inpath

# DevPlayer@gmail.com
# 2011-Oct-06
# License: LGPL
# Python 2.7
# inpath.py
# revision 0.9.0-beta

# TO DO:
#   test with no PATHEXT and or no PATH environment variables
#   fix for on Mac and linux/unix

import os
import sys
import glob

'''Find a runnable program in PATH or supplied list of paths.

Search the PATH environment variable for all runnable
file names that match. Wildcards are not supported.

If at the DOS prompt you type "somecommand" and it runs
you may not know where in the PATH that program is and or
what file name extension the "somecommand" has.

This tool will find it.'''


help = ['-h', '--h', '-help', '--help', '/h', '/help']


# -----------------------------
# prep the running environment
if True: # <- my-trick-to-force-editor-block-folding

    # - - - - - - - - - - - -
    # Microsoft usually has an environment variable PATHEXT

    if os.environ.has_key('PATHEXT'):

        # remove dups from runnables extension list;
        _runnables = [ext for ext in os.environ['PATHEXT'].split(os.pathsep)]
        runnables = []

        # Remember that NOT all extensions are
        # ".xxx" chars long. And some filenames are like
        # myfile.someext.someother_ext.ext

        for ext in _runnables:
            if ext not in runnables:
                runnables.append(ext)
        del _runnables, ext

    else: # No PATHEXT found

        if sys.platform == 'win32':
            runnables = ['.COM', '.EXE', '.BAT']
        else:
            # Unix/Linux does not have that requirement
            runnables = []


    # - - - - - - - - - - - -
    # The wild card is different on different OSes
    # This script presumes MS and linux wildcards
    # I don't know Mac wildcards

    if sys.platform == 'win32':
        os_wild = '.*'
    else:
        os_wild = '*'



# -----------------------------
def compile_envar_paths(filename, envar='PATH'):

    # envar is short for "operating system environment variable"

    '''compile_envar_paths() returns a list of paths
    used by glob.glob() or glob.iglob().

    Each path in the list contains the filename to help
    filter out and reduce directory-listing functions
    to only those filenames that match.'''

    import os

    paths = []

    # Allow this program to crash if no PATH environment
    # variable is set.
    # Alternatively we could use os.path.defpath
    # but I'd rather the coder know of such a rare thing

    for pth in os.environ[envar].split(os.pathsep):
        # sometimes paths have the added '\' at the end
        # remove '\' or '//' if at end.
        if pth[-1] == os.sep:
            spath = pth + filename + os_wild
        else:
            spath = pth + os.sep + filename + os_wild
        paths.append(spath)

    return paths


# -----------------------------
def icompile_envar_paths(filename, envar='PATH'):

    # envar is short for "operating system environment variable"

    '''icompile_envar_paths() returns a generator that lists
    paths used by glob.glob() or glob.iglob().

    Each path in the list contains the filename to help
    filter out and reduce directory-listing functions
    to only those filenames that match.'''

    import os


    # Allow this program to crash if no PATH environment
    # variable is set.
    # Alternatively we could use os.path.defpath
    # but I'd rather the coder know of such a rare thing

    for pth in os.environ[envar].split(os.pathsep):
        # sometimes paths have the added '\' at the end
        # remove '\' or '//' if at end.
        if pth[-1] == os.sep:
            spath = pth + filename + os_wild
        else:
            spath = pth + os.sep + filename + os_wild
        yield spath




# -----------------------------
def find(filename, in_paths=None, show=False):

    '''Search each glob-like string in in_paths for filename;
    which expects no extension
    if "show" == True print results to stdout
    "show" defaults to False
    returns a list of matching fully qualified filenames

    If in_paths is None then find() uses the PATH environment variable.'''

    import os
    import glob

    if in_paths is None:
        in_paths = compile_envar_paths(filename)

    found = []
    for pth in in_paths:
        #print( pth )
        for fn in glob.glob( pth ):
            # ignore directories; << remove this check
            if os.path.isdir(fn): continue
            for ext in runnables:
                if fn.upper().endswith(ext):
                    found.append(fn)
                    if show:
                        print('%s' % fn)

    if len(found) == 0 and show:
        print('File not found.')

    return found



# -----------------------------
def ifind(filename, in_paths=None):

    '''Search each glob-like string in in_paths for filename;
    which expects no extension.
    This is an iterator that returns each matching
    fully qualified filename.

    If in_paths is None then ifind() uses the PATH environment variable.'''

    import os
    import glob

    if in_paths is None:
        in_paths = icompile_envar_paths(filename)

    for pth in in_paths:
        for fn in glob.iglob( pth ):
            # ignore directories; << remove this check?
            if os.path.isdir(fn): continue
            for ext in runnables:
                if fn.upper().endswith(ext):
                    yield fn


# -----------------------------
def usage():
    if __name__ == '__main__':
        print('')
        print('inpath will search the PATH for the runnable filename')
        print('')
        print('Run from the command prompt will print the results to stdout.')
        print('Wildcards * and ? are supported before the extension.')
        print('The return order is revelent.')
        print('This script will not find internal commands.')
        print('This script trys to use os envar PATHEXT.')
        print('You many want to see if .py and .pyc are included in PATHEXT.')
        print('')
        print('Sytnax:')
        print('    inpath <filename>')
        print('    C:\\inpath <some-file-name-without-extension-that-is-runnable>')
        print('')
        print('Example syntax:')
        print('    C:\\>python.exe inpath.py net')
        print('    C:\\>inpath python')
        print('    C:\\>inpath pyth*')
        print('    C:\\>inpath pyth?')
        print('    C:\\>inpath python.24')
        print('    C:\\>inpath python2?')
        print('    C:\\>inpath "double quoted file name with space"')
        print('    C:\\>inpath python ignored "extra arguments"')
        print('    C:\\>inpath /h')
        print('A favorite:')
        print('    C:\\>inpath py*')
        print('')
        print('Doing:')
        print('    C:\\>inpath net.exe')
        print('')
        print('will look for:')
        print('    net.exe.com, net.exe.exe, net.exe.bat, etc...')
        print('')
        print('To see usage from within Python interpreter')
        print('    >import inpath')
        print('    >inpath.usage()')
        print('')
    else:
        print """    '''
    # inpath will search the PATH for the runnable filename

    # Run from the command prompt will print the results to stdout.
    # Wildcards * and ? are supported before the extension.
    # The return order is revelent.
    # This script will not find internal commands.

    # Example syntax:

    import inpath
    filename = "pytho*"
    paths = inpath.compile_envar_paths( filename )

    found = inpath.find( filename )
    found = inpath.find( filename, paths, show= True )
    found = inpath.find( filename, my_made_paths_list )

    from inpath import *
    for found in ifind( 'python' ):
        print( repr( found ) )


    # To see usage for command line at the command line just type
    "inpath" or "inpath -h"
    '''"""

# -----------------------------
if __name__ == '__main__':

    import sys

    if len(sys.argv) < 2 or sys.argv[1].lower() in help:
        usage()

    elif len(sys.argv) >= 2:
        if len(sys.argv) > 2:
            extras = ', '.join([repr(arg) for arg in sys.argv[2:]])
            print('')
            print('These command line arguments are ignored: %s' % extras)

        filename = sys.argv[1]
        print('')
        print('Searching in PATH for %s%s:' % (filename, os_wild))
        print('')
        in_paths = compile_envar_paths(filename)
        found = find(filename, in_paths, show=True)