PathValidator

validator.py

class PathValidator(object):
    '''Class for validating paths

    It checks whether a file or directory exists at the location pointed by path
    If the file or directory exists it must be non-empty and readable,
    else InvalidpathError is raised

    If the class is instantiated like this:
    pathsV = PathValidator(True, '/home/path')

    Then write permissions will be checked, too.

    Multiple paths can be checked at once too:
    pathsV = PathValidator(True, '/home/path', '/etc/rc.d') - here write
    permissions are checked

    pathsV = PathValidator('/home/path', '/etc/rc.d') - write permissions are
    not checked
    '''
    #TODO think about readable/writeable


    def __init__(self, writeable = False, *paths):
        self.paths = []
        self.writeable = writeable

        for path in paths:
            self.paths.append(path)

    def validate(self):
        '''Call various test functions on the paths

        Tests if the path exists, is non-empty
        '''

        import os

        for path in self.paths:
            if not os.path.exists(path):
                raise InvalidPathError(path)
            elif 0 == os.path.getsize(path):
                raise InvalidPathError(path)
            elif not os.access(path, os.R_OK):
                raise InvalidPathError(path)
            elif self.writeable and not os.access(path, os.W_OK):
                raise InvalidPathError(path)


class InvalidPathError(Exception):
    '''Exception raised when an invalid path is found'''

    def __init__(self, arg):
        self.args = arg;

    def __str__(self):
        return 'Invalid path: {0}'.format(''.join(self.args))