GiveMeGold.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;
using System.Web;
using Newtonsoft.Json.Linq;

namespace GiveMeGold
{
	internal class Program
	{
		private static string ReadPassword()
		{
			// Taken from http://stackoverflow.com/questions/3404421/password-masking-console-application
			string pass = "";
			ConsoleKeyInfo key;
			do
			{
				key = Console.ReadKey(true);

				if (key.Key != ConsoleKey.Backspace && key.Key != ConsoleKey.Enter)
				{
					pass += key.KeyChar;
					Console.Write("*");
				}
				else
				{
					if (key.Key == ConsoleKey.Backspace && pass.Length > 0)
					{
						pass = pass.Substring(0, (pass.Length - 1));
						Console.Write("\b \b");
					}
				}
			} while (key.Key != ConsoleKey.Enter);

			Console.WriteLine();

			return pass;
		}

		internal static void Main(string[] args)
		{
			Console.Write("Enter user name: ");
			string userName = Console.ReadLine();
			Console.Write("Enter password: ");
			string password = ReadPassword();

			dynamic login = JObject.Parse(
				PostToReddit("api/login", null,
				             new Dictionary<string, string>
				             {
					             ["user"] = userName,
					             ["passwd"] = password,
					             ["api_type"] = "json",
					             ["rem"] = "true"
				             }));

			login = login.json;

			dynamic errors = login.errors;
			if (errors.Count > 0)
			{
				Console.WriteLine("Error: {0}", string.Join(", ", errors));
				Console.ReadLine();
				return;
			}

			dynamic data = login.data;
			string cookie = "reddit_session=" + HttpUtility.UrlEncode((string)data.cookie, Encoding.UTF8);
			string modhash = data.modhash;

			const string clientId = "ohXpoqrZYub1kg";
			const string redirectUri = "http://localhost:65010/callback";
			const string allScopes =
				"identity,read,vote,report,submit,edit,history,flair,modconfig," +
				"modflair,modlog,modposts,modwiki,save,mysubreddits," +
				"privatemessages,subscribe,wikiedit,wikiread,account,creddits";

			string guid = Guid.NewGuid().ToString();
			PostToReddit("api/v1/authorize",
			             req =>
			             {
				             req.Headers.Add("Cookie", cookie);
				             req.Headers.Add("X-Modhash", modhash);
			             },
			             new Dictionary<string, string>
			             {
				             ["client_id"] = clientId,
				             ["redirect_uri"] = redirectUri,
				             ["scope"] = allScopes,
				             ["state"] = guid,
				             ["duration"] = "permanent",
				             ["authorize"] = "allow",
				             ["response_type"] = "code",
			             });

			Console.WriteLine("Done! Check your Reddit inbox!");
			Console.ReadLine();
		}

		private static string PostToReddit(string api, Action<HttpWebRequest> setup,
		                                   Dictionary<string, string> formParams)
		{
			HttpWebRequest request = WebRequest.CreateHttp($"https://www.reddit.com/{api}");
			request.Method = "POST";
			request.UserAgent = "RedditAndroid 0.3.2";
			request.AllowAutoRedirect = false;
			setup?.Invoke(request);
			using (StreamWriter sw = new StreamWriter(request.GetRequestStream()))
			{
				bool first = true;
				foreach (KeyValuePair<string, string> kvp in formParams)
				{
					if (!first)
						sw.Write('&');

					sw.Write(kvp.Key);
					sw.Write('=');
					sw.Write(kvp.Value);
					first = false;
				}
			}

			using (WebResponse response = request.GetResponse())
			{
				var respStr = new StreamReader(response.GetResponseStream()).ReadToEnd();
				return respStr;
			}
		}
	}
}