A simple Node HTTP server that executes JavaScript files and displays the results

dynamic_server.js

/*jslint onevar: true, undef: true, newcap: true, nomen: true, regexp: true, plusplus: true, bitwise: true, node: true, indent: 4, white: false */

/// Usage: node dynamic_server.js PORT

var fs    = require("fs"),
    http  = require("http"),
    path  = require("path"),
    spawn = require('child_process').spawn,
    url   = require("url"),
    qs    = require('querystring'),
    
    port = process.argv[2] || 8888; /// Defaults to port 8888

/// Start the server.
http.createServer(function (request, response)
{
    var filename,
        post_data = "",
        uri = url.parse(request.url).pathname;
    
    filename = path.join(process.cwd(), uri);
    
    function request_page(post_data)
    {
        path.exists(filename, function (exists)
        {
            /// If the URI does not exist, display a 404 error.
            if (!exists) {
                response.writeHead(404, {"Content-Type": "text/plain"});
                response.write("404 Not Found\n");
                response.end();
                return;
            }
            
            /// If the URI is a directory, try to load index.js, then index.html, then index.htm.
            if (fs.statSync(filename).isDirectory()) {
                if (path.existsSync(filename + "/index.js")) {
                    filename += "/index.js";
                } else if (path.existsSync(filename + "/index.html")) {
                    filename += "/index.html";
                } else {
                    filename += "/index.htm";
                }
            }
            
            /// The dynamic part:
            /// If the file is a JavaScript file, execute it and write the results.
            if (filename.slice(-3) === ".js") {
                ///NOTE: Executing a command is not secure, but right now, node always caches files that are require'd().
                (function ()
                {
                    var cmd = spawn("node", (typeof post_data === "undefined" ? [filename] : [filename, post_data])),
                        has_written_head = false;
                    
                    cmd.stdout.on("data", function (data)
                    {
                        if (!has_written_head) {
                            response.writeHead(200);
                            has_written_head = true;
                        }
                        response.write(data);
                    });
                    
                    cmd.stderr.on("data", function (data)
                    {
                        if (!has_written_head) {
                            response.writeHead(500, {"Content-Type": "text/plain"});
                            has_written_head = true;
                        }
                        /// Display any errors.
                        response.write(data);
                    });
                    
                    cmd.on("exit", function (code)
                    {
                        response.end();
                    });
                }());
            } else {
                /// Write the static file.
                fs.readFile(filename, "binary", function (err, file)
                {
                    /// If the file cannot be loaded, display a 500 error.
                    if (err) {
                        response.writeHead(500, {"Content-Type": "text/plain"});
                        response.write(err + "\n");
                        response.end();
                        return;
                    }
                    
                    /// If the file loads correctly, write it to the client.
                    response.writeHead(200);
                    response.write(file, "binary");
                    response.end();
                });
            }
        });
    }
    
    /// Is there POST data?
    if (request.method === "POST") {
        
        request.on("data", function(chunk)
        {
            /// Get the POST data.
            post_data += chunk.toString();
        });
        
        request.on("data", function(chunk)
        {
            ///NOTE: POST data can be retrieved via the following code:
            ///      post_data = JSON.parse(process.argv[2]);
            request_page(JSON.stringify(qs.parse(post_data)));
        });
        
    } else {
        request_page();
    }
}).listen(parseInt(port, 10));

console.log("Static file server running at\n  => http://localhost:" + port + "/\nCTRL + C to shutdown");

Rewrote the way the script executes programs to make it safer and get around the max limit exceeded error.

It now handles POST data. To get access to the POST data, you can use the following code in the child script.

if (process.argv[2]) {
post_data = JSON.parse(process.argv[2]);
}