'use strict';
const inherits = require('util').inherits;
const MongoError = require('mongodb-core').MongoError;
const Readable = require('stream').Readable;
const CoreCursor = require('./cursor');
const deprecate = require('util').deprecate;
const SUPPORTS = require('./utils').SUPPORTS;
/**
* @fileOverview The **AggregationCursor** class is an internal class that embodies an aggregation cursor on MongoDB
* allowing for iteration over the results returned from the underlying query. It supports
* one by one document iteration, conversion to an array or can be iterated as a Node 4.X
* or higher stream
*
* **AGGREGATIONCURSOR Cannot directly be instantiated**
* @example
* const MongoClient = require('mongodb').MongoClient;
* const test = require('assert');
* // Connection url
* const url = 'mongodb://localhost:27017';
* // Database Name
* const dbName = 'test';
* // Connect using MongoClient
* MongoClient.connect(url, function(err, client) {
* // Create a collection we want to drop later
* const col = client.db(dbName).collection('createIndexExample1');
* // Insert a bunch of documents
* col.insert([{a:1, b:1}
* , {a:2, b:2}, {a:3, b:3}
* , {a:4, b:4}], {w:1}, function(err, result) {
* test.equal(null, err);
* // Show that duplicate records got dropped
* col.aggregation({}, {cursor: {}}).toArray(function(err, items) {
* test.equal(null, err);
* test.equal(4, items.length);
* client.close();
* });
* });
* });
*/
/**
* Namespace provided by the browser.
* @external Readable
*/
/**
* Creates a new Aggregation Cursor instance (INTERNAL TYPE, do not instantiate directly)
* @class AggregationCursor
* @extends external:Readable
* @fires AggregationCursor#data
* @fires AggregationCursor#end
* @fires AggregationCursor#close
* @fires AggregationCursor#readable
* @return {AggregationCursor} an AggregationCursor instance.
*/
var AggregationCursor = function(bson, ns, cmd, options, topology, topologyOptions) {
CoreCursor.apply(this, Array.prototype.slice.call(arguments, 0));
var state = AggregationCursor.INIT;
var streamOptions = {};
// MaxTimeMS
var maxTimeMS = null;
// Get the promiseLibrary
var promiseLibrary = options.promiseLibrary || Promise;
// Set up
Readable.call(this, { objectMode: true });
// Internal state
this.s = {
// MaxTimeMS
maxTimeMS: maxTimeMS,
// State
state: state,
// Stream options
streamOptions: streamOptions,
// BSON
bson: bson,
// Namespace
ns: ns,
// Command
cmd: cmd,
// Options
options: options,
// Topology
topology: topology,
// Topology Options
topologyOptions: topologyOptions,
// Promise library
promiseLibrary: promiseLibrary,
// Optional ClientSession
session: options.session
};
};
/**
* AggregationCursor stream data event, fired for each document in the cursor.
*
* @event AggregationCursor#data
* @type {object}
*/
/**
* AggregationCursor stream end event
*
* @event AggregationCursor#end
* @type {null}
*/
/**
* AggregationCursor stream close event
*
* @event AggregationCursor#close
* @type {null}
*/
/**
* AggregationCursor stream readable event
*
* @event AggregationCursor#readable
* @type {null}
*/
// Inherit from Readable
inherits(AggregationCursor, Readable);
// Extend the Cursor
for (var name in CoreCursor.prototype) {
AggregationCursor.prototype[name] = CoreCursor.prototype[name];
}
if (SUPPORTS.ASYNC_ITERATOR) {
AggregationCursor.prototype[
Symbol.asyncIterator
] = require('./async/async_iterator').asyncIterator;
}
/**
* Set the batch size for the cursor.
* @method
* @param {number} value The batchSize for the cursor.
* @throws {MongoError}
* @return {AggregationCursor}
*/
AggregationCursor.prototype.batchSize = function(value) {
if (this.s.state === AggregationCursor.CLOSED || this.isDead())
throw MongoError.create({ message: 'Cursor is closed', driver: true });
if (typeof value !== 'number')
throw MongoError.create({ message: 'batchSize requires an integer', driver: true });
if (this.s.cmd.cursor) this.s.cmd.cursor.batchSize = value;
this.setCursorBatchSize(value);
return this;
};
/**
* Add a geoNear stage to the aggregation pipeline
* @method
* @param {object} document The geoNear stage document.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.geoNear = deprecate(function(document) {
this.s.cmd.pipeline.push({ $geoNear: document });
return this;
}, 'The `$geoNear` stage is deprecated in MongoDB 4.0, and removed in version 4.2.');
/**
* Add a group stage to the aggregation pipeline
* @method
* @param {object} document The group stage document.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.group = function(document) {
this.s.cmd.pipeline.push({ $group: document });
return this;
};
/**
* Add a limit stage to the aggregation pipeline
* @method
* @param {number} value The state limit value.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.limit = function(value) {
this.s.cmd.pipeline.push({ $limit: value });
return this;
};
/**
* Add a match stage to the aggregation pipeline
* @method
* @param {object} document The match stage document.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.match = function(document) {
this.s.cmd.pipeline.push({ $match: document });
return this;
};
/**
* Add a maxTimeMS stage to the aggregation pipeline
* @method
* @param {number} value The state maxTimeMS value.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.maxTimeMS = function(value) {
if (this.s.topology.lastIsMaster().minWireVersion > 2) {
this.s.cmd.maxTimeMS = value;
}
return this;
};
/**
* Add a out stage to the aggregation pipeline
* @method
* @param {number} destination The destination name.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.out = function(destination) {
this.s.cmd.pipeline.push({ $out: destination });
return this;
};
/**
* Add a project stage to the aggregation pipeline
* @method
* @param {object} document The project stage document.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.project = function(document) {
this.s.cmd.pipeline.push({ $project: document });
return this;
};
/**
* Add a lookup stage to the aggregation pipeline
* @method
* @param {object} document The lookup stage document.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.lookup = function(document) {
this.s.cmd.pipeline.push({ $lookup: document });
return this;
};
/**
* Add a redact stage to the aggregation pipeline
* @method
* @param {object} document The redact stage document.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.redact = function(document) {
this.s.cmd.pipeline.push({ $redact: document });
return this;
};
/**
* Add a skip stage to the aggregation pipeline
* @method
* @param {number} value The state skip value.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.skip = function(value) {
this.s.cmd.pipeline.push({ $skip: value });
return this;
};
/**
* Add a sort stage to the aggregation pipeline
* @method
* @param {object} document The sort stage document.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.sort = function(document) {
this.s.cmd.pipeline.push({ $sort: document });
return this;
};
/**
* Add a unwind stage to the aggregation pipeline
* @method
* @param {number} field The unwind field name.
