Develop Reference

Render API response body content with node.js

Working with Node.js, I wrote a router implementation as follows:
router.get('/fileshare', oauth2.required, (req, res, next) => {
var apiResponse = null;
// Consume GCP API
const queryObject = {
project: config.get('GCLOUD_PROJECT'),
prefix: 'msf-test-fs'
};
request.get({
url: 'https://www.googleapis.com/storage/v1/b',
qs: queryObject,
auth: {
'bearer': req.user.token
}
}, function(err, res) {
if (err) {
self.callback(err, null);
return;
}
console.log(res.body); // Has content
apiResponse = res.body
});
// Render content
// I WOULD LIKE TO HAVE HERE THE API RESPONSE BODY!!!
console.log(apiResponse); // Is null
res.render('pages/list', { }); // <<-- response body here as param
});
It basically invoke an API endpoint and retrieve an response body.
I would now like to pass the API response body to render a webpage.
However, the apiResponse is null while invoking console.log(apiResponse);.
How could I fix it?

The callback invoked by request is called asynchronously after res.render. You need to move res.render to the callback and stop shadowing res variable.
router.get('/fileshare', oauth2.required, (req, res, next) => {
// Consume GCP API
const queryObject = {
project: config.get('GCLOUD_PROJECT'),
prefix: 'msf-test-fs'
};
request.get({
url: 'https://www.googleapis.com/storage/v1/b',
qs: queryObject,
auth: {
'bearer': req.user.token
}
}, function(err, response) {
if (err) {
self.callback(err, null);
return;
}
console.log(response.body); // Has content
// Render content
console.log(response.body);
res.render('pages/list', JSON.parse(response.body)); // <<-- response body here as param
});
});

Node.JS with Express async API call

I'm using Node.JS with Express (and ejs for the views) and I want to call two API endpoints to render them in the same page and use the data. I've tried doing it with async but I get
ECONNRESET: Request could not be proxied!
This is my code
app.get('/profile', function(req, res) {
async.parallel([
function(next) {
var query = req.query.search;
var url = '1st url' + query;
var request = require('request');
request(url, function(error, body) {
var data = JSON.parse(body);
next(error, data);
});
},
function(next) {
request('2nd url', function(error, tlist) {
var list = JSON.parse(tlist);
next(error, list);
});
}], function(err, results) {
if (!err && results.statusCode == 200)
var data = results[0];
var list = results[1];
res.render('profile', {data: data, list: list});
});
});

Unsure about Cloud9, but if the issue is around parsing data, there's a couple of things here.
You should handle the error on each request before you attempt to parse; if parse throws an exception, your callback won't be executed:
request(url, function(error, body) {
if (error) return next(error);
var data = JSON.parse(body);
next(null, data);
});
You should probably also have a try/catch around the parse, and execute your callback with an error if there's an exception:
request(url, function(error, body) {
if (error) return next(error);
var data;
try {
data = JSON.parse(body);
} catch (e) {
return next(new Error('Unable to parse body for ' + url));
}
next(null, data);
});
Finally, your current check for results.statusCode will always return false, since it's an array, so you won't reach the end of the request. I'm guessing this is probably where the problem lies. I would also recommend passing any errors from async on to the Express error handler:
function(err, results) {
if (err) {
// pass to Express error handler...
}
var data = results[0];
var list = results[1];
res.render('profile', {data: data, list: list});
});

Node.JS server side script to update JSON file

I have partially written a NODE.JS file to update the JSON file with data received from the client. The post works successfully. The Get command does not. I was wondering if there's a better way to do this? I have about 6 different callback options to write for. All different. I was wondering if there's a node.JS script already done that has all of the things I need. Or if there's a different language that would make it easier.
Here's the NODE:
var http = require('http');
var fs = require('fs');
http.createServer(function (req, res) {
console.log('Request received: ');
if (req.method == 'POST') {
req.on('data', function (chunk) {
fs.writeFile("comments-data.json", chunk, function(err) {
if(err) {
return console.log(err);
}
console.log("The file was saved!");
})
});
res.end('{"msg": "success"}');
};
if (req.method == 'GET') {
req.on('data', function (chunk) {
fs.readFile('comments-data.json', 'utf8', function (err, data) {
if (err) throw err;
obj = JSON.parse(data);
return data;
});
});
res.end(data);
};
}).listen(8080, '127.0.0.1');
console.log('Server running at http://127.0.0.1:8080/');
Here's the AJAX call:
postComment: function(commentJSON, success, error) {
$.ajax({
type: 'post',
url: 'http://127.0.0.1:8080',
data: commentJSON,
success: function(comment) {
success(comment)
},
error: error
});
},
But there's an ajax call for all sorts of things with the jquery plugin that i'm using. I need to GET, POST, PUT, DELETE, and sometimes multiple within the call.
Here's a full list of all of the callbacks i'm using:
http://viima.github.io/jquery-comments/#link-3-6

Using express you can do this much easily.
const express = require('express');
const app = express.Router();
//POST Request
app.post('/',(req, res, next)=>{
fs.writeFile("comments-data.json", chunk, function(err) {
if(err) {
return console.log(err);
}
console.log("The file was saved!");
res.json({'status': 'Success'})
})
})
//GET Request
app.get('/',(req, res, next)=>{
fs.readFile('comments-data.json', 'utf8', function (err, data) {
if (err) throw err;
obj = JSON.parse(data);
res.json({'status': 'Success', 'data':data})
});
})
As for your question regarding writing it in a different module. That is based on the pattern adopted by you. There are various nodejs patterns available eg. Controller based or classes based. It all depends on what you find comfortable.

