I'm making some requests from my express server, and I'm wondering how I can pass an error message to the client side. I want to be able to see the error message when I console log from the client as well as from the server, but I'm not sure how to relay this message back to the client to make that possible.
Here is an example of a request from my server.js file
app.get('/assign*', (request, response) => {
var baseurl = 'https://OURACC.nocrm.io/api/v2/'
var apikey = crmkey;
var pathname = request.url; // retrieves the requested pathname (ie, /crm/path)
pathname = pathname.split('?');
pathname = pathname[0].split('/')
var parameters = request.query.params;
var path = pathname[2]; // gets request path for the crm
var lead_id = parameters.lead_id
var user_id = parameters.user_id
var params = {
user_id: user_id
}
if(path === 'leads'){
axios.post(baseurl + path + '/' + lead_id + '/assign',
params
,{
headers: {'X-API-KEY': apikey, content_type: "json", accept: "application/json"}
}).then(function(res){
response.send(res.data);
}).catch(function(error){
console.log("ERROR in /assign/leads/{id}/assign" + error);
})
}
})
This is what the call to this request looks like client side
$.get('/assign/leads', {params: data}).then(response => {
console.log(response);
}).catch(error => {
console.log(error);
})
I've tried this server side
response.send(error)
but this doesn't return me anything client side like I was expecting.
I'm sure this is something simple, but I couldn't find much online about it, thanks.
If I read your code correctly, just put response.send(yourErrorMessage) in the catch block
You have to specify response code. For example:
res.status(400);
res.send('None shall pass');
I have been working on setting up a cache server for my nodejs application.
Below is my project I am working on. Simple one.
I have an external API that gives me a JSON response for a GET request.
I want to store those key and JSON (value) in a redis cache server. And I am able to do that.
Now when the GET request is called it comes to my node URL --> External API <-- JSON as response (which is stored in the cache).
For next request if the same GET comes, it goes to cache to fetch the key/value pair.
But here, if my cache server is not reachable or available, I have to go to API again to fetch the value.
I tried the code like below and it is failing when the Cache server is shutdown. How do I do a if-loop for getting the connection status of the redis cache server?
Below is my controller.js
function getRedisCacheConnection(){
const REDIS_PORT = process.env.PORT || 6379;
const client = redis.createClient(REDIS_PORT);
client.on('connect', function() {
console.log('Redis client connected');
console.log(`${client.connected}`);
});
client.on('error', function (err) {
console.log('Something went wrong ' + err);
})
return client;
}
exports.getCityCode = (req,res)=>{
var originCity = req.query.origincity;
var originState = req.query.originstate;
function setReponse(originCity, response){
return response;
}
const options = {
method: 'GET',
uri: `http://webapi.external.com/api/v3/locations?name=${originCity}`,
headers: {
'Content-Type': 'application/json'
}
}
request(options).then(function (response){
res.status(200).send(setReponse(originCity, response));
const client1 = getRedisCacheConnection();
console.dir("setting key to Cache " + originCity);
client1.setex(originCity, 3600, response);
});
}
exports.Cache = (req,res,next) => {
const originCity = req.query.origincity;
function setReponse(originCity, response){
return response;
}
const client1 = getRedisCacheConnection();
client1.get(originCity, (err,data) =>{
if(err) throw err;
if(data !== null){
console.dir(originCity + " Getting Key from Cache");
res.status(200).send(setReponse(originCity,data));
}
else{
next();
}
});
}
Here is my router.js
app.get('/citycode/', city.Cache, city.getCityCode);
you are throwing an error:
if(err) throw err;
Log the error and don't create an exception.
