Error myFunction(...).then is not a function - javascript

I have the following module that basically performs a GET request to Google:
// my-module.js
var request = require('request');
var BPromise = require('bluebird');
module.exports = get;
function get() {
return BPromise.promisify(doRequest);
}
function doRequest(callback) {
request.get({
uri: "http://google.com",
}, function (err, res, body) {
if (!err && res.statusCode == 200) {
callback(null, body);
}
else {
callback(err, null);
}
});
}
And I want to use this module like so:
//use-module.js
var myModule = require('./my-module');
myModule().then(function (body) {
console.log(body);
});
The error I'm facing is the following:
myModule(...).then is not a function.
What am I doing wrong?

BPromise.promisify(doRequest) does not call doRequest, but returns a "promisified" version of that function. You should do that once, not at each call. This should work:
module.exports = BPromise.promisify(doRequest);

Related

Unable to initiate the route from the beginning after else statement deadend

Firstly, I'm sorry if this has been posted before. I searched but couldn't find any credible solution.
So I'm working on this route in nodejs where I make an API call for a piece of information and then using that info in an if statement to check if it's the correct info(the server sometimes sends wrong info).
If I get the correct info then I use that in another API to get more info about it and render it into my template. Everything works fine.
But I want the first API call to take place again if the info doesn't match or it's wrong. How can I initiate the API call again from the start(like a loop) and it will break only if the info is correct. Please check the "comment" in the code below. That is where I don't know what to put. Your help would be highly appreciated.
PS. I am a beginner in nodejs and javascript.
Route
router.get("/check", (req, res) => {
if(req.query.search) {
var input = req.query.search;
var url = "http://firstapi.com/json/" + input + "?fields=query";
request(url, function(error, response, body) {
if(!error && response.statusCode === 200) {
var data = JSON.parse(body);
if(data.query.match(/((^|\.)((25[0-5])|(2[0-4]\d)|(1\d\d)|([1-9]?\d))){4}$/)){
var url = "https://secondapi.com/" + data.query + "?key=something";
request(url, function(error, response, body) {
if(!error && response.statusCode === 200) {
var Data = JSON.parse(body);
res.render("index", {data: Data});
}
});
}else{
//want to use the input at the top and check the firstapi again. All the code above should run again until its the correct one which I will use in my template.
}
}
});
}else{
res.render("index", {data: null});
}
});
I would probably do it this way:
router.get('/check', (req, res) => {
if (req.query.search) {
var input = req.query.search;
// Put this logic away in a `checkData` function
checkData(input)
.then(data => {
res.render('index', { data }); // Short version of {data: data}
})
.catch(err => {
console.error(err);
res.render('index', { data: null });
});
} else {
res.render('index', { data: null });
}
});
// Here, we have a `retries` parameter, set to 0 initially
function checkData (input, retries = 0) {
const maxRetries = 3;
// Return a promise (you could also use callbacks)
return new Promise((resolve, reject) => {
// Define a retry method
const retry = () => {
if (retries < maxRetries) {
// Increment the retries count and go for another try
checkData(input, retries + 1).then(resolve).catch(reject);
} else {
reject(`Could not get the data after ${retries} retries.`);
}
};
var url = `http://firstapi.com/json/${input}?fields=query`;
request(url, function (error, response, body) {
if (!error && response.statusCode === 200) {
var data = JSON.parse(body);
if (data.query.match(/((^|\.)((25[0-5])|(2[0-4]\d)|(1\d\d)|([1-9]?\d))){4}$/)) {
var url = 'https://secondapi.com/' + data.query + '?key=something';
request(url, function (error, response, body) {
if (!error && response.statusCode === 200) {
var Data = JSON.parse(body);
// If it worked, resolve with the data
resolve(Data);
} else {
retry();
}
});
} else {
retry();
}
}
});
});
}

