Fix #476 issue - problem with sprockets 3.0

Remove `asset_exists?` method. Replace it with `File.file?` at `read_asset`.
Fix issue handled by `asset_exists?` at `wicked_pdf_stylesheet_link_tag` by
changing `asset_pathname` method.
`asset_exists?` coused problems with sprockets 3.0 so removing it fixes that.

Always process assets at `wicked_pdf_stylesheet_link_tag` with
`wicked_pdf_asset_path`. This fixes issue when
`url(http://example.com/rails.png)` was removed.

Rename `precompiled_asset?` to `precompiled_or_absolute_asset?` - this more
precisely describe what this method does. Additionally return `true` if
argument string starts with "http://" or "http://".

Change `asset_pathname` to always return some value when assets compilation
is enabled. This fixes problem when exception is raised when asset doesn't
exists.

Change `read_asset` to check if file exists before read it.

Fix test

lib/wicked_pdf/wicked_pdf_helper/assets.rb

@@ -21,8 +21,7 @@ def wicked_pdf_stylesheet_link_tag(*sources)
         if Regexp.last_match[1].starts_with?('data:')
           "url(#{Regexp.last_match[1]})"
         else
-          asset = Regexp.last_match[1]
-          "url(#{wicked_pdf_asset_path(asset)})" if asset_exists?(asset)
+          "url(#{wicked_pdf_asset_path(Regexp.last_match[1])})"
         end
       end.html_safe
     end
@@ -57,15 +56,17 @@ def wicked_pdf_asset_path(asset)
     URI_REGEXP = %r{^[-a-z]+://|^(?:cid|data):|^//}
 
     def asset_pathname(source)
-      if precompiled_asset?(source)
-        if (pathname = set_protocol(asset_path(source))) =~ URI_REGEXP
+      if precompiled_or_absolute_asset?(source)
+        asset = asset_path(source)
+        if (pathname = set_protocol(asset)) =~ URI_REGEXP
           # asset_path returns an absolute URL using asset_host if asset_host is set
           pathname
         else
-          File.join(Rails.public_path, asset_path(source).sub(/\A#{Rails.application.config.action_controller.relative_url_root}/, ''))
+          File.join(Rails.public_path, asset.sub(/\A#{Rails.application.config.action_controller.relative_url_root}/, ''))
         end
       else
-        Rails.application.assets.find_asset(source).pathname
+        asset = Rails.application.assets.find_asset(source)
+        asset ? asset.pathname : File.join(Rails.public_path, source)
       end
     end
 
@@ -81,25 +82,27 @@ def set_protocol(source)
       source
     end
 
-    def precompiled_asset?(source)
-      Rails.configuration.assets.compile == false || source.to_s[0] == '/'
+    def precompiled_or_absolute_asset?(source)
+      Rails.configuration.assets.compile == false ||
+        source.to_s[0] == '/' ||
+        source.to_s.match(/\Ahttps?\:\/\//)
     end
 
     def read_asset(source)
-      if precompiled_asset?(source)
-        if set_protocol(asset_path(source)) =~ URI_REGEXP
-          read_from_uri(source)
-        elsif asset_exists?(source)
-          IO.read(asset_pathname(source))
+      if precompiled_or_absolute_asset?(source)
+        if (pathname = asset_pathname(source)) =~ URI_REGEXP
+          read_from_uri(pathname)
+        elsif File.file?(pathname)
+          IO.read(pathname)
         end
       else
         Rails.application.assets.find_asset(source).to_s
       end
     end
 
-    def read_from_uri(source)
+    def read_from_uri(uri)
       encoding = ':UTF-8' if RUBY_VERSION > '1.8'
-      asset = open(asset_pathname(source), "r#{encoding}") { |f| f.read }
+      asset = open(uri, "r#{encoding}") { |f| f.read }
       asset = gzip(asset) if WickedPdf.config[:expect_gzipped_remote_assets]
       asset
     end
@@ -110,9 +113,5 @@ def gzip(asset)
       gzipper.read
     rescue Zlib::GzipFile::Error
     end
-
-    def asset_exists?(source)
-      Rails.application.assets.find_asset(source).present?
-    end
   end
 end

