node.js - Accessing >=2 collections from the same db connection using Mongo-lite results in error -
i trying access more single mongo collection same db connection using mongo-lite. here sample express app.
var express = require('express') ; var app = express(); var http = require('http'); var mongolite = require('mongo-lite'); db = mongolite.connect("mongodb://localhost/fnard", ['col1','col2']); app.use(express.bodyparser()); app.use(app.router); app.get('/', function(request, response){ db.collection('col1').insert({hi:5},function(){}); db.collection('col2').insert({hi:5},function(){}); console.log(request.body); // json response.send(request.body); // echo result }); http.createserver(app).listen(3000, function () { console.log('express server listening on port ' + '3000'); }); here error getting on doing on /:
error: server or replsetservers instance cannot shared across multiple db instances however if use following code inserts documents expected
var express = require('express') ; var app = express(); var http = require('http'); var mongolite = require('mongo-lite'); db = mongolite.connect("mongodb://localhost/fnard", ['col1']); db2 = mongolite.connect("mongodb://localhost/fnard", ['col2']); app.use(express.bodyparser()); app.use(app.router); app.get('/', function(request, response){ db.collection('col1').insert({hi:5},function(){}); db2.collection('col2').insert({hi:5},function(){}); console.log(request.body); // json response.send(request.body); // echo result }); do need create new connection each collection want access? mongo-lite docs seem suggest isn't case - .connect() option lets specify collections want use doesn't seem work.
a race condition giving error. following works me:
var express = require('express'); var app = express(); var http = require('http'); var mongolite = require('mongo-lite'); db = mongolite.connect("mongodb://localhost/fnard", ['col1','col2']); app.use(express.bodyparser()); app.use(app.router); app.get('/', function(request, response){ db.collection('col1').insert({hi:5},function(){ db.collection('col2').insert({hi:5},function(){ console.log(request.body); // json response.send(request.body); // echo result }); }); }); http.createserver(app).listen(3000, function () { console.log('express server listening on port ' + '3000'); }); you need nest callbacks. or, can use library async:
var express = require('express'); var async = require( 'async' ); var app = express(); var http = require('http'); var mongolite = require('mongo-lite'); db = mongolite.connect("mongodb://localhost/fnard", ['col1','col2']); app.use(express.bodyparser()); app.use(app.router); app.get('/', function(request, response){ async.series( [ // first insert function ( callback ) { db.collection('col1').insert({hi:5},callback); }, // second insert function ( callback ) { db.collection('col2').insert({hi:5},callback); } // send response ], function ( error, results ) { console.log(request.body); // json response.send(request.body); // echo result } ); }); http.createserver(app).listen(3000, function () { console.log('express server listening on port ' + '3000'); });
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