I'm migrating a project to Sails.js, I decided use Sails because I need to chaing many functions to single path and in it's documentation sais it is posible but I tryed a single example and I can not make it works, when I try to execute two functions on a path i got this error:
Error: next (as in req,res,next) should never be called in an action function (but in action algo/fn1, it was!) It was called with no arguments. Please use a method like res.ok() or res.json() instead.
What am I doing wrong or how can I make it works?
this is my code:
routes.js
// ...
'get /chain': [
'AlgoController.fn1',
'AlgoController.fn2'
],
// ...
AlgoController.js
let Controller = {};
Controller.fn1 = function(req, res, next) {
req.executed = ['executed fn1'];
next();
};
Controller.fn2 = function(req, res, next) {
req.executed.push('executed fn2');
res.send(req.executed.join(' and '));
};
module.exports = Controller;
If I delete the next() or use res.ok() / res.json(), the second function is never executed.
Well, I solved this using req.next() instead next(), so this is the code:
let Controller = {};
Controller.fn1 = function(req, res) {
req.executed = ['executed fn1'];
return req.next(); // this is how you call next fn
};
Controller.fn2 = function(req, res) {
req.executed.push('executed fn2');
res.send(req.executed.join(' and '));
};
module.exports = Controller;
This works well, hope this help somebody else.
Related
I'm a newbie trying to learn sails js, please bear with me.
As instructed in a tutorial I tried to set up my controllers and views to show a simple page just to make sure that the routing is working as expected.
So I have a PersonalController.js inside api/controllers folder. This was generated automatically from the generate cli command so I'm sure the location is correct.
Then I create a test view inside views/pages. I named it personal.ejs.
And so I modified my PersonalController to this
module.exports = {
list: function(req, res) {
return res.view('personal');
}
};
I don't know why but I'm getting an error.
I tried to just return json but I still get the same result, 404.
module.exports = {
list: function(req, res) {
return res.json({
todo: 'test'
});
}
};
I know I am missing something, just not sure what it is.
I would like to completely redefine res.render method in sailsjs app:
my template engine is not compatible with consolidate.
I decided to use hook for it, but can't understand, how I can to write my own realization of res.render.
Any thoughts or suggestions?
Thanks!
You can do the same as here lib/hooks/views/index.js (in your sails hook)
sails.on('router:before', function() {
sails.router.bind('/*', function(req, res, next) {
// here you can reimplement the res.render method, of example:
res.render = function render(data) {
// For access `req` data in your template engine,
// many useful info stored here like:
// req.options.controller – current `controller`
// req.options.action – current `action`
data.req = req;
var html = yourTemplateEngineRender(data);
res.set({
'Content-Type': 'text/html',
'Content-Length': Buffer.byteLength(html, 'utf8')
});
res.send(html);
}
}, 'all');
});
See my hook which enables bem rendering for sails: sails-hook-bem-render
I've tried to understand this post regarding this concept, however, I'm failing to get it. I have the following simple setup:
/server/test.js
Meteor.methods({
abc: function() {
var result = {};
result.foo = "Hello ";
result.bar = "World!";
return result;
}
});
/client/myapp.js
var q = Meteor.call('abc');
console.log(q);
This structure returns to the console undefined.
If I change the myapp.js file to:
Meteor.call('abc', function(err, data) {
!err ? console.log(data) : console.log(err);
}
I receive the Object in my console.
Ideally this is what I'd like to be able to do, but it doesn't work, stating in the console: Cannot read property 'greeting' of undefined
/client/myapp.js
var q = Meteor.call('abc');
Template.hello.greeting = function() {
return q.foo;
}
Any help in passing the data from the server object into the template would be greatly appreciated. I'm still learning JavaScript & Meteor.
Thanks!
From the Meteor.call documentation:
On the client, if you do not pass a callback and you are not inside a stub, call will return undefined, and you will have no way to get the return value of the method. That is because the client doesn't have fibers, so there is not actually any way it can block on the remote execution of a method.
