From 8713d4141a17bc03ceb825f3d8e6df2e9e2814b6 Mon Sep 17 00:00:00 2001
From: Justin Tormey <jrtormey@gmail.com>
Date: Thu, 19 Nov 2020 09:40:47 -0600
Subject: [PATCH 1/2] Add handle_href option for href pre-processing

---
 lib/linkify.ex         | 5 +++--
 lib/linkify/builder.ex | 7 +++++--
 test/linkify_test.exs  | 8 ++++++++
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/lib/linkify.ex b/lib/linkify.ex
index d15d01c..0f97ad5 100644
--- a/lib/linkify.ex
+++ b/lib/linkify.ex
@@ -34,13 +34,14 @@ defmodule Linkify do
   * `email` - link email links (default: `false`)
   * `mention` - link @mentions (when `true`, requires `mention_prefix` or `mention_handler` options to be set) (default: `false`)
   * `mention_prefix` - a prefix to build a link for a mention (example: `https://example.com/user/`, default: `nil`)
-  * `mention_handler` - a custom handler to validate and formart a mention (default: `nil`)
+  * `mention_handler` - a custom handler to validate and format a mention (default: `nil`)
   * `hashtag: false` - link #hashtags (when `true`, requires `hashtag_prefix` or `hashtag_handler` options to be set)
   * `hashtag_prefix: nil` - a prefix to build a link for a hashtag (example: `https://example.com/tag/`)
-  * `hashtag_handler: nil` - a custom handler to validate and formart a hashtag
+  * `hashtag_handler: nil` - a custom handler to validate and format a hashtag
   * `extra: false` - link urls with rarely used schemes (magnet, ipfs, irc, etc.)
   * `validate_tld: true` - Set to false to disable TLD validation for urls/emails, also can be set to :no_scheme to validate TLDs only for urls without a scheme (e.g `example.com` will be validated, but `http://example.loki` won't)
   * `iodata` - Set to `true` to return iodata as a result, or `:safe` for iodata with linkified anchor tags wrapped in Phoenix.HTML `:safe` tuples (removes need for further sanitization)
+  * `href_handler: nil` - a custom handler to process a url before it is set as the link href, useful for generating exit links
   """
   def link(text, opts \\ []) do
     parse(text, opts)
diff --git a/lib/linkify/builder.ex b/lib/linkify/builder.ex
index 8edf7e8..0ce3661 100644
--- a/lib/linkify/builder.ex
+++ b/lib/linkify/builder.ex
@@ -42,8 +42,11 @@ defmodule Linkify.Builder do
     end
   end
 
-  defp build_attrs(attrs, url, _opts, :href) do
-    [{:href, url} | attrs]
+  defp build_attrs(attrs, url, opts, :href) do
+    case Map.get(opts, :href_handler) do
+      handler when is_function(handler) -> [{:href, handler.(url)} | attrs]
+      _ -> [{:href, url} | attrs]
+    end
   end
 
   defp add_scheme("http://" <> _ = url), do: url
diff --git a/test/linkify_test.exs b/test/linkify_test.exs
index 2568052..a86d0fe 100644
--- a/test/linkify_test.exs
+++ b/test/linkify_test.exs
@@ -339,6 +339,14 @@ defmodule LinkifyTest do
 
       assert MapSet.to_list(mentions) == [{"@friend", "friend"}]
     end
+
+    test "href handler" do
+      text = ~s(google.com)
+
+      result_text = Linkify.link(text, href_handler: & "/redirect?#{URI.encode_query(to: &1)}")
+
+      assert result_text == ~s(<a href="/redirect?to=http%3A%2F%2Fgoogle.com">google.com</a>)
+    end
   end
 
   describe "mentions" do

From d84ca4d0b74354e3a56f29370f3dbfc25380e7ae Mon Sep 17 00:00:00 2001
From: Justin Tormey <jrtormey@gmail.com>
Date: Thu, 19 Nov 2020 09:48:28 -0600
Subject: [PATCH 2/2] Fix formatting in test

---
 test/linkify_test.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/linkify_test.exs b/test/linkify_test.exs
index a86d0fe..81f9688 100644
--- a/test/linkify_test.exs
+++ b/test/linkify_test.exs
@@ -343,7 +343,7 @@ defmodule LinkifyTest do
     test "href handler" do
       text = ~s(google.com)
 
-      result_text = Linkify.link(text, href_handler: & "/redirect?#{URI.encode_query(to: &1)}")
+      result_text = Linkify.link(text, href_handler: &"/redirect?#{URI.encode_query(to: &1)}")
 
       assert result_text == ~s(<a href="/redirect?to=http%3A%2F%2Fgoogle.com">google.com</a>)
     end