I am developing a website (client + server) that runs from the same machine.
I haven't found any errors in chrome's developer tools, so I don't know where the problem is.
I try to POST a string from the client to the Node back-end, but upon performing
url.parse(request.url, true).query
the result is empty.
Here is my client:
var xhttp = new XMLHttpRequest();
xhttp.open("POST", "http://localhost:8080/newComment", true);
xhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xhttp.send("val=" + commentString);
My commentString is "hey there"
Here is my server:
var path = url.parse(request.url).pathname;
else if (path == "/newComment") {
console.log("query: " + url.parse(request.url, true).body);
//setNewComment(comment);
response.writeHead(200, {
'Content-Type': 'text/plain',
'Access-Control-Allow-Origin' : '*',
'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE'
}); // enable cors
response.write("Recieved request");
response.end();
}
And I am at the website
file:///C:/Users/.../website.html?name=hey+there
So I'd like my Node server to print out "query: hey there" but instead it prints "query undefined"
You are trying to access the body, and this is right, yet the url doesn't hold the body's content, you should either accumulate it by listening to 'data' events:
let body = [];
request.on('data', (chunk) => {
body.push(chunk);
}).on('end', () => {
body = Buffer.concat(body).toString();
// at this point, `body` has the entire request body stored in it as a string
});
or use "express" and "body-parser".
1.Go to the request body section: https://nodejs.org/en/docs/guides/anatomy-of-an-http-transaction/
Related
I am trying to build a Node.js App to Monitor some Raspberry Pi's.
Since those Raspberries don’t have a static IP, they send an UDP Broadcast every 5 seconds.
I'm able to catch that Broadcast with Node.js, but I'm failing to trigger a new function to notify the Node.js Clients.
I tried WebSockets, ServerSendEvents and Socket.io.
I'm able to use Example Code and they work just fine.
But I'm not Experienced enough to build a function which will send data to the clients.
Node.js App:
// ==============================================================================================================
// ===== Dependencies ===========================================================================================
// ==============================================================================================================
var dgram = require('dgram');
var http = require('http');
var url = require("url");
var path = require("path");
var fs = require("fs");
// ==============================================================================================================
// ===== HTTP Serv ==============================================================================================
// ==============================================================================================================
var server = http.createServer(function(request, response) {
var uri = url.parse(request.url).pathname, filename = path.join(process.cwd(), uri);
var contentTypesByExtension = {
'.html': "text/html",
'.css': "text/css",
'.js': "text/javascript",
'.svg': "image/svg+xml"
};
fs.exists(filename, function(exists) {
if(!exists) {
response.writeHead(404, {"Content-Type": "text/plain"});
response.write("404 Not Found\n");
response.end();
return;
}
if (fs.statSync(filename).isDirectory()) filename += '/index.html';
fs.readFile(filename, "binary", function(err, file) {
if(err) {
response.writeHead(500, {"Content-Type": "text/plain"});
response.write(err + "\n");
response.end();
return;
}
var headers = {};
var contentType = contentTypesByExtension[path.extname(filename)];
if (contentType) headers["Content-Type"] = contentType;
response.writeHead(200, headers);
response.write(file, "binary");
response.end();
});
});
});
// ==============================================================================================================
// ===== HeartBeat Broadcast ====================================================================================
// ==============================================================================================================
var bcast = dgram.createSocket('udp4');
bcast.on('message', function (message) {
console.log("Triggered: UDP Broadcast");
// If UDP Broadcast is received, send message/data to client.
});
bcast.bind(5452, "0.0.0.0");
// ==============================================================================================================
// ===== Start Server ===========================================================================================
// ==============================================================================================================
server.listen(80);
console.log("Static file server running/\nCTRL + C to shutdown");
EDIT:
I think I did not explain myself accurate enough.
I do not want to send a UDP message back.
This UDP Broadcast should fire an (Node.js) event, which should update the html and display the raspberry pi (whom send the UDP Package) as online.
EDIT:
In documentation from official page of nodejs (DOCUMENTATION):
var socket = require('socket.io')(http);
var bcast = dgram.createSocket('udp4');
bcast.bind(5452, "0.0.0.0");
bcast.on('message', function (message, remote) {
////if message is an Object pushed into Buffer////
message = message.toString('utf8');
socket.emit("HTML_Update", message);
//////////////////////////////////Solution for unedited question//////////////////////////
// var msgBuffer = Buffer.from(message.toString(); //creating a buffer //
// bcast.send(msgBuffer, 0, msgBuffer.length, remote.port, remote.address, (err) => { //
// bcast.close(); //
// }); //sending message to remote.address:remote.port (like localhost:23456) //
// //
// **build a function which will send data to the clients** //
//////////////////////////////////Solution for unedited question//////////////////////////
});
"If message is an Object pushed into Buffer" - lets say that one of the RPI turned on and started sending UDP message, what should the message pass to server so server can pass it to display: mac address only because if it sends something You can be sure its on, if it does not send its off simple as that. Also to show that change on client You should initialize TCP sockets on server to pass info to servers web page to update content on html with jquery.
