Update MongoDB connector

lib/api-functions.js

@@ -196,7 +196,8 @@ function connectionRequest(deviceId, callback) {
     "CONNECTION_REQUEST_ALLOW_BASIC_AUTH",
     deviceId
   );
-  const proj = {
+  const options = {
+    projection: {
       "Device.ManagementServer.ConnectionRequestURL._value": 1,
       "Device.ManagementServer.UDPConnectionRequestAddress._value": 1,
       "Device.ManagementServer.ConnectionRequestUsername._value": 1,
@@ -205,9 +206,10 @@ function connectionRequest(deviceId, callback) {
       "InternetGatewayDevice.ManagementServer.UDPConnectionRequestAddress._value": 1,
       "InternetGatewayDevice.ManagementServer.ConnectionRequestUsername._value": 1,
       "InternetGatewayDevice.ManagementServer.ConnectionRequestPassword._value": 1
+    }
   };
 
-  db.devicesCollection.findOne({ _id: deviceId }, proj, (err, device) => {
+  db.devicesCollection.findOne({ _id: deviceId }, options, (err, device) => {
     if (err) return void callback(err);
     if (!device) return void callback(new Error("No such device"));
 
@@ -284,13 +286,19 @@ function connectionRequest(deviceId, callback) {
 
 function watchTask(deviceId, taskId, timeout, callback) {
   setTimeout(() => {
-    db.tasksCollection.findOne({ _id: taskId }, { _id: 1 }, (err, task) => {
+    db.tasksCollection.findOne(
+      { _id: taskId },
+      { projection: { _id: 1 } },
+      (err, task) => {
         if (err) return void callback(err);
 
         if (!task) return void callback(null, "completed");
 
         const q = { _id: `${deviceId}:task_${taskId}` };
-      db.faultsCollection.findOne(q, { _id: 1 }, (err, fault) => {
+        db.faultsCollection.findOne(
+          q,
+          { projection: { _id: 1 } },
+          (err, fault) => {
             if (err) return void callback(err);
 
             if (fault) return void callback(null, "fault");
@@ -298,8 +306,10 @@ function watchTask(deviceId, taskId, timeout, callback) {
             if ((timeout -= 500) <= 0) return void callback(null, "timeout");
 
             watchTask(deviceId, taskId, timeout, callback);
-      });
+          }
-    });
+        );
+      }
+    );
   }, 500);
 }
 
@@ -323,23 +333,23 @@ function insertTasks(tasks, callback) {
   for (const task of tasks) {
     sanitizeTask(task, t => {
       if (t.uniqueKey) {
-        db.tasksCollection.remove(
+        db.tasksCollection.deleteOne(
           { device: t.device, uniqueKey: t.uniqueKey },
           () => {}
         );
       }
 
-      if (--counter === 0) db.tasksCollection.insert(tasks, callback);
+      if (--counter === 0) db.tasksCollection.insertMany(tasks, callback);
     });
   }
 }
 
 function deleteDevice(deviceId, callback) {
-  db.tasksCollection.remove({ device: deviceId }, err => {
+  db.tasksCollection.deleteMany({ device: deviceId }, err => {
     if (err) return void callback(err);
-    db.devicesCollection.remove({ _id: deviceId }, err => {
+    db.devicesCollection.deleteOne({ _id: deviceId }, err => {
       if (err) return void callback(err);
-      db.faultsCollection.remove(
+      db.faultsCollection.deleteMany(
         {
           _id: {
             $regex: `^${common.escapeRegExp(deviceId)}\\:`
@@ -347,7 +357,7 @@ function deleteDevice(deviceId, callback) {
         },
         err => {
           if (err) return void callback(err);
-          db.operationsCollection.remove(
+          db.operationsCollection.deleteMany(
             {
               _id: {
                 $regex: `^${common.escapeRegExp(deviceId)}\\:`

lib/cache.js

@@ -23,7 +23,7 @@ const config = require("./config");
 const MAX_CACHE_TTL = config.get("MAX_CACHE_TTL");
 
 let redisClient;
-let mongoDb;
+let mongoClient;
 let mongoCollection;
 let mongoTimeOffset = 0;
 
@@ -49,15 +49,17 @@ function connect(callback) {
 
     mongodb.MongoClient.connect(
       MONGODB_CONNECTION_URL,
-      (err, db) => {
+      { useNewUrlParser: true },
+      (err, client) => {
         if (err) return void callback(err);
 
