Add transform for decoding base64 strings. Closes elastic#4358

src/kibana/components/stringify/types/String.js

@@ -36,20 +36,31 @@ define(function (require) {
       { id: false, name: '- none -' },
       { id: 'lower', name: 'Lower Case' },
       { id: 'upper', name: 'Upper Case' },
-      { id: 'short', name: 'Short Dots' }
+      { id: 'short', name: 'Short Dots' },
+      { id: 'binary', name: 'Base64 Decode'}
     ];
 
     _String.sampleInputs = [
       'A Quick Brown Fox.',
       'com.organizations.project.ClassName',
-      'hostname.net'
+      'hostname.net',
+      'SGVsbG8gd29ybGQ='
     ];
 
+    _String.prototype._base64Decode = function (val) {
+      try {
+        return window.atob(val);
+      } catch (e) {
+        return _.asPrettyString(val);
+      }
+    };
+
     _String.prototype._convert = function (val) {
       switch (this.param('transform')) {
       case 'lower': return String(val).toLowerCase();
       case 'upper': return String(val).toUpperCase();
       case 'short': return _.shortenDottedString(val);
+      case 'binary': return this._base64Decode(val);
       default: return _.asPrettyString(val);
       }
     };

test/unit/specs/components/stringify/_string.js

@@ -0,0 +1,19 @@
+define(function (require) {
+  return ['String Format', function () {
+    var fieldFormats;
+
+    beforeEach(module('kibana'));
+    beforeEach(inject(function (Private) {
+      fieldFormats = Private(require('registry/field_formats'));
+    }));
+
+    it('decode a base64 string', function () {
+      var StringFormat = fieldFormats.getType('string');
+      var string = new StringFormat({
+        transform: 'binary'
+      });
+      expect(string.convert('Zm9vYmFy')).to.be('foobar');
+    });
+
+  }];
+});

test/unit/specs/components/stringify/index.js

@@ -3,6 +3,7 @@ define(function (require) {
     describe(require('specs/components/stringify/_conformance'));
     describe(require('specs/components/stringify/_ip'));
     describe(require('specs/components/stringify/_source'));
+    describe(require('specs/components/stringify/_string'));
     describe(require('specs/components/stringify/_url'));
   });
 });