From f8cd38564ac27d44d7605d71abce41b63c7bd4f6 Mon Sep 17 00:00:00 2001
From: Eric Adams <adams.ea@gmail.com>
Date: Fri, 19 Jun 2015 12:39:55 -0400
Subject: [PATCH] Add _expand parameter when retrieving single resource

---
 README.md     |  6 ++++++
 src/router.js | 15 +++++++++++++++
 test/index.js | 40 +++++++++++++++++++++++++++++++++++-----
 3 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index f8895b4..fa93499 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,12 @@ To embed other resources, add `_embed`.
 GET /posts/1?_embed=comments
 ```
 
+To expand related resources, add `_expand`.
+
+```
+GET /comments/1?_expand=posts
+```
+
 Returns database.
 
 ```
diff --git a/src/router.js b/src/router.js
index 1472c99..463cb1d 100644
--- a/src/router.js
+++ b/src/router.js
@@ -159,6 +159,7 @@ module.exports = function (source) {
   // GET /:resource/:id
   function show (req, res, next) {
     var _embed = req.query._embed
+    var _expand = req.query._expand
     var id = utils.toNative(req.params.id)
     var resource = db(req.params.resource)
       .getById(id)
@@ -168,6 +169,7 @@ module.exports = function (source) {
       resource = _.cloneDeep(resource)
       // Always use an array
       _embed = _.isArray(_embed) ? _embed : [_embed]
+      _expand = _.isArray(_expand) ? _expand : [_expand]
 
       // Embed other resources based on resource id
       _embed.forEach(function (otherResource) {
@@ -183,6 +185,19 @@ module.exports = function (source) {
         }
       })
 
+      // Expand inner resources based on id
+      _expand.forEach(function (innerResource) {
+
+        if (innerResource
+          && innerResource.trim().length > 0
+          && db.object[innerResource]) {
+          var query = {}
+          var prop = pluralize.singular(innerResource) + 'Id'
+          query.id = resource[prop]
+          resource[innerResource] = db(innerResource).where(query)
+        }
+      })
+
       res.locals.data = resource
     } else {
       res.status(404)
diff --git a/test/index.js b/test/index.js
index abc43b0..65d1bf7 100644
--- a/test/index.js
+++ b/test/index.js
@@ -24,12 +24,17 @@ describe('Server', function () {
       {id: 3, body: 'photo'}
     ]
 
+    db.users = [
+      {id: 1, username: 'Jim'},
+      {id: 2, username: 'George'}
+    ]
+
     db.comments = [
-      {id: 1, published: true, postId: 1},
-      {id: 2, published: false, postId: 1},
-      {id: 3, published: false, postId: 2},
-      {id: 4, published: false, postId: 2},
-      {id: 5, published: false, postId: 2}
+      {id: 1, published: true, postId: 1, userId: 1},
+      {id: 2, published: false, postId: 1, userId: 2},
+      {id: 3, published: false, postId: 2, userId: 1},
+      {id: 4, published: false, postId: 2, userId: 2},
+      {id: 5, published: false, postId: 2, userId: 1}
     ]
 
     db.refs = [
@@ -242,6 +247,31 @@ describe('Server', function () {
     })
   })
 
+  describe('GET /:resource/:id?_expand=', function () {
+    it('should respond with corresponding resource and expanded inner resources', function (done) {
+      var comments = db.comments[0]
+      comments.posts = [db.posts[0]]
+      request(server)
+        .get('/comments/1?_expand=posts')
+        .expect('Content-Type', /json/)
+        .expect(comments)
+        .expect(200, done)
+    })
+  })
+
+  describe('GET /:resource/:id?_expand=&_expand=', function () {
+    it('should respond with corresponding resource and expanded inner resources', function (done) {
+      var comments = db.comments[0]
+      comments.posts = [db.posts[0]]
+      comments.users = [db.users[0]]
+      request(server)
+        .get('/comments/1?_expand=posts&_expand=users')
+        .expect('Content-Type', /json/)
+        .expect(comments)
+        .expect(200, done)
+    })
+  })
+
   describe('POST /:resource', function () {
     it('should respond with json, create a resource and increment id',
       function (done) {