-        mongoDb = db;
+        const db = client.db();
+        mongoClient = client;
         mongoCollection = db.collection("cache");
-        mongoCollection.ensureIndex({ expire: 1 }, { expireAfterSeconds: 0 });
+        mongoCollection.createIndex({ expire: 1 }, { expireAfterSeconds: 0 });
 
         const now = Date.now();
-        mongoDb.command({ hostInfo: 1 }, (err, res) => {
+        db.command({ hostInfo: 1 }, (err, res) => {
           if (err) return void callback(err);
           mongoTimeOffset = res.system.currentTime.getTime() - now;
           exports.get = mongoGet;
@@ -74,8 +76,7 @@ function connect(callback) {
 
 function disconnect() {
   if (redisClient) redisClient.quit();
-
+  if (mongoClient) mongoClient.close();
-  if (mongoDb) mongoDb.close();
 }
 
 function redisGet(key, callback) {
@@ -171,8 +172,8 @@ function mongoGet(key, callback) {
 
 function mongoDel(key, callback) {
   if (Array.isArray(key))
-    mongoCollection.remove({ _id: { $in: key } }, callback);
+    mongoCollection.deleteMany({ _id: { $in: key } }, callback);
-  else mongoCollection.remove({ _id: key }, callback);
+  else mongoCollection.deleteOne({ _id: key }, callback);
 }
 
 function mongoSet(key, value, ttl, callback) {
@@ -184,24 +185,23 @@ function mongoSet(key, value, ttl, callback) {
   if (!ttl) ttl = MAX_CACHE_TTL;
 
   const expire = new Date(Date.now() - mongoTimeOffset + ttl * 1000);
-  mongoCollection.save({ _id: key, value: value, expire: expire }, callback);
+  mongoCollection.replaceOne(
+    { _id: key },
+    { _id: key, value: value, expire: expire },
+    { upsert: true },
+    callback
+  );
 }
 
 function mongoPop(key, callback) {
-  mongoCollection.findAndModify(
+  mongoCollection.findOneAndDelete({ _id: key }, (err, res) => {
-    { _id: key },
-    null,
-    null,
-    { remove: true },
-    (err, res) => {
     if (err || !res["value"]) return void callback(err);
 
     if (res["value"]["expire"] > new Date(Date.now() - mongoTimeOffset))
       return void callback(null, res["value"]["value"]);
 
     callback();
-    }
+  });
-  );
 }
 
 function mongoLock(lockName, ttl, callback) {
@@ -211,13 +211,13 @@ function mongoLock(lockName, ttl, callback) {
 
   function unlockOrExtend(extendTtl) {
     if (!extendTtl) {
-      mongoCollection.remove({ _id: lockName, value: token }, (err, res) => {
+      mongoCollection.deleteOne({ _id: lockName, value: token }, (err, res) => {
         if (err || res["result"]["n"] !== 1)
           throw err || new Error("Lock expired");
       });
     } else {
       const expire = new Date(Date.now() - mongoTimeOffset + extendTtl * 1000);
-      mongoCollection.update(
+      mongoCollection.updateOne(
         { _id: lockName, value: token },
         { expire: expire },
         (err, res) => {
@@ -231,7 +231,7 @@ function mongoLock(lockName, ttl, callback) {
   const expireTest = new Date(Date.now() - mongoTimeOffset);
   const expireSet = new Date(Date.now() - mongoTimeOffset + ttl * 1000);
 
-  mongoCollection.update(
+  mongoCollection.updateOne(
     { _id: lockName, expire: { $lte: expireTest } },
     { $set: { value: token, expire: expireSet } },
     { upsert: true },

lib/db.js

@@ -33,85 +33,39 @@ let tasksCollection,
   operationsCollection;
 
 function connect(callback) {
-  let callbackCounter = 9;
   mongodb.MongoClient.connect(
     config.get("MONGODB_CONNECTION_URL"),
-    (err, db) => {
+    { useNewUrlParser: true },
+    (err, client) => {
       if (err) return void callback(err);
+      exports.client = client;
+      const db = client.db();
 
-      exports.mongoDb = db;
+      exports.tasksCollection = tasksCollection = db.collection("tasks");
-      db.collection("tasks", (err, collection) => {
+      tasksCollection.createIndex({ device: 1, timestamp: 1 });
-        exports.tasksCollection = tasksCollection = collection;
-        if (collection != null)
-          collection.ensureIndex({ device: 1, timestamp: 1 });
 
