Add post preview via uuid (/p/:uuid)

Refs #5097

- All drafts will show a preview link (this needs real css)
- Published posts will redirect
- prev/next post helpers only activate on published posts
- Powered by ~10 pints between the two of us (@ErisDS, @novaugust)

ghost/admin/app/models/post.js

@@ -35,6 +35,17 @@ var Post = DS.Model.extend(NProgressSaveMixin, ValidationEngine, {
         return this.get('ghostPaths.url').join(blogUrl, postUrl);
     }),
 
+    previewUrl: Ember.computed('uuid', 'ghostPaths.url', 'config.blogUrl', 'config.routeKeywords.preview', function () {
+        var blogUrl = this.get('config.blogUrl'),
+            uuid = this.get('uuid'),
+            previewKeyword = this.get('config.routeKeywords.preview');
+        // New posts don't have a preview
+        if (!uuid) {
+            return '';
+        }
+        return this.get('ghostPaths.url').join(blogUrl, previewKeyword, uuid);
+    }),
+
     scratch: null,
     titleScratch: null,
 

ghost/admin/app/styles/layouts/editor.scss

@@ -692,6 +692,13 @@ body.zen {
     }
 }//.post-settings-menu
 
+.post-preview-link {
+    position: absolute;
+    top: 0;
+    right: 0;
+    font-size: 1.3rem;
+}
+
 
 //
 // Post Settings Menu meta Data

ghost/admin/app/templates/post-settings-menu.hbs

@@ -11,6 +11,11 @@
             <form>
             <div class="form-group">
                 <label for="url">Post URL</label>
+                {{#if model.isDraft}}
+                <a class="post-preview-link" target="_blank" href="{{model.previewUrl}}">
+                    Preview<span class="icon-external"></span>
+                </a>
+                {{/if}}
                 <span class="input-icon icon-link">
                     {{gh-input class="post-setting-slug" id="url" value=slugValue name="post-setting-slug" focus-out="updateSlug" selectOnClick="true" stopEnterKeyDownPropagation="true"}}
                 </span>

ghost/admin/app/utils/config-parser.js

@@ -11,6 +11,8 @@ var isNumeric = function (num) {
             return false;
         } else if (isNumeric(val)) {
             return +val;
+        } else if (val.indexOf('{') === 0) {
+            return JSON.parse(val);
         } else {
             return val;
         }