I tried to follow an example on the web for creating a NodeJS server and router, but have ran into problems. What follows is primarily the example with a bit of other code.
Index.js
var server = require("./server");
var router = require("./router");
server.start(router.route);'
Router.js
var fs = require("fs");
function route(filename) {
fs.readFile(filename, 'utf8', function (err, data) {
if (err) {
console.log('Error: ' + err);
return;
}
console.log("About to route a request for " + filename);
data = JSON.parse(data);
})
}
exports.route = route;
Server.js
var http = require('http');
var url = require("url");
function start(route) {
function onRequest(request, response) {
var filename = request.url.substr(1);
// call for specific json file here
if (filename == "favicon.ico") {
response.writeHead(200, {'Content-Type': 'image/x-icon'} );
response.end();
console.log('favicon requested');
return;
}
else {
filename += ".json";
console.log("Request for " + filename + " received.");
response.writeHead(200, { 'Content-Type': 'application/json', "Access-Control-Allow-Origin":"*" });
response.write("" + route(filename),0,4);
response.end();
}
}
http.createServer(onRequest).listen(8124);
}
exports.start = start;
console.log('Server running at http://127.0.0.1:8124/');
The question I have is, among others, how does the route command work?
What I get when I browse to the server is 'undefined'. How do I get the actual json from the Router?
I tried: var result = route(filename); but that failed badly.
In essence, how to get the data from the router and write it to the response. If you haven't guessed, javascript and NodeJS is rather new to me.
Any pointers would be greatly appreciated.
Thank you.
Your route function has an async method, fs.readFile. You'll need to pass in a callback to the route function, so that it can return the data properly. Otherwise, route will return immediately with no data (since it's async) regardless if you have a return statement inside readFile.
router.js
function route(filename, callback) {
fs.readFile(filename, 'utf8', function (err, data) {
if (err) {
console.log('Error: ' + err);
return;
}
console.log("About to route a request for " + filename);
data = JSON.parse(data);
callback(data); // Call this function after the data is grabbed.
})
}
server.js portion:
response.writeHead(200, { 'Content-Type': 'application/json', "Access-Control-Allow-Origin":"*" });
route(filename, function (data) {
response.write("" + JSON.stringify(data),0,4);
response.end();
});
Related
I'm trying to upload an external url to my server. Here's what I got so far
var fs = require('fs');
var request = require('request');
var path = require('path');
const imagesFolder = 'downloadedAssets/imgs';
function download(url, dest, filename, cb) {
var file = fs.createWriteStream(dest + "/" + filename + path.extname(url));
request( {url: url}, function(err, response) {
if(err) {
console.log(err.message);
return;
}
response.pipe(file);
file.on('error', function(err) {
console.log(err.message);
file.end();
});
file.on('finish', function() {
file.close(cb);
});
});
}
and then executing the function...
var url = 'http://pngimg.com/uploads/spongebob/spongebob_PNG44.png';
download(url, imagesFolder, 'sponge', function onComplete(err) {
if (err) {
console.log(err.message);
} else {
console.log('image uploaded to server');
}
});
This doesn't throw any errors, and it creates a file name sponge.png, but the file is empty. Any idea why?
You might have mixed up the examples on the official website
Try using pipe() like below.
function download(url, dest, filename, cb) {
var file = fs.createWriteStream(dest + "/" + filename + path.extname(url));
request( {url: url}).pipe(file);
}
I'm using nodejs for my rfid that is hook up on my raspberry pi. What I'm trying to do is when I tap the id "6f124628" the led won't turn on unless another pin on the arduino is high. I'm using firmata protocol for arduino communication.
