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86 lines
2.5 KiB
86 lines
2.5 KiB
4 years ago
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'use strict';
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const Aspect = require('./operation').Aspect;
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const defineAspects = require('./operation').defineAspects;
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const CommandOperationV2 = require('./command_v2');
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const decorateWithCollation = require('../utils').decorateWithCollation;
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const decorateWithReadConcern = require('../utils').decorateWithReadConcern;
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/**
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* Return a list of distinct values for the given key across a collection.
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*
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* @class
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* @property {Collection} a Collection instance.
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* @property {string} key Field of the document to find distinct values for.
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* @property {object} query The query for filtering the set of documents to which we apply the distinct filter.
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* @property {object} [options] Optional settings. See Collection.prototype.distinct for a list of options.
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*/
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class DistinctOperation extends CommandOperationV2 {
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/**
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* Construct a Distinct operation.
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*
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* @param {Collection} a Collection instance.
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* @param {string} key Field of the document to find distinct values for.
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* @param {object} query The query for filtering the set of documents to which we apply the distinct filter.
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* @param {object} [options] Optional settings. See Collection.prototype.distinct for a list of options.
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*/
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constructor(collection, key, query, options) {
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super(collection, options);
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this.collection = collection;
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this.key = key;
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this.query = query;
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}
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/**
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* Execute the operation.
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*
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* @param {Collection~resultCallback} [callback] The command result callback
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*/
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execute(server, callback) {
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const coll = this.collection;
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const key = this.key;
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const query = this.query;
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const options = this.options;
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// Distinct command
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const cmd = {
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distinct: coll.collectionName,
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key: key,
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query: query
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};
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// Add maxTimeMS if defined
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if (typeof options.maxTimeMS === 'number') {
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cmd.maxTimeMS = options.maxTimeMS;
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}
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// Do we have a readConcern specified
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decorateWithReadConcern(cmd, coll, options);
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// Have we specified collation
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try {
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decorateWithCollation(cmd, coll, options);
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} catch (err) {
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return callback(err, null);
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}
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super.executeCommand(server, cmd, (err, result) => {
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if (err) {
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callback(err);
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return;
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}
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callback(null, this.options.full ? result : result.values);
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});
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}
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}
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defineAspects(DistinctOperation, [
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Aspect.READ_OPERATION,
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Aspect.RETRYABLE,
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Aspect.EXECUTE_WITH_SELECTION
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]);
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module.exports = DistinctOperation;
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