python 跨平台python脚本启动器

------------------------------------调用方式-------------------------------- import Launcher Launcher.launchBookExamples(['PyDemos.pyw'], trace=False) ----------------------------------Launcher.py--------------------------------

!/usr/bin/env python

"""

Tools to find files, and run Python demos even if your environment has not been manually configured yet. For instance, provided you have already installed Python, you can launch Tkinter GUI demos directly from the book's examples distribution tree by double-clicking this file's icon, without first changing your environment configuration.

Assumes Python has been installed first (double-click on the python self installer on Windows), and tries to find where Python and the examples distribution live on your machine. Sets Python module and system search paths before running scripts: this only works because env settings are inherited by spawned programs on both Windows and Linux.

You may want to edit the list of directories searched for speed, and will probably want to configure your PYTHONPATH eventually to avoid this search. This script is friendly to already-configured path settings, and serves to demo platform-independent directory path processing. Python programs can always be started under the Windows port by clicking (or spawning a 'start' DOS command), but many book examples require the module search path too for cross-directory package imports. ========================================================================== """

import sys, os try: PyInstallDir = os.path.dirname(sys.executable) except: PyInstallDir = r'C:\Python37' # for searches, set for older pythons BookExamplesFile = 'README-PP4E.txt' # for pythonpath configuration

def which(program, trace=True): """ Look for program in all dirs in the system's search path var, PATH; return full path to program if found, else None. Doesn't handle aliases on Unix (where we could also just run a 'which' shell cmd with os.popen), and it might help to also check if the file is really an executable with os.stat and the stat module, using code like this: os.stat(filename)[stat.ST_MODE] & 0111 """ try: ospath = os.environ['PATH'] except: ospath = '' # OK if not set systempath = ospath.split(os.pathsep) if trace: print('Looking for', program, 'on', systempath)

for sysdir in systempath:
    filename = os.path.join(sysdir, program)      # adds os.sep between
    if os.path.isfile(filename):                  # exists and is a file?
        if trace: print('Found', filename)
        return filename
    else:
        if trace: print('Not at', filename)
if trace: print(program, 'not on system path')
return None

def findFirst(thisDir, targetFile, trace=False): """ Search directories at and below thisDir for a file or dir named targetFile. Like find.find in standard lib, but no name patterns, follows Unix links, and stops at the first file found with a matching name. targetFile must be a simple base name, not dir path. could also use os.walk or PP4E.Tools.find to do this. """ if trace: print('Scanning', thisDir) for filename in os.listdir(thisDir): # skip . and .. if filename in [os.curdir, os.pardir]: # just in case continue elif filename == targetFile: # check name match return os.path.join(thisDir, targetFile) # stop at this one else: pathname = os.path.join(thisDir, filename) # recur in subdirs if os.path.isdir(pathname): # stop at 1st match below = findFirst(pathname, targetFile, trace) if below: return below

def guessLocation(file, isOnWindows=(sys.platform[:3]=='win'), trace=True): """ Try to find directory where file is installed by looking in standard places for the platform. Change tries lists as needed for your machine. """ cwd = os.getcwd() # directory where py started tryhere = cwd + os.sep + file # or os.path.join(cwd, file) if os.path.exists(tryhere): # don't search if it is here return tryhere # findFirst(cwd,file) descends

if isOnWindows:
    tries = []
    for pydir in [PyInstallDir]:
        if os.path.exists(pydir):
            tries.append(pydir)
    tries = tries + [cwd, r'C:\Program Files']
    for drive in 'CDEFG':
        tries.append(drive + ':\\')
else:
    tries = [cwd, os.environ['HOME'], '/usr/bin', '/usr/local/bin']

for dir in tries:
    if trace: print('Searching for %s in %s' % (file, dir))
    try:
        match = findFirst(dir, file)
    except OSError:
        if trace: print('Error while searching', dir)    # skip bad drives
    else:
        if match: return match
if trace: print(file, 'not found! - configure your environment manually')
return None

PP4EpackageRoots = [ # python module search path

'%sPP4E' % os.sep, # pass in your own elsewhere

'']                                            # '' adds examplesDir root

def configPythonPath(examplesDir, packageRoots=PP4EpackageRoots, trace=True): """ Set up the Python module import search-path directory list as necessary to run programs in the book examples distribution, in case it hasn't been configured already. Add examples package root + any nested package roots that imports are relative to (just top root currently).