test/functional/wicked_pdf_helper_assets_test.rb

@@ -18,28 +18,74 @@ class WickedPdfHelperAssetsTest < ActionView::TestCase
     end
 
     test 'wicked_pdf_asset_path should return a url when assets are served by an asset server using HTTPS' do
-      expects(:asset_path => 'https://assets.domain.com/dummy.png', 'precompiled_asset?' => true)
+      Rails.configuration.assets.expects(:compile => false)
+      expects(:asset_path => 'https://assets.domain.com/dummy.png')
       assert_equal 'https://assets.domain.com/dummy.png', wicked_pdf_asset_path('dummy.png')
     end
 
     test 'wicked_pdf_asset_path should return a url with a protocol when assets are served by an asset server with relative urls' do
+      Rails.configuration.assets.expects(:compile => false)
       expects(:asset_path => '//assets.domain.com/dummy.png')
-      expects('precompiled_asset?' => true)
       assert_equal 'http://assets.domain.com/dummy.png', wicked_pdf_asset_path('dummy.png')
     end
 
     test 'wicked_pdf_asset_path should return a url with a protocol when assets are served by an asset server with no protocol set' do
+      Rails.configuration.assets.expects(:compile => false)
       expects(:asset_path => 'assets.domain.com/dummy.png')
-      expects('precompiled_asset?' => true)
       assert_equal 'http://assets.domain.com/dummy.png', wicked_pdf_asset_path('dummy.png')
     end
 
-    test 'wicked_pdf_asset_path should return a path when assets are precompiled' do
-      expects('precompiled_asset?' => false)
+    test 'wicked_pdf_asset_path should return a path' do
+      Rails.configuration.assets.expects(:compile => true)
       path = wicked_pdf_asset_path('application.css')
 
-      assert path.include?('/assets/stylesheets/application.css')
+      assert path.include?('/app/assets/stylesheets/application.css')
       assert path.include?('file:///')
+
+      Rails.configuration.assets.expects(:compile => false)
+      expects(:asset_path => '/assets/application-6fba03f13d6ff1553477dba03475c4b9b02542e9fb8913bd63c258f4de5b48d9.css')
+      path = wicked_pdf_asset_path('application.css')
+
+      assert path.include?('/public/assets/application-6fba03f13d6ff1553477dba03475c4b9b02542e9fb8913bd63c258f4de5b48d9.css')
+      assert path.include?('file:///')
+    end
+
+    # This assets does not exists so probably it doesn't matter what is
+    # returned, but lets ensure that returned value is the same when assets
+    # are precompiled and when they are not
+    test 'wicked_pdf_asset_path should return a path when asset does not exist' do
+      Rails.configuration.assets.expects(:compile => true)
+      path = wicked_pdf_asset_path('missing.png')
+
+      assert path.include?('/public/missing.png')
+      assert path.include?('file:///')
+
+      Rails.configuration.assets.expects(:compile => false)
+      expects(:asset_path => '/missing.png')
+      path = wicked_pdf_asset_path('missing.png')
+
+      assert path.include?('/public/missing.png')
+      assert path.include?('file:///')
+    end
+
+    test 'wicked_pdf_asset_path should return a url when asset is url' do
+      Rails.configuration.assets.expects(:compile => true)
+      expects(:asset_path => 'http://example.com/rails.png')
+      assert_equal 'http://example.com/rails.png', wicked_pdf_asset_path('http://example.com/rails.png')
+
+      Rails.configuration.assets.expects(:compile => false)
+      expects(:asset_path => 'http://example.com/rails.png')
+      assert_equal 'http://example.com/rails.png', wicked_pdf_asset_path('http://example.com/rails.png')
+    end
+
+    test 'wicked_pdf_asset_path should return a url when asset is url without protocol' do
+      Rails.configuration.assets.expects(:compile => true)
+      expects(:asset_path => '//example.com/rails.png')
+      assert_equal 'http://example.com/rails.png', wicked_pdf_asset_path('//example.com/rails.png')
+
+      Rails.configuration.assets.expects(:compile => false)
+      expects(:asset_path => '//example.com/rails.png')
+      assert_equal 'http://example.com/rails.png', wicked_pdf_asset_path('//example.com/rails.png')
     end
 
     test 'WickedPdfHelper::Assets::ASSET_URL_REGEX should match various URL data type formats' do