Resolv

Resolv is a DNS resolver library in Crystal that supports UDP, TCP, and DoH (DNS-over-HTTPS).

Supported Resource Record (RR) TYPEs :

	Type	Value	Meaning	Defining RFC
✓	A	1	a host address	RFC 1035
✓	NS	2	an authoritative name server	RFC 1035
	MD	3	a mail destination (Obsolete - use MX)	RFC 1035
	MF	4	a mail forwarder (Obsolete - use MX)	RFC 1035
✓	CNAME	5	the canonical name for an alias	RFC 1035
✓	SOA	6	marks the start of a zone of authority	RFC 1035
	MB	7	a mailbox domain name (EXPERIMENTAL)	RFC 1035
	MG	8	a mail group member (EXPERIMENTAL)	RFC 1035
	MR	9	a mail rename domain name (EXPERIMENTAL)	RFC 1035
	NULL	10	a null RR (EXPERIMENTAL)	RFC 1035
	WKS	11	a well known service description	RFC 1035
✓	PTR	12	a domain name pointer	RFC 1035
	HINFO	13	host information	RFC 1035
	MINFO	14	mailbox or mail list information	RFC 1035
✓	MX	15	mail exchange	RFC 1035
✓	TXT	16	text strings	RFC 1035
✓	AAAA	28	IPv6 host address	RFC 3596
✓	SRV	33	service location	RFC 2782
✓	CAA	257	certification authority authorization	RFC 8659

• [RFC 1035]
• [RFC 3596]
• [RFC 2782]
• [RFC 8659]

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     resolv:
       github: mamantoha/resolv-crystal

2. Run shards install

Usage

require "resolv"

dns = Resolv::DNS.new("8.8.8.8", read_timeout: 10.seconds, retry: 3, requester: :tcp)

dns.resources("crystal-lang.org", :a)
# #<Resolv::DNS::Resource::A:0x1010d0c40 @address="18.66.112.124">

dns.mx_resources("gmail.com")
# #<Resolv::DNS::Resource::MX:0x1010d0560 @preference=40, @exchange="alt4.gmail-smtp-in.l.google.com">

dns.soa_resources("gmail.com")
# => #<Resolv::DNS::Resource::SOA:0x10245c100 @mname="ns1.google.com", @rname="dns-admin.google.com", @serial=646797294, @refresh=900, @retry=900, @expire=1800, @minimum=60>

dns.srv_resources("_xmpp-client._tcp.jabber.org")
# #<Resolv::DNS::Resource::SRV:0x74689eebdf60 @priority=30, @weight=30, @port=5222, @target="zeus.jabber.org">

dns = Resolv::DNS.new("dns.toys")
dns.txt_resources("lviv.weather")
# #<Resolv::DNS::Resource::TXT:0x104cf00a0 @txt_data=["Lviv (UA)", "28.00C (82.40F)", "43.90% hu.", "partlycloudy_day", "14:00, Thu"]>

Alternatives

Other alternatives are:

• https://gitlab.com/jgillich/crystal-dns
• https://github.com/636f7374/durian.cr
• https://github.com/spider-gazelle/dns

Contributing

1. Fork it (https://github.com/mamantoha/resolv-crystal/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Anton Maminov - creator and maintainer