filesegmenter.py

import os


def split_file(file_path, directory, size):
    '''Given a path to a file and create size byte partitions of the file.
    Partitions are stored in the directory directory.

    Create the directory if it does not exist.

    Return a list of file paths to these partitions.'''

    fileNumber = 0
    files_created = []
    file_name = file_path.split('/')[-1]

    # Check that the directory exists by attempting to create it.
    # Creation successful when it doens't exist.
    try:
        os.makedirs(directory)
    except OSError:
        if not os.path.isdir(directory):
            raise

    with open(file_path, "rt") as f:
        while True:
            buf = f.read(int(size))
            if not buf:
                 # we've read the entire file in, so we're done.
                break

            create_file = os.path.join(
                directory,
                "{}-{}.txt".format(
                    file_name, "%04d" % fileNumber
                )
            )
            outFile = open(create_file, "wt")
            outFile.write(buf)
            outFile.close()
            files_created.append(create_file)
            fileNumber += 1
    return files_created


def create_file_path(directory, file_path):
    '''Given a directory to store a file in and a file_path, create the
    requried directories within directory to mimic file_path.

    Return the path created.'''

    try:
        os.makedirs(directory)
    except OSError:
        if not os.path.isdir(directory):
            raise

    # End case, when file_path is just a file within directory
    directories = file_path.split('/', 1)
    if os.path.isfile(file_path) or len(directories) <= 1:
        return ''

    # Make directory
    create_directory = directories[0]
    os.makedirs(create_directory)
    # Create subdirectories
    return os.path.join(
        create_directory,
        create_file_path(create_directory, directories[1])
    )