use local IP address by default

shard.lock

@@ -4,6 +4,10 @@ shards:
     git: https://github.com/naqvis/crystar.git
     version: 0.4.0+git.commit.3975502cbe89bca528e1af4b86fbfc0f0bfacce1
 
+  ip_address_list:
+    git: https://github.com/mamantoha/ip_address_list.git
+    version: 0.1.0
+
   qr-code:
     git: https://github.com/spider-gazelle/qr-code.git
     version: 1.0.3

shard.yml

@@ -13,6 +13,8 @@ dependencies:
     version: ">= 0.2.0"
   qr-code:
     github: spider-gazelle/qr-code
+  ip_address_list:
+    github: mamantoha/ip_address_list
 
 targets:
   zipstream:

spec/zipstream/config_spec.cr

@@ -0,0 +1,11 @@
+require "../spec_helper"
+
+describe Zipstream::Config do
+  config = Zipstream::Config.new
+
+  context "host" do
+    it "should has host as local IP address" do
+      config.host.should match(/\d+\.\d+\.\d+\.\d+/)
+    end
+  end
+end

src/zipstream.cr

@@ -5,6 +5,7 @@ require "option_parser"
 require "crystar"
 require "zip64"
 require "qr-code"
+require "ip_address_list"
 
 require "./zipstream/**"
 

src/zipstream/config.cr

@@ -2,7 +2,7 @@ module Zipstream
   class Config
     INSTANCE = Config.new
 
-    property host
+    setter host : String? = nil
     property port
     property? log : Bool = false
     property? web : Bool = false
@@ -21,7 +21,6 @@ module Zipstream
     property? no_banner : Bool = false
 
     def initialize
-      @host = "0.0.0.0"
       @port = 8090
       @format = "zip"
       @output = "download"
@@ -30,6 +29,10 @@ module Zipstream
       @env = "development"
     end
 
+    def host
+      @host || local_ip_address.try(&.address) || "0.0.0.0"
+    end
+
     def filename
       [output, format].join(".")
     end
@@ -53,5 +56,11 @@ module Zipstream
         str << url_path
       end
     end
+
+    def local_ip_address : Socket::IPAddress?
+      Socket.ip_address_list.find do |ip_address|
+        ip_address.family == Socket::Family::INET && ip_address.private? && !ip_address.address.starts_with?("127")
+      end
+    end
   end
 end