meteor-mongodb-mapreduce-aggregation
Very simple implementation of some of mongodb aggregation framework functions for Meteor.
meteor-mongodb-mapreduce-aggregation is a fork of meteor-mongo-server based on meteor-mongo-extensions that do not expose the aggregation framework to the client, being available only on server side.
Unfortunately the original source was not working for me anymore as a plugin and seems to be not maintained. So I created this plugin and bugfixed it.
- Added
out: 'inline' support
It extends Collection
with 3 methods so far, mapReduce, distinct and aggregate, so that you can do:
col = new Meteor.Collection "name"
if Meteor.isServer
# mapReduce
map = function() {emit(this.Region, this.Amount);}
reduce = function(reg, am) { return Array.sum(am);};
col.mapReduce map, reduce, {out: "out_collection_name", verbose: true}, (err,res)->
console.dir res.stats # statistics object for running mapReduce
# distinct
result = col.distinct "Field Name"
console.dir result
#aggregate
result = col.aggregate pipeline
console.dir result
Another mapReduce example in javascript:
// on the server side
/////////////////////
Posts = new Mongo.Collection("Posts");
Tags = new Mongo.Collection("Tags");
Meteor.methods({
mostUsedTags: function() {
var map = function() {
if (!this.tags) {
return;
}
for (index in this.tags) {
emit(this.tags[index], 1);
}
}
var reduce = function(previous, current) {
var count = 0;
for (index in current) {
count += current[index];
}
return count;
}
// keep in mind that executing the mapReduce function will override every time the collection Tags
var result = Posts.mapReduce(map, reduce, {query: {}, out: "Tags", verbose: true});
// now return all the tags, ordered by usage
// as an alternative solution you can also publish the collection Tags and use this one at the client side
return Tags.find({},{ sort: {'value': -1}, limit:10}).fetch();
}
});
// on the client side you could do
//////////////////////////////////
Meteor.call("mostUsedTags", function(err, data) {
console.log(data);
});
To install it, run:
$ meteor add laboratory:mongodb-mapreduce-aggregation
This package is MIT Licensed. Do whatever you like with it but any responsibility for doing so is your own.