-        if (--callbackCounter === 0 || err) {
+      exports.devicesCollection = devicesCollection = db.collection("devices");
-          callbackCounter = 0;
+      exports.presetsCollection = presetsCollection = db.collection("presets");
-          callback(err);
+      exports.objectsCollection = objectsCollection = db.collection("objects");
-        }
+      exports.filesCollection = filesCollection = db.collection("fs.files");
-      });
+      exports.provisionsCollection = provisionsCollection = db.collection(
-      db.collection("devices", (err, collection) => {
+        "provisions"
-        exports.devicesCollection = devicesCollection = collection;
+      );
-        if (--callbackCounter === 0 || err) {
+      exports.virtualParametersCollection = virtualParametersCollection = db.collection(
-          callbackCounter = 0;
+        "virtualParameters"
-          callback(err);
+      );
-        }
+      exports.faultsCollection = faultsCollection = db.collection("faults");
-      });
+      exports.operationsCollection = operationsCollection = db.collection(
-      db.collection("presets", (err, collection) => {
+        "operations"
-        exports.presetsCollection = presetsCollection = collection;
+      );
-        if (--callbackCounter === 0 || err) {
+
-          callbackCounter = 0;
+      callback();
-          callback(err);
-        }
-      });
-      db.collection("objects", (err, collection) => {
-        exports.objectsCollection = objectsCollection = collection;
-        if (--callbackCounter === 0 || err) {
-          callbackCounter = 0;
-          callback(err);
-        }
-      });
-      db.collection("fs.files", (err, collection) => {
-        exports.filesCollection = filesCollection = collection;
-        if (--callbackCounter === 0 || err) {
-          callbackCounter = 0;
-          callback(err);
-        }
-      });
-      db.collection("provisions", (err, collection) => {
-        exports.provisionsCollection = provisionsCollection = collection;
-        if (--callbackCounter === 0 || err) {
-          callbackCounter = 0;
-          callback(err);
-        }
-      });
-      db.collection("virtualParameters", (err, collection) => {
-        exports.virtualParametersCollection = virtualParametersCollection = collection;
-        if (--callbackCounter === 0 || err) {
-          callbackCounter = 0;
-          callback(err);
-        }
-      });
-      db.collection("faults", (err, collection) => {
-        exports.faultsCollection = faultsCollection = collection;
-        if (--callbackCounter === 0 || err) {
-          callbackCounter = 0;
-          callback(err);
-        }
-      });
-      db.collection("operations", (err, collection) => {
-        exports.operationsCollection = operationsCollection = collection;
-        if (--callbackCounter === 0 || err) {
-          callbackCounter = 0;
-          callback(err);
-        }
-      });
     }
   );
 }
 
 function disconnect() {
-  if (exports.mongoDb) exports.mongoDb.close();
+  if (exports.client) exports.client.close();
 }
 
 // Optimize projection by removing overlaps
@@ -279,12 +233,13 @@ function fetchDevice(id, timestamp, patterns, callback) {
     }
   }
 
-  let proj;
+  const options = {};
-  if (projection[""]) proj = {};
+  if (!projection[""]) {
-  else if (!Object.keys(projection).length) proj = { _id: 1 };
+    if (!Object.keys(projection).length) options.projection = { _id: 1 };
-  else proj = projection;
+    else options.projection = projection;
+  }
 
-  devicesCollection.findOne({ _id: id }, proj, (err, device) => {
+  devicesCollection.findOne({ _id: id }, options, (err, device) => {
     if (err || !device) return void callback(err);
 
     function storeParams(obj, path, ts, descendantsFetched, projTree) {
@@ -358,12 +313,14 @@ function fetchDevice(id, timestamp, patterns, callback) {
       }
 
       if (!descendantsFetched) {
+        if (projTree) {
           for (const k of Object.keys(projTree)) {
             const p = path.concat(k);
             loaded.push([p, ((1 << path.length) - 1) ^ ((1 << MAX_DEPTH) - 1)]);
             if ((obj["_object"] || !path.length) && obj["_timestamp"])
               res.push([p, obj["_timestamp"]]);
           }
+        }
       } else if ((obj["_object"] || !path.length) && obj["_timestamp"]) {
         res.push([path.concat("*"), obj["_timestamp"]]);
       }
@@ -740,26 +697,26 @@ function saveDevice(deviceId, deviceData, isNew, sessionTimestamp, callback) {
     delete update["$pull"];
   }
 
