No-bullshit file hosting and URL shortening service
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Jonas Wunderlich 3950f6e8eb
fix 500 error when file extension could not be guessed
when a file without an extension was uploaded
and the mimetypes.guess_extension returned None
because there is no official file extension
for that mimetype a NoneType was subscripted
which yielded a 500 http error
8 months ago
instance Add moderation TUI 9 months ago
migrations migrations: Fix file expirations on SQLite 9 months ago
modui ModUI: Add application/xml to text handler 9 months ago
nsfw_model Add NSFW detection 6 years ago
templates index.html: Document appending file names 10 months ago
tests Fix URL test issue 9 months ago
.gitignore Support instance config 2 years ago
.mailmap Add mailmap 2 years ago
0x0-prune.service Add example systemd unit files for prune job 10 months ago
0x0-prune.timer Add example systemd unit files for prune job 10 months ago
0x0-vscan.service Add support for ClamAV 10 months ago
0x0-vscan.timer Add support for ClamAV 10 months ago
LICENSE Change license to EUPL 3 years ago
README.rst README: Kitty support was merged in mpv 9 months ago Add support for expiring files 10 months ago fix 500 error when file extension could not be guessed 8 months ago
mod.css Add moderation TUI 9 months ago ModUI: Fix crash when encountering null NSFW score 9 months ago
modui.webp README: Add ModUI screenshot 9 months ago nsfw_detect: Use PyAV instead of ffmpegthumbnailer 10 months ago
pyproject.toml Add tests 2 years ago
requirements.txt Update requirements.txt 9 months ago


The Null Pointer

This is a no-bullshit file hosting and URL shortening service that also runs Use with uWSGI.


To configure 0x0, copy instance/ to instance/, then edit it. Resonable defaults are set, but there's a couple options you'll need to change before running 0x0 for the first time.

By default, the configuration is stored in the Flask instance directory. Normally, this is in ./instance, but it might be different for your system. For details, see the Flask documentation.

To customize the home and error pages, simply create a templates directory in your instance directory and copy any templates you want to modify there.

If you are running nginx, you should use the X-Accel-Redirect header. To make it work, include this in your nginx configs server block:

location /up {

where /up is whatever youve configured as FHOST_STORAGE_PATH.

For all other servers, set FHOST_USE_X_ACCEL_REDIRECT to False and USE_X_SENDFILE to True, assuming your server supports this. Otherwise, Flask will serve the file with chunked encoding, which has several downsides, one of them being that range requests will not work. This is a problem for example when streaming media files: It wont be possible to seek, and some ISOBMFF (MP4) files will not play at all.

To make files expire, simply run FLASK_APP=fhost flask prune every now and then. You can use the provided systemd unit files for this:


Make sure to edit them to match your system configuration. In particular, set the user and paths in 0x0-prune.service.

Before running the service for the first time and every time you update it from this git repository, run FLASK_APP=fhost flask db upgrade.

Moderation UI


0x0 features a TUI program for file moderation. With it, you can view a list of uploaded files, as well as extended information on them. It allows you to take actions like removing files temporarily or permanently, as well as blocking IP addresses and associated files.

If a sufficiently recent version of python-mpv with libmpv is present and your terminal supports it, you also get graphical file previews, including video playback. Upstream mpv currently supports sixels and the kitty graphics protocol. For this to work, set the MOD_PREVIEW_PROTO option in instance/



  • python-mpv (graphical previews)
  • PyAV (information on multimedia files)
  • PyMuPDF (previews and file information for PDF, XPS, EPUB, MOBI and FB2)
  • libarchive-c (archive content listing)


Mosh currently does not support sixels or kitty graphics.


You may need to set the COLORTERM environment variable to truecolor.


Using compression with SSH (-C option) can significantly reduce the bandwidth requirements for graphics.

NSFW Detection

0x0 supports classification of NSFW content via Yahoos open_nsfw Caffe neural network model. This works for images and video files and requires the following:

  • Caffe Python module (built for Python 3)
  • PyAV

Virus Scanning

0x0 can scan its files with ClamAVs daemon. As this can take a long time for larger files, this does not happen immediately but instead every time you run the vscan command. It is recommended to configure a systemd timer or cronjob to do this periodically. Examples are included:


Remember to adjust your size limits in clamd.conf, including StreamMaxLength!

This feature requires the clamd module.

Network Security Considerations

Keep in mind that 0x0 can fetch files from URLs. This includes your local network! You should take precautions so that this feature cannot be abused. 0x0 does not (yet) have a way to filter remote URLs, but on Linux, you can use firewall rules and/or namespaces. This is less error-prone anyway.

For instance, if you are using the excellent FireHOL, its very easy to create a group on your system and use it as a condition in your firewall rules. You would then run the application server under that group.