JS:
function arduinoReady(err) {
if (err) {
console.log(err);
return;
}
console.log('Firmware: ' + board.firmware.name +
'-' + board.firmware.version.major +
'.' + board.firmware.version.minor);
var ledOn = true;
board.pinMode(ledPin, board.MODES.OUTPUT);
rc522(function(rfidSerialNumber) {
console.log(rfidSerialNumber);
if (rfidSerialNumber == "216264a9") {
onjie.writeSync(1);
}
data = board.digitalRead(ledPin);
if (rfidSerialNumber == "6f124628" && data == "board.HIGH") {
LED1.writeSync(1);
return;
}
});
But my code doesn't work and Typerror :
"listener" argument must be a function
var http = require('http').createServer(handler);
app.listen(8080);
function handler (req, res) {
fs.readFile(__dirname + '/firmata.html',
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading firmata.html');
}
res.writeHead(200);
res.end(data);
});
}
The problem is with the method createServer
You have to change the initialization of your method handler
Try changing the handler declaration to this:
var handler = function(req, res) {
fs.readFile(__dirname + '/firmata.html',
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading firmata.html');
}
res.writeHead(200);
res.end(data);
});
}
And now, you're able to declare your server with:
var http = require('http').createServer(handler);
So I have been wondering how to save an image to node.js server without the use of express.(just learning node and want to make everything myself to learn node better, without express).
So far I have a form with the image as only input which I send with a post request. This is what I have so far on my server, which does not log anything.
if(req.method === 'POST') {
if (req.url === '/upload') {
req.on('error', function(e) {
console.log('Problem with request: ' + e.message);
});
res.writeHead(200, {'Content-Type': 'image/jpg; charset=utf8'});
req.on('data', function (chunk) {
fs.writeFile(__dirname + "/uploads/dada.jpg", chunk, function(err) {
if(err) {
console.log(err);
} else {
console.log("The file was saved!");
}
});
});
}
}
This is my form:
<form method="post" action="/upload" enctype="multipart/form-data">
EDIT: I fixed most of the problems, but the file is only saved as an image, but cannot be viewed like one. (Something is wrong with the content-type I guess, but don't know how to fix it)
Here is fiddle of my whole app. I know I need to separate it in different modules, but I will do that later
I completely forgot about this old question but now that I see it has quite some views, here is the solution I found:
var port = 1357;
var http = require('http'),
path = require('path'),
mime = require('mime'),
fs = require('fs'),
GUID = require('GUID'),
formidable = require('formidable'),
util = require('util');
var app = http.createServer(function (req, res) {
if (req.method === 'POST') {
if (req.url === '/upload') {
req.on('error', function (e) {
console.log('Problem with request: ' + e.message);
});
var fileDirectory = __dirname + '/db/',
form = new formidable.IncomingForm();
form.keepExtensions = true;
form.uploadDir =fileDirectory;
form.parse(req, function (err, fields, files) {
if (err) throw (err);
var pic = JSON.stringify(util.inspect(files)),
upIndx = pic.indexOf('db'),
path = pic.slice(upIndx + 6, upIndx + 42);
res.writeHead(200, {
'Content-Type': 'text/html'
});
fs.readFile('views/index.html', function (err, page) {
res.writeHead(200, {
'Content-Type': 'text/html'
});
res.write(page);
res.write('<div>Download Link: </div><div>' + fileDirectory + path + '</div>');
res.end();
});
});
}
} else {
//not important for question, handle other request
}
});
app.listen(port);
console.log('Server running on port: ' + port)
I've just managed to connect to a server script with socket.io, so I'm happy about that. I'm less happy though about the weird behavior my script generates: I send one emit to the server script on a buttonclick, and the server test script sends back a message 6x to the console log. Googling this problem description gets ideas about spotty, repeating connections, but I don't think that's it.
