From 5cfec5920a01b63d3b5383dcf955e0acdfe22873 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carl=20H=C3=B6rberg?= <carl@84codes.com>
Date: Sat, 20 Mar 2021 16:12:21 +0100
Subject: [PATCH 1/2] Use Ruby Resolv instead of LibC for hostname lookup

This way DNS resolver can be replaced with:

```ruby
Resolv::DefaultResolver.replace_resolvers [Resolv::DNS.new(nameserver: ['8.8.8.8']]
```

Related: #159, #184
---
 lib/excon/socket.rb | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/lib/excon/socket.rb b/lib/excon/socket.rb
index d2d256bf..0c09a57e 100644
--- a/lib/excon/socket.rb
+++ b/lib/excon/socket.rb
@@ -1,4 +1,6 @@
 # frozen_string_literal: true
+require 'resolv'
+
 module Excon
   class Socket
     include Utils
@@ -95,20 +97,17 @@ def local_port
     def connect
       @socket = nil
       exception = nil
+      hostname = @data[:hostname]
+      port = @port
+      family = @data[:family]
 
       if @data[:proxy]
-        family = @data[:proxy][:family] || ::Socket::Constants::AF_UNSPEC
-        args = [@data[:proxy][:hostname], @data[:proxy][:port], family, ::Socket::Constants::SOCK_STREAM]
-      else
-        family = @data[:family] || ::Socket::Constants::AF_UNSPEC
-        args = [@data[:hostname], @port, family, ::Socket::Constants::SOCK_STREAM]
+        hostname = @data[:proxy][:hostname]
+        port = @data[:proxy][:port]
+        family = @data[:proxy][:family]
       end
-      if RUBY_VERSION >= '1.9.2' && defined?(RUBY_ENGINE) && RUBY_ENGINE == 'ruby'
-        args << nil << nil << false # no reverse lookup
-      end
-      addrinfo = ::Socket.getaddrinfo(*args)
 
-      addrinfo.each do |_, port, _, ip, a_family, s_type|
+      ::Resolv.each_address(hostname) do |ip|
         # already succeeded on previous addrinfo
         if @socket
           break
@@ -120,8 +119,8 @@ def connect
         # nonblocking connect
         begin
           sockaddr = ::Socket.sockaddr_in(port, ip)
-
-          socket = ::Socket.new(a_family, s_type, 0)
+          addrinfo = Addrinfo.getaddrinfo(ip, port, family, :STREAM).first
+          socket = ::Socket.new(addrinfo.pfamily, addrinfo.socktype, addrinfo.protocol)
 
           if @data[:reuseaddr]
             socket.setsockopt(::Socket::Constants::SOL_SOCKET, ::Socket::Constants::SO_REUSEADDR, true)

From b3d3f896b37c68a6067e2048313f4befdd3c32fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carl=20H=C3=B6rberg?= <carl@84codes.com>
Date: Sat, 20 Mar 2021 16:48:39 +0100
Subject: [PATCH 2/2] Raise ResolvError if no hostnames were found

---
 lib/excon/socket.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/excon/socket.rb b/lib/excon/socket.rb
index 0c09a57e..fa99fe94 100644
--- a/lib/excon/socket.rb
+++ b/lib/excon/socket.rb
@@ -107,7 +107,7 @@ def connect
         family = @data[:proxy][:family]
       end
 
-      ::Resolv.each_address(hostname) do |ip|
+      Resolv.each_address(hostname) do |ip|
         # already succeeded on previous addrinfo
         if @socket
           break
@@ -150,6 +150,8 @@ def connect
         end
       end
 
+      exception ||= Resolv::ResolvError.new("no address for #{hostname}")
+
       # this will be our last encountered exception
       fail exception unless @socket