From 0af96636187d96fd2ceea3bbe22f0964a7026504 Mon Sep 17 00:00:00 2001
From: missprogrammer <missprogrammer94@gmail.com>
Date: Tue, 31 Jan 2017 06:17:23 +0330
Subject: [PATCH 1/2] Added support for the creation of views (db.createView)

---
 lib/db.js                   | 55 +++++++++++++++++++++++++++++++++++++
 test/functional/db_tests.js | 25 +++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/lib/db.js b/lib/db.js
index 3d10dc3f6b0..4b900eaa55b 100644
--- a/lib/db.js
+++ b/lib/db.js
@@ -594,6 +594,61 @@ Db.prototype.createCollection = function(name, options, callback) {
 
 define.classMethod('createCollection', {callback: true, promise:true});
 
+/**
+ * Create view on MongoDB 3.4 or higher
+ *
+ * @method
+ * @param {string} name Name of view
+ * @param {string} viewOn The name of the source collection or view from which to create the view. The name is not the full namespace of the collection or view; i.e. does not include the database name and implies the same database as the view to create on MongoDB 3.4 or higher.
+ * @param {array} pipeline An array that consists of the aggregation pipeline stage. create creates the view by applying the specified pipeline to the viewOn collection or view on MongoDB 3.4 or higher.
+ * @param {object} [options=null] Optional settings.
+ * @param {Db~resultCallback} [callback] The results callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+Db.prototype.createView = function(name, viewOn, pipeline, options, callback) {
+  var self = this;
+  if(typeof pipeline == 'function') callback = pipeline, pipeline = [];
+  if(typeof options == 'function') callback = options, options = {};
+  options = options || {};
+
+  // Create view command
+  var cmd = {'create': name};
+
+  if (viewOn == undefined) {
+    throw Error("Must specify a backing view or collection");
+  }
+
+  if (pipeline != undefined) {
+    if (!Array.isArray(pipeline)) {
+      pipeline = [pipeline];
+    }
+  }
+
+  cmd.pipeline = pipeline;
+  cmd.viewOn = viewOn;
+
+  // Check if the callback is in fact a string
+  if(typeof callback == 'function') return this.command(cmd, options, function(err, result) {
+    // Did the user destroy the topology
+    if(callback == null) return;
+    if(err) return handleCallback(callback, err, null);
+    handleCallback(callback, null, result.ok ? true : false);
+  });
+
+  // Execute the command
+  return new this.s.promiseLibrary(function(resolve, reject) {
+    // Execute command
+    self.command(cmd, options, function(err, result) {
+      // Did the user destroy the topology
+      if(err) return reject(err);
+      if(result.ok) return resolve(true);
+      resolve(false);
+    });
+  });
+}
+
+define.classMethod('createView', {callback: true, promise:true});
+
 /**
  * Get all the db statistics.
  *
diff --git a/test/functional/db_tests.js b/test/functional/db_tests.js
index 0bf9029d66a..e843c717351 100644
--- a/test/functional/db_tests.js
+++ b/test/functional/db_tests.js
@@ -539,3 +539,28 @@ exports['should correctly execute close function in order'] = {
     });
   }
 }
+
+/**
+ * @ignore
+ */
+exports.shouldCorrectlyGetErrorCreatingExistingView = {
+  metadata: { requires: { topology: ['single', 'replicaset', 'sharded', 'ssl', 'heap', 'wiredtiger'] } },
+
+  // The actual test we wish to run
+  test: function(configuration, test) {
+    var db = configuration.newDbInstance(configuration.writeConcernMax(), {poolSize:1, auto_reconnect:false});
+
+    // Establish connection to db
+    db.open(function(err, db) {
+      var _db = db.db("nonexistingdb");
+      // Let's create the view
+      _db.createView('test_create_view', 'test_resave_dbref', function(err, result) {
+        test.equal(null, err);
+        test.equal(true, result);
+
+        db.close();
+        test.done();
+      });
+    });
+  }
+}

From ca429d4d91ea0c6eeec34c8ccd07b27093e97528 Mon Sep 17 00:00:00 2001
From: missprogrammer <missprogrammer94@gmail.com>
Date: Fri, 3 Feb 2017 01:18:32 +0330
Subject: [PATCH 2/2] Fixed typo string to function

Callback should be a function to enter this scope. so it's can't be null
---
 lib/db.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/db.js b/lib/db.js
index 4b900eaa55b..3e1fd1382d5 100644
--- a/lib/db.js
+++ b/lib/db.js
@@ -627,10 +627,9 @@ Db.prototype.createView = function(name, viewOn, pipeline, options, callback) {
   cmd.pipeline = pipeline;
   cmd.viewOn = viewOn;
 
-  // Check if the callback is in fact a string
+  // Check if the callback is in fact a function
   if(typeof callback == 'function') return this.command(cmd, options, function(err, result) {
     // Did the user destroy the topology
-    if(callback == null) return;
     if(err) return handleCallback(callback, err, null);
     handleCallback(callback, null, result.ok ? true : false);
   });