.NET FrameworkHTTP servers

Basic read-only HTTP file server (HttpListener)

Notes:

This example must be run in administrative mode.

Only one simultaneous client is supported.

For simplicity, filenames are assumed to be all ASCII (for the filename part in the Content-Disposition header) and file access errors are not handled.

using System;
using System.IO;
using System.Net;

class HttpFileServer
{
    private static HttpListenerResponse response;
    private static HttpListener listener;
    private static string baseFilesystemPath;

    static void Main(string[] args)
    {
        if (!HttpListener.IsSupported)
        {
            Console.WriteLine(
                "*** HttpListener requires at least Windows XP SP2 or Windows Server 2003.");
            return;
        }

        if(args.Length < 2)
        {
            Console.WriteLine("Basic read-only HTTP file server");
            Console.WriteLine();
            Console.WriteLine("Usage: httpfileserver <base filesystem path> <port>");
            Console.WriteLine("Request format: http://url:port/path/to/file.ext");
            return;
        }

        baseFilesystemPath = Path.GetFullPath(args[0]);
        var port = int.Parse(args[1]);

        listener = new HttpListener();
        listener.Prefixes.Add("http://*:" + port + "/");
        listener.Start();

        Console.WriteLine("--- Server stated, base path is: " + baseFilesystemPath);
        Console.WriteLine("--- Listening, exit with Ctrl-C");
        try
        {
            ServerLoop();
        }
        catch(Exception ex)
        {
            Console.WriteLine(ex);
            if(response != null)
            {
                SendErrorResponse(500, "Internal server error");
            }
        }
    }

    static void ServerLoop()
    {
        while(true)
        {
            var context = listener.GetContext();

            var request = context.Request;
            response = context.Response;
            var fileName = request.RawUrl.Substring(1);
            Console.WriteLine(
                "--- Got {0} request for: {1}", 
                request.HttpMethod, fileName);

            if (request.HttpMethod.ToUpper() != "GET")
            {
                SendErrorResponse(405, "Method must be GET");
                continue;
            }

            var fullFilePath = Path.Combine(baseFilesystemPath, fileName);
            if(!File.Exists(fullFilePath))
            {
                SendErrorResponse(404, "File not found");
                continue;
            }

            Console.Write("    Sending file...");
            using (var fileStream = File.OpenRead(fullFilePath))
            {
                response.ContentType = "application/octet-stream";
                response.ContentLength64 = (new FileInfo(fullFilePath)).Length;
                response.AddHeader(
                    "Content-Disposition",
                    "Attachment; filename=\"" + Path.GetFileName(fullFilePath) + "\"");
                fileStream.CopyTo(response.OutputStream);
            }

            response.OutputStream.Close();
            response = null;
            Console.WriteLine(" Ok!");
        }
    }

    static void SendErrorResponse(int statusCode, string statusResponse)
    {
        response.ContentLength64 = 0;
        response.StatusCode = statusCode;
        response.StatusDescription = statusResponse;
        response.OutputStream.Close();
        Console.WriteLine("*** Sent error: {0} {1}", statusCode, statusResponse);
    }
}

Basic read-only HTTP file server (ASP.NET Core)

1 - Create an empty folder, it will contain the files created in the next steps.

2 - Create a file named project.json with the following content (adjust the port number and rootDirectory as appropriate):

{
  "dependencies": {
    "Microsoft.AspNet.Server.Kestrel": "1.0.0-rc1-final",
    "Microsoft.AspNet.StaticFiles": "1.0.0-rc1-final"
  },

  "commands": {
    "web": "Microsoft.AspNet.Server.Kestrel --server.urls http://localhost:60000"
  },

  "frameworks": {
    "dnxcore50": { }
  },

  "fileServer": {
    "rootDirectory": "c:\\users\\username\\Documents" 
  }
}

3 - Create a file named Startup.cs with the following code:

using System;
using Microsoft.AspNet.Builder;
using Microsoft.AspNet.FileProviders;
using Microsoft.AspNet.Hosting;
using Microsoft.AspNet.StaticFiles;
using Microsoft.Extensions.Configuration;

public class Startup
{
    public void Configure(IApplicationBuilder app)
    {
        var builder = new ConfigurationBuilder();
        builder.AddJsonFile("project.json");
        var config = builder.Build();
        var rootDirectory = config["fileServer:rootDirectory"];
        Console.WriteLine("File server root directory: " + rootDirectory);

        var fileProvider = new PhysicalFileProvider(rootDirectory);

        var options = new StaticFileOptions();
        options.ServeUnknownFileTypes = true;
        options.FileProvider = fileProvider;
        options.OnPrepareResponse = context =>
        {
            context.Context.Response.ContentType = "application/octet-stream";
            context.Context.Response.Headers.Add(
                "Content-Disposition",
                $"Attachment; filename=\"{context.File.Name}\"");
        };
        
        app.UseStaticFiles(options);
    }
}

4 - Open a command prompt, navigate to the folder and execute:

dnvm use 1.0.0-rc1-final -r coreclr -p
dnu restore

Note: These commands need to be run only once. Use dnvm list to check the actual number of the latest installed version of the core CLR.

5 - Start the server with: dnx web. Files can now be requested at http://localhost:60000/path/to/file.ext.

For simplicity, filenames are assumed to be all ASCII (for the filename part in the Content-Disposition header) and file access errors are not handled.