Node.js: chunked transfer encoding

Question

Is that code valid HTTP/1.1?

var fs = require('fs')
var http = require('http')

var buf=function(res,fd,i,s,buffer){
 if(i+buffer.length<s){
  fs.read(fd,buffer,0,buffer.length,i,function(e,l,b){
   res.write(b.slice(0,l))
   //console.log(b.toString('utf8',0,l))
   i=i+buffer.length
   buf(res,fd,i,s,buffer)
  })
 }
 else{
  fs.read(fd,buffer,0,buffer.length,i,function(e,l,b){
   res.end(b.slice(0,l))
   fs.close(fd)
  })
 }
}

var app = function(req,res){
 var head={'Content-Type':'text/html; charset=UTF-8'}
 switch(req.url.slice(-3)){
  case '.js':head={'Content-Type':'text/javascript'};break;
  case 'css':head={'Content-Type':'text/css'};break;
  case 'png':head={'Content-Type':'image/png'};break;
  case 'ico':head={'Content-Type':'image/x-icon'};break;
  case 'ogg':head={'Content-Type':'audio/ogg'};break;
  case 'ebm':head={'Content-Type':'video/webm'};break;
 }
 head['Transfer-Encoding']='chunked'
 res.writeHead(200,head)
 fs.open('.'+req.url,'r',function(err,fd){
  fs.fstat(fd,function(err, stats){
   console.log('.'+req.url+' '+stats.size+' '+head['Content-Type']+' '+head['Transfer-Encoding'])
   var buffer = new Buffer(100)
   buf(res,fd,0,stats.size,buffer)
  })
 })
}

http.createServer(app).listen(8000,"127.0.0.1")
console.log('GET http://127.0.0.1:8000/appwsgi/www/index.htm')

I think I am violating HTTP/1.1 here? Text files do seem to work fine, but that could be coincidental. Is my header "200 OK" or need it to be "100"? Is one header sufficient?

Answer 1

If you're doing chunked transfer encoding, you actually need to set that header:

Transfer-Encoding: chunked

You can see from the headers returned by google, which does chunked transfers for the homepage and most likely other pages:

HTTP/1.1 200 OK
Date: Sat, 04 Jun 2011 00:04:08 GMT
Expires: -1
Cache-Control: private, max-age=0
Content-Type: text/html; charset=ISO-8859-1
Set-Cookie: PREF=ID=f9c65f4927515ce7:FF=0:TM=1307145848:LM=1307145848:S=fB58RFtpI5YeXdU9; expires=Mon, 03-Jun-2013 00:04:08 GMT; path=/; domain=.google.com
Set-Cookie: NID=47=UiPfl5ew2vCEte9JyBRkrFk4EhRQqy4dRuzG5Y-xeE---Q8AVvPDQq46GYbCy9VnOA8n7vxR8ETEAxKCh-b58r7elfURfiskmrOCgU706msiUx8L9qBpw-3OTPsY-6tl; expires=Sun, 04-Dec-2011 00:04:08 GMT; path=/; domain=.google.com; HttpOnly
Server: gws
X-XSS-Protection: 1; mode=block
Transfer-Encoding: chunked

EDIT Yikes, that read is way too complicated:

var app = function(req,res){
 var head={'Content-Type':'text/html'}
 switch(req.url.slice(-3)){
  case '.js':head={'Content-Type':'text/javascript'};break;
  case 'css':head={'Content-Type':'text/css'};break;
  case 'png':head={'Content-Type':'image/png'};break;
  case 'ico':head={'Content-Type':'image/x-icon'};break;
  case 'ogg':head={'Content-Type':'audio/ogg'};break;
  case 'ebm':head={'Content-Type':'video/webm'};break;
 }
 res.writeHead(200,head)
 var file_stream = fs.createReadStream('.'+req.url);
 file_stream.on("error", function(exception) {
   console.error("Error reading file: ", exception);
 });
 file_stream.on("data", function(data) {
   res.write(data);
 });
 file_stream.on("close", function() {
   res.end();
 });
}

There you go, a nice streamed buffer for you to write with. Here's a blog post I wrote on different ways to read in files. I recommend looking that over so you can see how to best work with files in node's asynchronous environment.