adding e621 support

Thanks baer!

lib/philomena/scrapers.ex

@@ -5,6 +5,7 @@ defmodule Philomena.Scrapers do
     Philomena.Scrapers.Twitter,
     Philomena.Scrapers.Tumblr,
     Philomena.Scrapers.Inkbunny,
+    Philomena.Scrapers.e621,
     Philomena.Scrapers.Raw
   ]
 

lib/philomena/scrapers/e621.ex

@@ -0,0 +1,26 @@
+defmodule Philomena.Scrapers.E621 do
+  @url_regex ~r|\Ahttps?://e621\.net/posts/([0-9]+)|
+
+  @spec can_handle?(URI.t(), String.t()) :: true | false
+  def can_handle?(_uri, url) do
+    String.match?(url, @url_regex)
+  end
+
+  def scrape(_uri, url) do
+    api_url = "#{url}.json"
+    {:ok, %Tesla.Env{status: 200, body: body}} = Philomena.Http.get(api_url)
+
+    json = Jason.decode!(body)
+    [submission] = json["post"]
+
+    %{
+      source_url: url,
+      author_name: Enum.join(submission["tags"]["artist"], ", "),
+      description: submission["description"],
+      images: [%{
+        url: "#{submission["file"]["url"]}",
+        camo_url: Camo.Image.image_url(submission["file"]["url"])
+      }]
+    }
+  end
+end