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 exactly what I needed for previewing thousands of large images quickly. Thanks!

I'm glad you like it. I'm surprised the default gnome config doesn't support any concurrency in this. Feel free to share, and lmk if it needs any improvements.

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.