Async.waterfall function gets called twice

I have an async waterfall Array where the function otherIngrLists() is the 3rd to be executed. Every function before that worked fine.
function otherIngrLists(userslist, callback){
collection = db.get('ingrList');
collection.find({"userid":{$ne:userid}},{},function(err,docs){
if(!err){
var otherLists = docs;
var otherListsCount = docs.count();
console.log(otherListsCount);
callback(null, otherLists, otherListsCount, userslist);
} else {
callback(err, null);
}
});
},
The Problem is that this function is called twice. I assured this with a simple console.log().
How did I manage to call this function again? Did I get the concept of callbacks wrong as I use them to be passed on to the next function?
Also after this function executing twice an error ist thrown. It has nothing to to with this problem though and I will concern my self with that later.
Thank you for your time!
Waterfall Array in router.get:
router.get('/:userid', function(req, res) {
var db = req.db;
var collection;
var userid = req.params.userid;
async.waterfall(
[
function getIngrList(callback, userid) {
var route = 'http://localhost:3000/users/zutatenliste/'+userid;
request(route, function(err, response, body){
if (!err && response.statusCode === 200) {
var userlist = body;
callback(null, userlist);
} else {
callback(err, null);
return;
}
});
},
function otherIngrLists(userlist, callback){
collection = db.get('zutatenListe');
console.log(userid);
collection.find({"userid":{$ne:userid}},{},function(err,docs){
if(!err){
var otherLists = docs;
var otherListsCount = docs.count();
callback(null, otherLists, otherListsCount, userlist);
} else {
callback(err, null);
}
});
},
function pushInArray(otherLists, otherListsCount, userlist, callback){
console.log("test");
...
...}
}
}
Edit 1: --Also either if cases are executed, first the true one then the false--
// Does not happen anymore
Edit 2: Added the whole Thing until the problematic function
Please provide some Additional details as this function seems perfect and No, You haven't misunderstood the concept of callback you are using it correctly.
Structure of Async Waterfall
var create = function (req, res) {
async.waterfall([
_function1(req),
_function2,
_function3
], function (error, success) {
if (error) { alert('Something is wrong!'); }
return alert('Done!');
});
};
function _function1 (req) {
return function (callback) {
var something = req.body;
callback (null, something);
}
}
function _function2 (something, callback) {
return function (callback) {
var somethingelse = function () { // do something here };
callback (err, somethingelse);
}
}
function _function3 (something, callback) {
return function (callback) {
var somethingmore = function () { // do something here };
callback (err, somethingmore);
}
}
so, in waterfall you can pass the values to the next function and your 3rd function is correct.
Edited
async.waterfall(
[
//can not give userId as second parameter
function getIngrList(callback) {
//if you want userId you can pass as I shown above or directly use here if it's accessible
var route = 'http://localhost:3000/users/zutatenliste/'+userid;
request(route, function(err, response, body){
if (!err && response.statusCode === 200) {
var userlist = body;
callback(null, userlist);
} else {
callback(err, null);
// return; no need
}
});
},
function otherIngrLists(userlist, callback){
collection = db.get('zutatenListe');
console.log(userid);
collection.find({"userid":{$ne:userid}},{},function(err,docs){
if(!err){
var otherLists = docs;
var otherListsCount = docs.count();
callback(null, otherLists, otherListsCount, userlist);
} else {
callback(err, null);
}
});
},
function pushInArray(otherLists, otherListsCount, userlist, callback){
console.log("test");
...
...}
As said you can not pass userId as last parameter over there. Let me know if you still get the same error.
First you need to declare you function:
function myFuntion(userId, callback) {
async.waterfall([
function(callback) {
//do some thing here
callback(null, userlist);
}, function(userId, callback) {
//do something here
callback(null, orderList, orderListCount, userlist);
}
], function(err, orderList, orderListCount, userlist) {
if(err)
console.log(err);
else
callback(orderList, orderList, userlist);
})
}
After that you can use function:
myFuntion(userId, function(orderList, orderListCount, userlist) {
console.log(orderList);
console.log(orderListCount);
console.log(userlist);
})

