Dns

DNS resolution module.

Resolves hostnames to IPv4 addresses via the platform's getaddrinfo(3). Results reflect the system's resolver configuration (e.g. /etc/hosts, /etc/resolv.conf, mDNS, and any configured search domains).

Public API: Dns.resolve(host) : Result(List(String), DnsError) Dns.resolve_one(host) : Result(String, DnsError) Dns.is_ip(s) : Bool Dns.error_message(e) : String

Types

typeDnsErrorDnsError#

Functions

fnerror_messageerror_message(e : DnsError) : String#

Return a human-readable description of a DnsError.

fnis_ipis_ip(s : String) : Bool#

Return true if s looks like an IPv4 address (four dot-separated octets). Does not validate octet ranges.

    Dns.is_ip("127.0.0.1")    -- true
    Dns.is_ip("example.com")  -- false

fnresolveresolve(host : String) : Result(List(String), DnsError)#

Resolve hostname to a list of IPv4 address strings. Returns Ok(addrs) where addrs is non-empty, or Err on failure.

    match Dns.resolve("example.com") do
    Ok(ips)  -> List.head_opt(ips)
    Err(e)   -> panic(Dns.error_message(e))
    end

fnresolve_oneresolve_one(host : String) : Result(String, DnsError)#

Resolve hostname to its primary IPv4 address. Returns Ok(ip_string) or Err.

    match Dns.resolve_one("example.com") do
    Ok(ip) -> ip
    Err(e) -> panic(Dns.error_message(e))
    end