Backport PR #8758

---------

**Commit 1:**
URI-encode forwarded location header in proxy

Right now there are situations in which ElasticSearch puts characters in
the character code range between 128 and 255 into the `Location` header.
This leads to an exception when trying to pass on that header through
the hapi proxy in versions before 15.0.0, because it validates that only
US-ASCII characters are used in headers.

To work around that situation, the `Location` header is encoded using
`encodeURI()` for now.

Closes #8705

* Original sha: 18c23c1
* Authored by Felix Stürmer <[email protected]> on 2016-10-18T17:55:31Z

**Commit 2:**
Add test to verify umlaut in vis name

Relates to #8705

* Original sha: e100e1f
* Authored by Felix Stürmer <[email protected]> on 2016-10-19T09:01:46Z

**Commit 3:**
[elasticsearch/proxy] use different code path with erorr

* Original sha: fec5e1a
* Authored by spalger <[email protected]> on 2016-10-19T19:06:39Z

src/core_plugins/elasticsearch/lib/create_proxy.js

@@ -20,7 +20,17 @@ function createProxy(server, method, route, config) {
         xforward: true,
         timeout: server.config().get('elasticsearch.requestTimeout'),
         onResponse: function (err, responseFromUpstream, request, reply) {
-          reply(err, responseFromUpstream);
+          if (err) {
+            reply(err);
+            return;
+          }
+
+          if (responseFromUpstream.headers.location) {
+            // TODO: Workaround for #8705 until hapi has been updated to >= 15.0.0
+            responseFromUpstream.headers.location = encodeURI(responseFromUpstream.headers.location);
+          }
+
+          reply(null, responseFromUpstream);
         }
       }
     },

test/functional/apps/visualize/_area_chart.js

@@ -74,6 +74,16 @@ bdd.describe('visualize app', function describeIndexTests() {
       });
     });
 
+    bdd.it('should save and load with non-ascii characters', async function () {
+      const vizNamewithSpecialChars = `${vizName1} with Umlaut ä`;
+      const message = await PageObjects.visualize.saveVisualization(vizNamewithSpecialChars);
+
+      PageObjects.common.debug(`Saved viz message with umlaut = ${message}`);
+      expect(message).to.be(`Visualization Editor: Saved Visualization "${vizNamewithSpecialChars}"`);
+
+      await PageObjects.visualize.waitForToastMessageGone();
+    });
+
     bdd.it('should save and load', function () {
       return PageObjects.visualize.saveVisualization(vizName1)
       .then(function (message) {