Hey! I learned something!
playing with Html5 Canvas – doing a control loop with thrusters (blue) and rotation control — adding in two fixed points which have gravity.
I’m using m/(r^2) here .. its not quite right, as the two objects are not orbiting each other. I can’t get it to orbit nicely 
I turned off the “clear canvas” bit so that the paths could be seen.
The red bits are drawing of the force lines due to gravity calculations.
As of https://github.com/sunnywiz/dotnetmud2015/tree/blog20160110, I have the following things working:
I am now at a crossroads. There are many directions I can go. I’m crossing things out as I decide that they are not the priority:
1. Develop the “mud” as a communication mud more:
2. Add in realms
3. HTML/Pretty the mud
4. Clean up referencing
4.5 Deploy as a website to Azure
5. Deal with Polling
If I get the above stuff done – definitely 4 and 5 – I think I’ll be in a place where I can start working on my 2D space game.
One day at a time, one session at a time.
There is now a structure by which items can state that they handle various verbs that the users could type in. I use a JIT lookup to figure out what verbs are available to a player – verbs may be sourced from things in their inventory, in themselves, in the room they are in, or from other objects in the room they are in.
I created some more plumbing so that rooms are now aware of other rooms and can get directions to go to those rooms.
As a result, I added a tell_room driver level thing to make communication easier. However, it needs to be updated to handle different messages, one for the person doing the action, and one for everybody else in the room.
The original mud was a single-threaded thing. So whenever a command was executing, this_player() was “who was the command running for”.
My version is multithreaded. I have to pass around a lot more information – hence the “user action execution context” uaec above. I had to know who the player was, what the verb was that was executing, etc. There were several instances where I was using “this.SendOutput()” and the result was that user “Sunny” got messages intended for user “Bunny”.
I keep running into this problem – that I have to pass around “who the current player is”. This will probably become a generic “execution context” like HttpContext is in web apps.
I also know that the verb system I have in place won’t work when we get monsters. We need the ability to have a monster override a user’s ability to go in a certain direction easily. The way this was done in the past was, the monster would override “east”. In my current setup, this would not work as the dictionary of verbs wouldn’t get refreshed. Then again, I’m leaving this whole verb things as a “Sample Mudlib” implementation, not part of the driver – all the driver does is get a command to the right user object and its done.
I also know that I need to create a MyStdObject that’s specific to the implemented mudlib.
Probably the global player list – who – shout – say, emote, tell.
Possibly switch the client to be true HTML rather than monospaced font. Philosophical question if I should do that or not.
And then, the hard bit: Adding polling cycles.
If I can get polling cycles working here, then I’m ready for the space game version.
Code since the last blog post: https://github.com/sunnywiz/dotnetmud2015/compare/7da38a6f…2497ec8
In the original LPC land, the driver was the only way you could create an in-game object. Along with this came several little things like:
In my DotNet world, I’m not limited by who can create which objects. What to do?
Don’t Jit-Load anything. If users want a singleton, they have to implement Instance. All assemblies are loaded into the same appdomain. To change code, have to restart the mud.
This is doable, like a Diku, but not where I want to go. Writing that Instance stuff over and over gets old. Granted, there’s all kinds of C# stuff you could do, but the target audience for LPC was beginner programmers and game designers, not code poets. Less code the better..
I could go with “all code is on disk and I run the compiler against it to generate it and then suck it in”. Not going there yet either.
This is the route I went.
What I’m doing is leaving open some possibilities:
I’m also not saying “Everybody must use the driver to create their in-game objects.” No, I’m saying “if you want to use the driver, you can, and I’ll track things, but if you don’t, I can’t guarantee I can keep track of it.”
The code referenced by this blog post is at this diff: https://github.com/sunnywiz/dotnetmud2015/compare/blog20160106…blog20160107
Here’s some of it running:
Code: https://github.com/sunnywiz/dotnetmud2015/tree/blog20160106
Heading back home today, vacation is about over. For my little pet project, its been a nice little run. Here’s what I got done:
This is the Signal/R Hub. It currently only has two methods / routines / channels – SendOutput and ReceiveInput. It deals with new players connecting.
It tries to offload everything it can to Driver.
Driver is what used to be the driver (efun) level stuff in the old LPC muds. Its where these kinds of things live:
However, Driver does not pretend to know what kind of mud you want to write. So for that purpose, it relies on IGameSpecifics – which I only have one implementation of – to deal with things like “what object do players use” and “what to do with a new connection”.
As mentioned above, this is effectively “master.cs” from the LPC days. However, there’s not a lot of stuff in it about permissions, and stuff like that, as we’re not yet compiling C# code on the fly.