I am trying to scrape a website using nodejs and it works perfectly on sites that do not require any authentication. But whenever I try to scrape a site with a form that requires username and password I only get the HTML from the authentication page (that is, if you would click 'view page source' on the authentication page it self, that is the HTML I get). I am able to get the desired HTML using curl
curl -d "username=myuser&password=mypw&submit=Login" URL
Here is my code...
var express = require('express');
var fs = require('fs'); //access to file system
var request = require('request');
var cheerio = require('cheerio');
var app = express();
app.get('/scrape', function(req, res){
url = 'myURL'
request(url, function(error, response, html){
// check errors
if(!error){
// Next, we'll utilize the cheerio library on the returned html which will essentially give us jQuery functionality
var $ = cheerio.load(html);
var title, release, rating;
var json = { title : "", release : "", rating : ""};
$('.span8 b').filter(function(){
// Let's store the data we filter into a variable so we can easily see what's going on.
var data = $(this);
title = data.first().text();
release = data.text();
json.title = title;
json.release = release;
})
}
else{
console.log("Error occurred: " + error);
}
fs.writeFile('output.json', JSON.stringify(json, null, 4), function(err){
console.log('File successfully written! - Check your project directory for the output.json file');
})
res.send('Check your console!')
})
})
app.listen('8081')
console.log('Magic happens on port 8081');
exports = module.exports = app;
I have tried the following...
var request = require('request',
username:'myuser',
password:'mypw');
This just returns the authentication page's HTML
request({form: {username:myuser, password:mypw, submit:Login}, url: myURL}, function(error, response, html){
...
...
...
}
This also just returns the authentication page's HTML
So my question is how do I achieve this using nodejs?
you shouldn't use .get but .post and put the post param (username and password) in your call
request.post({
headers: {'content-type' : 'application/x-www-form-urlencoded'},
url: url,
body: "username=myuser&password=mypw&submit=Login"
}, function(error, response, html){
//do your parsing...
var $ = cheerio.load(html)
});
I'd like to use node.js to query a mySQL-database and return the results as JSON to be used in a mobile application. Unfortunately, my request just sorta times out and the server does nothing for a good 2 minutes until the log-files show my console.log()-statements.
Also, the callback doesn't return anything as result. It's just empty.
// Check dependencies
var http = require('http');
// Create the http server.
// reference: http://net.tutsplus.com/tutorials/javascript-ajax/node-js-for-beginners/
http.createServer(function(request, response) {
// Attach listener on end event.
request.on('close', function() {
console.log('request');
// run asynchronous
getSQL(function(err, result) {
console.log('json:', result);
response.writeHead(200, {
'Content-Type' : 'x-application/json'
});
// Send data as JSON string.
response.end(result);
});
});
}).listen(3000);
// Access MySQL via node-mysql
// https://github.com/felixge/node-mysql
function getSQL(callback) {
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'localhost',
user : 'user',
password : 'pw',
database : 'db',
socketPath : '/var/run/mysqld/mysqld.sock', // socket for communication from debian <-> client, seems not to be set correcly by default?
});
connection.connect();
var json = '';
var query = 'SELECT * FROM test';
connection.query(query, function(err, results, fields) {
if (err)
return callback(err, null);
console.log('The result is: ', results[0]);
// wrap result-set as json
json = JSON.stringify(results);
});
connection.end();
callback(null, json);
};
Output after like 2 minutes:
$ node app.js
request
json:
The result is: { test: 'avc' }
json2: [{"test":"avc"}]
Based on my very basic understanding of the whole node.js-concept, my code should query the db (it does) and return a json once it's finished via the callback-function (apparently doesn't) which than is sent back as a response to the client (can't really check that since the json's empty).
I guess I made one (or a couple) major mistakes. Help and/or helpful links would be much appreciated. Thanks!
Solution, thanks to hexacyanide
// Check dependencies
var http = require('http');
// Create the http server.
// reference: http://net.tutsplus.com/tutorials/javascript-ajax/node-js-for-beginners/
/***************
* Correction 1: Using the request.on('close', function()( ... )-listener isn't required anymore
***************/
http.createServer(function(req, res) {
console.log('Receving request...');
var callback = function(err, result) {
res.writeHead(200, {
'Content-Type' : 'x-application/json'
});
console.log('json:', result);
res.end(result);
};
getSQL(callback);
}).listen(3000);
// Access MySQL via node-mysql
// https://github.com/felixge/node-mysql
function getSQL(callback) {
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'localhost',
user : 'user',
password : 'pw',
database : 'db',
socketPath : '/var/run/mysqld/mysqld.sock', // socket for communication from debian <-> client, seems not to be set correcly by default?
