将数据发送到Node.js服务器

Question

I'm learning nodejs at the moment and I'm stuck with a few things. I'm creating a server that's serving a html file. That html file has a js that does an xmlHttpRequest to get data. The data I'm retrieving I want to send back to my server to process it. And that last step is where I'm stuck. every time the server stops, while I would like to receive the urls in the server to process them.

Server.js

var http = require('http'),
    url = require('url'),
    path = require('path'),
    fs = require('fs');

var mimeTypes = {
    "html": "text/html",
    "js": "text/javascript",
    "css": "text/css"};

    http.createServer(function(request, response){

        var uri = url.parse(request.url).pathname;
        var filename = path.join(process.cwd(), uri);

        fs.exists(filename, function(exists){
            if(!exists){
                console.log(filename + " does not exist");
                response.writeHead(200, {'Content-Type' : 'text/plain'});
                response.write('404 Not found\n');
                response.end();
                return;
            }

            var mimeType = mimeTypes[path.extname().split(".")[1]];
            response.writeHead(200, {'Content-Type' : mimeType});

            var fileStream = fs.createReadStream(filename);
            fileStream.pipe(response);
        });

    response.on('end', function(){
        console.log("Request: " + request);
        console.log("Response: " + response);
    });

    }).listen(1337);

Client.js

function getURLs(){
    var moduleURL = document.getElementById("url").value;
    var urls = [];
    console.log(moduleURL);

    xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange=function(){
      if (xmlhttp.readyState==4 && xmlhttp.status==200){
            var xml = xmlhttp.responseXML;
            var items = xml.children[0].children[0].children;

            for(var i = 13; i<items.length; i++){
                urls.push(items[i].children[1].getAttribute("url")+"&hd=yes");
            }

            //console.log(urls);
            sendDataToServer(urls);
        }
      }
    xmlhttp.open("GET", moduleURL, true); 
    xmlhttp.send();

}

function sendDataToServer(urls){
    //console.log(urls);

    var http = new XMLHttpRequest();
    http.open("POST", "http://127.0.0.1:1337/", true);
    http.send(urls);
}

I'm getting this in the console of the browser

POST http://127.0.0.1:1337/ net::ERR_CONNECTION_REFUSED

And this in cmd of node

events.js:72 throw er; // Unhandled 'error' event ^ Error: EISDIR, read

And while it's processing the data I would like to send back the progress to the client to show it on the html page for the end user. I already have the function of the progress it's only the sending/receiving of data where I am stuck. Can someone point me in the correct direction please?

I also know that there is express and other modules that I can use, but to learn node I'm trying it to do it this way. So I hope someone can push me in the correct direction.

Answer 1

events.js:72 throw er; // Unhandled 'error' event ^ Error: EISDIR, read

This error means that the file you're trying to read is actually a directory.

What you need to do is make sure that the file is really a file as the function fs.exists() is only for files.

In this example fs.lstat() is used to get a fs.stat object which has the methods you need to make sure that a file is of the right type.

var http = require('http'),
url = require('url'),
path = require('path'),
fs = require('fs');

var mimeTypes = {
    "html": "text/html",
    "js": "text/javascript",
    "css": "text/css"
};

http.createServer(function(request, response){

    var uri = url.parse(request.url).pathname;
    var filename = path.resolve(path.join(process.cwd(), uri));
    console.log(filename);

    // Get some information about the file
    fs.lstat(filename, function(err, stats) {

      // Handle errors
      if(err) {
        response.writeHead(500, {'Content-Type' : 'text/plain'});
        response.write('Error while trying to get information about file\n');
        response.end();
        return false;
      }

      // Check if the file is a file.
      if (stats.isFile()) {

        fs.exists(filename, function(exists){
            if(!exists){
                console.log(filename + " does not exist");
                response.writeHead(200, {'Content-Type' : 'text/plain'});
                response.write('404 Not found\n');
                response.end();
                return;
            }

            var mimeType = mimeTypes[path.extname().split(".")[1]];
            response.writeHead(200, {'Content-Type' : mimeType});

            var fileStream = fs.createReadStream(filename);
            fileStream.pipe(response);
        });

      } else {
        // Tell the user what is going on.
        response.writeHead(404, {'Content-Type' : 'text/plain'});
        response.write('Request url doesn\'t correspond to a file. \n');
        response.end();
      }

    });

response.on('end', function(){
    console.log("Request: " + request);
    console.log("Response: " + response);
});

}).listen(1337);