These are all the things that would go into writing your own mud. I have a standard room and user object, and a single room (Lobby). The code for “look” is currently built into User, that will need to move out sometime.
There are many places left to explore in this little codebase:
Uh oh, time to go. Lunch with the family.
The original muds didn’t need this because telnet, but with the spaceship game in mind, I need some way to sync game-data back and forth between server and client.
Without any hard work, the poll looks like this:
So if you have a 200msec lag time, you get a hit every 400msec. That’s assuming upload and download lag are similar.
If you go a little crazier you can work with intermediate frames:
I haven’t coded it yet, but the client is in charge of throttling, and there’s going to be some interesting “what did I try before” “what shall I try now” logic.
There’s also a limit. If the client requested too many intermediate frames, the actual network transport might start bundling the frames together and/or delivering them out of order.
Note that upload and download lag are different – so it might be completely plausible to have 2 or 3 intermediate frames before the client can actually send back its next update.
A more advanced algorithm would have the server asking the client for intermediate frames, but I don’t live in a reality where that needs to be solved.
There’s also some work in the above protocol to figure out server to client time offset. Its not an easy question to handle. And there are also drifting lag speeds – as I write this attached to a 3G Karma Go device. which keeps going from 2 to 3 circles and back.
I don’t need to solve it all now. For starters – all I need is a simple loop. When I get to space ships floating around and changing direction based on user input, then I’ll need the intermediate frame update stuff. Just need to know it is solvable.
I have had some wonderful things happen.
The first is, I married my wife. This happened 8 years ago (I asked her), and its been a fun trip so far. But the best thing is, we keep growing. In this case, I decided that I trusted her to a new level, and I asked her a question: Would she be willing to design a schedule for me?
I struggle with scheduling. More specifically, I struggle with “how much should I be available for others” and life balance.
I also told her of the desire within me to work on this game. Its been an omnipresent inside push since 1991. And there’s so much of it, in the past, when I open up the gates, it floods over and drowns out everything, and burns me out quickly. And.. I don’t know if she understands, but she’s accepting of me, and nurturing of me.
So, I gave her the guidelines of what I had to fit into my life, and she drew me up a plausible schedule. It includes:
AND, it also includes:
As it is wife-suggested, I believe it has a high WAF. (Wife Approval Factor).
So with this established, I can now relax, and let this project flow. It may flow slow, or it may go very fast, but its accounted for.
“Honey, what are you doing?”
“Coding”
As I sit there, leaned back, eyes closed. That is how much stuff is shifting through my brain. Its going very fast. Its like a probe algorithm trying to sort things out. How the heck do I capture this?
Well, in the end, its what gets committed to github: https://github.com/sunnywiz/dotnetmud2015
But its also going to be blog posts here. I run into a quandry. Do I:
The 2nd and 3rd options seem to be the way to go. In general, everything is “here’s what is intended at this time, things may change in the future”, kinda like pre-documenatation.
I’m going to tag them here with the tag “dotnetmud”.
I want to write:
Then, the fun stuff can happen, where I start making a more advanced game of sort, building on the above. While trying to keep the above nicely packaged. This is where my space game really happens, and/or my 2D mud game.
These could all be individual blog posts. Either before, or after, code. All of these have been handled already by industry, I want to expose them for my use with my game(s)
So, yeah, my brain is alive with the sound of code self-organizing. Easy there big boy .. need to do the long haul, not the short burnout.
And I love my wife. She is awesome.
I was listening to Tim Ferris interview Jane McGonigal on the neuro-programming that occurs around playing games. One of the games mentioned was Candy Crush Saga. Curious, I decided to start playing it – and now I find it relaxing, a good place to put my mind when my mind is obsessing about other things.
But of course, being me, I started to wonder, “can I program a solution for this?” Well, of course not – the boards are actually random – but I could write a helper to detect available moves, and possibly future moves.
Turns out a guy already wrote one. See his video explaining how it works here. However, I couldn’t get it to run, and it required me running candy crush on my laptop. And, it didn’t look ahead moves – just the currently available ones. Still, an impressive piece of work.
So I started coding one for fun. I started with this screen:
Question: How many possible moves do you see? (A move for the uninitiated, is swapping adjacent candies so they form at least 3 in a row or 3 in a column). I counted 11 on my initial count.
| I wrote some code to load this into a class, and wrote some methods to load candies. It was a very zen-kata-exercise thing to figure out how to save the board – turns out I didn’t know 2D arrays in C# very well at all (and I still don’t, I chose a different method): |  |
| I wrote a some “possible candy swap” code, and wrote some stuff to find solutions, and wrapped that in a test: |  |
| It says there are 14 moves. What? I don’t have a clean way of outputting the moves yet, so I will have to highlight them by hand. |  (89 ms) |
Here’s what it found:
My attempted fix of the code didn’t work. And its getting late.
