Allow the `customHTML` helper to look up fragments outside of the

preloadStore, so plugins can stuff HTML in there when overriding a whole
template doesn't make sense.

app/assets/javascripts/discourse/helpers/application_helpers.js

@@ -341,18 +341,13 @@ Ember.Handlebars.registerBoundHelper('date', function(dt) {
 });
 
 /**
-  Look for custom html content in the preload store.
+  Look for custom html content using `Discourse.HTML`
 
   @method customHTML
   @for Handlebars
 **/
 Handlebars.registerHelper('customHTML', function(property) {
-  var html = PreloadStore.get("customHTML");
-
-  if (html && html[property] && html[property].length) {
-    return new Handlebars.SafeString(html[property]);
-  }
-
+  return Discourse.HTML.getCustomHTML(property);
 });
 
 Ember.Handlebars.registerBoundHelper('humanSize', function(size) {

app/assets/javascripts/discourse/lib/html.js

@@ -1,12 +1,47 @@
 /**
-  Helpers to build HTML strings such as rich links to categories and topics.
+  Helpers to build HTML strings as well as custom fragments.
 
   @class HTML
   @namespace Discourse
   @module Discourse
 **/
+
+var customizations = {};
+
 Discourse.HTML = {
 
+  /**
+    Return a custom fragment of HTML by key. It can be registered via a plugin
+    using `setCustomHTML(key, html)`. This is used by a handlebars helper to find
+    the HTML content it wants. It will also check the `PreloadStore` for any server
+    side preloaded HTML.
+
+    @method getCustomHTML
+    @param {String} key to lookup
+  **/
+  getCustomHTML: function(key) {
+    var c = customizations[key];
+    if (c) {
+      return new Handlebars.SafeString(c);
+    }
+
+    var html = PreloadStore.get("customHTML");
+    if (html && html[key] && html[key].length) {
+      return new Handlebars.SafeString(html[key]);
+    }
+  },
+
+  /**
+    Set a fragment of HTML by key. It can then be looked up with `getCustomHTML(key)`.
+
+    @method setCustomHTML
+    @param {String} key to store the html
+    @param {String} html fragment to store
+  **/
+  setCustomHTML: function(key, html) {
+    customizations[key] = html;
+  },
+
   /**
     Returns the CSS styles for a category
 

test/javascripts/lib/html_test.js

@@ -1,7 +1,9 @@
 module("Discourse.HTML");
 
+var html = Discourse.HTML;
+
 test("categoryLink without a category", function() {
-  blank(Discourse.HTML.categoryLink(), "it returns no HTML");
+  blank(html.categoryLink(), "it returns no HTML");
 });
 
 test("Regular categoryLink", function() {
@@ -12,7 +14,7 @@ test("Regular categoryLink", function() {
         color: 'ff0',
         text_color: 'f00'
       }),
-      tag = parseHTML(Discourse.HTML.categoryLink(category))[0];
+      tag = parseHTML(html.categoryLink(category))[0];
 
   equal(tag.name, 'a', 'it creates an `a` tag');
   equal(tag.attributes['class'], 'badge-category', 'it has the correct class');
@@ -26,7 +28,7 @@ test("Regular categoryLink", function() {
 
 test("undefined color", function() {
   var noColor = Discourse.Category.create({ name: 'hello', id: 123 }),
-      tag = parseHTML(Discourse.HTML.categoryLink(noColor))[0];
+      tag = parseHTML(html.categoryLink(noColor))[0];
 
   blank(tag.attributes.style, "it has no color style because there are no colors");
 });
@@ -35,7 +37,18 @@ test("allowUncategorized", function() {
   var uncategorized = Discourse.Category.create({name: 'uncategorized', id: 345});
   this.stub(Discourse.Site, 'currentProp').withArgs('uncategorized_category_id').returns(345);
 
-  blank(Discourse.HTML.categoryLink(uncategorized), "it doesn't return HTML for uncategorized by default");
-  present(Discourse.HTML.categoryLink(uncategorized, {allowUncategorized: true}), "it returns HTML");
+  blank(html.categoryLink(uncategorized), "it doesn't return HTML for uncategorized by default");
+  present(html.categoryLink(uncategorized, {allowUncategorized: true}), "it returns HTML");
 });
 
+
+test("customHTML", function() {
+  blank(html.getCustomHTML('evil'), "there is no custom HTML for a key by default");
+
+  html.setCustomHTML('evil', 'trout');
+  equal(html.getCustomHTML('evil'), 'trout', 'it retrieves the custom html');
+
+  PreloadStore.store('customHTML', {cookie: 'monster'});
+  equal(html.getCustomHTML('cookie'), 'monster', 'it returns HTML fragments from the PreloadStore');
+
+});