-  devicesCollection.update(
+  devicesCollection.updateOne(
     { _id: deviceId },
     update,
     { upsert: isNew },
     (err, result) => {
-      if (!err && result.result.n !== 1) {
+      if (err || result.result.n !== 1) {
         return void callback(
-          new Error(`Device ${deviceId} not found in database`)
+          err || new Error(`Device ${deviceId} not found in database`)
         );
       }
 
       if (update2) {
-        return void devicesCollection.update(
+        return void devicesCollection.updateOne(
           { _id: deviceId },
           update2,
           callback
         );
       }
 
-      callback(err);
+      callback();
     }
   );
 }
@@ -786,17 +743,18 @@ function getFaults(deviceId, callback) {
 }
 
 function saveFault(deviceId, channel, fault, callback) {
+  const id = `${deviceId}:${channel}`;
   fault = Object.assign({}, fault);
-  fault._id = `${deviceId}:${channel}`;
+  fault._id = id;
   fault.device = deviceId;
   fault.channel = channel;
   fault.timestamp = new Date(fault.timestamp);
   fault.provisions = JSON.stringify(fault.provisions);
-  faultsCollection.save(fault, callback);
+  faultsCollection.replaceOne({ _id: id }, fault, { upsert: true }, callback);
 }
 
 function deleteFault(deviceId, channel, callback) {
-  faultsCollection.remove({ _id: `${deviceId}:${channel}` }, callback);
+  faultsCollection.deleteOne({ _id: `${deviceId}:${channel}` }, callback);
 }
 
 function getDueTasks(deviceId, timestamp, callback) {
@@ -804,7 +762,7 @@ function getDueTasks(deviceId, timestamp, callback) {
   const tasks = [];
 
   let f;
-  cur.nextObject(
+  cur.next(
     (f = (err, task) => {
       if (err) return void callback(err);
 
@@ -835,17 +793,17 @@ function getDueTasks(deviceId, timestamp, callback) {
               task.fileName = res[0].filename || res[0]._id.toString();
           }
 
-          cur.nextObject(f);
+          cur.next(f);
         });
       } else {
-        cur.nextObject(f);
+        cur.next(f);
       }
     })
   );
 }
 
 function clearTasks(deviceId, taskIds, callback) {
-  tasksCollection.remove(
+  tasksCollection.deleteMany(
     { _id: { $in: taskIds.map(id => new mongodb.ObjectID(id)) } },
     callback
   );
@@ -873,17 +831,26 @@ function getOperations(deviceId, callback) {
 }
 
 function saveOperation(deviceId, commandKey, operation, callback) {
+  const id = `${deviceId}:${commandKey}`;
   operation = Object.assign({}, operation);
-  operation._id = `${deviceId}:${commandKey}`;
+  operation._id = id;
   operation.timestamp = new Date(operation.timestamp);
   operation.provisions = JSON.stringify(operation.provisions);
   operation.retries = JSON.stringify(operation.retries);
   operation.args = JSON.stringify(operation.args);
-  operationsCollection.save(operation, callback);
+  operationsCollection.replaceOne(
+    { _id: id },
+    operation,
+    { upsert: true },
+    callback
+  );
 }
 
 function deleteOperation(deviceId, commandKey, callback) {
-  operationsCollection.remove({ _id: `${deviceId}:${commandKey}` }, callback);
+  operationsCollection.deleteOne(
+    { _id: `${deviceId}:${commandKey}` },
+    callback
+  );
 }
 
 function getPresets(callback) {

lib/fs.js

@@ -27,19 +27,27 @@ function listener(request, response) {
   const urlParts = url.parse(request.url, true);
   if (request.method === "GET") {
     const filename = querystring.unescape(urlParts.pathname.substring(1));
-    const gs = new mongodb.GridStore(db.mongoDb, filename, "r", {});
+    db.filesCollection.findOne({ _id: filename }, (err, file) => {
-    gs.open(err => {
       if (err) {
+        response.writeHead(500, { Connection: "close" });
+        response.end(`${err.name}: ${err.message}`);
+        throw err;
+      }
+
+      if (!file) {
         response.writeHead(404);
         response.end();
         return;
       }
-      const stream = gs.stream(true);
+
       response.writeHead(200, {
-        "Content-Type": "application/octet-stream",
+        "Content-Type": file.contentType || "application/octet-stream",
-        "Content-Length": gs.length
+        "Content-Length": file.length
       });
-      stream.pipe(response);
+
+      const bucket = new mongodb.GridFSBucket(db.client.db());
+      const downloadStream = bucket.openDownloadStream(filename);
+      downloadStream.pipe(response);
     });
   } else {
     response.writeHead(405, { Allow: "GET" });