os.environ assignments call os.putenv internally in 1.5+,
so these settings will be inherited by spawned programs.
Python source lib dir and '.' are automatically searched;
unix|win os.sep is '/' | '\\', os.pathsep is ':' | ';'.
sys.path is for this process only--must set os.environ.
adds new dirs to front, in case there are two installs.
"""
try:
    ospythonpath = os.environ['PYTHONPATH']
except:
    ospythonpath = '' # OK if not set
if trace: print('PYTHONPATH start:\n', ospythonpath)

addList = []
for root in packageRoots:
    importDir = examplesDir + root
    if importDir in sys.path:
        if trace: print('Exists', importDir)
    else:
        if trace: print('Adding', importDir)
        sys.path.append(importDir)
        addList.append(importDir)

if addList:
    addString = os.pathsep.join(addList) + os.pathsep
    os.environ['PYTHONPATH'] = addString + ospythonpath
    if trace: print('PYTHONPATH updated:\n', os.environ['PYTHONPATH'])
else:
    if trace: print('PYTHONPATH unchanged')

def configSystemPath(pythonDir, trace=True): """ Add python executable dir to system search path if needed """ try: ospath = os.environ['PATH'] except: ospath = '' # OK if not set if trace: print('PATH start:\n', ospath)

if ospath.lower().find(pythonDir.lower()) == -1:            # not found?
    os.environ['PATH'] = ospath + os.pathsep + pythonDir    # not case diff
    if trace: print('PATH updated:\n', os.environ['PATH'])
else:
    if trace: print('PATH unchanged')

def runCommandLine(pypath, exdir, command, isOnWindows=False, trace=True): """ Run python command as an independent program/process on this platform, using pypath as the Python executable, and exdir as the installed examples root directory.

Need full path to Python on Windows, but not on Unix.
On Windows, an os.system('start ' + command) is similar,
except that .py files pop up a DOS console box for I/O.
Could use launchmodes.py too but pypath is already known.
"""
command = exdir + os.sep + command          # rooted in examples tree
command = os.path.normpath(command)         # fix up mixed slashes
os.environ['PP4E_PYTHON_FILE'] = pypath     # export directories for
os.environ['PP4E_EXAMPLE_DIR'] = exdir      # use in spawned programs

if trace: print('Spawning:', command)
if isOnWindows:
    os.spawnv(os.P_DETACH, pypath, ('python', command))
else:
    cmdargs = [pypath] + command.split()
    if os.fork() == 0:
        os.execv(pypath, cmdargs)           # run prog in child process

def launchBookExamples(commandsToStart, trace=True): """ Toplevel entry point: find python exe and examples dir, configure environment, and spawn programs. Spawned programs will inherit any configurations made here. """ isOnWindows = (sys.platform[:3] == 'win') pythonFile = (isOnWindows and 'python.exe') or 'python' # or if/esle if trace: print(os.getcwd(), os.curdir, os.sep, os.pathsep) print('starting on %s...' % sys.platform)

# find python executable: check system path, then guess
try:
    pypath = sys.executable     # python executable running me
except:
    # on older pythons
    pypath = which(pythonFile) or guessLocation(pythonFile, isOnWindows)
assert pypath
pydir, pyfile = os.path.split(pypath)               # up 1 from file
if trace:
    print('Using this Python executable:', pypath)
    input('Press <enter> key')

# find examples root dir: check cwd and others
expath = guessLocation(BookExamplesFile, isOnWindows)
assert expath
updir  = expath.split(os.sep)[:-2]                  # up 2 from file
exdir  = os.sep.join(updir)                         # to PP4E pkg parent
if trace:
    print('Using this examples root directory:', exdir)
    input('Press <enter> key')

# export python and system paths if needed
configSystemPath(pydir)
configPythonPath(exdir)
if trace:
    print('Environment configured')
    input('Press <enter> key')

# spawn programs: inherit configs
for command in commandsToStart:
    runCommandLine(pypath, os.path.dirname(expath), command, isOnWindows)

if name == 'main': # # if no args, spawn all in the list of programs below # else rest of cmd line args give single cmd to be spawned # if len(sys.argv) == 1: commandsToStart = [ 'Gui/TextEditor/textEditor.py', # either slash works 'Lang/Calculator/calculator.py', # launcher normalizes path 'PyDemos.pyw', #'PyGadgets.py', 'echoEnvironment.pyw' ] else: commandsToStart = [ ' '.join(sys.argv[1:]) ] launchBookExamples(commandsToStart) if sys.platform[:3] == 'win': input('Press Enter') # to read msgs if clicked