Node.js API returns JSON in terminal but not in browser

Having a strange problem. Been searching for answers but nothing turns up. I'm doing a node api tutorial and it returns JSON from my mongoDB database in my terminal when I perform any GET request but in my browser or postman I get nothing back, only in the terminal do I get any response. When I try a POST in postman it says it can't connect to the backend.
here is my code :
var http = require('http');
var url = require('url');
var database = require('./database');
// Generic find methods (GET)
function findAllResources(resourceName, req, res) {
database.find('OrderBase', resourceName, {}, function (err, resources) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resources));
});
};
var findResourceById = function (resourceName, id, req, res) {
database.find('OrderBase', resourceName, {'_id': id}, function (err, resource) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
});
};
// Product methods
var findAllProducts = function (req, res) {
findAllResources('Products', req, res);
};
var findProductById = function (id, req, res) {
findResourceById('Products', id, req, res);
};
// Generic insert/update methods (POST, PUT)
var insertResource = function (resourceName, resource, req, res) {
database.insert('OrderBase', resourceName, resource, function (err, resource) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
});
};
// Product methods
var insertProduct = function (product, req, res) {
insertResource('OrderBase', 'Product', product, function (err, result) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(result));
});
};
var server = http.createServer(function (req, res) {
// Break down the incoming URL into its components
var parsedURL = url.parse(req.url, true);
// determine a response based on the URL
switch (parsedURL.pathname) {
case '/api/products':
if (req.method === 'GET') {
// Find and return the product with the given id
if (parsedURL.query.id) {
findProductById(id, req, res)
}
// There is no id specified, return all products
else {
findAllProducts(req, res);
}
}
else if (req.method === 'POST') {
//Extract the data stored in the POST body
var body = '';
req.on('data', function (dataChunk) {
body += dataChunk;
});
req.on('end', function () {
// Done pulling data from the POST body.
// Turn it into JSON and proceed to store it in the database.
var postJSON = JSON.parse(body);
insertProduct(postJSON, req, res);
});
}
break;
default:
res.end('You shall not pass!');
}
});
server.listen(8080);
console.log('Up and running, ready for action!');

You have several callbacks with err as first argument but you are not treating any potential error. It means if something is going wrong, you are not catching it and returning an error. I don't know if this has anything to do with it, but as a practice (not even "best", but general practice) instead of doing this
function (err, resource) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
}
do this
function (err, resource) {
if(err){
// do something to warn the client and stop here
}
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
}
Try that, see if you are actually running into errors before trying to output an answer.

https://nodejs.org/api/http.html#http_response_end_data_encoding_callback
The response end method not send data to response socket. Maybe you change it
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
res.writeHead(200, {'Content-Type': 'application/json'});
res.write(JSON.stringify(resource));
res.end();
if you want socket to close to do something, you can into callback to end.
res.end(#logHandle());

var MongoClient = require('mongodb').MongoClient;
var assert = require('assert');
var connect = function (databaseName, callback) {
var url = 'mongodb://localhost:27017/' + databaseName;
MongoClient.connect(url, function (error, database) {
assert.equal(null, error);
console.log("Successfully connected to MongoDB instance!");
callback(database);
})
};
exports.find = function (databaseName, collectioName, query, callback) {
connect(databaseName, function (database) {
var collection = database.collection(collectioName);
collection.find(query).toArray(
function (err, documents) {
assert.equal(err, null);
console.log('MongoDB returned the following documents:');
console.dir(JSON.parse(JSON.stringify(documents)));
//console.dir(documents);
callback(null, documents);
}
)
database.close();
})
};
I think we are going through the same tutorial, this is my solution of 'database.js', works for me.

Send a response from a function to route in expressjs

I am trying to return JSON data from an api back along my route on an express server. I am a little confused about how nodejs handles this kind of operation. I have both a function and a route in the same file, the route works because I get the view returned, and the data I want in the console. The route and method look like this:
function getData() {
request(url, function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log(body) // Show the HTML for the Google homepage.
return response.body;
};
});
};
/* GET home page. */
router.get('/', function(req, res, next) {
res.render('index', { title: 'About', data: getData() });
});
I want the data from getData() in my response to the route. I thought this would do it but it will only print the data to the console and I can't see the problem.

That simply isn't possible due to the asynchronous nature of http requests. You'll have to instead restructure it to have a callback.
function getData(callback) {
request(url, function (error, response, body) {
if (error) {
return callback(error);
}
if (response.statusCode == 200) {
console.log(body) // Show the HTML for the Google homepage.
//return response.body;
callback(null, response.body);
} else {
callback(response.statusCode);
}
});
};
/* GET home page. */
router.get('/', function(req, res, next) {
getData(function (err, data) {
if (err) {
return next(err);
}
res.render('index', { title: 'About', data: data });
});
});