From 4108db894558daf12325dfed4c565094399c5f9b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jannis=20=C3=96tjengerdes?= <joetjengerdes@rightmart.de>
Date: Fri, 13 Jul 2018 16:18:25 +0200
Subject: [PATCH] fix: return null when findById/findOne returns 404
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Co-authored-by: Maxim Sharai <maxim.sharai@tispr.com>
Co-authored-by: Jannis Ötjengerdes <joetjengerdes@rightmart.de>
---
 lib/remote-connector.js    | 19 ++++++++++++++++++-
 test/remote-models.test.js | 38 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/lib/remote-connector.js b/lib/remote-connector.js
index eef404e..0e28c04 100644
--- a/lib/remote-connector.js
+++ b/lib/remote-connector.js
@@ -16,6 +16,8 @@ var jutil = require('loopback-datasource-juggler/lib/jutil');
 var RelationMixin = require('./relations');
 var InclusionMixin = require('loopback-datasource-juggler/lib/include');
 
+var findMethodNames = ['findById', 'findOne'];
+
 /**
  * Export the RemoteConnector class.
  */
@@ -120,6 +122,11 @@ function createProxyMethod(Model, remotes, remoteMethod) {
     } else {
       callback = utils.createPromiseCallback();
     }
+    var callbackPromise = callback.promise;
+
+    if (findMethodNames.includes(remoteMethod.name)) {
+      callback = proxy404toNull(callback);
+    }
 
     if (remoteMethod.isStatic) {
       remotes.invoke(remoteMethod.stringName, args, callback);
@@ -128,7 +135,17 @@ function createProxyMethod(Model, remotes, remoteMethod) {
       remotes.invoke(remoteMethod.stringName, ctorArgs, args, callback);
     }
 
-    return callback.promise;
+    return callbackPromise;
+  }
+
+  function proxy404toNull(cb) {
+    return function(err, data) {
+      if (err && err.code === 'MODEL_NOT_FOUND') {
+        cb(null, null);
+        return;
+      }
+      cb(err, data);
+    };
   }
 
   scope[remoteMethod.name] = remoteMethodProxy;
diff --git a/test/remote-models.test.js b/test/remote-models.test.js
index 1d1454f..edb1207 100644
--- a/test/remote-models.test.js
+++ b/test/remote-models.test.js
@@ -191,9 +191,8 @@ describe('Remote model tests', function() {
           ClientModel.deleteById(user.id, function(err) {
             if (err) return done(err);
             ClientModel.findById(user.id, function(err, notFound) {
+              if (err) return done(err);
               assert.equal(notFound, null);
-              assert(err && err.statusCode === 404,
-                'should have failed with HTTP 404');
               done();
             });
           });
@@ -202,6 +201,15 @@ describe('Remote model tests', function() {
   });
 
   describe('Model.findById(id, callback)', function() {
+    it('should return null when an instance does not exist',
+      function(done) {
+        ClientModel.findById(23, function(err, notFound) {
+          if (err) return done(err);
+          assert.equal(notFound, null);
+          done();
+        });
+      });
+
     it('should find an instance by id from the attached data source',
       function(done) {
         ServerModel.create({first: 'michael', last: 'jordan', id: 23},
@@ -218,6 +226,32 @@ describe('Remote model tests', function() {
       });
   });
 
+  describe('Model.findOne([filter], callback)', function() {
+    it('should return null when an instance does not exist',
+      function(done) {
+        ClientModel.findOne({where: {id: 24}}, function(err, notFound) {
+          if (err) return done(err);
+          assert.equal(notFound, null);
+          done();
+        });
+      });
+
+    it('should find an instance from the attached data source',
+      function(done) {
+        ServerModel.create({first: 'keanu', last: 'reeves', id: 24},
+          function(err) {
+            if (err) return done(err);
+            ClientModel.findOne({where: {id: 24}}, function(err, user) {
+              if (err) return done(err);
+              assert.equal(user.id, 24);
+              assert.equal(user.first, 'keanu');
+              assert.equal(user.last, 'reeves');
+              done();
+            });
+          });
+      });
+  });
+
   describe('Model.count([query], callback)', function() {
     it('should return the count of Model instances from both data source',
       function(done) {