jaf - Just Another Fileshare

jaf is a simple Go program to handle file uploads. If you also want to serve the uploaded files, consider a web server like nginx.

Installation

Clone the directory:

git clone https://github.com/leon-richardt/jaf.git

Build the executable:

go build

Run tests (optional):

go test

If you plan on using a systemd service or another init system, you might want to move the jaf executable to a different directory (e.g. /opt) at this point; you know your setup best.

Configuration

jaf

There are just a few parameters that need to be configured for jaf. Refer to the example.conf file:

Port:       4711
# a comment
LinkPrefix: https://jaf.example.com/
FileDir:    /var/www/jaf/
LinkLength: 5
ScrubExif: true
# Both IDs also refer to the "Orientation" tag, included for illustrative purposes only
ExifAllowedIds: 0x0112 274
ExifAllowedPaths: IFD/Orientation
ExifAbortOnError: true

Option	Use
Port	the port number jaf will listen on
LinkPrefix	a string that will be prepended to the file name generated by jaf
FileDir	path to the directory jaf will save uploaded files in
LinkLength	the number of characters the generated file name is allowed to have
ScrubExif	whether to remove EXIF tags from uploaded JPEG and PNG images (true or false)
ExifAllowedIds	a space-separated list of EXIF tag IDs that should be preserved through EXIF scrubbing (only relevant if ScrubExif is true)
ExifAllowedPaths	a space-separated list of EXIF tag paths that should be preserved through EXIF scrubbing (only relevant if ScrubExif is true)
ExifAbortOnError	whether to abort JPEG and PNG uploads if an error occurs during EXIF scrubbing (only relevant if ScrubExif is true)

Make sure the user running jaf has suitable permissions to read, and write to, FileDir. Also note that LinkLength directly relates to the number of files that can be saved. Since jaf only uses alphanumeric characters for file name generation, a maximum of (26 + 26 + 10)^LinkLength names can be generated.

A Note on EXIF Scrubbing

EXIF scrubbing can be enabled via the ScrubExif config key. When enabled, all standard EXIF tags are removed on uploaded JPEG and PNG images per default. It is meant as a last-line "defense mechanism" against leaking PII, such as GPS information on pictures. If possible, you should always prefer disabling capturing potentially sensitive EXIF tags when creating the images!

Obviously, EXIF tags serve a purpose and you may want to keep some of the information, e.g., image orientation. The ExifAllowedIds and ExifAllowedPaths config keys can be used to selectively allow specific tags to survive the scrubbing. The IDs for standard tags can be found in 1. You may specify tag IDs in decimal and hexadecimal notation. (In the latter case, the ID must start with 0x.)

The path specification for ExifAllowedPaths relies on the format implemented in go-exif which is "documented" in machine-readable format in 2. Multiple paths can be specified, separated by a space. The path format is as follows:

1. For tags in the main section: IFD/<GroupName>/<FieldName>. Examples: IFD/Orientation, IFD/Exif/Flash, IFD/GPSInfo/GPSTimeStamp. You will probably want to use both 1 and 2 in combination if you plan to specify allowed tags by path.

2. Tags in the thumbnail section follow the same format but paths start with IFD1/ instead of IFD.

nginx

If you use a reverse-proxy to forward requests to jaf, make sure to correctly forward the original request headers. For nginx, this is achieved via the proxy_pass_request_headers on; option.

If you want to limit access to jaf (e.g. require basic authentication), you will also need to do this via your reverse-proxy.

Running

After adjusting the configuration file to your needs, run:

jaf -configFile example.conf

Of course, you can also write a init system script to handle this for you.

Running from Docker

Running it from the GitHub Container Registry

docker run \
    -p 4712:4711 \
    -v /path/to/your/config.conf:/app/jaf.conf \
    -v /path/to/local/filedir:/var/www/jaf \
    ghcr.io/leon-richardt/jaf:latest

Building the Docker image and running it locally

docker build -t jaf .
docker run \
    -p 4712:4711 \
    -v /path/to/your/config.conf:/app/jaf.conf \
    -v /path/to/local/filedir:/var/www/jaf \
    jaf

Port 4711 is the default port for the server in example.conf, if you've changed this in your config you'll need to change this in the docker run invocations above too.
The above runs forwards the jaf port from 4711 in the container to 4712 on your local system.

Usage

You can use jaf with any application that can send POST requests (e.g. ShareX/ShareNix or just curl). Make sure the file you want to upload is attached as a multipart/form-data field named file. In curl, a request to upload the file /home/alice/foo.txt could look like this:

curl -L -F "file=@/home/alice/foo.txt" jaf.example.com/upload

The response will include a link to the newly uploaded content. Note that you may have to add additional header fields to the request, e.g. if you have basic authentication enabled.

Inspiration

• i by fourtf – a project very similar in scope and size
• filehost by nuuls – a more integrated, fully-fledged solution that offers a web interface and also serves the files