So, you'll want to do it like this:
Meteor.call('abc', function(err, data) {
if (err)
console.log(err);
Session.set('q', data);
});
Template.hello.greeting = function() {
return Session.get('q').foo;
};
This will reactively update the template once the data is available.
This happens because Npm.require has Async behavior. That's the reason that you have to write a callback for Meteor.call.
But there is a solution, just use install(mrt add npm) and you'll get a function named Meteor.sync(//...) with this you can do both games: sync and async in your Meteor.call().
Reference: http://www.sitepoint.com/create-a-meteor-app-using-npm-module/
You can get the return value of a Meteor method for use in a template by using a reactive variable. Check out the working demonstration on Meteorpad
I went for a ghetto solution. But, it works for me, which is what matters, to me. Below is my code, which, in concept, I think, solves OP's problem.
In the client's main.js:
Meteor.setInterval(function() {
confirmLogin();
}, 5000);
This runs the confirmLogin() function every five seconds.
The confirmLogin function (in the client's main.js):
function confirmLogin() {
Meteor.call('loggedIn', function (error, result) {
Session.set("loggedIn", result);
});
}
The loggedIn method (in the server's main.js):
loggedIn: function () {
var toReturn = false;
var userDetails = Meteor.user();
if (typeof userDetails["services"] !== "undefined") {
if (typeof userDetails["services"]["facebook"] != "undefined") {
toReturn = true;
}
}
return toReturn;
},
The relevant helper:
loggedIn: function () {
return Session.get("loggedIn");
}
I am building a small app primarily with socket io, however with a few things from expressjs.
One function of the socket io piece is to send an email when a certain event occurs. I've got this working fine with node_mailer.
The problem I'm running into is that I want to use the express view engine to render the emails from template files. The render method seems to be explicitly attached to the res object prototype.
What I've done feels pretty dirty:
// setup express server
var render;
app.get('/', function (req, res) {
if (typeof render == 'undefined') render = res.render;
res.end('Welcome to app');
});
// socket io code
socket.on('event', function (data) {
var email_content;
render('template', {}, function (err, result) { email_content = result; });
});
Is there a better way to gain access to expressjs's components outside the context of an http request, or even a better way to approach this problem? I tried rigging up a call to the exported express.view.compile function but that both didn't work and seemed like a high hoo
Here is where the information you seek comes from:
https://github.com/Ravelsoft/node-jinjs/wiki
With templates as modules
To have node load your templates as if they were modules, you first have to register your module extension :
require("jinjs").registerExtension(".tpl");
If you want your file to be transformed prior to being submitted to jinjs, you can pass a callback ;
var pwilang = require("pwilang");
require("jinjs").registerExtension(".pwx", function (txt) {
return pwilang.parse(txt);
});
You can now write this to user Jin:
var my_template = require("./mytemplate");
var context = { foo: "foo", bar: "bar" };
var result = my_template.render(context);
Because you are sticking Jin into express (as opposed to making express work with Jin) this is your best option. The res variable is only available in the route callback.
On express 3.x there is the alias app.render
// socket io code
socket.on('event', function (data) {
var email_content;
app.render('template', {}, function (err, result) { email_content = result; });
});
Everything I can find for rending a page with mongoose results says to do it like this:
users.find({}, function(err, docs){
res.render('profile/profile', {
users: docs
});
});
How could I return the results from the query, more like this?
var a_users = users.find({}); //non-working example
So that I could get multiple results to publish on the page?
like:
/* non working example */
var a_users = users.find({});
var a_articles = articles.find({});
res.render('profile/profile', {
users: a_users
, articles: a_articles
});
Can this be done?