* @return {AggregationCursor}
*/
AggregationCursor.prototype.unwind = function(field) {
this.s.cmd.pipeline.push({ $unwind: field });
return this;
};
/**
* Return the cursor logger
* @method
* @return {Logger} return the cursor logger
* @ignore
*/
AggregationCursor.prototype.getLogger = function() {
return this.logger;
};
AggregationCursor.prototype.get = AggregationCursor.prototype.toArray;
/**
* Get the next available document from the cursor, returns null if no more documents are available.
* @function AggregationCursor.prototype.next
* @param {AggregationCursor~resultCallback} [callback] The result callback.
* @throws {MongoError}
* @return {Promise} returns Promise if no callback passed
*/
/**
* Check if there is any document still available in the cursor
* @function AggregationCursor.prototype.hasNext
* @param {AggregationCursor~resultCallback} [callback] The result callback.
* @throws {MongoError}
* @return {Promise} returns Promise if no callback passed
*/
/**
* The callback format for results
* @callback AggregationCursor~toArrayResultCallback
* @param {MongoError} error An error instance representing the error during the execution.
* @param {object[]} documents All the documents the satisfy the cursor.
*/
/**
* Returns an array of documents. The caller is responsible for making sure that there
* is enough memory to store the results. Note that the array only contain partial
* results when this cursor had been previously accessed. In that case,
* cursor.rewind() can be used to reset the cursor.
* @method AggregationCursor.prototype.toArray
* @param {AggregationCursor~toArrayResultCallback} [callback] The result callback.
* @throws {MongoError}
* @return {Promise} returns Promise if no callback passed
*/
/**
* The callback format for results
* @callback AggregationCursor~resultCallback
* @param {MongoError} error An error instance representing the error during the execution.
* @param {(object|null)} result The result object if the command was executed successfully.
*/
/**
* Iterates over all the documents for this cursor. As with **{cursor.toArray}**,
* not all of the elements will be iterated if this cursor had been previously accessed.
* In that case, **{cursor.rewind}** can be used to reset the cursor. However, unlike
* **{cursor.toArray}**, the cursor will only hold a maximum of batch size elements
* at any given time if batch size is specified. Otherwise, the caller is responsible
* for making sure that the entire result can fit the memory.
* @method AggregationCursor.prototype.each
* @param {AggregationCursor~resultCallback} callback The result callback.
* @throws {MongoError}
* @return {null}
*/
/**
* Close the cursor, sending a AggregationCursor command and emitting close.
* @method AggregationCursor.prototype.close
* @param {AggregationCursor~resultCallback} [callback] The result callback.
* @return {Promise} returns Promise if no callback passed
*/
/**
* Is the cursor closed
* @method AggregationCursor.prototype.isClosed
* @return {boolean}
*/
/**
* Execute the explain for the cursor
* @method AggregationCursor.prototype.explain
* @param {AggregationCursor~resultCallback} [callback] The result callback.
* @return {Promise} returns Promise if no callback passed
*/
/**
* Clone the cursor
* @function AggregationCursor.prototype.clone
* @return {AggregationCursor}
*/
/**
* Resets the cursor
* @function AggregationCursor.prototype.rewind
* @return {AggregationCursor}
*/
/**
* The callback format for the forEach iterator method
* @callback AggregationCursor~iteratorCallback
* @param {Object} doc An emitted document for the iterator
*/
/**
* The callback error format for the forEach iterator method
* @callback AggregationCursor~endCallback
* @param {MongoError} error An error instance representing the error during the execution.
*/
/*
* Iterates over all the documents for this cursor using the iterator, callback pattern.
* @method AggregationCursor.prototype.forEach
* @param {AggregationCursor~iteratorCallback} iterator The iteration callback.
* @param {AggregationCursor~endCallback} callback The end callback.
* @throws {MongoError}
* @return {null}
*/
AggregationCursor.INIT = 0;
AggregationCursor.OPEN = 1;
AggregationCursor.CLOSED = 2;
module.exports = AggregationCursor;