Anyway, here's the client app.js:
var commentapp={
init: function(){
var commentapp=this;
commentapp.btn_api=$('#btn_api');
commentapp.btn_api.click(this.get_comment_data);
},
get_comment_data: function(btn_event){
var commentapp=this;
console.log('trying to connect');
commentapp.socket=io.connect('http://localhost:8080');
commentapp.socket.on('connect', function() {
commentapp.socket.emit('btn_api_call');
}); //commentapp.socket.on 'connect',
commentapp.socket.on('serverMessage', function(content){
console.log(content);
}
); //commentapp.socket.on('serverMessage'
}
};
$(function() {
commentapp.init();
});
The server script is as follows:
var httpd = require("http").createServer(handler);
var io=require('/Users/user/Virtualenvs/node_modules/socket.io/lib/socket.io').listen(httpd);
var fs = require('fs');
var url = require("url");
var path = require("path");
var port = process.argv[2] || 8080;
httpd.listen(parseInt(port, 10));
function handler (request, response) {
var uri = url.parse(request.url).pathname,
filename = path.join(process.cwd(), uri);
console.log(uri);
path.exists(filename, function(exists) {
if(!exists) {
response.writeHead(404, {"Content-Type": "text/plain"});
response.write("404 Not Found\n");
response.end();
return; //these returns get you out of the function I think
}
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;
}
response.writeHead(200);
response.write(file, "binary"); //otherwise here's where the file gets finally served
response.end();
}); //fs.readFile
}); //path.exists
io.sockets.on('connection',function(socket) {
socket.on('btn_api_call', function() {
socket.emit('serverMessage', 'Server heard you.');
});
});
};
console.log("Static file server running at\n => http://localhost:" + port + "/\nCTRL + C to shutdown");
Both of these are cannibalized from https://github.com/accbel/nodejs-socketio-example and Pedro Teixeira's book.
So if I click the button to generate the 'btn_api_call'emit, the console log will say "'Server heard you.'" 6x. Hopefully this is a rookie mistake easily set straight.
Thanks for your help!
This is likely due to having your registration for connections inside of a route handler.
Each time a request comes in that is handled by that route, the code is adding a new listener for connections.
You likely have a similar problem in your client - connecting each time the button is clicked.
Move your connection listener outside the route like this:
function handler (request, response) {
var uri = url.parse(request.url).pathname,
filename = path.join(process.cwd(), uri);
console.log(uri);
path.exists(filename, function(exists) {
if(!exists) {
response.writeHead(404, {"Content-Type": "text/plain"});
response.write("404 Not Found\n");
response.end();
return; //these returns get you out of the function I think
}
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;
}
response.writeHead(200);
response.write(file, "binary"); //otherwise here's where the file gets finally served
response.end();
}); //fs.readFile
}); //path.exists
};
io.sockets.on('connection',function(socket) {
socket.on('btn_api_call', function() {
socket.emit('serverMessage', 'Server heard you.');
});
});
On the client move the connect logic to init - something like:
var commentapp={
init: function(){
var commentapp=this;
commentapp.btn_api=$('#btn_api');
commentapp.btn_api.click(this.get_comment_data);
console.log('trying to connect');
commentapp.socket=io.connect('http://localhost:8080');
commentapp.socket.on('connect', function() {
commentapp.socket.emit('btn_api_call');
}); //commentapp.socket.on 'connect',
commentapp.socket.on('serverMessage', function(content){
console.log(content);
}
); //commentapp.socket.on('serverMessage'
},
get_comment_data: function(btn_event){
var commentapp=this;
commentapp.socket.emit('btn_api_call');
}
};
I have a a node.js server that serves an index.html with a text input for a password.
After a serverside password check the download should start for the client.
The client shouldn't be able to see the location path where the file lies on the server.
here is my server.js:
var
http = require('http'),
qs = require('querystring'),
fs = require('fs') ;
console.log('server started');
var host = process.env.VCAP_APP_HOST || "127.0.0.1";
var port = process.env.VCAP_APP_PORT || 1337;
http.createServer(function (req, res) {
if(req.method=='GET') {
console.log ( ' login request from ' + req.connection.remoteAddress );
fs.readFile(__dirname +'/index.html', function(error, content) {
if (error) {
res.writeHead(500);
res.end();
}
else {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.end(content, 'utf-8');
}
});
} // method GET end
else{ // method POST start
console.log('POST request from ' + req.connection.remoteAddress);
var body = '';
req.on('data', function (data) {
body += data;
if (body.length > 500) {
// FLOOD ATTACK OR FAULTY CLIENT, NUKE REQUEST
req.connection.destroy(); console.log('too much data')}
});
req.on('end', function () {
var postdata = qs.parse(body);
var password = postdata.passwordpost ;
if (password == '7777777') {
console.log('the password is right, download starting');
// ??????????????????????????????????? here I need help from stackoverflow
}
else{
console.log ('password wrong');
fs.readFile(__dirname +'/wrongpassword.html', function(error, content) {
if (error) {
res.writeHead(500);
res.end();
}
else {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.end(content, 'utf-8');
}
});
}
}); // req on end function end
}
}).listen(port, host);
the part where I need help is marked with ????????
