无法使用流/highland.js 从结果中获取 mongodb 的数据

Question

I am new to streams and I am trying to fetch the data from my collection using reactive-superglue/highland.js ( https://github.com/santillaner/reactive-superglue ).

var sg = require("reactive-superglue")
var query = sg.mongodb("mongodb://localhost:27017/qatrackerdb").collection("test1")

exports.findAll = function (err, res) {
    query.find()
        .map(JSON.stringify)
        .done(function(data) {
            console.log(data)
            res.end(data)
        })
}

my curl request:

curl -i -X GET http://localhost:3000/queries/

Answer 1

Your code snippet does not work because highland.js's .done() does not return the result. You should either use Stream.each to iterate each element or Stream.toArray to get them all as an array.

BTW, I'm reactive-superglue's author. reactive-superglue is my (work-in-progress) take on real-world usage of highland's streams, built on top of highland.js

Cheers!

Answer 2

I was able to retrieve the payload using this approach, not sure if this is the best way, would greatly appreciate any other suggestions or explanations.

exports.findAll = function (err, res) {
    query.find()
        .map(JSON.stringify)
        .toArray(function(x){
          res.end(x + '')
        })
}

Answer 3

I'm not really sure what reactive-superglue is doing for you here. It looks like it's just a compilation of highland shortcuts for getting different data sources to respond.

You can use highland to do this directly like this:

var collection = sg.mongodb("mongodb://localhost:27017/qatrackerdb").collection("test1");
return h( collection.find({}) )
    .map(h.extend({foo: "bar"})
    .pipe(res);

Edit: The above snippet still uses reactive-superglue , but you could just use the node mongo driver:

var url = 'mongodb://localhost:27017/qatrackerdb';
MongoClient.connect(url, function(err, db) {
  h( db.collection("test1").find({}) )
    .map(h.extend({foo: "bar"})
    .pipe(res);
});