Develop Reference

How to write something into input() built-in function from code directly

I have a need to fill stdin from code directly when input() is waiting for filling.
Is there to do the next:
# Here suppose to be some code that will automatically fill input() below
string = input("Input something: ")
# Or here
I've heard about subprocess.Popen, but I don't understand how to use it in my case. Thank you.

This code is something:
import sys
from io import StringIO
class File(StringIO):
def __init__(self):
self._origin_out = sys.stdout
self._origin_in = sys.stdin
sys.stdout = self
sys.stdin = self
self._in_data = ''
super(File, self).__init__()
def write(self, data):
if data == 'My name is:':
self._in_data = 'Vasja\n'
else:
self._origin_out.write(data)
def readline(self, *args, **kwargs):
res = self._in_data
if res:
self._in_data = ''
return res
else:
return sys.stdin.readline(*args, **kwargs)
def __del__(self):
sys.stdout = self._origin_out
sys.stdin = self._origin_in
global_out_file = File()
a = input('My name is:')
print('Entered name is:', a)

print X items from list at scheduled time intervals

I have a json array with some data (name,address), I'd like to print one name every five minutes: so far I've got this:
def get_data(i):
f = open('data.json' , 'r')
infos = json.load(f)
name = infos['people'][i]['name']
print(name)
i+=1
schedule.every(5).minutes.do(get_data, i=0)
while True:
schedule.run_pending()
time.sleep(1)
but it obviously doesn't work because I'm setting i to zero every time that get_data gets called, is there a better way to do this?

You could wrap this function in a class like so:
import schedule
import json
import time
class Run:
def __init__(self):
self.i = 0
def get_data(self):
with open('data.json') as f:
infos = json.load(f)
try:
name = infos['people'][self.i]['name']
print(name)
except IndexError:
print('No name for index:', self.i)
else:
self.i += 1
if __name__ == '__main__':
run = Run()
schedule.every(5).minutes.do(Run.get_data, run)
while True:
schedule.run_pending()
time.sleep(1)

