Category: C#

Using JSON as a datastore in C#

Using JSON as a datastore in C#

Shapes
Image by Gerd Altmann from Pixabay

For some not too complex applications, JSON can be a very handy way to store data rather than say using a database. It also has the advantage of storing data of varying sizes. For instance Lists with varying numbers of items. I created a Saveable generic class below that you use as an ancestor class for that you wish to Save/Load an IList of whatever.

 

 

    public class SaveAble<T>
    {
        private string _error = "";
        string LastError()
        {
            return _error;
        }
        public IList<T>? Load(string filePath)
        {
            if (!File.Exists(filePath))
            {
                Log.Error("Missing file {filePath}");
                _error = $"Missing file {filePath}";
                return null;
            }

            var content = File.ReadAllText(filePath);
            if (string.IsNullOrEmpty(content))
            {
                Log.Error("{filePath} file is empty");
                _error=$"{filePath} file is empty";
                return null;
            }

            return JsonSerializer.Deserialize<IList<T>>(content, new JsonSerializerOptions
            {
                PropertyNameCaseInsensitive = true
            })!;
        }

        public bool Save(string filename,IList<T> collection)
        {
            var options = new JsonSerializerOptions
            {
                WriteIndented = true,
                PropertyNameCaseInsensitive = true
            };
            try
            {
                var bytes = JsonSerializer.SerializeToUtf8Bytes(collection, options);
                File.WriteAllBytes(filename, bytes);
                return true;
            }catch (Exception ex)
            {
                _error = $"Exception:{ex.Message}";
                return false;
            }
        }

    }

Just define your class MyClasses from SaveAble<MyClass>

where MyClass is the class you have a List of. Then you can do

MyClasses myclasses;
myclasses.Save("filename",List<MyClass>) and

List<MyClass> list = myclasses.Load("filename");

It is fast. On my PC (now six years old), it can load a 99,000 line JSON file in well under a second.

Why C# for the server?

Why C# for the server?

https://commons.wikimedia.org/wiki/File:Csharp_Logo.png
From Wikimedia

There are plenty of other programming languages that would do.  Programming languages are just tools but C# comes with several advantages.

  1. I know it pretty well, having been using it since 2005.
  2. With .NET 6 (and 5), it’s easy to create applications that run on Linux. This lowers the cost for hosting. I’m setting the game on a low cost VPS.
  3. Also on Linux, ASP.NET works pretty well for both Websites and Web Apis.
  4. I like some of the recent changes in C#. And Visual Studio 2022 Community Edition is pretty good. For instance the JSON handling has got better and better.

Do you know what Hello World in C# looks like now? Here it is in its entirety.

Console.WriteLine("Hello, World!");

That’s a console application. One line! Follow the link for more details about the C# templates. Note, there’s no usings there either. That’s because applications now start with a default set in C# 10 and .NET 6 (you get both if you install VS 2022). And if you want a particular namespace that you’ve written to be available to all source code in a project, you can just add this:

global using xyz;

And it becomes available everywhere without needing any more usings.

 

A new beginning – C#

A new beginning – C#

Postage
Image by Please Don’t sell My Artwork AS IS from Pixabay

You may have noticed, I stopped posting here a while back because basically I ran out of ideas for C related games stuff plus I was doing other stuff that wasn’t relevant (Delphi, C#).

I will get back to finishing my 2nd eBook, but for now, I’m working on a web/mobile game that isn’t really C related. However I thought I’d cover development of it here. as (a) part of it is C# (so technically it’s C and (b) it’s a game.  The backend part is C#, the front end Flutter which is Dart. I’m also going back to my old game design roots as the game architecture is ‘Postal Game’.

What is ‘Postal Game’ architecture?

Well first a little potted history.

Back before the web existed (late 80s), people used to play games by post. They’d fill in a postcard with the orders, post it to the game provider who would enter the details in a computer, process the game then print the results out and post that back. I discovered this (in the UK) back in 1986 and created a postal game: Casus Belli. A 16 player version of Empire. It ran for a year or so and I even attended a postal games conference with a stall back at the start of 1987 in London. By chance, the stall next to mine was run by KJC Games and we got chatting. Kevin J Cropper (The KJC of KJC Games) said “If I ever wanted to sell the game contact me” and at the end of 1987 I did and found myself working for KJC Games as a game designer and programmer in Cleveleys (just North of Blackpool). It was a small cottage industry in the UK and KJC Games was the biggest fish in this admittedly small pond.

Over the next two and a half years I created the 100 player version of Casus called Warlord. Long after I left they ran games across the web and though they don’t run it any more you can still see the page for it. My big creation was a 1,000 player postal game called Quest which KJC still runs. Not bad for a game created in 1989! They still have my name in the Advanced rules which is nice as I last did some work on it in 1996. It took me a year and 40,000 lines of code (Turbo Pascal 5) to create. The others listed helped test it, made suggestions and Steven Fairbrother who came along after I left, fixed my bugs.  When you write 40,000 lines of code in a year, there are a few bugs included…

So each turn gets posted in, processed, printed and posted back. The architecture is the same except its all now sent across the web. There’s a front end programmed in Flutter. This makes it possible to use the same code for Web and mobile development. The game is processed at a fixed rate. In this case I’m going for every three hours but slower or faster is possible. When it’s time, all orders are processed and the results made available to be fetched from the web or mobile device.