You're trying to force a synchronous paradigm. Just does't work. node.js is single threaded, for the most part -- when io is done, the execution context is yielded. Signaling is managed with a callback. What this means is that you either have nested callbacks, named functions, or a flow control library to make things nicer looking.
https://github.com/caolan/async#parallel
async.parallel([
function(cb){
users.find({}, cb);
},
function(cb){
articles.find({}, cb);
}
], function(results){
// results contains both users and articles
});
I'll play the necromancer here, as I still see another, better way to do it.
Using wonderful promise library Bluebird and its promisifyAll() method:
var Promise = require('bluebird');
var mongoose = require('mongoose');
Promise.promisifyAll(mongoose); // key part - promisification
var users, articles; // load mongoose models "users" and "articles" here
Promise.props({
users: users.find().execAsync(),
articles: articles.find().execAsync()
})
.then(function(results) {
res.render('profile/profile', results);
})
.catch(function(err) {
res.send(500); // oops - we're even handling errors!
});
Key parts are as follows:
Promise.promisifyAll(mongoose);
Makes all mongoose (and its models) methods available as functions returning promises, with Async suffix (.exec() becomes .execAsync(), and so on). .promisifyAll() method is nearly-universal in Node.JS world - you can use it on anything providing asynchronous functions taking in callback as their last argument.
Promise.props({
users: users.find().execAsync(),
articles: articles.find().execAsync()
})
.props() bluebird method takes in object with promises as its properties, and returns collective promise that gets resolved when both database queries (here - promises) return their results. Resolved value is our results object in the final function:
results.users - users found in the database by mongoose
results.articles - articles found in the database by mongoose (d'uh)
As you can see, we are not even getting near to the indentation callback hell. Both database queries are executed in parallel - no need for one of them to wait for the other. Code is short and readable - practically corresponding in length and complexity (or rather lack of it) to wishful "non-working example" posted in the question itself.
Promises are cool. Use them.
The easy way:
var userModel = mongoose.model('users');
var articleModel = mongoose.model('articles');
userModel.find({}, function (err, db_users) {
if(err) {/*error!!!*/}
articleModel.find({}, function (err, db_articles) {
if(err) {/*error!!!*/}
res.render('profile/profile', {
users: db_users,
articles: db_articles
});
});
});
Practically every function is asynchronous in Node.js. So is Mongoose's find. And if you want to call it serially you should use something like Slide library.
But in your case I think the easiest way is to nest callbacks (this allows f.e. quering articles for selected previously users) or do it completly parallel with help of async libraries (see Flow control / Async goodies).
I have a function that I use quite a bit as a return to Node functions.
function freturn (value, callback){
if(callback){
return callback(value);
}
return value;
};
Then I have an optional callback parameter in all of the signatures.
I was dealing with a very similar thing but using socket.io and DB access from a client. My find was throwing the contents of my DB back to the client before the database had a chance to get the data... So for what it's worth I will share my findings here:
My function for retrieving the DB:
//Read Boards - complete DB
var readBoards = function() {
var callback = function() {
return function(error, data) {
if(error) {
console.log("Error: " + error);
}
console.log("Boards from Server (fct): " + data);
}
};
return boards.find({}, callback());
};
My socket event listener:
socket.on('getBoards', function() {
var query = dbConnection.readBoards();
var promise = query.exec();
promise.addBack(function (err, boards) {
if(err)
console.log("Error: " + err);
socket.emit('onGetBoards', boards);
});
});
So to solve the problem we use the promise that mongoose gives us and then once we have received the data from the DB my socket emits it back to the client...
For what its worth...
You achieve the desired result by the following code. Hope this will help you.
var async = require('async');
// custom imports
var User = require('../models/user');
var Article = require('../models/article');
var List1Objects = User.find({});
var List2Objects = Article.find({});
var resourcesStack = {
usersList: List1Objects.exec.bind(List1Objects),
articlesList: List2Objects.exec.bind(List2Objects),
};
async.parallel(resourcesStack, function (error, resultSet){
if (error) {
res.status(500).send(error);
return;
}
res.render('home', resultSet);
});