Shared variables in Python

I am trying to create multiple threads of bot and they share some variables, but I am failing miserably in getingt the shared variables to work.
Here is the code:
import requests
import sys
import threading
import signal
import time
class bot(threading.Thread):
terminate = False
#def __init__(self):
# threading.Thread.__init__(self)
# self.terminate = False
def getCode():
code_lock.acquire()
work_code = code
try:
code += 1
finally:
code_lock.release()
return work_code
def checkCode(code):
try:
#if(code % 1000000 == 0):
print("Code "+str(code)+" is being checked...\n")
html = requests.get(url+str(code))
html.encoding = 'utf-8'
return not 'Page Not Found' in html.text
except requests.exceptions.ConnectionError:
print("Connection Error! Retrying...\n")
time.sleep(0.5)
except KeyboardInterrupt:
logCode(code)
sys.exit()
def storeCode(code):
file_lock.acquire()
try:
file.write(code+'\n')
finally:
file_lock.release()
def logCode(code):
log_lock.acquire()
try:
log.write(code+'\n')
finally:
log_lock.release()
#def run(self):
# global bots
# global url
# global file
# global log
# global code_lock
# global file_lock
# global log_lock
while(not terminate):
code = getCode()
if(checkCode(code)):
storeCode(code)
logCode(code)
def main(code = 0, threads = 16):
#bots = [threading.Thread(target=bot) for bot in range(threads)]
bots = []
url = 'https://test.ing/codes/'
file = open("valid-codes.txt", "a")
log = open("log.txt", "a")
code_lock = threading.Lock()
file_lock = threading.Lock()
log_lock = threading.Lock()
def signal_handler(signal, frame):
print('Exiting...\n')
log_lock.acquire()
try:
log.write("\n\n"+str(time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime()))+"\n")
finally:
log_lock.release()
for bot in bots:
bot.terminate = True
for bot in bots:
bot.join()
sys.exit(0)
#for bot in bots:
# bot.start()
for i in range(threads):
t = bot()
bots.append(t)
t.start()
signal.signal(signal.SIGINT, signal_handler)
while True:
signal.pause()
main(736479509787350, 1)
With this code I get this error:
Traceback (most recent call last): File "bot.py", line 7, in
class bot(threading.Thread): File "bot.py", line 59, in bot
code = getCode() File "bot.py", line 14, in getCode
code_lock.acquire() NameError: name 'code_lock' is not defined
I don't know if I should override the run(self) method of bot, but when I tried that it never actually ran the method run and I also receive the same error from all the threads created: that int is not callable (and I can't see where I can possibly be using an int as object).
Additionaly I don't know if I am handling correctly the exit signal from keyboard, as you can see I am trying to deal with that using a terminate variable, but I don't think that this is the problem...
One last thing, the ConnectionError exception is not being appropriately handled, as it's saying "Retrying...", but in fact it will not retry, but I am aware of that and it should be ok, I'll fix it latter.
Worth mentioning that I'm not very used to deal with multi-threading and when I do deal with it, it is in C or C++.
Edit
I can make the code work by using global variables, but I do not want to do that, I prefer to avoid using globals. My attempts of passing the variables directly to the instances of the class bot or by passing an data-object to it weren't successful so far, whenever I pass the variables or the auxiliar object to bot I am unable to access them as attributes using self. and without self. Python claims that the variable was not defined.
Here is the updated code, without success yet:
import requests
import sys
import threading
import signal
import time
class Shared:
def __init__(self, code, url, file, log, code_lock, file_lock, log_lock):
self.code = code
self.url = url
self.file = file
self.log = log
self.code_lock = code_lock
self.file_lock = file_lock
self.log_lock = log_lock
class bot(threading.Thread):
def __init__(self, data):
threading.Thread.__init__(self)
self.terminate = False
self.data = data
#classmethod
def getCode(self):
self.data.code_lock.acquire()
work_code = self.data.code
try:
self.data.code += 1
finally:
self.data.code_lock.release()
return work_code
#classmethod
def checkCode(self, work_code):
try:
#if(code % 1000000 == 0):
print("Code "+str(work_code)+" is being checked...\n")
html = requests.get(self.data.url+str(work_code))
html.encoding = 'utf-8'
return not 'Page Not Found' in html.text
except requests.exceptions.ConnectionError:
print("Connection Error! Retrying...\n")
time.sleep(0.5)
except KeyboardInterrupt:
self.logCode(work_code)
sys.exit()
#classmethod
def storeCode(self, work_code):
self.data.file_lock.acquire()
try:
self.data.file.write(work_code+'\n')
finally:
self.data.file_lock.release()
#classmethod
def logCode(self, work_code):
self.data.log_lock.acquire()
try:
self.data.log.write(work_code+'\n')
finally:
self.data.log_lock.release()
#classmethod
def run(self):
while(not self.terminate):
work_code = self.getCode()
if(self.checkCode(work_code)):
self.storeCode(work_code)
self.logCode(work_code)
def main(code = 0, threads = 16):
#bots = [threading.Thread(target=bot) for bot in range(threads)]
bots = []
url = 'https://www.test.ing/codes/'
file = open("valid-codes.txt", "a")
log = open("log.txt", "a")
code_lock = threading.Lock()
file_lock = threading.Lock()
log_lock = threading.Lock()
data = Shared(code, url, file, log, code_lock, file_lock, log_lock)
def signal_handler(signal, frame):
print('Exiting...\n')
log_lock.acquire()
try:
log.write("\n\n"+str(time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime()))+"\n")
finally:
log_lock.release()
for bot in bots:
bot.terminate = True
for bot in bots:
bot.join()
sys.exit(0)
#for bot in bots:
# bot.start()
for i in range(threads):
t = bot(data)
bots.append(t)
t.start()
signal.signal(signal.SIGINT, signal_handler)
while True:
signal.pause()
main(736479509787350, 4)
Yet, the working code with global variables:
import requests
import sys
import threading
import signal
import time
code = 736479509787350
url = 'https://www.test.ing/codes/'
file = open("valid-codes.txt", "a")
log = open("log.txt", "a")
code_lock = threading.Lock()
file_lock = threading.Lock()
log_lock = threading.Lock()
terminate = False
class bot(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
#classmethod
def getCode(self):
global code
code_lock.acquire()
work_code = code
try:
code += 1
finally:
code_lock.release()
return work_code
#classmethod
def checkCode(self, work_code):
try:
if(code % 1000000 == 0):
print("Code "+str(work_code)+" is being checked...\n")
html = requests.get(url+str(work_code))
html.encoding = 'utf-8'
if(not 'Page Not Found' in html.text):
time.sleep(0.5)
html = requests.get(url+str(work_code)+":999999999")
html.encoding = 'utf-8'
return 'Page Not Found' in html.text
except requests.exceptions.ConnectionError:
#print("Connection Error! Retrying...\n")
time.sleep(1)
return self.checkCode(work_code)
except KeyboardInterrupt:
self.logCode(work_code)
sys.exit()
#classmethod
def storeCode(self, work_code):
global file_lock
global file
file_lock.acquire()
try:
file.write(str(work_code)+'\n')
finally:
file_lock.release()
#classmethod
def logCode(self, work_code):
global log_lock
global log
log_lock.acquire()
try:
log.write(str(work_code)+'\n')
finally:
log_lock.release()
#classmethod
def run(self):
global terminate
while(not terminate):
work_code = self.getCode()
if(self.checkCode(work_code)):
print("Code "+str(work_code)+" is a valid code!\n")
self.storeCode(work_code)
self.logCode(work_code)
def main(threads = 16):
#bots = [threading.Thread(target=bot) for bot in range(threads)]
bots = []
#url = 'https://www.facebook.com/leticia.m.demenezes/posts/'
#file = open("valid-codes.txt", "a")
#log = open("log.txt", "a")
#code_lock = threading.Lock()
#file_lock = threading.Lock()
#log_lock = threading.Lock()
def signal_handler(signal, frame):
global terminate
print('Exiting...\n')
log_lock.acquire()
try:
log.write("\n\n"+str(time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime()))+"\n")
finally:
log_lock.release()
terminate = True
for bot in bots:
bot.join()
sys.exit(0)
#for bot in bots:
# bot.start()
for i in range(threads):
t = bot()
bots.append(t)
t.start()
signal.signal(signal.SIGINT, signal_handler)
while True:
signal.pause()
main()

