Added the ability to render UUIDs as a :slug. (#31)

.travis.yml

@@ -1,6 +1,6 @@
 language: elixir
 elixir:
-- 1.3.4
+- 1.7.3
 otp_release:
-- 18.0
+- 21.0
 sudo: false

lib/uuid.ex

@@ -233,6 +233,8 @@ defmodule UUID do
   iex> UUID.uuid1(:raw)
   <<205, 253, 175, 68, 238, 53, 17, 227, 132, 107, 20, 16, 159, 241, 163, 4>>
 
+  iex> UUID.uuid1(:slug)
+  "zf2vRO41EeOEaxQQn_GjBA"
   ```
 
   """
@@ -263,6 +265,8 @@ defmodule UUID do
   iex> UUID.uuid1(:raw)
   <<205, 253, 175, 68, 238, 53, 17, 227, 132, 107, 20, 16, 159, 241, 163, 4>>
 
+  iex> UUID.uuid1(:slug)
+  "zf2vRO41EeOEaxQQn_GjBA"
   ```
 
   """
@@ -308,6 +312,8 @@ defmodule UUID do
   iex> UUID.uuid3("cdfdaf44-ee35-11e3-846b-14109ff1a304", "my.domain.com")
   "8808f33a-3e11-3708-919e-15fba88908db"
 
+  iex> UUID.uuid3(:dns, "my.domain.com", :slug)
+  "A78HBrfpM7iu5cYUKoFkeA"
   ```
 
   """
@@ -364,6 +370,8 @@ defmodule UUID do
   iex> UUID.uuid4(:raw)
   <<251, 73, 160, 236, 214, 12, 77, 32, 146, 100, 59, 76, 254, 39, 33, 6>>
 
+  iex> UUID.uuid4(:slug)
+  "-0mg7NYMTSCSZDtM_ichBg"
   ```
 
   """
@@ -406,6 +414,8 @@ defmodule UUID do
   iex> UUID.uuid5("fb49a0ec-d60c-4d20-9264-3b4cfe272106", "my.domain.com")
   "822cab19-df58-5eb4-98b5-c96c15c76d32"
 
+  iex> UUID.uuid5("fb49a0ec-d60c-4d20-9264-3b4cfe272106", "my.domain.com", :slug)
+  "giyrGd9YXrSYtclsFcdtMg"
   ```
 
   """
@@ -461,21 +471,24 @@ defmodule UUID do
   defp uuid_to_string(<<_::128>> = u, :raw) do
     u
   end
-  defp uuid_to_string(_u, format) when format in [:default, :hex, :urn] do
+  defp uuid_to_string(<<u::128>>, :slug) do
+    Base.url_encode64(<<u::128>>, [padding: false])
+  end
+  defp uuid_to_string(_u, format) when format in [:default, :hex, :urn, :slug] do
     raise ArgumentError, message:
     "Invalid binary data; Expected: <<uuid::128>>"
   end
   defp uuid_to_string(_u, format) do
     raise ArgumentError, message:
-    "Invalid format #{format}; Expected: :default|:hex|:urn"
+    "Invalid format #{format}; Expected: :default|:hex|:urn|:slug"
   end
 
   # Extract the type (:default etc) and pure byte value from a UUID String.
   defp uuid_string_to_hex_pair(<<uuid::128>>) do
     {:raw, <<uuid::128>>}
   end
-  defp uuid_string_to_hex_pair(<<uuid::binary>>) do
-    uuid = String.downcase(uuid)
+  defp uuid_string_to_hex_pair(<<uuid_in::binary>>) do
+    uuid = String.downcase(uuid_in)
     {type, hex_str} = case uuid do
       <<u0::64, ?-, u1::32, ?-, u2::32, ?-, u3::32, ?-, u4::96>> ->
         {:default, <<u0::64, u1::32, u2::32, u3::32, u4::96>>}
@@ -484,8 +497,14 @@ defmodule UUID do
       <<@urn, u0::64, ?-, u1::32, ?-, u2::32, ?-, u3::32, ?-, u4::96>> ->
         {:urn, <<u0::64, u1::32, u2::32, u3::32, u4::96>>}
       _ ->
-        raise ArgumentError, message:
-          "Invalid argument; Not a valid UUID: #{uuid}"
+        case uuid_in do
+          _ when byte_size(uuid_in) == 22 ->
+            case Base.url_decode64(uuid_in <> "==") do
+              {:ok, decoded} -> {:slug, Base.encode16(decoded)}
+              _ -> raise ArgumentError, message: "Invalid argument; Not a valid UUID: #{uuid}"
+            end
+          _ -> raise ArgumentError, message: "Invalid argument; Not a valid UUID: #{uuid}"
+        end
     end
 
     try do

mix.exs

@@ -7,7 +7,7 @@ defmodule UUID.Mixfile do
     [app: :elixir_uuid,
      name: "UUID",
      version: @version,
-     elixir: "~> 1.3",
+     elixir: "~> 1.7",
      docs: [extras: ["README.md", "CHANGELOG.md"],
             main: "readme",
             source_ref: "v#{@version}"],