});
connection.connect();
var json = '';
var query = 'SELECT * FROM test';
connection.query(query, function(err, results, fields) {
if (err)
return callback(err, null);
console.log('The query-result is: ', results[0]);
// wrap result-set as json
json = JSON.stringify(results);
/***************
* Correction 2: Nest the callback correctly!
***************/
connection.end();
console.log('JSON-result:', json);
callback(null, json);
});
};
You're following an older guide which instructs you to wait for the request's close event before sending the response, but you actually no longer need to do that.
What's happening is you aren't sending your response, so your client is timing out. Only until the client times out is when close events fires. Since the client has disconnected by the time you send your response, you don't get anything on the client and only see it in the terminal.
To fix this problem, just stop waiting for the close event and run code immediately when the request handler is called:
var http = require('http');
http.createServer(function(req, res) {
getSQL(function(err, result) {
res.writeHead(200, {
'Content-Type' : 'x-application/json'
});
res.end(result);
});
}).listen(3000);
How can I make an HTTP request from within Node.js or Express.js? I need to connect to another service. I am hoping the call is asynchronous and that the callback contains the remote server's response.
Here is a snippet of some code from a sample of mine. It's asynchronous and returns a JSON object. It can do any form of GET request.
Note that there are more optimal ways (just a sample) - for example, instead of concatenating the chunks you put into an array and join it etc... Hopefully, it gets you started in the right direction:
const http = require('http');
const https = require('https');
/**
* getJSON: RESTful GET request returning JSON object(s)
* #param options: http options object
* #param callback: callback to pass the results JSON object(s) back
*/
module.exports.getJSON = (options, onResult) => {
console.log('rest::getJSON');
const port = options.port == 443 ? https : http;
let output = '';
const req = port.request(options, (res) => {
console.log(`${options.host} : ${res.statusCode}`);
res.setEncoding('utf8');
res.on('data', (chunk) => {
output += chunk;
});
res.on('end', () => {
let obj = JSON.parse(output);
onResult(res.statusCode, obj);
});
});
req.on('error', (err) => {
// res.send('error: ' + err.message);
});
req.end();
};
It's called by creating an options object like:
const options = {
host: 'somesite.com',
port: 443,
path: '/some/path',
method: 'GET',
headers: {
'Content-Type': 'application/json'
}
};
And providing a callback function.
For example, in a service, I require the REST module above and then do this:
rest.getJSON(options, (statusCode, result) => {
// I could work with the resulting HTML/JSON here. I could also just return it
console.log(`onResult: (${statusCode})\n\n${JSON.stringify(result)}`);
res.statusCode = statusCode;
res.send(result);
});
UPDATE
If you're looking for async/await (linear, no callback), promises, compile time support and intellisense, we created a lightweight HTTP and REST client that fits that bill:
Microsoft typed-rest-client
Try using the simple http.get(options, callback) function in node.js:
var http = require('http');
var options = {
host: 'www.google.com',
path: '/index.html'
};
var req = http.get(options, function(res) {
console.log('STATUS: ' + res.statusCode);
console.log('HEADERS: ' + JSON.stringify(res.headers));
// Buffer the body entirely for processing as a whole.
var bodyChunks = [];
res.on('data', function(chunk) {
// You can process streamed parts here...
bodyChunks.push(chunk);
}).on('end', function() {
var body = Buffer.concat(bodyChunks);
console.log('BODY: ' + body);
// ...and/or process the entire body here.
})
});
req.on('error', function(e) {
console.log('ERROR: ' + e.message);
});
There is also a general http.request(options, callback) function which allows you to specify the request method and other request details.