You could make the code_lock global as you're trying to do, but why not just pass it into each bot class?
t = bot(code_lock)
Next create a constructor for your class:
class bot(threading.Thread):
def __init__(self, code_lock):
threading.Thread.__init__(self)
self.code_lock = code_lock
Now, whenever you try to use code_lock inside your bot class, always prefix it with self (self.code_lock).
If you really insist on using global variables, then look into the global keyword.

It's clear that you are trying to access code_lock out of it's scope, may be you can follow #MartinKonecny suggestion to fix that.
I could see that even after fixing code_lock problem, your code has lot of problems. as soon as you fix code_lock problem you'll face similar issue with the variable code in the same function getCode.
After fixing all those compiled time issues, you'll face issues with your whole class implementation, this is not the way to implement Python classes.
It's better that you go through this to know more about python name spaces and classes.

Multithreading (?): Manual interference in a loop

I've been looking into a way to directly change variables in a running module.
What I want to achieve is that a load test is being run and that I can manually adjust the call pace or whatsoever.
Below some code that I just created (not-tested e.d.), just to give you an idea.
class A():
def __init__(self):
self.value = 1
def runForever(self):
while(1):
print self.value
def setValue(self, value):
self.value = value
if __name__ == '__main__':
#Some code to create the A object and directly apply the value from an human's input
a = A()
#Some parallelism or something has to be applied.
a.runForever()
a.setValue(raw_input("New value: "))
Edit #1: Yes, I know that now I will never hit the a.setValue() :-)

Here is a multi-threaded example. This code will work with the python interpreter but not with the Python Shell of IDLE, because the raw_input function is not handled the same way.
from threading import Thread
from time import sleep
class A(Thread):
def __init__(self):
Thread.__init__(self)
self.value = 1
self.stop_flag = False
def run(self):
while not self.stop_flag:
sleep(1)
print(self.value)
def set_value(self, value):
self.value = value
def stop(self):
self.stop_flag = True
if __name__ == '__main__':
a = A()
a.start()
try:
while 1:
r = raw_input()
a.set_value(int(r))
except:
a.stop()