Cannot unit test JavaScript functions with Tape/ Sinon

I have a module that I want to test using Tape and Sinon. Unfortunately I'm not doing very well. Here is the module code:
let config = require('./config');
let request = require('request');
let restify = require('restify');
let certificateUtils = require('utilities');
const validateTheToken = function (token, requestId, callback) {
const options = {
url: config.userServiceRootUrl + config.validationPath,
method: 'POST',
headers: {
'token': token,
'caller': config.callingService,
'x-request-id': requestId
}
};
if (typeof process.env.CA_STORE !== 'undefined') {
const certAuth = process.env.CA_STORE + '/trustedCA.pem';
options.ca = certificateUtils.getAuthorisedCerts(certAuth);
}
request(options, function (error, response, body) {
callback(error, response, body);
});
};
// add token validation middleware
const authenticateTheToken = function (req, res, next) {
if (config.enableTokenValidation) {
const receivedToken = getToken(req);
if (!receivedToken) {
return next(new restify.NotAuthorizedError('No token'));
}
validateTheToken(receivedToken, req.requestId, function (err, response, body) {
if (err || response.statusCode != 200) {
req.logger.error({
err: err,
response: response ? {
statusCode: response.statusCode,
statusMessage: response.statusMessage,
body: body
} : undefined,
}, 'validation failed');
return next(new restify.NotAuthorizedError('Not a valid token'));
} else {
return next();
}
});
}
else {
return next();
}
};
function getTheToken(req) {
if (req.headers.token) {
return req.headers.token;
} else if (req.headers.user) {
req.logger.warn({req, user: req.headers.user}, `request was sent with header 'user'`);
try {
return JSON.parse(req.headers.user).token;
} catch (e) {
req.logger.warn({user: req.headers.user}, `is not valid JSON`);
return null;
}
} else {
return null;
}
}
module.exports = {getTheToken, authenticateTheToken};
How could I first of all unit test that authenticateTheToken has been called? Here is my attempt:
test('accessed authenticateTheToken', function (t) {
const tokenAuthentication = require('../tokenAuthentication');
const authenticateToken = tokenAuth.authenticateToken;
let req = {
headers: {
token: 1
}
};
let res = {};
let next = {};
let stub = sinon.stub(tokenAuth, 'getToken');
stub.yields('next');
authenticateToken(req, res, next);
t.equal(authenticateToken.callCount, 1);
t.end();
});
When I run the test I cam getting the following error:
C:\source\my-project\tokenAuthentication.js:40
req.logger.error({
^
TypeError: Cannot read property 'error' of undefined
at C:\source\my-project\tokenAuthentication.js:40:19
at Request._callback (C:\source\my-project\tokenAuthentication.js:25:5)
at self.callback (C:\source\my-project\node_modules\request\request.js:188:22)
at emitOne (events.js:96:13)
at Request.emit (events.js:188:7)
at Request.init (C:\source\my-project\node_modules\request\request.js:234:17)
at new Request (C:\source\my-project\node_modules\request\request.js:130:8)
at request (C:\source\my-project\node_modules\request\index.js:54:10)
at validateTheToken (C:\source\my-project\tokenAuthentication.js:24:3)
at authenticateTheToken (C:\source\tokenAuthentication.js:38:5)
npm ERR! Test failed. See above for more details.
You are mocking req here, so req in your test needs to have all of the properties of req in your code. This would include the logger.
req = {
...
logger: {
warn: () => {},
error: () => {},
}
}
req probably has a lot of properties, so you may either want to create a real Request object or use another library for mocking http requests such as nock