Request and Superagent are pretty good libraries to use.
note: request is deprecated, use at your risk!
Using request:
var request=require('request');
request.get('https://someplace',options,function(err,res,body){
if(err) //TODO: handle err
if(res.statusCode === 200 ) //etc
//TODO Do something with response
});
You can also use Requestify, a really cool and very simple HTTP client I wrote for nodeJS + it supports caching.
Just do the following for GET method request:
var requestify = require('requestify');
requestify.get('http://example.com/api/resource')
.then(function(response) {
// Get the response body (JSON parsed or jQuery object for XMLs)
response.getBody();
}
);
This version is based on the initially proposed by bryanmac function which uses promises, better error handling, and is rewritten in ES6.
let http = require("http"),
https = require("https");
/**
* getJSON: REST get request returning JSON object(s)
* #param options: http options object
*/
exports.getJSON = function (options) {
console.log('rest::getJSON');
let reqHandler = +options.port === 443 ? https : http;
return new Promise((resolve, reject) => {
let req = reqHandler.request(options, (res) => {
let output = '';
console.log('rest::', options.host + ':' + res.statusCode);
res.setEncoding('utf8');
res.on('data', function (chunk) {
output += chunk;
});
res.on('end', () => {
try {
let obj = JSON.parse(output);
// console.log('rest::', obj);
resolve({
statusCode: res.statusCode,
data: obj
});
}
catch (err) {
console.error('rest::end', err);
reject(err);
}
});
});
req.on('error', (err) => {
console.error('rest::request', err);
reject(err);
});
req.end();
});
};
As a result you don't have to pass in a callback function, instead getJSON() returns a promise. In the following example the function is used inside of an ExpressJS route handler
router.get('/:id', (req, res, next) => {
rest.getJSON({
host: host,
path: `/posts/${req.params.id}`,
method: 'GET'
}).then(({ statusCode, data }) => {
res.json(data);
}, (error) => {
next(error);
});
});
On error it delegates the error to the server error handling middleware.
Unirest is the best library I've come across for making HTTP requests from Node. It's aiming at being a multiplatform framework, so learning how it works on Node will serve you well if you need to use an HTTP client on Ruby, PHP, Java, Python, Objective C, .Net or Windows 8 as well. As far as I can tell the unirest libraries are mostly backed by existing HTTP clients (e.g. on Java, the Apache HTTP client, on Node, Mikeal's Request libary) - Unirest just puts a nicer API on top.
Here are a couple of code examples for Node.js:
var unirest = require('unirest')
// GET a resource
unirest.get('http://httpbin.org/get')
.query({'foo': 'bar'})
.query({'stack': 'overflow'})
.end(function(res) {
if (res.error) {
console.log('GET error', res.error)
} else {
console.log('GET response', res.body)
}
})
// POST a form with an attached file
unirest.post('http://httpbin.org/post')
.field('foo', 'bar')
.field('stack', 'overflow')
.attach('myfile', 'examples.js')
.end(function(res) {
if (res.error) {
console.log('POST error', res.error)
} else {
console.log('POST response', res.body)
}
})
You can jump straight to the Node docs here
Check out shred. It's a node HTTP client created and maintained by spire.io that handles redirects, sessions, and JSON responses. It's great for interacting with rest APIs. See this blog post for more details.
Check out httpreq: it's a node library I created because I was frustrated there was no simple http GET or POST module out there ;-)
For anyone who looking for a library to send HTTP requests in NodeJS, axios is also a good choice. It supports Promises :)
Install (npm): npm install axios
Example GET request:
const axios = require('axios');
axios.get('https://google.com')
.then(function (response) {
// handle success
console.log(response);
})
.catch(function (error) {
// handle error
console.log(error);
})
Github page
Update 10/02/2022
Node.js integrates fetch in v17.5.0 in experimental mode. Now, you can use fetch to send requests just like you do on the client-side. For now, it is an experimental feature so be careful.
