deviantart: take artist name from url when unavailable from API.

In some cases we can't get the artist name from the API, either because
we can't do the API call because the url doesn't contain a deviation id,
or because the work is deleted:

* http://fc08.deviantart.net/files/f/2007/120/c/9/cool_like_me_by_47ness.jpg (work: http://fav.me/dwcohb)
* https://pre00.deviantart.net/423b/th/pre/i/2017/281/e/0/mindflayer_girl01_by_nickbeja-dbpxdt8.png (work: http://fav.me/dbpxd58)

Switch to taking the artist name from the url (when present) to deal
with these cases. Fixes the artist finder and the artist url normalizer
to work in this situation.

app/logical/sources/strategies/deviant_art.rb

@@ -86,19 +86,20 @@ module Sources
       end
 
       def profile_url
-        if url =~ PATH_PROFILE
-          return url
-        end
-
-        if artist_name.blank?
-          return nil
-        end
-
-        return "https://www.deviantart.com/#{artist_name}"
+        return "" if artist_name.blank?
+        "https://www.deviantart.com/#{artist_name.downcase}"
       end
 
+      # Prefer the name from the url because the api metadata won't be present when
+      # the input url doesn't contain a deviation id, or the deviation is private or deleted.
       def artist_name
-        api_metadata.dig(:author, :username).try(&:downcase)
+        if artist_name_from_url.present?
+          artist_name_from_url
+        elsif api_metadata.present?
+          api_metadata.dig(:author, :username)
+        else
+          ""
+        end
       end
 
       def artist_commentary_title
@@ -114,7 +115,7 @@ module Sources
       end
 
       def normalizable_for_artist_finder?
-        url =~ PATH_ART || url =~ SUBDOMAIN_ART
+        normalize_for_artist_finder.present?
       end
 
       def normalize_for_artist_finder
@@ -173,10 +174,24 @@ module Sources
         end
       end
 
+      def self.artist_name_from_url(url)
+        if url =~ ASSET || url =~ PATH_ART || url =~ PATH_PROFILE
+          $~[:artist]
+        elsif url !~ RESERVED_SUBDOMAINS && (url =~ SUBDOMAIN_ART || url =~ SUBDOMAIN_PROFILE)
+          $~[:artist]
+        else
+          nil
+        end
+      end
+
       def deviation_id
         self.class.deviation_id_from_url(url) || self.class.deviation_id_from_url(referer_url)
       end
 
+      def artist_name_from_url
+        self.class.artist_name_from_url(url) || self.class.artist_name_from_url(referer_url)
+      end
+
       def page
         return nil if deviation_id.blank?
         deviation_url = "https://www.deviantart.com/deviation/#{deviation_id}"

test/unit/sources/deviantart_test.rb

@@ -15,14 +15,21 @@ module Sources
       should "work" do
         assert_equal(["http://origin-orig.deviantart.net/d533/f/2014/004/8/d/holiday_elincia_by_aeror404-d70rm0s.jpg"], @site.image_urls)
         assert_equal(@site.image_url, @site.canonical_url)
+        assert_equal("aeror404", @site.artist_name)
+        assert_equal("https://www.deviantart.com/aeror404", @site.profile_url)
       end
     end
 
     context "The source for a deleted DeviantArt image URL" do
       should "work" do
         @site = Sources::Strategies.find("https://pre00.deviantart.net/423b/th/pre/i/2017/281/e/0/mindflayer_girl01_by_nickbeja-dbpxdt8.png")
+        @artist = FactoryBot.create(:artist, name: "nickbeja", url_string: "https://nickbeja.deviantart.com")
+
         assert_equal("https://pre00.deviantart.net/423b/th/pre/i/2017/281/e/0/mindflayer_girl01_by_nickbeja-dbpxdt8.png", @site.image_url)
         assert_equal(@site.image_url, @site.canonical_url)
+        assert_equal("nickbeja", @site.artist_name)
+        assert_equal("https://www.deviantart.com/nickbeja", @site.profile_url)
+        assert_equal([@artist], @site.artists)
         assert_nothing_raised { @site.to_h }
       end
     end
@@ -79,6 +86,7 @@ module Sources
       setup do
         @url = "http://fc08.deviantart.net/files/f/2007/120/c/9/cool_like_me_by_47ness.jpg"
         @ref = "https://47ness.deviantart.com/art/Cool-Like-Me-54339311"
+        @artist = FactoryBot.create(:artist, name: "47ness", url_string: "https://www.deviantart.com/47ness")
       end
 
       context "without a referer" do
@@ -90,6 +98,7 @@ module Sources
           assert_equal("https://www.deviantart.com/47ness", @site.profile_url)
           assert_equal("", @site.page_url)
           assert_equal(@site.image_url, @site.canonical_url)
+          assert_equal([@artist], @site.artists)
           assert_nothing_raised { @site.to_h }
         end
       end
@@ -103,6 +112,7 @@ module Sources
           assert_equal("https://www.deviantart.com/47ness", @site.profile_url)
           assert_equal("https://www.deviantart.com/47ness/art/Cool-Like-Me-54339311", @site.page_url)
           assert_equal(@site.page_url, @site.canonical_url)
+          assert_equal([@artist], @site.artists)
           assert_nothing_raised { @site.to_h }
         end
       end
@@ -112,6 +122,7 @@ module Sources
       setup do
         @url = "http://pre06.deviantart.net/8497/th/pre/f/2009/173/c/c/cc9686111dcffffffb5fcfaf0cf069fb.jpg"
         @ref = "https://www.deviantart.com/edsfox/art/Silverhawks-Quicksilver-126872896"
+        @artist = FactoryBot.create(:artist, name: "edsfox", url_string: "https://edsfox.deviantart.com")
       end
 
       context "without a referer" do
@@ -123,6 +134,7 @@ module Sources
           assert_equal("", @site.profile_url)
           assert_equal("", @site.page_url)
           assert_equal(@site.image_url, @site.canonical_url)
+          assert_equal([], @site.artists)
           assert_nothing_raised { @site.to_h }
         end
       end
@@ -136,6 +148,7 @@ module Sources
           assert_equal("https://www.deviantart.com/edsfox", @site.profile_url)
           assert_equal("https://www.deviantart.com/edsfox/art/Silverhawks-Quicksilver-126872896", @site.page_url)
           assert_equal(@site.page_url, @site.canonical_url)
+          assert_equal([@artist], @site.artists)
           assert_nothing_raised { @site.to_h }
         end
       end