[3/22/2012] Challenge #29 [intermediate]

var querystring = require("querystring"),
    http = require("http"),
    path = require("path"),
    url = require("url"),
    fs = require("fs");

http.createServer(function(req,res){
    var URL = url.parse(req.url);
    if(URL.pathname === "/favicon.ico") return pipe(__dirname+"/favicon.ico",res);
    if(URL.pathname === "/submit.html"){
        if(req.method == "POST"){
            var body = '';
            req.on("data",function(data){
                body += data;
                if(body.length > 1e6) req.connection.destroy();
            });
            req.on("end",function(){
                saveFormData(querystring.parse(body),res);
            });
            return;
        }else{
            return res.end("No data sent, please try again.");
        }
    }
    return form(res);
}).listen(8000);

function saveFormData(data,res){
    if(data.text){
        var s = fs.createWriteStream(__dirname+"/submitted.txt",{"flags":"a"});
        s.write(data.text+"\n");
        pipe(__dirname+"/submitted.txt",res,{"content-type":"text/plain"});
    }else{
        return res.end("No data sent, please try again.");
    }
}
function form(res){
    res.writeHead(200,{"content-type":"text/html"});
    res.end('<form action="submit.html" method="POST"><textarea name="text"></textarea><input type="submit" /></form>')
}
function pipe(file,res,headers){
    path.exists(file,function(exists){
        if(exists){
            var s = fs.createReadStream(file);
            s.on('error',function(e){
                res.end();
            });
            res.writeHead(200,(headers ? headers:{}));
            s.pipe(res);
        }else{
            res.writeHead(404);
            res.end("The requested file does not exist.");
        }
    });
}