------------------------------------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