I believe the test needs to Assert(13, allPossibleMoves.Count):
Or am I missing something? I will resume this.. some day.
In the mean time, it raises interesting things like:
Happy crushes. I’m at level 35, FWIW.
Oh, and I’m using the test-adapter to run NUnit Tests using Microsoft’s test-running tools.
I have been working on an Asp.Net MVC project (personal) that needed to do Twitter authentication. I learned some things implementing it – presenting here so that I don’t forget them, and also in case anybody else runs into the same problems.
Rather than do a bunch of links below, doing it here – this code depends a lot on LinqToTwitter (https://linqtotwitter.codeplex.com/) to talk to Twitter after getting logged in. Also, for all the snippets of code – I could have used the “C# colorization” CSS stuff, but I chose not to. My wordpress is set up a bit weird, and it doesn’t work quite right.
I created an ASP.Net MVC app with the standard starter template, which gave me an Owin layer that did registration, and allowed for adding an external login to the system.
It didn’t work well for me.
I have to give kudos to @EdCharbeneau. I know him personally, and I was quite surprised to find he had written a blog post about Owin that was the perfect post for me: https://www.simple-talk.com/dotnet/.net-framework/creating-custom-oauth-middleware-for-mvc-5/. It cleared up several things that were not obvious to me.
Here’s how the flow works:
// GET: Read
[Authorize]
public async System.Threading.Tasks.Task<actionresult> Index()
{
You want in, but [Authorize] says you should be authorized. So, do something to authorize the user.
At this point, we have to step back and go to the startup.auth that MVC / Owin likes to do. I won’t get into the details of IAppBuilder and what Owin is, but here’s the relevant configuration code:
app.UseCookieAuthentication(new CookieAuthenticationOptions {
AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
LoginPath = new PathString("/Login"),
ReturnUrlParameter = "redirectUri",
Provider = new CookieAuthenticationProvider() {
}
});
We’re telling OWIN that we want to use a cookie to prove that the user is logged in. If the user aint got the cookie, then send them to /Login to go get them the cookie. When sending them to /Login, pass a parameter of ?redirectUri=xxxx to tell Login where to send the user back to.
So the user shows up at /Login. What happens next? LoginController:
public class LoginController : Controller
{
// GET: Login
public ActionResult Index(string redirectUri)
{
var whenDoneLoggingInUrl = Url.Action("ExternalLoginCallback", "Login", new { ReturnUrl = redirectUri });
return new ChallengeResult("Twitter", whenDoneLoggingInUrl);
}
...
So the way that Oauth works – every provider, has a slightly different way of initiating the go-log-thyself-in thing. In order to work with everybody – there’s a particular type of response that needs to get sent back. In order to hook how to send the right kind of challenge back, we have to write a custom ChallengeResult where we can execute some code as we’re building the result to send back to the browser. This is almost directly lifted from the MVC boilerplate app that ASP.Net provides:
internal class ChallengeResult : HttpUnauthorizedResult
{
public ChallengeResult(string provider, string redirectUri)
{
LoginProvider = provider;
RedirectUri = redirectUri;
}
public string LoginProvider { get; set; }
public string RedirectUri { get; set; }
// public string UserId { get; set; }
public override void ExecuteResult(ControllerContext context)
{
var properties = new AuthenticationProperties { RedirectUri = RedirectUri };
// this does the 302 or whatever the login provider wants you to do.
context.HttpContext.GetOwinContext().Authentication.Challenge(properties, LoginProvider);
}
}
Ah, but that LoginProvider — how is there code that knows what to do there? That comes in a bit more of startup.auth.cs code:
var options = new TwitterAuthenticationOptions()
{
ConsumerKey = ConfigurationManager.AppSettings["TwitterConsumerKey"],
ConsumerSecret = ConfigurationManager.AppSettings["TwitterConsumerSecret"],
Provider = new LinqToTwitterAuthenticationProvider()
};
app.UseTwitterAuthentication(options);
TwitterAuthenticationOptions is a microsoft-provided class that does the right challenge to send stuff to Twitter; it also handles when twitter redirects back to our app, and handles getting the claims and all that. Perhaps. The LinqToTwitterAuthenticationProvider might do some of that as well, I haven’t delved too deeply into what that does differently from the microsoft provided one.
There’s one more little bit of code that needs to happen to get things to work:
app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);
This tells the authentication provider how to hold on to information as its doing the login process.