here is my index.html:
<html>
<body>
<br> <br>
please enter your password to start your download
<br> <br>
<form method="post" action="http://localhost:1337">
<input type="text" name="passwordpost" size="50"><br><br>
<input type="submit" value="download" />
</form>
</body>
</html>
Do you know how to do this?
Sure, you can use this in your code :
res.setHeader('Content-disposition', 'attachment; filename='+filename);
//filename is the name which client will see. Don't put full path here.
res.setHeader('Content-type', 'application/x-msdownload'); //for exe file
res.setHeader('Content-type', 'application/x-rar-compressed'); //for rar file
var file = fs.createReadStream(filepath);
//replace filepath with path of file to send
file.pipe(res);
//send file
You needs to declare and require the path: path = require("path")
then can do:
var uri = url.parse(request.url).pathname
, filename = path.join(process.cwd(), uri);
path.exists(filename, function(exists) {
if(!exists) {
response.writeHead(404, {"Content-Type": "text/plain"});
response.write("404 Not Found\n");
response.end();
return;
}
response.writeHead(200);
response.write(file, "binary");
response.end();
}
check these complete example.
If you are willing to use express web framework, then it can be done in a much easier way.
app.get('/download', function(req, res){
var file = __dirname + 'learn_express.mp4';
res.download(file); // Sets disposition, content-type etc. and sends it
});
Express download API
I found some additional information about fs.createReadStream() ( especially error handling ) here and combined it with the answer of user568109. Here is my working downloadserver:
var
http = require('http'),
qs = require('querystring'),
fs = require('fs') ;
console.log('server started');
var host = process.env.VCAP_APP_HOST || "127.0.0.1";
var port = process.env.VCAP_APP_PORT || 1337;
http.createServer(function (req, res) {
if(req.method=='GET') {
console.log ( ' login request from ' + req.connection.remoteAddress );
fs.readFile(__dirname +'/index.html', function(error, content) {
if (error) {
res.writeHead(500);
res.end();
}
else {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.end(content, 'utf-8');
}
});
} // method GET end
else{ // method POST start
console.log('POST request from ' + req.connection.remoteAddress);
var body = '';
req.on('data', function (data) {
body += data;
if (body.length > 500) {
// FLOOD ATTACK OR FAULTY CLIENT, NUKE REQUEST
req.connection.destroy(); console.log('too much data')}
});
req.on('end', function () {
var postdata = qs.parse(body);
var password = postdata.passwordpost ;
if (password == '7777777') {
console.log('the password is right, download starting');
res.setHeader('Content-disposition', 'attachment; filename='+'test1.exe');
//filename is the name which client will see. Don't put full path here.
res.setHeader('Content-type', 'application/x-msdownload'); //for exe file
res.setHeader('Content-type', 'application/x-rar-compressed'); //for rar file
var readStream = fs.createReadStream('/test1.exe');
//replace filepath with path of file to send
readStream.on('open', function () {
// This just pipes the read stream to the response object (which goes to the client)
readStream.pipe(res);
});
// This catches any errors that happen while creating the readable stream (usually invalid names)
readStream.on('error', function(err) {
console.log (err) ;
res.writeHead(200, { 'Content-Type': 'text/html' });
res.end('an error occured', 'utf-8');
});
//send file
}
else{
console.log ('password wrong');
fs.readFile(__dirname +'/wrongpassword.html', function(error, content) {
if (error) {
res.writeHead(500);
res.end();
}
else {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.end(content, 'utf-8');
}
});
}
}); // req on end function end
}
}).listen(port, host);