I want to resolve the domain name asynchronously before connecting to the target;
one way is parse sql connect parameters string; like
if ("host=" in conn_params) and ("hostaddr=" not in conn_params):
get_domain_name_and_resolv_and_add_hostaddr_to_conn_params_string()
Another way is to add it to libq;
I write a simple example:
https://github.com/gamefunc/Aiolibpq_simple
I added the code to libq the build for use:
https://github.com/gamefunc/Aiolibpq_simple/blob/main/Modify_Libpq_Source_Code.py
and use it in(awaitable<int> Aiolibpq::connect()):
https://github.com/gamefunc/Aiolibpq_simple/blob/main/Aiolibpq_simple.cpp
const char* host_name = nullptr;
while((host_name = PQgetUnresolvHost(conn)) != nullptr){
tcp::resolver resolver(loop);
tcp::resolver::iterator ep_iter =
co_await resolver.async_resolve(
host_name, "", use_awaitable);
tcp::endpoint ep = *ep_iter;
PQSetUnresolvHost(
conn, host_name,
ep.address().to_string().data(),
ep.address().to_string().size());
}// while()
Of course, there will be many situations in this code,
for example, when one of the domain names fails to resolve the ip, it will boom;