We Keep Coding

Adding Timestamp to Print Function

I am currently writing myself a program in python 3.7 and was wanting to add a timestamp to the front of my printing in the format:
<hh:mm:ss> WhateverImPrinting
I took a look at other forums and I get some code which used sys.stdout, overwriting the text using the write function.
My issue is it is returning the timestamp both before and after my print.
e.g. <14:21:51> Hello<14:21:51>
This should be:
<14:21:51> Hello
My code:
old_f = sys.stdout # Get old print output
class PrintTimestamp:
# #staticmethod
def write(self, x):
old_f.write("<{}> {}".format(str(pC.Timestamp.hhmmss()), x))
# #staticmethod
def flush(self):
pass
sys.stdout = PrintTimestamp() # Set new print output
I have run this after all my classes and functions, but before if __name__ == '__main__'

You can simply override print function in Python 3.x:
from datetime import datetime
old_print = print
def timestamped_print(*args, **kwargs):
old_print(datetime.now(), *args, **kwargs)
print = timestamped_print
then
print("Test")
should print
2019-09-30 01:23:44.67890 Test

Here you go.
from datetime import datetime
class PrintTimeStamp():
def write(self,x):
ts = str(datetime.now.hour())+":"+str(datetime.now().minute)+":"+str(datetime.now().second)
print("<{}> {}".format(str(ts),x)
pts = PrintTimeStamp()
pts.write("test")

python - remain in base class when calling parent method from child

I have the following base class:
class ClientRepo(Repository):
def __init__(self) -> None:
self.__clientList = []
def hasClientWithId(self, clientId):
for client in self.__clientList:
if client.getId() == clientId:
return True
return False
def addClient(self, client):
if type(client).__name__ == 'ClientDAO':
if not self.hasClientWithId(client.getId()):
client.setClientId(self.__maximumIndexInClientList() + 1)
self.__clientList.append(client)
else:
raise ObjectAlreadyInCollectionException
else:
raise TypeError
which basically only holds a list and can add a ClientDAO to it.
And the following, which derives from it:
class ClientFileRepository(ClientRepo):
def __init__(self, fileName) -> None:
super().__init__()
self.__fileName = fileName
self.__file = None
def hasClientWithId(self, clientId):
self.__loadRepo()
hasClientWithId = super().hasClientWithId(clientId)
super().clean()
return hasClientWithId
def addClient(self, client):
self.__loadRepo()
super().addClient(client)
self.__storeRepo()
super().clean()
def __loadFileReadMode(self):
self.__file = open(self.__fileName, "r")
def __loadFileWriteMode(self):
self.__file = open(self.__fileName, "w")
def __closeFile(self):
self.__file.close()
def __loadRepo(self):
self.__loadFileReadMode()
for line in self.__file:
splitLine = line.split()
clientToAdd = ClientDAO(splitLine[1])
clientToAdd.setClientId(int(splitLine[0]))
super().addClientWithId(clientToAdd)
self.__closeFile()
def __storeRepo(self):
self.__loadFileWriteMode()
self.__file.write("")
for client in super().getList():
self.__file.write(self.clientToString(client))
self.__closeFile()
def clientToString(self, clientDAO):
return str(clientDAO.getId()) + " " + clientDAO.getName() + "\n"
a class which should load the list from a file, call addClient from parent, and store the updated list in the file. The problem is that after child class loads the file in addClient, it calls the method in the parent, which calls hasClientWithId, from the child, again. But I want it to call hasClientWithId, from the parent, that is, the context it is in. Can I achieve that?