The pseudo code you wrote is quite similar to the way Threading / Multiprocessing works in python. You will want to start a (for example) thread that "runs forever" and then instead of modifying the internal rate value directly, you will probably just send a message through a Queue that gives the new value.
Check out this question.
Here is a demonstration of doing what you asked about. I prefer to use Queues to directly making calls on threads / processes.
import Queue # !!warning. if you use multiprocessing, use multiprocessing.Queue
import threading
import time
def main():
q = Queue.Queue()
tester = Tester(q)
tester.start()
while True:
user_input = raw_input("New period in seconds or (q)uit: ")
if user_input.lower() == 'q':
break
try:
new_speed = float(user_input)
except ValueError:
new_speed = None # ignore junk
if new_speed is not None:
q.put(new_speed)
q.put(Tester.STOP_TOKEN)
class Tester(threading.Thread):
STOP_TOKEN = '<<stop>>'
def __init__(self, q):
threading.Thread.__init__(self)
self.q = q
self.speed = 1
def run(self):
while True:
# get from the queue
try:
item = self.q.get(block=False) # don't hang
except Queue.Empty:
item = None # do nothing
if item:
# stop when requested
if item == self.STOP_TOKEN:
break # stop this thread loop
# otherwise check for a new speed
try:
self.speed = float(item)
except ValueError:
pass # whatever you like with unknown input
# do your thing
self.main_code()
def main_code(self):
time.sleep(self.speed) # or whatever you want to do
if __name__ == '__main__':
main()

python Returning data from a threaded def

I have a bit of code that gets the title of a .MP3 file
def getTitle(fileName):
print "getTitle"
audio = MP3(fileName)
try:
sTitle = str(audio["TIT2"])
except KeyError:
sTitle = os.path.basename(fileName)
sTitle = replace_all(sTitle) #remove special chars
return sTitle
I would call this function with
sTitle = getTitle("SomeSong.mp3")
To solve another problem I wanted to spawn this on its own thread so I altered my call to
threadTitle = Thread(target=getTitle("SomeSong.mp3"))
threadTitle.start()
This correctly calls the function and solves my other problem, but now I can't figure out how to get the return value of sTitle from the function into Main.

I would make a new object that extends thread so that you can get anything you want out of it at any time.
from threading import Thread
class GetTitleThread(Thread):
def __init__(self, fileName):
self.sTitle = None
self.fileName = fileName
super(GetTitleThread, self).__init__()
def run(self):
print "getTitle"
audio = MP3(self.fileName)
try:
self.sTitle = str(audio["TIT2"])
except KeyError:
self.sTitle = os.path.basename(self.fileName)
self.sTitle = replace_all(self.sTitle) #remove special chars
if __name__ == '__main__':
t = GetTitleThread('SomeSong.mp3')
t.start()
t.join()
print t.sTitle

One way to do it is to use a wrapper storing the result:
def wrapper(func, args, res):
res.append(func(*args))
res = []
t = threading.Thread(
target=wrapper, args=(getTitle, ("SomeSong.mp3",), res))
t.start()
t.join()
print res[0]

This one comfortably makes any function running in a thread taking care of its return value or exception:
def threading_func(f):
"""Decorator for running a function in a thread and handling its return
value or exception"""
def start(*args, **kw):
def run():
try:
th.ret = f(*args, **kw)
except:
th.exc = sys.exc_info()
def get(timeout=None):
th.join(timeout)
if th.exc:
raise th.exc[0], th.exc[1], th.exc[2] # py2
##raise th.exc[1] #py3
return th.ret
th = threading.Thread(None, run)
th.exc = None
th.get = get
th.start()
return th
return start
Usage Examples
def f(x):
return 2.5 * x
th = threading_func(f)(4)
print("still running?:", th.is_alive())
print("result:", th.get(timeout=1.0))
#threading_func
def th_mul(a, b):
return a * b
th = th_mul("text", 2.5)
try:
print(th.get())
except TypeError:
print("exception thrown ok.")