If you just need to make simple get requests and don't need support for any other HTTP methods take a look at: simple-get:
var get = require('simple-get');
get('http://example.com', function (err, res) {
if (err) throw err;
console.log(res.statusCode); // 200
res.pipe(process.stdout); // `res` is a stream
});
Use reqclient: not designed for scripting purpose
like request or many other libraries. Reqclient allows in the constructor
specify many configurations useful when you need to reuse the same
configuration again and again: base URL, headers, auth options,
logging options, caching, etc. Also has useful features like
query and URL parsing, automatic query encoding and JSON parsing, etc.
The best way to use the library is create a module to export the object
pointing to the API and the necessary configurations to connect with:
Module client.js:
let RequestClient = require("reqclient").RequestClient
let client = new RequestClient({
baseUrl: "https://myapp.com/api/v1",
cache: true,
auth: {user: "admin", pass: "secret"}
})
module.exports = client
And in the controllers where you need to consume the API use like this:
let client = require('client')
//let router = ...
router.get('/dashboard', (req, res) => {
// Simple GET with Promise handling to https://myapp.com/api/v1/reports/clients
client.get("reports/clients")
.then(response => {
console.log("Report for client", response.userId) // REST responses are parsed as JSON objects
res.render('clients/dashboard', {title: 'Customer Report', report: response})
})
.catch(err => {
console.error("Ups!", err)
res.status(400).render('error', {error: err})
})
})
router.get('/orders', (req, res, next) => {
// GET with query (https://myapp.com/api/v1/orders?state=open&limit=10)
client.get({"uri": "orders", "query": {"state": "open", "limit": 10}})
.then(orders => {
res.render('clients/orders', {title: 'Customer Orders', orders: orders})
})
.catch(err => someErrorHandler(req, res, next))
})
router.delete('/orders', (req, res, next) => {
// DELETE with params (https://myapp.com/api/v1/orders/1234/A987)
client.delete({
"uri": "orders/{client}/{id}",
"params": {"client": "A987", "id": 1234}
})
.then(resp => res.status(204))
.catch(err => someErrorHandler(req, res, next))
})
reqclient supports many features, but it has some that are not supported by other
libraries: OAuth2 integration and logger integration
with cURL syntax, and always returns native Promise objects.
If you ever need to send GET request to an IP as well as a Domain (Other answers did not mention you can specify a port variable), you can make use of this function:
function getCode(host, port, path, queryString) {
console.log("(" + host + ":" + port + path + ")" + "Running httpHelper.getCode()")
// Construct url and query string
const requestUrl = url.parse(url.format({
protocol: 'http',
hostname: host,
pathname: path,
port: port,
query: queryString
}));
console.log("(" + host + path + ")" + "Sending GET request")
// Send request
console.log(url.format(requestUrl))
http.get(url.format(requestUrl), (resp) => {
let data = '';
// A chunk of data has been received.
resp.on('data', (chunk) => {
console.log("GET chunk: " + chunk);
data += chunk;
});
// The whole response has been received. Print out the result.
resp.on('end', () => {
console.log("GET end of response: " + data);
});
}).on("error", (err) => {
console.log("GET Error: " + err);
});
}
Don't miss requiring modules at the top of your file:
http = require("http");
url = require('url')
Also bare in mind that you may use https module for communicating over secured network. so these two lines would change:
https = require("https");
...
https.get(url.format(requestUrl), (resp) => { ......
## you can use request module and promise in express to make any request ##
const promise = require('promise');
const requestModule = require('request');
const curlRequest =(requestOption) =>{
return new Promise((resolve, reject)=> {
requestModule(requestOption, (error, response, body) => {
try {
if (error) {
throw error;
}
if (body) {
try {
body = (body) ? JSON.parse(body) : body;
resolve(body);
}catch(error){
resolve(body);
}
} else {
throw new Error('something wrong');
}
} catch (error) {
reject(error);
}
})
})
};
const option = {
url : uri,
method : "GET",
headers : {
}
};
curlRequest(option).then((data)=>{
}).catch((err)=>{
})