I can think of several ways to achieve your goal. I ranked them from worst to best
1. Exactly what you asked for
You wanted that ClientRepo.addClient calls ClientRepo.hasClientWithId instead of ClientFileRepository.hasClientWithId. It is possible to enforce that:
class ClientRepo(Repository):
def addClient(self, client):
if type(client).__name__ == 'ClientDAO':
if not ClientRepo.hasClientWithId(self, client.getId()):
client.setClientId(self.__maximumIndexInClientList() + 1)
self.__clientList.append(client)
else:
raise ObjectAlreadyInCollectionException
else:
raise TypeError
This is not a good approach, because it's unintuitive and breaks the principles of OOP. Any other programmer writing a subclass of ClientRepo that overrides hasClientWithId would expect that this will have an effect for every call to hasClientWithId even inside of addClient
2. Let ClientFileRepository decide which function to use
Add a variable
self.__isFileOpen = False
in ClientFileRepository.__init__, set it to True when you open the file and to False when you close the file. Then change the hasClientWithId within ClientFileRepository to
def hasClientWithId(self, clientId):
if not self.__isFileOpen:
self.__loadRepo()
result = super().hasClientWithId(clientId)
super().clean()
return result
else:
return super().hasClientWithId(clientId)
to avoid opening the same file again. This works, but it is pretty difficult to write new functions for this class, because you always need to be aware if the function call is a call from within your class or from somewhere else. Also this seems pretty inefficient, because you read and write the entire file, even when you only add one client.
3. Read the file only once and modify the underlying ClientRepo
class ClientFileRepository(ClientRepo):
def __init__(self, fileName) -> None:
super().__init__()
self.__fileName = fileName
self.__loadRepo()
# No hasClientWithId needed
def addClient(self, client):
super().addClient(client)
self.__storeRepo()
def __loadRepo(self):
with open(self.__filename) as file:
for line in file:
splitLine = line.split()
clientToAdd = ClientDAO(splitLine[1])
clientToAdd.setClientId(int(splitLine[0]))
super().addClientWithId(clientToAdd)
def __storeRepo(self):
with open(self.__filename, "w") as file:
file.write("")
for client in super().getList():
file.write(self.clientToString(client))
This obviously assumes that the file is not changed by someone else between calls to addClient and the program still overwrites the entire file for every addClient. If this is a problem for you it is best to be explicit and make loadRepo and storeRepo public. Then the programmer using this class can decide when loading and saving are necessary and useful. You can use context managers for this.
Extra: Read and save the file for every method
You can use function decorators to use solution 2 without writing the same code for every function:
import functools
def loadAndStore(function):
#functoools.wraps(function)
def wrappedFunction(self, *args, **kwargs):
if self.__isFileOpen:
return function(self, *args, **kwargs)
else:
self.__isFileOpen = True
self.__loadRepo()
try:
return function(self, *args, **kwargs)
except Exception as e: # Only catch expected exceptions
raise
finally:
self.__storeRepo()
self.clear() # some cleanup
self.__isFileOpen = False
return wrappedFunction
class ClientFileRepository(ClientRepo):
def __init__(self, fileName) -> None:
super().__init__()
self.__fileName = fileName
self.__isFileOpen = False
#loadAndStore
def hasClientWithId(self, clientId):
return super().hasClientWithId(clientId)
#loadAndStore
def addClient(self, client):
super().addClient(client)
def __loadRepo(self):
with open(self.__filename) as file:
for line in file:
splitLine = line.split()
clientToAdd = ClientDAO(splitLine[1])
clientToAdd.setClientId(int(splitLine[0]))
super().addClientWithId(clientToAdd)
def __storeRepo(self):
with open(self.__filename, "w") as file:
file.write("")
for client in super().getList():
file.write(self.clientToString(client))
Be careful here, using this is not very intuitive. For example self.__isFileOpen is defined in __init__, but none of the methods below directly use it. Instead its use is hidden in the loadAndStore decorator.
Some quick hints at the end:
type(client).__name__ == 'ClientDAO' is bad practice. Use isinstance(client, ClientDAO) to fully adopt OOP
If this is not part of a bigger project with given naming conventions use the python style guide
Using private variables like __fileName is generally considered unnecessary, just prefix the variable with one underscore to indicate "internal use". The same is true for functions.

Python : Object is not avaialbe on different file

I have created a singlton Here is the class description.
allsms.py
from DB.models import ApiKey,ServiceProvider
from DB.messagenet import MessageNet
class SMSMgr( object ):
_instance = None
_allsp = []
def __init__(self):
pass
def __new__(cls, *args, **kwargs):
if not cls._instance :
cls._instance = super(SMSMgr, cls).__new__(
cls, *args, **kwargs)
return cls._instance
def loadsettings(self):
get_all_sp = ServiceProvider.objects.filter(status = False)
for obj in get_all_sp:
cla = obj.class_Name
a=globals()[str(obj.class_Name)](obj.userName,obj.password,obj.sendingurl)
self._allsp.append(a)
#print self._allsp
def reload(self):
self._allsp = []
get_all_sp = ServiceProvider.objects.filter(status = False)
for obj in get_all_sp:
cla = obj.class_Name
a=globals()[str(obj.class_Name)](obj.userName,obj.password,obj.sendingurl)
self._allsp.append(a)
def send(self):
print "+++++++++++++++++++== Global send "
if __name__ == "__main__":
b = SMSMgr()
b.loadsettings()
Now in test.py file of the same directory I am trying to use the singleton object which stored in the _allsp variable like.
from SMShandler.allsms import SMSMgr
b = SMSMgr()
#b.loadsettings()
print b._allsp
This is printing empty list. But when I am doing like this:
b = SMSMgr()
b.loadsettings()
print b._allsp
it is printing the list of objects .
My question is, if the above design is singlton then why print b._allsp is printing empty list in test.py? I am already loading loadsettings in the allsms.py file .

You are running loadsettings() in an if __name__ == "__main__" block:
if __name__ == "__main__":
b = SMSMgr()
b.loadsettings()
The purpose of such a block is to happen only when the code is run directly (like python allsms.py). That means it won't happen when it is imported in the line:
from SMShandler.allsms import SMSMgr
If you put the line b.loadsettings() outside of the if block, you'll see that it will already be loaded.