So where does this leave us at? Well, the negotiation with twitter happens; it comes back to the Oauth provider (which we can’t see the code of), the user gets approved, and we pick up some claims from twitter, and everything calls back into the “whenDoneLoggingIn” url we defined above. That leads us to:
public ActionResult ExternalLoginCallback(string returnUrl)
{
var owinContext = HttpContext.GetOwinContext();
var loginInfo = owinContext.Authentication.GetExternalLoginInfo();
if (loginInfo == null)
{
// did not survive the login process
return View("LoginFailure");
}
// log them in persistently here!
// we have to create a new claims identity with authentication type cookie.
// i could probably copy the claims over easier...
var claims = new List<Claim>();
foreach (var externalClaim in loginInfo.ExternalIdentity.Claims)
{
claims.Add(externalClaim);
}
var id = new ClaimsIdentity(claims,
DefaultAuthenticationTypes.ApplicationCookie);
// https://stackoverflow.com/questions/23180896/how-to-remember-the-login-in-mvc5-when-an-external-provider-is-used/23228005#23228005
owinContext.Authentication.SignIn(
new AuthenticationProperties
{
IsPersistent = true,
AllowRefresh = true
}, id);
return new RedirectResult(returnUrl);
}
Whoo that’s a lot of code. Lets walk it. Side note: Every time I find an answer that I use on StackOverflow, I try to attribute it in the code that I generate, and up arrow the answer I used.
First is, the possibility that we didn’t get a successful login from twitter. If so, login failed. Boom. Done.
Otherwise, we have a list of claims about the user. Twitter gives us about 6 claims –
I need to copy these claims over to a new list of claims, create a new ClaimsIdentity based on those claims (but with a different AuthenticationType – remember that you can be logged in with 3 identities at the same time), and then log that new identity in; the user gets logged in via CookieAuthentication.
The result of this is a persistent cookie in the browser which is an encrypted version of the 6 claims, plus an expiration time and several other things:
And finally, the user is re-directed back to where they started – the Controller which had the [Authorize] attribute that intercepted the request.
This time, when the user requests the page, the cookie is decrypted and unraveled into a list of claims that we know about the user. Then, in the page that was requested, if I want to talk to twitter to get stuff, I can do the following:
var userInfo = _cq.GetLoggedInUser();
using (var twitterCtx = await _cq.GetTwitterContextAsync())
{
var tweets = _cq.GetHomeTweetsQueryable(twitterCtx).ToList();
}
The heavy lifting I’ve put into a CommandsAndQueries class (* controversial; seprate topic) –
public LoggedInUser GetLoggedInUser()
{
if (_context == null) return null;
var owinContext = _context.GetOwinContext();
if (owinContext == null) return null;
var authman = owinContext.Authentication;
if (authman == null) return null;
if (authman.User == null) return null;
// C#6 will make this prettier.
var loggedInUser = new LoggedInUser();
foreach (var claim in authman.User.Claims)
{
// Claims:
// http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier = 152333310
// http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name = sunjeevgulati
// urn:twitter:userid = 152333310
// urn:twitter:screenname = sunjeevgulati
// TwitterAccessToken = ;
// TwitterAccessTokenSecret = ;
switch (claim.Type)
{
case "urn:twitter:userid": loggedInUser.TwitterId = ulong.Parse(claim.Value); continue;
case "urn:twitter:screenname": loggedInUser.TwitterScreenName = claim.Value; continue;
default:
continue;
}
}
return loggedInUser;
}
This is code which looks at the logged in user, interrogates the claims, and if it finds the claim that has a particular piece of information, extracts just that claim, into a little DTO helper object.
A more complicated one to get a LinqToTwitter context:
public async Task GetTwitterContextAsync()
{
var credStore = new SessionStateCredentialStore(); // i frequently loose session, so need to rejigger this
if (!credStore.HasAllCredentials())
{
if (_context == null) return null;
var owinContext = _context.GetOwinContext();
if (owinContext == null) return null;
var authman = owinContext.Authentication;
if (authman == null) return null;
if (authman.User == null) return null;
foreach (var claim in authman.User.Claims)
{
switch (claim.Type)
{
case "urn:twitter:userid": credStore.UserID = ulong.Parse(claim.Value); continue;
case "urn:twitter:screenname": credStore.ScreenName = claim.Value; continue;
case "TwitterAccessToken": credStore.OAuthToken = claim.Value; continue;
case "TwitterAccessTokenSecret": credStore.OAuthTokenSecret = claim.Value; ; continue;
default:
continue;
}
}
credStore.ConsumerKey = ConfigurationManager.AppSettings["TwitterConsumerKey"];
credStore.ConsumerSecret = ConfigurationManager.AppSettings["TwitterConsumerSecret"];
await credStore.StoreAsync();
if (!credStore.HasAllCredentials()) throw new NotSupportedException("Could not get credential store to have all credentials!");
}
return new TwitterContext(new MvcAuthorizer() { CredentialStore = credStore });
}
Its the same idea, except that it needs a few more claims, as well as the two things stored in AppSettings.