lib/nbi.js

@@ -83,7 +83,11 @@ function listener(request, response) {
       if (request.method === "PUT") {
         const preset = JSON.parse(body);
         preset._id = presetName;
-        db.presetsCollection.save(preset, err => {
+        db.presetsCollection.replaceOne(
+          { _id: presetName },
+          preset,
+          { upsert: true },
+          err => {
             if (err) return void throwError(err, response);
 
             cache.del("presets_hash", err => {
@@ -92,9 +96,10 @@ function listener(request, response) {
               response.writeHead(200);
               response.end();
             });
-        });
+          }
+        );
       } else if (request.method === "DELETE") {
-        db.presetsCollection.remove({ _id: presetName }, err => {
+        db.presetsCollection.deleteOne({ _id: presetName }, err => {
           if (err) return void throwError(err, response);
 
           cache.del("presets_hash", err => {
@@ -115,7 +120,11 @@ function listener(request, response) {
       if (request.method === "PUT") {
         const object = JSON.parse(body);
         object._id = objectName;
-        db.objectsCollection.save(object, err => {
+        db.objectsCollection.replaceOne(
+          { _id: objectName },
+          object,
+          { upsert: true },
+          err => {
             if (err) return void throwError(err, response);
 
             cache.del("presets_hash", err => {
@@ -124,9 +133,10 @@ function listener(request, response) {
               response.writeHead(200);
               response.end();
             });
-        });
+          }
+        );
       } else if (request.method === "DELETE") {
-        db.objectsCollection.remove({ _id: objectName }, err => {
+        db.objectsCollection.deleteOne({ _id: objectName }, err => {
           if (err) return void throwError(err, response);
 
           cache.del("presets_hash", err => {
@@ -158,7 +168,11 @@ function listener(request, response) {
           return;
         }
 
-        db.provisionsCollection.save(object, err => {
+        db.provisionsCollection.replaceOne(
+          { _id: provisionName },
+          object,
+          { upsert: true },
+          err => {
             if (err) return void throwError(err, response);
 
             cache.del("presets_hash", err => {
@@ -167,9 +181,10 @@ function listener(request, response) {
               response.writeHead(200);
               response.end();
             });
-        });
+          }
+        );
       } else if (request.method === "DELETE") {
-        db.provisionsCollection.remove({ _id: provisionName }, err => {
+        db.provisionsCollection.deleteOne({ _id: provisionName }, err => {
           if (err) return void throwError(err, response);
 
           cache.del("presets_hash", err => {
@@ -201,7 +216,11 @@ function listener(request, response) {
           return;
         }
 
-        db.virtualParametersCollection.save(object, err => {
+        db.virtualParametersCollection.replaceOne(
+          { _id: virtualParameterName },
+          object,
+          { upsert: true },
+          err => {
             if (err) return void throwError(err, response);
 
             cache.del("presets_hash", err => {
@@ -210,9 +229,10 @@ function listener(request, response) {
               response.writeHead(200);
               response.end();
             });
-        });
+          }
+        );
       } else if (request.method === "DELETE") {
-        db.virtualParametersCollection.remove(
+        db.virtualParametersCollection.deleteOne(
           { _id: virtualParameterName },
           err => {
             if (err) return void throwError(err, response);
@@ -234,7 +254,7 @@ function listener(request, response) {
       const deviceId = querystring.unescape(r[1]);
       const tag = querystring.unescape(r[2]);
       if (request.method === "POST") {
-        db.devicesCollection.update(
+        db.devicesCollection.updateOne(
           { _id: deviceId },
           { $addToSet: { _tags: tag } },
           { safe: true },
@@ -245,7 +265,7 @@ function listener(request, response) {
           }
         );
       } else if (request.method === "DELETE") {
-        db.devicesCollection.update(
+        db.devicesCollection.updateOne(
           { _id: deviceId },
           { $pull: { _tags: tag } },
           { safe: true },
@@ -267,12 +287,12 @@ function listener(request, response) {
         );
         const deviceId = faultId.split(":", 1)[0];
         const channel = faultId.slice(deviceId.length + 1);
-        db.faultsCollection.remove({ _id: faultId }, err => {
+        db.faultsCollection.deleteOne({ _id: faultId }, err => {
           if (err) return void throwError(err, response);
 
           if (channel.startsWith("task_")) {
             const objId = new mongodb.ObjectID(channel.slice(5));
-            return void db.tasksCollection.remove({ _id: objId }, err => {
+            return void db.tasksCollection.deleteOne({ _id: objId }, err => {
               if (err) return void throwError(err, response);
 
               cache.del(`${deviceId}_tasks_faults_operations`, err => {
@@ -396,7 +416,7 @@ function listener(request, response) {
         if (request.method === "DELETE") {
           db.tasksCollection.findOne(
             { _id: new mongodb.ObjectID(taskId) },
-            { device: 1 },
+            { projection: { device: 1 } },
             (err, task) => {
               if (err) return void throwError(err, response);
 
