🐛 Handle missing to-one related resource.

Correctly handle missing to-one related resource by returning a `null`
resource that following the specification (see
http://jsonapi.org/format/#fetching-relationships). Fixes #97.

Author: pmcnr-hx

example/resources/comments.js

@@ -35,6 +35,13 @@ jsonApi.define({
       body: "I like XML better",
       timestamp: "2017-06-20",
       author: { type: "people", id: "32fb0105-acaa-4adb-9ec4-8b49633695e1", meta: { created: "2010-01-01" } }
+    },
+    {
+      id: "2f716574-cef6-4238-8285-520911af86c1",
+      type: "comments",
+      body: "Wibble wibble.",
+      timestamp: "2017-12-31",
+      author: null
     }
   ]
 });

lib/postProcess.js

@@ -35,6 +35,9 @@ postProcess._fetchRelatedResources = function(request, mainResource, callback) {
 
   // Fetch the other objects
   var dataItems = mainResource[request.params.relation];
+
+  if (!dataItems) return callback(null, [ null ]);
+
   if (!(dataItems instanceof Array)) dataItems = [ dataItems ];
 
   var resourcesToFetch = dataItems.reduce(function(map, dataItem) {

lib/routes/related.js

@@ -57,7 +57,9 @@ relatedRoute.register = function() {
         }
         request.resourceConfig = jsonApi._resources[relation._settings.__one || relation._settings.__many];
         response = responseHelper._generateResponse(request, resourceConfig, relatedResources);
-        response.included = [ ];
+        if (relatedResources !== null) {
+          response.included = [ ];
+        }
         postProcess.handle(request, response, callback);
       }
     ], function(err) {

test/_preResourceValidationCheck.js

@@ -7,7 +7,7 @@ var jsonApiTestServer = require("../example/server.js");
 describe("Testing jsonapi-server", function() {
 
   [ { name: "articles", count: 4 },
-    { name: "comments", count: 2 },
+    { name: "comments", count: 3 },
     { name: "people", count: 4 },
     { name: "photos", count: 3 },
     { name: "tags", count: 5 }

test/get-resource-id-related.js

@@ -66,6 +66,23 @@ describe("Testing jsonapi-server", function() {
       });
     });
 
+    it("with null data", function(done) {
+      var url = "http://localhost:16006/rest/comments/2f716574-cef6-4238-8285-520911af86c1/author";
+      helpers.request({
+        method: "GET",
+        url: url
+      }, function(err, res, json) {
+        assert.equal(err, null);
+        json = helpers.validateJson(json);
+        assert.equal(res.statusCode, "200", "Expecting 200 OK");
+        assert.strictEqual(json.data, null);
+        assert(!("included" in json), "Null resource not NOT have `includes` attribute");
+
+        done();
+
+      });
+    });
+
     it("with fields", function(done) {
       var url = "http://localhost:16006/rest/articles/de305d54-75b4-431b-adb2-eb6b9e546014/author?fields[people]=email";
       helpers.request({

test/zzPostResourceValidationCheck.js

@@ -7,7 +7,7 @@ var jsonApiTestServer = require("../example/server.js");
 describe("Testing jsonapi-server", function() {
 
   [ { name: "articles", count: 4 },
-    { name: "comments", count: 1 },
+    { name: "comments", count: 2 },
     { name: "people", count: 4 },
     { name: "photos", count: 4 },
     { name: "tags", count: 5 }