You can pass the hostname to Req as part of connect_options:
Req.get(
"https://123.456.789.123",
connect_options: [hostname: "www.example.com"]
)
Req will dynamically start or reuse a Finch pool with those options.
Pools don’t shut down by default so you may also want to specify a pool_max_idle_time, and you probably also want to disable redirects:
Req.get(
"https://123.456.789.123",
connect_options: [hostname: "not.actually.example.com"],
pool_max_idle_time: :timer.minutes(5),
redirect: false
)
