Optimize model class methods

No Issue
- Reorder promise chains to defer database queries until they
  are needed.
- Execute database queries that are not dependent on each other in
  parallel instead of sequentially.
- Reduce the number of variables used to hold state across multiple
  promise blocks.
- Do not go async unless necessary.

core/server/models/post.js

@@ -340,8 +340,7 @@ Post = ghostBookshelf.Model.extend({
     findPage: function (options) {
         options = options || {};
 
-        var postCollection = Posts.forge(),
-            tagInstance = options.tag !== undefined ? ghostBookshelf.model('Tag').forge({slug: options.tag}) : false,
+        var tagInstance = options.tag !== undefined ? ghostBookshelf.model('Tag').forge({slug: options.tag}) : false,
             authorInstance = options.author !== undefined ? ghostBookshelf.model('User').forge({slug: options.author}) : false;
 
         if (options.limit && options.limit !== 'all') {
@@ -379,12 +378,6 @@ Post = ghostBookshelf.Model.extend({
             options.where.status = options.status;
         }
 
-        // If there are where conditionals specified, add those
-        // to the query.
-        if (options.where) {
-            postCollection.query('where', options.where);
-        }
-
         // Add related objects
         options.withRelated = _.union(options.withRelated, options.include);
 
@@ -405,12 +398,21 @@ Post = ghostBookshelf.Model.extend({
         }
 
         return Promise.join(fetchTagQuery(), fetchAuthorQuery())
-
             // Set the limit & offset for the query, fetching
             // with the opts (to specify any eager relations, etc.)
             // Omitting the `page`, `limit`, `where` just to be sure
             // aren't used for other purposes.
             .then(function () {
+                var postCollection = Posts.forge(),
+                    collectionPromise,
+                    countPromise,
+                    qb;
+
+                // If there are where conditionals specified, add those
+                // to the query.
+                if (options.where) {
+                    postCollection.query('where', options.where);
+                }
                 // If we have a tag instance we need to modify our query.
                 // We need to ensure we only select posts that contain
                 // the tag given in the query param.
@@ -431,22 +433,15 @@ Post = ghostBookshelf.Model.extend({
                         .query('offset', options.limit * (options.page - 1));
                 }
 
-                return postCollection
+                collectionPromise = postCollection
                     .query('orderBy', 'status', 'ASC')
                     .query('orderBy', 'published_at', 'DESC')
                     .query('orderBy', 'updated_at', 'DESC')
                     .fetch(_.omit(options, 'page', 'limit'));
-            })
 
-            // Fetch pagination information
-            .then(function () {
-                var qb,
-                    tableName = _.result(postCollection, 'tableName'),
-                    idAttribute = _.result(postCollection, 'idAttribute');
+                // Find the total number of posts
 
-                // After we're done, we need to figure out what
-                // the limits are for the pagination values.
-                qb = ghostBookshelf.knex(tableName);
+                qb = ghostBookshelf.knex('posts');
 
                 if (options.where) {
                     qb.where(options.where);
@@ -460,13 +455,13 @@ Post = ghostBookshelf.Model.extend({
                     qb.where('author_id', '=', authorInstance.id);
                 }
 
-                return qb.count(tableName + '.' + idAttribute + ' as aggregate');
-            })
+                countPromise = qb.count('posts.id as aggregate');
 
-            // Format response of data
-            .then(function (resp) {
-                var totalPosts = parseInt(resp[0].aggregate, 10),
+                return Promise.join(collectionPromise, countPromise);
+            }).then(function (results) {
+                var totalPosts = parseInt(results[1][0].aggregate, 10),
                     calcPages = Math.ceil(totalPosts / options.limit) || 0,
+                    postCollection = results[0],
                     pagination = {},
                     meta = {},
                     data = {};

core/server/models/tag.js

@@ -1,4 +1,5 @@
 var _              = require('lodash'),
+    Promise        = require('bluebird'),
     errors         = require('../errors'),
     ghostBookshelf = require('./base'),
     sitemap        = require('../data/sitemap'),
@@ -73,7 +74,10 @@ Tag = ghostBookshelf.Model.extend({
         options = options || {};
 
         var tagCollection = Tags.forge(),
-        tagTotal;
+            collectionPromise,
+            totalPromise,
+            countPromise,
+            qb;
 
         if (options.limit && options.limit !== 'all') {
             options.limit = parseInt(options.limit, 10) || 15;
@@ -98,43 +102,32 @@ Tag = ghostBookshelf.Model.extend({
                 .query('offset', options.limit * (options.page - 1));
         }
 
-        return tagCollection
-            .fetch(_.omit(options, 'page', 'limit'))
-        // Fetch pagination information
-        .then(function () {
-            var qb,
-                tableName = _.result(tagCollection, 'tableName'),
-                idAttribute = _.result(tagCollection, 'idAttribute');
+        collectionPromise = tagCollection.fetch(_.omit(options, 'page', 'limit'));
 
-            // After we're done, we need to figure out what
-            // the limits are for the pagination values.
-            qb = ghostBookshelf.knex(tableName);
+        // Find total number of tags
 
-            if (options.where) {
-                qb.where(options.where);
-            }
+        qb = ghostBookshelf.knex('tags');
 
-            return qb.count(tableName + '.' + idAttribute + ' as aggregate');
-        })
-        // Fetch post count information
-        .then(function (resp) {
-            var qb;
-            tagTotal = resp;
+        if (options.where) {
+            qb.where(options.where);
+        }
 
-            if (options.include) {
-                if (options.include.indexOf('post_count') > -1) {
-                    qb = ghostBookshelf.knex('posts_tags');
+        totalPromise = qb.count('tags.id as aggregate');
 
-                    return qb.select('tag_id').count('* as postCount').groupBy('tag_id');
-                }
-            } else {
-                return null;
+         // Fetch post count information
+
+        if (options.include) {
+            if (options.include.indexOf('post_count') > -1) {
+                qb = ghostBookshelf.knex('posts_tags');
+                countPromise = qb.select('tag_id').count('* as postCount').groupBy('tag_id');
             }
-        })
-        // Format response of data
-        .then(function (postsPerTagCollection) {
-            var totalTags = parseInt(tagTotal[0].aggregate, 10),
+        }
+
+        return Promise.join(collectionPromise, totalPromise, countPromise).then(function (results) {
+            var totalTags = results[1][0].aggregate,
                 calcPages = Math.ceil(totalTags / options.limit) || 0,
+                tagCollection = results[0],
+                postsPerTagCollection = results[2],
                 pagination = {},
                 meta = {},
                 data = {};
@@ -148,12 +141,12 @@ Tag = ghostBookshelf.Model.extend({
 
             data.tags = tagCollection.toJSON();
 
-            if (postsPerTagCollection !== null) {
+            if (postsPerTagCollection) {
                 // Merge two result sets
                 _.each(data.tags, function (tag) {
                     var postsPerTag = _.find(postsPerTagCollection, function (obj) { return obj.tag_id === tag.id; });
                     if (postsPerTag) {
-                        tag.post_count = parseInt(postsPerTag.postCount, 10);
+                        tag.post_count = postsPerTag.postCount;
                     } else {
                         tag.post_count = 0;
                     }