Support for virtual and host paths

lib/better_errors/editor.rb

@@ -70,12 +70,30 @@ def initialize(url_proc)
       @url_proc = url_proc
     end
 
-    def url(file, line)
+    def url(raw_path, line)
+      if virtual_path && raw_path.start_with?(virtual_path)
+        if host_path
+          file = raw_path.sub(%r{\A#{virtual_path}}, host_path)
+        else
+          file = raw_path.sub(%r{\A#{virtual_path}/}, '')
+        end
+      else
+        file = raw_path
+      end
+
       url_proc.call(file, line)
     end
 
     private
 
     attr_reader :url_proc
+
+    def virtual_path
+      @virtual_path ||= ENV['BETTER_ERRORS_VIRTUAL_PATH']
+    end
+
+    def host_path
+      @host_path ||= ENV['BETTER_ERRORS_HOST_PATH']
+    end
   end
 end

spec/better_errors/editor_spec.rb

@@ -230,4 +230,41 @@
       end
     end
   end
+
+  describe "#url" do
+    subject(:url) { described_instance.url("/full/path/to/lib/file.rb", 42) }
+    let(:described_instance) { described_class.for_formatting_string("%{file_unencoded}")}
+    before do
+      ENV['BETTER_ERRORS_VIRTUAL_PATH'] = virtual_path
+      ENV['BETTER_ERRORS_HOST_PATH'] = host_path
+    end
+    let(:virtual_path) { nil }
+    let(:host_path) { nil }
+
+    context "when $BETTER_ERRORS_VIRTUAL_PATH is set" do
+      let(:virtual_path) { "/full/path/to" }
+
+      context "when $BETTER_ERRORS_HOST_PATH is not set" do
+        let(:host_path) { nil }
+
+        it "removes the VIRTUAL_PATH prefix, making the path relative" do
+          expect(url).to eq("lib/file.rb")
+        end  
+      end
+
+      context "when $BETTER_ERRORS_HOST_PATH is set" do
+        let(:host_path) { '/Users/myname/Code' }
+
+        it "replaces the VIRTUAL_PATH prefix with the HOST_PATH" do
+          expect(url).to eq("/Users/myname/Code/lib/file.rb")
+        end  
+      end
+    end
+
+    context "when $BETTER_ERRORS_VIRTUAL_PATH is not set" do
+      it "does not alter file paths" do
+        expect(url).to eq("/full/path/to/lib/file.rb")
+      end
+    end
+  end
 end