Finally, the call to get tweets for the home screen, lifted almost directly from the LinqToTwitter documentation:
public IQueryable GetHomeTweetsQueryable(TwitterContext twitterCtx)
{
return (from tweet in twitterCtx.Status
where tweet.Type == StatusType.Home
&& tweet.Count == 200
&& tweet.IncludeContributorDetails == true
&& tweet.IncludeEntities==true
select tweet);
}
That’s a long way to go around; but, that is what it takes, with all these different black boxes talking to each other, to get the app to work. Hope this helps you save some time doing your own things.
I recently upgrade my mom’s store to use The Uniform Solution – it’s a point-of-sale + inventory + EDI ordering software designed specifically for stores that deal with uniforms and scrubs and stuff like that. And speaking as a software developer, the experience was awesome.
I want to call them out on some of the stuff they did well:
They don’t do anything overly fancy. They have a SQL Express database; they have a client that interfaces to the database. The “main computer” has a share, other clients map to the share and run the same executable. It’s a little unnerving – the share is wide open – however, if you’re enabling WIFI at your store direct to your internal network, you’ve got other problems going on. And, I’m sure it could be locked down; their target audience usually doesn’t have an IT department, so they did the right thing for their market.
For a web server, we’re not using it (yet), but it looks like a stand-alone executable that hosts the website. Well done.
Server install – Single executable – run – it detects if its upgrading or installing. It downloads SQLExpress 2012 and totally auto-scripts the install of it (much to my chagrin, I could not easily hack into their database and look at tables directly.. I wanted to see what their schema looked like).
They stick everything in C:\USW.
Client install – Map a network drive to the server share; run an executable – it makes sure that firewall settings are set up correctly, sets up an icon, done.
Once their software comes up, it has a failsafe option – if it can’t connect, you can configure it to help it find its SQL Server. Well done! as in, they didn’t assume that that part will work all the time.
The running software automatically keeps track of who is logged in concurrently. I suspect they use some network broadcast type stuff. I’m reminded of the 1990’s “net send” command, for some reason.
They provide their own backup and restore functionality – Everything gets dumped into a single file (extension .bsql – I think it’s a zip of schema + data). They automatically take a backup first thing in the morning (first time a person logs in to the system in a day). I found their auto-backup directory, and I added a script to it to sync the latest N files to dropbox as an off-site solution (different blog post). I did do one restore; I need to do another with the offsite stuff.
Side note: I tried to use an azure VM to do the DRP restore session, but their software had a hard time installing SQLEXPRESS on Windows Server 2012 and then finding it later. Will do the restore on my surface at some point just to make sure its possible. Which is actually perfect – my surface was used as a client for a while – we hooked a usb barcode scanner to it and mom walked through her shop importing inventory with it (we were waiting for the bluetooth wireless scanner to arrive. Prime is only so fast.) Ie, just like in the real world, if the server dies, we’ll probably promote client #1 to be the server – so test restoring on that laptop would be the ideal DRP test.
I had to call them a few times. Freaking awesome – they people I talked to, not just some help desk lackey. These were highly competent technical people (I can tell the difference). At the first sign of miscommunication, they immediately went into “let me remote in and look at your screen” mode and took it from there.
I could also tell that these people are a team. They trust each other. They like what they do. They don’t want to grow big and take over the world, they want to be excellent and do excellent and completely solve the one corner of the universe that they have adopted.
After using the software for a bit – especially on their point of sale screen – I came to appreciate the love and care they have put into their product. Little things, like “type in stuff in the text box – if its decimal and less than 1, it’s a %off; if its integer between 1 and 99, it’s a quantity” etc – made the system very efficient to use. I came home and used the same idea on our fridge-inventory-scanner app at work. (different blog post)
All in all, a big huge THUMBS UP for these dudes. If I ever get into providing a specific solution to a specific market, I’m totally going to try to live up to these folk’s standards.
The only thing that I would suggest to them – because they have such a wide-ranging system – is perhaps a “day in the life of” video series for prospective customers. Ie, show a real life scenario of “here’s how a clerk uses the system” vs “here’s how an owner users the system”, etc. Especially if its people who like using the system, who can show off their favorite shortcuts, etc.