Now here is the HTML java script part (I personally make main.js file and write all java script into it and use import it as src into html). Using jquery in main.js:
$(document).ready(function() {
var time = new Date();
var rpi = {
"list" : ["mac1", "mac2", "mac3"],
"time" : [time.getTime(), time.getTime(), time.getTime()],
"label" : ["label_ID1", "label_ID2", "label_ID3"]};
var socket = io.connect('http://your_server_address:80');
setInterval( function(){
for (var i = 0; i <= 2; i++){
if((rpi.time[i] + 10000) < time.getTime()){
$(rpi.label[i]).text("RPI " + rpi.list[i] + " is DOWN");
}
}
}, 5000);
socket.on("HTML_Update", function(data){
for (var i = 0; i<=2; i++) {
if (data.toString().equals(rpi.list[i])) {
$(rpi.label[i]).text("RPI: "+ rpi.list[i] + " is UP");
rpi.time[i] = time.getTime();
}
}
});
}
If You put text label in html to show if specific rpi is up or down this part of code works in this scheme:
Multiple RPI + Server - RPI sends UDP data with mac to server. Server device is used to receive data and show it on any device as web page and change data if RPI is UP/DOWN.
I'm trying to do a "Server sent event" with express.
I can get the data by requesting it from the browser but i need to elaborate this data.
Running the script(client) from shell I can not see anything.
What am I doing wrong or am i forgetting?
Server side:
var express = require("express")
, http = require("http")
, fs = require('fs')
, ursa = require('ursa')
, url = require('url')
, querystring = require('querystring')
, jsonObject;
var app = express();
app.use(function(request, response) {
response.writeHead(200, {
'Connection': 'keep-alive',
'Content-Type': 'text/event-stream',
'Cache-Control': 'no-cache'
});
console.log("sending data over eventsource...");
response.write("\n");
response.write("data:ok");
});
http.createServer(app).listen(8080);
Client side:
var EventSource = require('eventsource');
var source = new EventSource("http://localhost:8080");
source.addEventListener('data', function (e) {
var log = e.data;
console.log(log);
});
You need to write a \n after the data to signify the end of that event.
Solved,
i changed simply the type of event in addEventListener() from 'data' to 'message', like this:
var EventSource = require("eventsource");
var source = new EventSource("http://localhost:8080");
source.addEventListener("message", function (e) {
var log = e.data;
console.log(log);
});
I'm trying to get node.js to print http request properties to the browser. However, the properties of the request url either return null or don't print at all. Here is the code for the server (server.js):
var http = require('http');
var url = require('url');
function start() {
function onRequest(request, response) {
var pathname = url.parse(request.url, true).pathname;
var protocol = url.parse(request.url, true).protocol;
var hostname = url.parse(request.url, true).host;
var path = url.parse(request.url, true).path;
response.writeHead(200, {"Content-Type": "text/plain"});
response.write("Hello World"); //this is the text that is sent back
response.write("\nThe HTTP response is " + response.statusCode);
response.write("\nRequest for "+ pathname +" has been received. The request url is " + request.url + " and our protocol is " + protocol +".Also, our host is " + hostname);
response.write("\nThe concatenated path is " + path);
response.end(); //this is the end of the response
}
var new_server = http.createServer(onRequest).listen(8888);
} //end of start function
exports.start = start;
And the index file that executes this is index.js
var server = require("./server");
console.log("To see what the sever responds with, go to localhost:8888.");
server.start();
My browser output is, when I type in the url bar localhost:8888
Hello World
The HTTP response is 200
Request for / has been received. The request url is / and our protocol is null.Also, our host is null
The concatenated path is /
I need to get the url properties. Thank you.
The reason these variables are returning undefined is because the url only contains the path. The protocol and the host are stored elsewhere. Take this example from the node.js documentation:
var url = require('url');
console.log( url.parse(
'http://user:pass#host.com:8080/p/a/t/h?query=string#hash', true
));
That will return the following object:
{
href: 'http://user:pass#host.com:8080/p/a/t/h?query=string#hash',
protocol: 'http:',
host: 'user:pass#host.com:8080',
auth: 'user:pass',
hostname: 'host.com',
port: '8080',
pathname: '/p/a/t/h',
search: '?query=string',
query: { query: 'string' },
hash: '#hash',
slashes: true
}
These values are present in the URL, so they are present in the object. The localhost:8888 URL has none of these.
