If proxy is down, get a new one - bash

Question

I'm writing my first bash script
LANG="en_US.UTF8" ; export LANG
PROXY=$(shuf -n 1 proxy.txt)
export https_proxy=$PROXY
RUID=$(php -f randuid.php)
curl --data "mydata${RUID}" --user-agent "myuseragent" https://myurl.com/url -o "ticket.txt"
This script also use curl, but if proxy is down it gives me this error:
failed to connect PROXY:PORT
How can I make bash script run again, so it can get another proxy address from proxy.txt
Thanks in advance

Answer 1

Run it in a loop until the curl succeeds, for example:
export LANG="en_US.UTF8"
while true; do
PROXY=$(shuf -n 1 proxy.txt)
export https_proxy=$PROXY
RUID=$(php -f randuid.php)
curl --data "mydata${RUID}" --user-agent "myuseragent" https://myurl.com/url -o "ticket.txt" && break
done
Notice the && break at the end of the curl command.
That is, if the curl succeeds, break out of the infinite loop.
If you have multiple curl commands and you need all of them to succeed,
then chain them all together with &&, and add the break after the last one:
curl url1 && \
curl url2 && \
break
Lastly, as #Inian pointed out,
you could use the --proxy flag to pass a proxy URL to curl without the extra step of setting https_proxy, for example:
curl --proxy "$(shuf -n 1 proxy.txt)" --data "mydata${RUID}" --user-agent "myuseragent"
Lastly, note that due to the randomness, a randomly selected proxy may come up more than once until you find one that works.
Avoid that, you could read iterate over the shuffled proxies instead of an infinite loop:
export LANG="en_US.UTF8"
shuf proxy.txt | while read -r proxy; do
ruid=$(php -f randuid.php)
curl --proxy "$proxy" --data "mydata${ruid}" --user-agent "myuseragent" https://myurl.com/url -o "ticket.txt" && break
done
I also lowercased your user-defined variables,
as capitalization is not recommended for those.

Answer 2

I know i accepted #janos answer but since I can't edit his I'm going to add this
response=$(curl --proxy "$proxy" --silent --write-out "\n%{http_code}\n" https://myurl.com/url)
status_code=$(echo "$response" | sed -n '$p')
html=$(echo "$response" | sed '$d')
case "$status_code" in
200) echo 'Working!'
;;
*)
echo 'Not working, trying again!';
exec "$0" "$#"
esac
This will run my script again if it gives 503 status code which i wanted :)
And with #janos code it will run again if proxy is not working.
Thank you everyone i achieved what i wanted.