Don't pass external urls through createUrl

refs #4852, refs #4862, refs #4541

- fixes urlFor for the combination of an external url and a blog using a subdirectory

core/server/config/url.js

@@ -161,10 +161,6 @@ function urlFor(context, data, absolute) {
                 // mismatch in http/https etc, force absolute
                 urlPath = '/' + urlPath.split(hostname)[1];
                 absolute = true;
-            } else { // not hosted on this ghost instance, so
-                     // urls with protocols are already absolute
-                     // and otherwise respect the passed in value
-                absolute = (urlPath.indexOf('://') === -1) && absolute;
             }
         }
         // other objects are recognised but not yet supported
@@ -173,6 +169,11 @@ function urlFor(context, data, absolute) {
         urlPath = knownPaths[context] || '/';
     }
 
+    // This url already has a protocol so is likely an external url to be returned
+    if (urlPath && urlPath.indexOf('://') !== -1) {
+        return urlPath;
+    }
+
     return createUrl(urlPath, absolute, secure);
 }
 

core/test/unit/server_helpers/url_spec.js

@@ -142,4 +142,13 @@ describe('{{url}} helper', function () {
         should.exist(rendered);
         rendered.should.equal('http://testurl.com/blog/xyzzy');
     });
+
+    it('external urls should be retained in a nav context with subdir', function () {
+        utils.overrideConfig({url: 'http://testurl.com/blog'});
+        var rendered = helpers.url.call(
+            {url: 'http://casper.website/baz', label: 'Baz', slug: 'baz', current: true},
+            {hash: {absolute: 'true'}});
+        should.exist(rendered);
+        rendered.should.equal('http://casper.website/baz');
+    });
 });