On another note, there are three important aspects to the request object: the url, the method, and the headers. If you try doing this, I suspect you will find the information you're looking for:
var urlStr = 'http://' + req.headers.host + req.url,
parsedURL = url.parse( urlStr ,true );
console.log(parsedURL);
//this should give you the data you are looking for.
I want to build a proxy with node.js to use in my browser.
I searched at google and saw that example, but some Apis are deprecated.
So I changed the code following:
var http = require('http');
http.createServer(function(request, response) {
console.log("req for:"+ request.headers['host'] + "\nmethod: "+ request.method);
var options = {
host : request.headers['host'],
method : request.method,
headers : request.headers
}
var callback = function(res){
// get the proxyclient response and write to the original response
res.addListener('data', function(chunk){
console.log("writing response");
response.write(chunk, 'binary');
});
res.addListener('end', function(){
console.log("end response");
response.end();
});
};
// send the original request
var proxy = http.request(options, callback);
// intercept the request and write to proxyclient
request.addListener('data', function(chunk){
console.log("new request");
proxy.write(chunk, 'binary');
});
request.addListener('end', function(){
console.log("end request");
proxy.end();
});
}).listen(3333);
After that, I changed my browser proxy settings to use localhost:3333.
My problem is that event "data" isn't fired.
This should work as I thought?
Maybe if you write this code;
response.writeHead(res.statusCode, res.headers); after res.addListener('end', function(){
console.log("end response");
response.end();
});
I'm sending an http request using the http.request function, and I would like to read the whole http response like text; that is, the raw http protocol text. Is it possible? I've written the below code but it's not working.
// Set up the request
console.log('Sending request');
var post_req = http.request(post_options, function(res) {
res.setEncoding('utf8');
console.log('Response statusCode: ' + res.statusCode);
// res.on('data', function (chunk) {
// console.log('Response: ' + chunk);
// });
// res.on('end', function() {});
});
post_req.on('socket', function (socket) {
var response = "";
socket.on('data', function(chunk){
console.log(chunk);
});
});
// post the data
post_req.write(post_data);
post_req.end();
If you want access to the raw http message, I'd suggest using the net module instead, and writing the request yourself. Something like this for a simple GET request:
var net = require('net');
var host = 'stackoverflow.com',
port = 80,
socket = net.connect(port, host, function() {
var request = "GET / HTTP/1.1\r\nHost: " + host + "\r\n\r\n",
rawResponse = "";
// send http request:
socket.end(request);
// assume utf-8 encoding:
socket.setEncoding('utf-8');
// collect raw http message:
socket.on('data', function(chunk) {
rawResponse += chunk;
});
socket.on('end', function(){
console.log(rawResponse);
});
});
For a POST request sending application/x-www-form-urlencoded data, you could write the request using something like:
function writePOSTRequest (data, host, path) {
return "POST " + path + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"Content-Type: application/x-www-form-urlencoded\r\n" +
"Content-Length: " + Buffer.byteLength(data) + "\r\n\r\n" +
data + "\r\n\r\n";
}
var data = "name1=value1&name2=value2",
request = writePOSTRequest(data, host, "/path/to/resource");
where I'm using Buffer.byteLength because Content-Length requires the length in bytes, not in characters. Also, remember that data must be URL encoded.
If you don't know much about the format of HTTP messages, then this is a decent place to start:
http://jmarshall.com/easy/http/
Also, if you don't know what the encoding of the response will be then you'll have to parse the headers first to find out, but UTF-8 is by far the most common so it's a pretty safe bet.
Streams2 and Streams1 not always able to inter-operate well, see "problem: streams1 and streams2 duality" in this video.
I tried to listen data at a bit lower level than streams and this code prints raw http response with headers for me:
var http = require('http');
var raw = '';
console.log('Sending request');
var req = http.request({host: 'stackoverflow.com'}, function(res) {
watch(res, 'res');
res.on('end', function() {
console.log(raw);
});
res.on('data', function(data) {
// if we don't attach 'data' handler here 'end' is not called
});
});
req.on('socket', function (socket) {
socket.resume();
var oldOndata = socket.ondata;
socket.ondata = function(buf, start, end) {
raw += buf.slice(start, end).toString();
oldOndata.call(socket, buf, start, end);
};
});
req.end();
Assuming these kind of tools are allowed in your environment, you could run up an HTTP debug proxy such as Fiddler http://www.fiddler2.com/, which enables you to inspect the HTTP calls and responses.