Multiple node.js requests

My controller is using the request package to make server-side HTTP requests to another API. My question is how can I make MULTIPLE of these requests? Here is my current code:
** UPDATED CODE **
module.exports = function (req, res) {
var context = {};
request('http://localhost:3000/api/single_project/' + req.params.id, function (err, resp1, body) {
context.first = JSON.parse(body);
request('http://localhost:3001/api/reports/' + req.params.id, function (err, resp2, body2) {
context.second = JSON.parse(body2); //this line throws 'SyntaxError: Unexpected token u' error
res.render('../views/project', context);
});
});
};
I need to make two more of those calls and send the data returned from it to my template...
Can someone help?
Thanks in advance!
function makePromise (url) {
return Promise(function(resolve, reject) {
request(url, function(err, resp, body) {
if (err) reject(err);
resolve(JSON.parse(body));
});
});
}
module.exprts = function (req, res) {
let urls = ['http://localhost:3000/api/1st',
'http://localhost:3000/api/2st',
'http://localhost:3000/api/3st'].map((url) => makePromise(url));
Promise
.all(urls)
.then(function(result) {
res.render('../views/project', {'first': result[0], 'second': result[1], 'third': result[2]});
})
.catch(function(error){
res.end(error);
});
}
You can use Promise lib in latest nodejs.
Simple solution
Nest request calls. This is how you can handle the dependency between requests. Just make sure your parameters are unique across scopes if needed.
module.exports = function (req, res) {
var context = {};
request('http://localhost:3000/api/1st', function (err, resp1, body) {
var context.first = JSON.parse(body);
request('http://localhost:3000/api/2nd', function (err, resp2, body) {
context.second = JSON.parse(body);
request('http://localhost:3000/api/3rd', function (err, resp3, body) {
context.third = JSON.parse(body);
res.render('../views/project', context);
});
});
});
};
Simplest way if you use bluebird promise library:
var Promise = require('bluebird');
var request = Promise.promisify(require('request'));
module.exports = function (req, res) {
var id = req.params.id;
var urls = [
'http://localhost:3000/api/1st/' + id,
'http://localhost:3000/api/2st/' + id,
'http://localhost:3000/api/3st/' + id
];
var allRequests = urls.map(function(url) { return request(url); });
Promise.settle(allRequests)
.map(JSON.parse)
.spread(function(json1, json2, json3) {
res.render('../views/project', { json1: json1 , json2: json2, json3: json3 });
});
});
it executes all requests even if one (or more) fails

NodeJS: creating a hash and return the value of a function

I have a list of tags that I need to extract. the list is called list.
I'm trying to find all 'og:*' meta that correspond to the list and are available in a fetched html. Then I need to return a hash to the user in JSON that contains these meta tags. But the process method return undefined rather than the hash.
var http = require('http');
var url = require('url');
var request = require('request');
var jsdom = require("jsdom");
var fs = require('fs');
var cssom = require('cssom');
var list = ['title', 'description']; //here the og-tags I need to extract
var meta = {};
function process(url) {
request(url, function (error, response, body) {
if (!error && response.statusCode == 200) {
jsdom.env({
html: body,
scripts: [
'http://code.jquery.com/jquery-1.5.min.js'
],
done: function(errors, window) {
var $ = window.$;
$('meta[property^="og:"]').each(function() {
for (var element in list) {
if ($(this).attr('property') == 'og:' + list[element]) {
meta[list[element]] = $(this).attr('content');
// this works well, if I do console.log(meta), I get the hash correctly filled.
}
}
});
}
});
}
});
return meta; // this is where the probleme is. This return undefined.
}
http.createServer(function (request, response) {
request.setEncoding('utf8');
response.writeHead(200, {'Content-Type': 'text/plain'});
process(url.parse(request.url, true).query['content'], function(result) {
console.log(result); // prints no result
});
response.end();
}).listen(8124);
console.log('Server running at http://0.0.0.0:8124');
Because request is asynchronous, you need to make process asynchronous as well. That means having process accept a callback parameter that it will call once meta is available. As it is now, process is returning meta before the request callback populates it.
function process(url, callback) {
request(url, function (error, response, body) {
if (!error && response.statusCode == 200) {
jsdom.env({
html: body,
scripts: [
'http://code.jquery.com/jquery-1.5.min.js'
],
done: function(errors, window) {
var $ = window.$;
$('meta[property^="og:"]').each(function() {
for (var element in list) {
if ($(this).attr('property') == 'og:' + list[element]) {
meta[list[element]] = $(this).attr('content');
callback(null, meta);
}
}
});
}
});
} else {
callback(error);
}
});
}
http.createServer(function (request, response) {
request.setEncoding('utf8');
response.writeHead(200, {'Content-Type': 'text/plain'});
process(url.parse(request.url, true).query['content'], function(error, result) {
console.log(result); // prints no result
});
response.end();
}).listen(8124);

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