Arch Linux

Create a systemd user unit that waits for the network-online.target.

A script something like:

[Unit]
Description=Startup script
Requires=network-online.target
After=network-online.target

[Service]
Type=oneshot # either simple or oneshot, but sounds like oneshot
ExecStart=/home/<user>/script.sh
RemainAfterExit=yes #if oneshot, otherwise no

[install]
WantedBy=default.target

Edit the template according to your needs and dump it into ~/.local/share/systemd/user/<unit>.service and enable it with systemctl --user enable --now <unit>

The simplest solution is probably a script that waits and retries until curl succeeds.

You can have your WiFi start with the rest of your network service before login if you choose. Maybe that's the limitation here.

Easiest way would be to just add a sleep 15 command at the top of the script. Time how long it takes your wifi to come up, and adjust the sleep time with like a 2-3 second buffer in case it takes linger for some reason.

More exact would be to create a systemd service for your script that depends on network connectivity to execute.

Nice. I will try the systemd unit. Meanwhile, i have added a loop in the script, which helps a little bit:

maxwait=15
if [[ $(nm-online -x) != *"online"* ]]; then
	echo "missing internet connection, waiting..."
	for (( i = 1; i <= maxwait; ++i )); do
		sleep 1 &
		echo $i
		if [[ $(nm-online -x) == *"online"* ]]; then
			break
		fi

		if [[ $i -eq $maxwait ]]; then
			echo "No internet connection"
			exit 1
		fi
		wait
	done 
fi

In my test, this exits the script after 15 seconds without connection, but continues, when the connection is available or is established within this time.

But i think, its a nice idea, to add this to the script AND use the systemd unit together.