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122 lines
4.1 KiB
JavaScript

5 years ago
'use strict';
const AggregationCursor = require('../aggregation_cursor');
const applyWriteConcern = require('../utils').applyWriteConcern;
const decorateWithCollation = require('../utils').decorateWithCollation;
const decorateWithReadConcern = require('../utils').decorateWithReadConcern;
const handleCallback = require('../utils').handleCallback;
const MongoError = require('mongodb-core').MongoError;
const resolveReadPreference = require('../utils').resolveReadPreference;
const toError = require('../utils').toError;
const DB_AGGREGATE_COLLECTION = 1;
/**
* Perform an aggregate operation. See Collection.prototype.aggregate or Db.prototype.aggregate for more information.
*
* @method
* @param {Db} db A Db instance.
* @param {Collection|string} coll A collection instance or the string '1', used for db.aggregate.
* @param {object} [pipeline=[]] Array containing all the aggregation framework commands for the execution.
* @param {object} [options] Optional settings. See Collection.prototype.aggregate or Db.prototype.aggregate for a list of options.
* @param {Db~aggregationCallback|Collection~aggregationCallback} callback The command result callback
*/
function aggregate(db, coll, pipeline, options, callback) {
const isDbAggregate = typeof coll === 'string';
const target = isDbAggregate ? db : coll;
const topology = target.s.topology;
let hasOutStage = false;
if (typeof options.out === 'string') {
pipeline = pipeline.concat({ $out: options.out });
hasOutStage = true;
} else if (pipeline.length > 0 && pipeline[pipeline.length - 1]['$out']) {
hasOutStage = true;
}
let command;
let namespace;
let optionSources;
if (isDbAggregate) {
command = { aggregate: DB_AGGREGATE_COLLECTION, pipeline: pipeline };
namespace = `${db.s.databaseName}.${DB_AGGREGATE_COLLECTION}`;
optionSources = { db };
} else {
command = { aggregate: coll.s.name, pipeline: pipeline };
namespace = coll.s.namespace;
optionSources = { db: coll.s.db, collection: coll };
}
const takesWriteConcern = topology.capabilities().commandsTakeWriteConcern;
if (!hasOutStage) {
decorateWithReadConcern(command, target, options);
}
if (pipeline.length > 0 && pipeline[pipeline.length - 1]['$out'] && takesWriteConcern) {
applyWriteConcern(command, optionSources, options);
}
try {
decorateWithCollation(command, target, options);
} catch (err) {
if (typeof callback === 'function') return callback(err, null);
throw err;
}
if (options.bypassDocumentValidation === true) {
command.bypassDocumentValidation = options.bypassDocumentValidation;
}
if (typeof options.allowDiskUse === 'boolean') command.allowDiskUse = options.allowDiskUse;
if (typeof options.maxTimeMS === 'number') command.maxTimeMS = options.maxTimeMS;
if (options.hint) command.hint = options.hint;
options = Object.assign({}, options);
// Ensure we have the right read preference inheritance
options.readPreference = resolveReadPreference(options, optionSources);
if (options.explain) {
if (command.readConcern || command.writeConcern) {
throw toError('"explain" cannot be used on an aggregate call with readConcern/writeConcern');
}
command.explain = options.explain;
}
if (typeof options.comment === 'string') command.comment = options.comment;
// Validate that cursor options is valid
if (options.cursor != null && typeof options.cursor !== 'object') {
throw toError('cursor options must be an object');
}
options.cursor = options.cursor || {};
if (options.batchSize && !hasOutStage) options.cursor.batchSize = options.batchSize;
command.cursor = options.cursor;
// promiseLibrary
options.promiseLibrary = target.s.promiseLibrary;
// Set the AggregationCursor constructor
options.cursorFactory = AggregationCursor;
if (typeof callback !== 'function') {
if (!topology.capabilities()) {
throw new MongoError('cannot connect to server');
}
return topology.cursor(namespace, command, options);
}
return handleCallback(callback, null, topology.cursor(namespace, command, options));
}
module.exports = {
aggregate
};