accessibility check tweaks

.gitignore

@@ -7,3 +7,4 @@ Gemfile.lock
 /tmp
 
 mkmf.log
+node_modules

lib/site-inspector/checks/accessibility.rb

@@ -5,58 +5,90 @@
 class SiteInspector
   class Endpoint
     class Accessibility < Check
-
-      def section508
-        pa11y(:section508)
+
+      STANDARDS = {
+        section508: 'Section508', # Default standard
+        wcag2a:     'WCAG2A',
+        wcag2aa:    'WCAG2AA',
+        wcag2aaa:   'WCAG2AAA'
+      }
+
+      DEFAULT_LEVEL = "error"
+
+      def level
+        @level ||= DEFAULT_LEVEL
       end
-
-      def wcag2a
-        pa11y(:wcag2a)
+
+      def level=(level)
+        raise ArgumentError, "Invalid level '#{level}'" unless %w[error, warning, notice].include?(level)
+        @level = level
       end
-      
-      def wcag2aa
-        pa11y(:wcag2aa)
+
+      def standard?(standard)
+        STANDARDS.keys.include?(standard)
       end
-      
-      def wcag2aaa
-        pa11y(:wcag2aaa)
+
+      def standard
+        @standard ||= STANDARDS.keys.first
       end
-
-      private
-
-      def pa11y_installed?
-        !`which pa11y`.empty?
+
+      def standard=(standard)
+        raise ArgumentError, "Unknown standard '#{standard}'" unless standard?(standard)
+        @standard = standard
       end
-
-      def pa11y(standard)
-        if pa11y_installed?
-          standards = {
-            section508: 'Section508',
-            wcag2a: 'WCAG2A',
-            wcag2aa: 'WCAG2AA',
-            wcag2aaa: 'WCAG2AAA'
-          }
-          standard = standards[standard]
-
-          cmd = "pa11y #{endpoint.uri} -s #{standard} -r json"
-          response = ""
-          error = nil
-
-          Open3.popen3(cmd) do |stdin, stdout, stderr, wait_thr|
-            response = stdout.read
-            error = stderr.read          
-          end    
-
-          if error && !error.empty?
-            raise error
-          end
-
-          JSON.parse(response) 
+
+      def valid?
+        pa11y(standard)[:status] == :valid
+      end
+
+      def pa11y_version
+        output, status = Open3.capture2e("pa11y", "--version")
+        output.strip if status == 0
+      end
+
+      def pa11y?
+        !pa11y_version.nil?
+      end
+
+      def method_missing(method_sym, *arguments, &block)
+        if standard?(method_sym)
+          pa11y(method_sym)
         else
-          raise "pa11y not found. To install: [sudo] npm install -g pa11y"
+          super
         end
       end
-
+
+      def respond_to?(method_sym, include_private = false)
+        if standard?(method_sym)
+          true
+        else
+          super
+        end
+      end
+
+      private
+
+      def pa11y(standard)
+        raise "pa11y not found. To install: [sudo] npm install -g pa11y" unless pa11y?
+        raise ArgumentError, "Unknown standard '#{standard}'" unless standard?(standard)
+
+        args = [
+          "--standard", STANDARDS[standard],
+          "--reporter", "json",
+          "--level", level,
+          endpoint.uri.to_s
+        ]
+        output, status = Open3.capture2e("pa11y", *args)
+
+        # Pa11y exit codes: https://github.com/nature/pa11y#exit-codes
+        # 0: No errors, 1: Technical error within pa11y, 2: accessibility error (configurable via --level)
+        raise "Command `pa11y #{args.join(" ")}` failed: #{output}" if status == 1
+
+        {
+          status:  status == 0 ? :valid : :invalid,
+          results: JSON.parse(output)
+        }
+      end
     end
   end
 end

package.json

@@ -0,0 +1,23 @@
+{
+  "name": "site-inspector",
+  "version": "2.0.0",
+  "description": "Returns information about a domain's technology and capabilities",
+  "main": "site-inspector",
+  "dependencies": {
+    "pa11y": "^2.1.0"
+  },
+  "devDependencies": {},
+  "scripts": {
+    "test": "script/cibuild"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/benbalter/site-inspector.git"
+  },
+  "author": "",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/benbalter/site-inspector/issues"
+  },
+  "homepage": "https://github.com/benbalter/site-inspector#readme"
+}