Nautilus Thumbnail Generator. Python 3 scalable and fast.

thumbnailer.py

#!/usr/bin/python3
import concurrent.futures
import hashlib
import os
import sys

import gi
gi.require_version('GnomeDesktop', '3.0')
from gi.repository import Gio, GnomeDesktop


def make_thumbnail(factory, filename, overwrite=False):
    mtime = os.path.getmtime(filename)
    # Use Gio to determine the URI and mime type
    f = Gio.file_new_for_path(filename)
    uri = f.get_uri()
    info = f.query_info('standard::content-type', Gio.FileQueryInfoFlags.NONE, None)
    mime_type = info.get_content_type()

    # Already thumbnailed
    path = factory.lookup(uri, mtime)
    if overwrite and path is not None:
        print("Removed:" + path)
        os.remove(path)

    if (not overwrite) and (path is not None):
        return False

    # Not thumbnailable
    if not factory.can_thumbnail(uri, mime_type, mtime):
        return False

    # Error during thumb
    thumbnail = factory.generate_thumbnail(uri, mime_type)
    if thumbnail is None:
        print("Error thumbnailing: " + str(uri))
        return False

    factory.save_thumbnail(thumbnail, uri, mtime)
    return True


def thumbnail_targets(factory, targets: list, overwrite=False):
    tcount = os.cpu_count() * 2
    with concurrent.futures.ThreadPoolExecutor(max_workers=tcount) as tpe:
        n_created = 0
        nails = tpe.map(lambda name: make_thumbnail(factory, name, overwrite=overwrite), targets)
        for n, f in enumerate(nails):
            update_txt = "Thumbnailing: {:.2%}".format((n + 1) / len(targets))
            print(update_txt, end="\r")
            n_created += f
        print("\nThumbnailed %i files." % n_created)


def gather_paths(targets: list, ignore_dot_prefixed=True):
    file_names = []

    for target in targets:
        if os.path.isdir(target):
            for dirpath, folders, filenames in os.walk(target):
                # Skip recursion into dotfiles if requested
                # This helps with windows/osx FS/trash/etc
                if ignore_dot_prefixed:
                    for folder in folders:
                        if folder.startswith("."):
                            folders.remove(folder)

                # Append files found to list
                for filename in filenames:
                    file_names.append(os.path.join(dirpath, filename))
            continue

        if os.path.isfile(target):
            file_names.append(target)
            continue

        raise ValueError("Don't know what to do with: " + target)

    file_names.sort()
    print(file_names)

    return file_names


if __name__ == '__main__':
    import argparse

    ap = argparse.ArgumentParser(
        description="A tool for generating Gnome thumbnails in parallel.")
    ap.add_argument(
        "paths",
        help="The path(s) to thumbnail (typically one or more folders)",
        nargs="+")
    ap.add_argument(
        "--overwrite",
        help="Overwrite existing thumbnails.",
        action="store_true")
    ap.add_argument(
        "--dotfiles",
        help="Don't ignore directories prefixed with '.'",
        action="store_false")

    parsed = ap.parse_args()
    factory = GnomeDesktop.DesktopThumbnailFactory()
    targets = gather_paths(parsed.paths, ignore_dot_prefixed=parsed.dotfiles)
    print("%i targets found" % len(targets))
    thumbnail_targets(factory, targets, overwrite=parsed.overwrite)

This is a very useful script. Thank you.

Here is a minor issue: running the script with no arguments generates a strange error, like this.

[x@localhost]$ python3 thumbnailer.py 
usage: meawoppl thumbnailer.py [-h] [--overwrite] [--dotfiles] paths [paths ...]
meawoppl thumbnailer.py: error: the following arguments are required: paths

I'd recommend making argparse handle this a bit more smoothly (i.e. printing the --help output and exiting if the script's invoked with no arguments, rather than exiting without explaining what the help flag is); I may make a pull request for this later if I remember.