM(getc, putc).recv(buffer, crc_mode = 0, quiet = 1)
contents = buffer.getvalue()
buffer.close()
readUntil()

I think you’re stuck with rolling your own.
You might be able to use sz, which implements X/Y/ZMODEM. You could call out to the binary, or port the necessary code to Python.

Here is a link to XMODEM documentation that will be useful if you have to write your own. It has detailed description of the original XMODEM, XMODEM-CRC and XMODEM-1K.
You might also find this c-code of interest.

You can try using SWIG to create Python bindings for the C libraries linked above (or any other C/C++ libraries you find online). That will allow you to use the same C API directly from Python.
The actual implementation will of course still be in C/C++, since SWIG merely creates bindings to the functions of interest.

There is a python module that you can use -> https://pypi.python.org/pypi/xmodem
You can see the transfer protocol in http://pythonhosted.org//xmodem/xmodem.html