Using one class from another class

I wrote a simple program to read through a log and to parse through and obtain the lowest beginning number (the head) and to print it. I am now editing that program and combining it with a class I wrote to parse an actual logfile. Essentially, as opposed to sorting based off of the simple number from the log from my previous program, I now need to reference the parsed information from one class into another class. I was wondering what the most convenient way to do this. I am a beginner programmer in python and don't know if I can explicitly reference the class.
Here are the classes.
Parser
class LogLine:
SEVERITIES = ['EMERG','ALERT','CRIT','ERR','WARNING','NOTICE','INFO','DEBUG']
severity = 1
def __init__(self, line):
try:
m = re.match(r"^(\d{4}-\d{2}-\d{2}\s*\d{2}:\d{2}:\d{2}),?(\d{3}),?(\s+\[(?:[^\]]+)\])+\s+[A-Z]+\s+(\s?[a-zA-Z0-9\.])+\s?(\((?:\s?\w)+\))\s?(\s?.)+", line)
timestr, msstr, sevstr, self.filename, linestr, self.message = m.groups()
self.line = int(linestr)
self.sev = self.SEVERITIES.index(sevstr)
self.time = float(calendar.timegm(time.strptime(timestr, "%Y-%m-%d %H:%M:%S,%f"))) + float(msstr)/1000.0
dt = datetime.strptime(t, "%Y-%m-%d %H:%M:%S,%f")
except Exception:
print 'error',self.filename
def get_time(self):
return self.time
def get_severity(self):
return self.sev
def get_message(self):
return self.message
def get_filename(self):
return self.filename
def get_line(self):
return self.line
Sorter
class LogFile:
def __init__(self,filepath):
self.logfile = open(filepath, "r")
self.head = None
def __str__(self):
return "x=" + str(self.x) + "y="+str(self.y)
def readline(self):
if self.head != None:
h = self.head
self.head = None
return h
else:
return self.logfile.readline().rstrip(' ')
def get_line(self):
if self.head == None:
self.head = self.readline().rstrip(' ')
return self.head.get.line()
else:
return self.head.get.line()
def close (self):
self.logfile.close()
I have begun to edit my second class by adding the get_line function. Don't know if I'm on the right track.
In simpler terms, I need the head to become "LogLine"

It is okay to use one class from another class. You have one class that parses a single line from a log file and builds an object that represents the line; and you have another class that reads lines from a log file. It would be very natural for the second class to call the first class.
Here is a very simple class that reads all lines from a log file and builds a list:
class LogFile(object):
def __init__(self,filepath):
with open(filepath, "r") as f:
self.lst = [LogLine(line) for line in f]
You can see that self.lst is being set to a list of lines from the input log file, but not just the text of the line; the code is calling LogLine(line) to store instances of LogLine. If you want, you can sort the list after you build it:
self.lst.sort(key=LogLine.get_line)
If the log files are very large, it might not be practical to build the list. You have a .get_line() method function, and we can use that:
class LogFile(object):
def __init__(self,filepath):
self.logfile = open(filepath, "r")
def get_line(self):
try:
line = next(self.logfile) # get next line from open file object
return LogLine(line)
except StopIteration: # next() raises this when you reach the end of the file
return None # return
def close(self):
self.logfile.close()
An open file object (returned by the open() function) can be iterated. We can call next() on this object and it will give us the next input line. When the end of file is reached, Python will raise StopIteration to signal the end of the file.
Here the code will catch the StopIteration exception and return None when the end of the log file is reached. But I think this isn't the best way to handle this problem. Let's make the LogFile class work in for loops and such:
class LogFile(object):
def __init__(self,filepath):
self.f = open(filepath)
def __next__(self): # Python 3.x needs this to be named "__next__"
try:
line = next(self.f)
return LogLine(line)
except StopIteration:
# when we reach the end of input, close the file object
self.f.close()
# re-raise the exception
raise
next = __next__ # Python 2.x needs this to be named "next"
A for loop in Python will repeatedly call the .__next__() method function (Python 3.x) or else the .next() method function (Python 2.x) until the StopIteration exception is raised. Here we have defined both method function names so this code should work in Python 2.x or in Python 3.x.
Now you can do this:
for ll in LogFile("some_log_file"):
... # do something with ll, which will always be a LogLine instance

Print a character to start of every line in Python

I'm wishing to print a character to the start of every line in python code. In particular, I want to print a "|" to the start of every outputted line. What would be the best way to achieve this in python?

Using Python 3? Replace print:
_realprint = print
def print(*args, **kwargs):
_realprint('|', end='')
_realprint(*args, **kwargs)
print.__doc__ = _realprint.__doc__
Now everything output by print will be prefixed by '|'. Extra credit for replacing \n with \n| in your _realprint() calls, remembering when called with end equal to something other than \n, etc. This should get you through 99% of cases, though.

Make your own file-like that defines write() and replace sys.stdout.
import sys
class forewrap(object):
def __init__(self, origfile, cseq='|'):
self.file = origfile
self.cseq = cseq
self.seen = False
def write(self, txt):
if not (self.seen and txt == '\n'):
self.seen = True
self.file.write(self.cseq)
else:
self.seen = False
self.file.write(txt)
print 'foo'
sys.stdout = forewrap(sys.stdout)
print 'foo'
print
print 'bar'