nijie: fix failure to handle certain image urls.

Fix IMAGE_URL regex not matching urls of this form:

* https://pic04.nijie.info/nijie_picture/diff/main/287736_161475_20181112032855_1.png

This caused the illust id to not be parsed from the url, which led to `#image_url`
returning nil, which led to uploads failing because the url to download was missing.

app/logical/sources/strategies/nijie.rb

@@ -5,6 +5,7 @@
 # * https://pic01.nijie.info/nijie_picture/diff/main/218856_0_236014_20170620101329.png (page: http://nijie.info/view.php?id=218856)
 # * https://pic01.nijie.info/nijie_picture/diff/main/218856_1_236014_20170620101330.png
 # * https://pic05.nijie.info/nijie_picture/diff/main/559053_20180604023346_1.png (page: http://nijie.info/view_popup.php?id=265428#diff_2)
+# * https://pic04.nijie.info/nijie_picture/diff/main/287736_161475_20181112032855_1.png (page: http://nijie.info/view_popup.php?id=287736#diff_2)
 #
 # Unhandled:
 #
@@ -47,11 +48,17 @@ module Sources
 
       # https://pic03.nijie.info/nijie_picture/28310_20131101215959.jpg
       # https://pic03.nijie.info/nijie_picture/236014_20170620101426_0.png
-      # https://pic01.nijie.info/nijie_picture/diff/main/218856_0_236014_20170620101329.png
       # https://pic05.nijie.info/nijie_picture/diff/main/559053_20180604023346_1.png
+      FILENAME1 = %r!(?<artist_id>\d+)_(?<timestamp>\d{14})(?:_\d+)?!i
+
+      # https://pic01.nijie.info/nijie_picture/diff/main/218856_0_236014_20170620101329.png
+      FILENAME2 = %r!(?<illust_id>\d+)_\d+_(?<artist_id>\d+)_(?<timestamp>\d{14})!i
+
+      # https://pic04.nijie.info/nijie_picture/diff/main/287736_161475_20181112032855_1.png
+      FILENAME3 = %r!(?<illust_id>\d+)_(?<artist_id>\d+)_(?<timestamp>\d{14})_\d+!i
+
       DIR = %r!(?:__rs_\w+/)?nijie_picture(?:/diff/main)?!
-      FILENAME = %r!(?:(?<illust_id>\d+)_(?<page>\d+_))?(?<artist_id>\d+)_(?<timestamp>\d{14})(?:_\d+)?!i
+      IMAGE_URL = %r!\Ahttps?://pic\d+\.nijie\.info/#{DIR}/#{Regexp.union(FILENAME1, FILENAME2, FILENAME3)}\.\w+\z!i
-      IMAGE_URL = %r!\Ahttps?://pic\d+\.nijie\.info/#{DIR}/#{FILENAME}\.\w+\z!i
 
       def domains
         ["nijie.info"]

test/unit/sources/nijie_test.rb

@@ -186,7 +186,7 @@ module Sources
       end
     end
 
-    context "An image url that contains the illust id" do
+    context "An image url that contains the illust id and artist id (format 1)" do
       should "fetch all the data" do
         site = Sources::Strategies.find("https://pic03.nijie.info/nijie_picture/diff/main/218856_4_236014_20170620101333.png")
 
@@ -200,6 +200,19 @@ module Sources
       end
     end
 
+    context "An image url that contains the illust id and artist id (format 2)" do
+      should "fetch all the data" do
+        site = Sources::Strategies.find("https://pic04.nijie.info/nijie_picture/diff/main/287736_161475_20181112032855_1.png")
+
+        assert_equal("https://nijie.info/view.php?id=287736", site.page_url)
+        assert_equal("https://nijie.info/view.php?id=287736", site.canonical_url)
+        assert_equal("https://nijie.info/members.php?id=161475", site.profile_url)
+        assert_equal("みな本", site.artist_name)
+        assert_equal(site.url, site.image_url)
+        assert_equal(3, site.image_urls.size)
+      end
+    end
+
     context "An artist profile url" do
       should "not fail" do
         site = Sources::Strategies.find("https://nijie.info/members_illust.php?id=236014")