Using cURL to retreive public IP for tmux config creates too many connections

Question

I am currently using the command: curl icanhazip.com and the option set -g status-left ... in my tmux.conf to retrieve and display my public IP in status bar.

This works great, although I am really bothered by the number of requests that are being made to retrieve the same IP over and over again.

Question:

How can I acheive this (retrieve/display public IP in tmux status–bar) with only one communication stream per session (or something less redundant) using the tmux configuration?

I have looked through curl's man page and tried various rate limiting args in the command [to no avail], though I think this is something specific to tmux.

I could use an external script or function of some kind to accomplish this although i'd like to keep this simple.

Any suggestions to solve this or alternate methods entirely would be great!

edit: formatting

Answer 1

Cache the information:

1. Add a cron job that runs every 5 or 10 minutes:

   curl http://icanhazip.com > ~/.cache/my-ip
   

   Some sources provide this information over connectionless protocols and therefore won't be as strict with their limits as connection-based HTTP sources:

   dig +short myip.opendns.com @208.67.222.222 > ~/.cache/my-ip
   

2. In tmux, change the command to simply read from your cache file:

   cat ~/.cache/my-ip
   

---

This could be done by a single script too, but it would be much less simple:

#!/usr/bin/env perl
use LWP::Simple;

sub read_cached_ip {
    my ($file) = @_;
    return undef if !-e $file; # check if file exists
    my $mtime = (stat $file)[9];
    return undef if time - $mtime >= 5*60; # check if file has expired
    if (open(my $fh, "<", $file)) {
        chomp(my $ip = <$fh>);
        close($ip);
        return $ip;
    }
    return undef;
}

sub update_ip {
    my ($file) = @_;
    my $ip = LWP::Simple::get("http://icanhazip.com");
    if (open(my $fh, ">", $file)) {
        print $fh "$ip\n";
        close($ip);
    }
    return $ip;
}

my $file = $ENV{HOME}."/.cache/my-ip";
my $ip = read_cached_ip($file) // update_ip($file);
print "$ip\n";