a Hosts class can now write changes to hosts file

.gitignore

@@ -1 +1,2 @@
 .DS_Store
+test/hosts

lib/hoster/hosts.rb

@@ -1,53 +1,62 @@
 class Hosts
 
   attr_reader :entries
-  
+
   def initialize(hosts_path = "/etc/hosts")
-    @hosts_file = File.new(hosts_path,"r+")
-    @entries    = extract_entries(hosts_path)
+    @hosts_path = hosts_path
+    @entries    = extract_entries
   end
-  
-  def raw_data
-    @hosts_file.read
+
+  def dump
+    File.open(@hosts_path,"r") { |f| f.read }
   end
-  
+
   def add(host, ip_address = "127.0.0.1")
     @entries[ip_address] << host
   end
-  
+
   def remove(host, ip_address)
     @entries[ip_address].delete_if { |x| x == host }
   end
-
-  def finalize_changes!
-    lines = @hosts_file.readlines
+
+  def write_changes!
     @entries.each do |entry|
-      exists_in_file = false
-      lines.each_with_index do |line,index|
-        if line.match(/#{entry.first}/)
-          exists_in_file = true
-          lines[index] = "#{entry.first} #{entry.last.join(' ')}\n"
+      append_this     = true
+      entry_exists    = false
+
+      File.open(@hosts_path,"r+") do |file|
+        lines = file.readlines
+        lines.each_with_index do |line,index|
+          if line =~ /#{entry.first}/
+            if entry_exists
+              lines.delete_at(index)
+            else
+              lines[index] = "#{entry.first} #{entry.last.join(' ')}\n"
+              # update the state of this entry
+              append_this  = false
+              entry_exists = true
+            end
+          end
         end
+        if append_this
+          # append entry to end of @hosts_file
+        end
+        # write out actual changes
+        file.pos = 0
+        file.print lines
+        file.truncate(file.pos)
       end
-      if !exists_in_file
-        # append entry to end of @hosts_file
-      end
-      # write out actual changes
-      @hosts_file.pos = 0
-      @hosts_file.print lines
-      @hosts_file.truncate(@hosts_file.pos)
     end
   end
-  
+
   private
-  
-  def extract_entries(hosts_path)
+
+  def extract_entries
     entries = Hash.new
-    @hosts_file.each do |line|
-      if line.match(/^(\d+\.\d+\.\d+\.\d) (.*)/)
+    File.open(@hosts_path,"r").each do |line|
+      if line =~ /^(\d+\.\d+\.\d+\.\d) (.*)/
         ip_address = $1
         hosts_list = $2.split(' ')
-
         if entries.has_key?(ip_address)
           hosts_list.each do |host|
             entries[ip_address] << host
@@ -59,5 +68,9 @@ def extract_entries(hosts_path)
     end
     entries
   end
-
+
+  def condense!
+    File.open(@hosts_path,"r+")
+  end
+
 end

test/test_hoster.rb

@@ -3,82 +3,82 @@
 require 'test/unit'
 require 'shoulda'
 
-TestContent = <<CONTENT
+BaseFile = <<CONTENT
 127.0.0.1 localhost
 127.0.1.1 localhost
 192.168.1.1 router.com router
 192.168.1.2 localhost
 127.0.0.1 test.com
+192.168.1.2 local.host
+CONTENT
+
+ModifiedFile = <<CONTENT
+127.0.0.1 localhost test.com test.dev
+127.0.1.1 localhost
+192.168.1.1 router router.org
+192.168.1.2 localhost local.host
 CONTENT
 
 class TestHoster < Test::Unit::TestCase
   context "Reading and parsing hosts file" do
     setup do
-      File.open("hosts","w") do |file|
-        file.puts TestContent
+      File.open("test/hosts","w") do |file|
+        file.puts BaseFile
       end
-      @hoster = Hosts.new("hosts")
+      @hoster = Hosts.new("test/hosts")
     end
-    
+
     should "create an object that stores a Hash" do
       assert_kind_of Hash, @hoster.entries
     end
-    
+
     should "assign ip addresses as hash keys" do
       assert @hoster.entries.has_key?("127.0.0.1")
     end
-    
+
     should "store a hosts array as hash values" do
       assert_kind_of Array, @hoster.entries.values.first
     end
-    
+
     should "map multiple hosts to ip addresses on the same line" do
       assert_equal "router.com", @hoster.entries["192.168.1.1"].first
       assert_equal "router", @hoster.entries["192.168.1.1"].last
     end
-    
+
     should "map multiple hosts to same ip address on different lines" do
       assert_equal "localhost", @hoster.entries["127.0.0.1"].first
       assert_equal "test.com", @hoster.entries["127.0.0.1"].last
     end
-    
+
   end
-  
+
   context "Manipulating hosts file" do
     setup do
-      File.open("hosts","w") do |file|
-        file.puts TestContent
+      File.open("test/hosts","w") do |file|
+        file.puts BaseFile
       end
-      @hoster = Hosts.new("hosts")
+      @hoster = Hosts.new("test/hosts")
     end
-    
+
     should "add a host to the correct line for specified ip address" do
       assert_equal 2, @hoster.entries["192.168.1.1"].size
       @hoster.add("router.org","192.168.1.1")
       assert_equal 3, @hoster.entries["192.168.1.1"].size
     end
-    
+
     should "remove correct host from line for specified ip address" do
       assert_equal 2, @hoster.entries["192.168.1.1"].size
       @hoster.remove("router.com", "192.168.1.1")
       assert_equal 1, @hoster.entries["192.168.1.1"].size
       assert_equal "router", @hoster.entries["192.168.1.1"].first
     end
-
- #    should "write correct changes to file" do
- #       @hoster.add("test.dev")
- #       @hoster.add("router.org","192.168.1.1")
- #       @hoster.remove("router.com", "192.168.1.1")
- #       #@hoster.finalize_changes!
- #       puts @hoster.raw_data
- #       new_content = <<CONTENT
- # 127.0.0.1 localhost test.dev
- # 127.0.1.1 localhost
- # 192.168.1.1 router router.org
- # 192.168.1.2 localhost
- # 127.0.0.1 test.com
- # CONTENT
- #       assert_equal new_content, @hoster.raw_data
- #     end
+
+    should "write correct changes to file" do
+      @hoster.add("test.dev")
+      @hoster.add("router.org","192.168.1.1")
+      @hoster.remove("router.com", "192.168.1.1")
+      @hoster.write_changes!
+      assert_equal ModifiedFile, @hoster.dump
+    end
   end
 end