Fix downloading from redirects

Depending on your region inkbunny can serve you urls
that redirect to a different content server. The downloaded file
would contain the redirect text from the initial request and fall
apart during analyzation.

app/logical/sites.rb

@@ -30,8 +30,10 @@ def download_headers_for_image_uri(uri)
   def download_file(outfile, url)
     fixed_uri = fix_url(url)
     headers = download_headers_for_image_uri(fixed_uri)
-    response = HTTParty.get(fixed_uri, { headers: headers }) do |chunk|
-      outfile.write(chunk)
+    response = HTTParty.get(fixed_uri, headers: headers) do |fragment|
+      next if [301, 302].include?(fragment.code)
+
+      outfile.write(fragment)
     end
     outfile.rewind
     response

test/logical/sites_test.rb

@@ -73,4 +73,19 @@ def assert_extracted(url:, site:, username:, valid: true)
       )
     end
   end
+
+  describe "download_file" do
+    it "properly handles redirects" do
+      redirect_url = "https://example.com/redirected"
+      initial_request = stub_request_once(:get, "https://example.com", body: "Your are being redirected", status: 302, headers: { Location: redirect_url })
+      redirect_request = stub_request_once(:get, redirect_url, body: "Actual content")
+
+      file = Tempfile.new(binmode: true)
+      Sites.download_file(file, "https://example.com")
+
+      assert_requested(initial_request)
+      assert_requested(redirect_request)
+      assert_equal("Actual content", file.read)
+    end
+  end
 end