This is a part 2 for the article I wrote previously how I tried to share files with people on Android. This time I am using a file synchronizing software called Syncthing because I'm using it already to sync files between my devices and it fits the purpose of sharing files also if you have a server with a web server, or perhaps a file server.

What you will need this time is:

• Syncthing
• Termux if using Android or Linux machine
• Server with nginx and Syncthing

I want to share public files that are meant for anyone, and private files that are meant only for a certain person or a group of people.

Therefore I created two folders for Syncthing to share: public_share and private_share and shared these folders with the server with Folder Type as Send Only.

Then I created a few bash functions to use to make copying files to be shared a little easier and also print the URL of shared files. These are for a PC on Linux.

Edit. It's good to automatically add others read permission to the files while uploading. With my nginx settings and user group, uploaded files can't be downloaded otherwise.

# usage: rand-str [len]
rand-str() {
    local len str

    len=30
    if [ -n "$1" ]; then
        echo "$1" | grep -qP '^\d+$' || {
            echo Argument is not a number >&2
            return 1
        }
        len="$1"
    fi
    str=$(tr -dc A-Za-z0-9 </dev/urandom | head -c "$len"; echo)
    echo "${str}"
}

share-public() {
    rsync -aqz --chmod o+r $* /home/jukka/syncthing/public_share/
    echo https://fluks.dy.fi/share/public/
}

share-private() {
    local dir

    dir=$(rand-str)
    mkdir "/home/jukka/syncthing/private_share/$dir"
    rsync -aqz --chmod o+r $* "/home/jukka/syncthing/private_share/$dir/"
    echo "https://fluks.dy.fi/share/private/$dir/"
}
      

And on Termux the share-public and share-private functions are a litte bit different. rand-str stays the same.

share-public() {
    local url

    rsync -qaz --chmod o+r --mkpath $* /data/data/com.termux/files/home/storage/public/
    url="https://fluks.dy.fi/share/public/"
    termux-clipboard-set "$url"
    echo "$url"
}

share-private() {
    local dir url

    dir=$(rand-str)
    mkdir "/data/data/com.termux/files/home/storage/private/$dir"
    rsync -qaz --chmod o+r --mkpath $* "/data/data/com.termux/files/home/storage/private/$dir/"
    url="https://fluks.dy.fi/share/private/$dir/"
    termux-clipboard-set "$url"
    echo "$url"
}
      

Then I approved sync requests on the server side and used directories that www server has access to. And I added the following lines to nginx config.

location /share/public/ {
    root /srv/;
    autoindex on;
    autoindex_exact_size off;
}

location /share/private/ {
    autoindex off;
}

location ~ ^/share/private/.+/ {
    root /srv/;
    autoindex on;
    autoindex_exact_size off;
}
    

Both shares are autoindexed but you can't follow links to private shares or guess the path.