Watch a folder for STL files, slice them, then upload the gcode to Octoprint

3dwatch.cs

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;
// csc 3dwatch.cs /r:System.Net.Http.dll
// Run this in a directory where there is a slic3r.ini and where STL or gcode files will be created.
namespace _3dwatch
{
    class Program
    {
        static void Main()
        {
            Func<Processor> processor = () => new Processor();
            var actions = new Dictionary<string, Action<string>>()
            {
                {".stl", (s) => processor().ProcessStl(s)},
                {".gcode", (s) => processor().ProcessGcode(s)},
            };
            Watcher.Create(".", "*.*", actions).Wait();
        }
    }
    public class Watcher
    {
        private readonly Dictionary<string, Action<string>> _actions;
        private readonly FileSystemWatcher _fsw;
        public static Task Create(string path, string mask, Dictionary<string, Action<string>> actions)
        {
            return (new Watcher(path, mask, actions)).Watch();
        }
        private Watcher(string path, string mask, Dictionary<string, Action<string>> actions)
        {
            _actions = actions;
            _fsw = new FileSystemWatcher(path, mask)
            {
                EnableRaisingEvents = true,
                InternalBufferSize = int.Parse(ConfigurationManager.AppSettings["FileSystemWatcher.InternalBufferSize"]),
            };
            _fsw.Created += fsw_Created;
        }
        private Task Watch()
        {
            return new Task(() => { while (true) _fsw.WaitForChanged(WatcherChangeTypes.Created); });
        }
        private void fsw_Created(object sender, FileSystemEventArgs e)
        {
            var action = _actions.FirstOrDefault(x => x.Key == Path.GetExtension(e.Name.ToLower()));
            if (action.Key != null) action.Value(e.Name);
        }
    }
    public class Processor
    {
        private const string CommandTemplate = "\"{0}\" --load {1}";
        private static readonly Func<string, string> Config = (key) => ConfigurationManager.AppSettings[key];
        public void ProcessStl(string name)
        {
            Console.WriteLine(name);
            var arguments = string.Format(CommandTemplate, name, Config("slic3r.ini"));
            var psi = new ProcessStartInfo(Config("slic3r.exe"), arguments)
            {
                RedirectStandardError = true,
                RedirectStandardOutput = true,
                UseShellExecute = false
            };
            try
            {
                var p = Process.Start(psi);
                if (p != null) p.WaitForExit();
                if (p.ExitCode != 0) Console.Write("slic3r: " + p.StandardError.ReadToEnd());
            }
            catch (Exception ex)
            {
                Console.WriteLine("slic3r choked processing {0}: {1}", name, ex.Message);
            }
        }
        public async void ProcessGcode(string name)
        {
            var httpClient = new HttpClient();
            var key = Config("octoprint.apikey");
            if (!string.IsNullOrWhiteSpace(key)) httpClient.DefaultRequestHeaders.Add("X-Api-Key", key);
            var form = new MultipartFormDataContent
            {
                {new StringContent(Config("octoprint.select")), "select"},
                {new StringContent(Config("octoprint.print")), "print"},
            };
            // Devel branch has gotten finicky about content types.
            foreach ( var content in form)
            {
                content.Headers.Remove("Content-Type");
            }
            var file = new ByteArrayContent(File.ReadAllBytes(name));
            file.Headers.Add("Content-Type", "application/octet-stream");
            form.Add(file, "file", name);
            var response = await httpClient.PostAsync(Config("octoprint.address") + "files/" + Config("octoprint.location"), form);
            Console.WriteLine(name + ":" + response.StatusCode);
        }
    }
}

3dwatch.exe.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <appSettings>
    <add key="slic3r.exe" value="c:\temp\slic3r-mswin-x64-1-1-7-stable\Slic3r\slic3r.exe"/>
    <add key="slic3r.ini" value=".\slic3r.ini"/>
    <add key="octoprint.apikey" value="2F91AC719336489CB8202B85B0118D08"/>
    <add key="octoprint.address" value="http://simple/api/"/>
    <add key="octoprint.select" value="false"/>
    <add key="octoprint.print" value="false"/>
    <add key="octoprint.location" value="local"/>
    <add key="FileSystemWatcher.InternalBufferSize" value="8000000" />
  </appSettings>
</configuration>