@@ -407,12 +427,12 @@ function listener(request, response) {
               }
 
               const deviceId = task.device;
-              db.tasksCollection.remove(
+              db.tasksCollection.deleteOne(
                 { _id: new mongodb.ObjectID(taskId) },
                 err => {
                   if (err) return void throwError(err, response);
 
-                  db.faultsCollection.remove(
+                  db.faultsCollection.deleteOne(
                     { _id: `${deviceId}:task_${taskId}` },
                     err => {
                       if (err) return void throwError(err, response);
@@ -437,12 +457,12 @@ function listener(request, response) {
         if (request.method === "POST") {
           db.tasksCollection.findOne(
             { _id: new mongodb.ObjectID(taskId) },
-            { device: 1 },
+            { projection: { device: 1 } },
             (err, task) => {
               if (err) return void throwError(err, response);
 
               const deviceId = task.device;
-              db.faultsCollection.remove(
+              db.faultsCollection.deleteOne(
                 { _id: `${deviceId}:task_${taskId}` },
                 err => {
                   if (err) return void throwError(err, response);
@@ -476,25 +496,19 @@ function listener(request, response) {
           productClass: request.headers.productclass,
           version: request.headers.version
         };
-        const gs = new mongodb.GridStore(db.mongoDb, filename, filename, "w", {
+        const bucket = new mongodb.GridFSBucket(db.client.db());
+        const uploadStream = bucket.openUploadStreamWithId(filename, filename, {
           metadata: metadata
         });
-        gs.open(err => {
+        uploadStream.end(body, err => {
-          if (err) return void throwError(err, response);
-
-          gs.write(body, err => {
-            if (err) return void throwError(err, response);
-
-            gs.close(err => {
           if (err) return void throwError(err, response);
 
           response.writeHead(201);
           response.end();
         });
-          });
-        });
       } else if (request.method === "DELETE") {
-        mongodb.GridStore.unlink(db.mongoDb, filename, err => {
+        const bucket = new mongodb.GridFSBucket(db.client.db());
+        bucket.delete(filename, err => {
           if (err) return void throwError(err, response);
 
           response.writeHead(200);
@@ -597,7 +611,7 @@ function listener(request, response) {
           projection[p.trim()] = 1;
       }
 
-      const cur = collection.find(q, projection, { batchSize: 50 });
+      const cur = collection.find(q, { projection: projection });
 
       if (urlParts.query.sort) {
         const s = JSON.parse(urlParts.query.sort);
@@ -613,9 +627,7 @@ function listener(request, response) {
 
       if (urlParts.query.skip) cur.skip(parseInt(urlParts.query.skip));
 
-      let limit;
+      if (urlParts.query.limit) cur.limit(parseInt(urlParts.query.limit));
-      if (urlParts.query.limit)
-        cur.limit((limit = parseInt(urlParts.query.limit)));
 
       cur.count(false, (err, total) => {
         if (err) return void throwError(err);
@@ -632,24 +644,16 @@ function listener(request, response) {
 
         response.write("[\n");
         i = 0;
-        cur.each((err, item) => {
+        cur.forEach(
-          if (err) {
+          item => {
-            throwError(err);
-            return false;
-          }
-
-          if (item) {
             if (i++) response.write(",\n");
             response.write(JSON.stringify(item));
-          }
+          },
-
+          err => {
-          if (!item || i >= limit) {
+            if (err) return void throwError(err);
             response.end("\n]");
-            return false;
           }
-
+        );
-          return null;
-        });
       });
     } else {
       response.writeHead(404);

package.json

@@ -21,7 +21,7 @@
   "dependencies": {
     "later": "^1.2.0",
     "libxmljs": "^0.18.7",
-    "mongodb": "^2.2.34",
+    "mongodb": "^3.1.10",
     "seedrandom": "^2.4.3"
   },
   "optionalDependencies": {