Simple Chat Room in NodeJS, expressJS and mongoDB in Docker Swarm
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4 years ago
'use strict';
const buildCountCommand = require('./common_functions').buildCountCommand;
const OperationBase = require('./operation').OperationBase;
class CountOperation extends OperationBase {
constructor(cursor, applySkipLimit, options) {
super(options);
this.cursor = cursor;
this.applySkipLimit = applySkipLimit;
}
execute(callback) {
const cursor = this.cursor;
const applySkipLimit = this.applySkipLimit;
const options = this.options;
if (applySkipLimit) {
if (typeof cursor.cursorSkip() === 'number') options.skip = cursor.cursorSkip();
if (typeof cursor.cursorLimit() === 'number') options.limit = cursor.cursorLimit();
}
// Ensure we have the right read preference inheritance
if (options.readPreference) {
cursor.setReadPreference(options.readPreference);
}
if (
typeof options.maxTimeMS !== 'number' &&
cursor.cmd &&
typeof cursor.cmd.maxTimeMS === 'number'
) {
options.maxTimeMS = cursor.cmd.maxTimeMS;
}
let finalOptions = {};
finalOptions.skip = options.skip;
finalOptions.limit = options.limit;
finalOptions.hint = options.hint;
finalOptions.maxTimeMS = options.maxTimeMS;
// Command
finalOptions.collectionName = cursor.namespace.collection;
let command;
try {
command = buildCountCommand(cursor, cursor.cmd.query, finalOptions);
} catch (err) {
return callback(err);
}
// Set cursor server to the same as the topology
cursor.server = cursor.topology.s.coreTopology;
// Execute the command
cursor.topology.command(
cursor.namespace.withCollection('$cmd'),
command,
cursor.options,
(err, result) => {
callback(err, result ? result.result.n : null);
}
);
}
}
module.exports = CountOperation;