Pros and Cons

A Game Processing Engine (GPE) is a completely different kettle of fish from your traditional multi player game server. Hardware requirements are much less and you don’t manage multiple players all at once. Basically the game web/mobile uploads a zip file from each player to send in the orders and then fetches one containing the results. The GPE maintains game state, processes all orders, outputs all results and backs up the game, both before processing each turn (in case it goes wrong so it can be fixed and rerun) and afterwards,

So I’ll be posting here about my progress, programming issues and so on. If you have any queries, please don’t add them as comments – I delete any non-technical comments so instead use the contact form via the About me link on the top.

 

 

Work in Progress – Web game

Work in Progress – Web game

Blazor AppI did some investigative work on this at the weekend, This is my Inselkampf type web game. Although I know C#, I’m fairly new to ASP.NET and Blazor. Now the first thing you’ll notice about most Blazor examples on the web is that many look like the screenshot. In particular, the purple gradient down the left hand side.

So my first job was find out where that’s defined and try changing it. In the project which is Blazor WebAssembly, there’s a shared folder and it contains two .css files. MainLayout.razor.css and NavMenu.razor.css. These are the files you need to alter.

Now its probably seven or eight years since I last touched CSS and it has come on quite a bit since then. I discovered css-grid which simplifies things enormously.  If you want to find out more about CSS, take a look on FreeCodeCamp.org. This site has lots of example layouts using CSS-Grid and I went for Redefining Grid Areas with Media Queries. 

This lets you specify a width so you can have a responsive website which adapts to mobile phones as well as desktop. I merged the css and HTML from the example into the project and although its an early stage, I’m quite pleased with it.

Game framework This is very early. The font, colours etc will all change but this has given me a web template with round corners, header, footer and two sidebars.

If I shrink the width of the browser the two sidebars move to positions above and below the main content like this below. It would have taken a lot more effort before css-grid to do this.

Narrow game framework

 

 

An interesting project- Converting BASIC Computer Games

An interesting project- Converting BASIC Computer Games

Basic Computer games bookYes it’s that book again, one I have mentioned a few times.  Now there’s a project to convert all of the games from the book into C#, Java, JavaScript, Python, Ruby and VB.NET. As with all Git sites, you can download all code from the site in a zip file or individual files. So far though its very early in the project and there’s only a .BAS file in each of the subfolders for each of the games in the book. If you fancy getting involved, pick a game, a language and start coding. Sadly there’s no desire for C or C++ but that still leaves C# .

I still have this book and its sequel (More BASIC Computer games!) but to be honest I wouldn’t have bothered with most of the games in either book. They are all very much of the era (1978) which was just on the cusp of the home computer revolution and so were mostly obsolete within seven or eight years, due mainly to the terminal I/O. They’re ok for learning programming and of course you could run them in a Linux terminal.

More Thoughts on the Blazor game design

More Thoughts on the Blazor game design

OpenGameArt
OpenGameArt

This is the latest in a series on the design of a web game based loosely on a no-longer-run game called Inselkampf. It won’t be exactly the same as the original game, I have my own ideas. To see other articles in this series, click here or on the category: Blazor on the right hand side.

There are two models with Blazor. Server and WebAssembly. Both are similar but the crucial difference is that WebAssembly can run completely standalone whereas Server needs a connection to a webserver. Server uses SignalR technology.

The danger with using the Server model is that each person playing the game implicitly creates a connection. With the WebAssembly version, there is no direct connection though it makes sense to have a connection of sorts perhaps a Restful type interface.  This means running a query to fetch game data and then running update queries.

So Blazor with WebAssembly it is. Why Blazor? Because it simplifies updating controls on the page.

Looking after Time

The nature of this type of game is any construction (buildings and units) takes a finite length of time. which can range from seconds to a day or so  I want to see how long before my gold mine goes up a level and so on. It’s normal to have all times countdown in the browser. This should put no strain on the server as its running in the browser. Keeping server and client in sync needs a bit of care in case someone figures out how to make the browser code run faster. Once it reaches 0, an update should be sent to the server which should do a quick comparison with its time and if shenanigans has occurred, return an update status and resync the browser to the server. The rule is “If you give em a chance to cheat- they will“.

Procuring Graphics

Much though I like the Inselkampf graphics for all the buildings, I’m not going to use theirs. It’s infringing copyright (reimagining the game is not copyright infringement BTW!) . As well as the free kenney graphics that I’ve mentioned before and various other websites such as opengameart, (shown in the screenshot) there is also the Reddit game assets subreddit so between these and some others I hope I can find what I’m looking for.  My requirements are quite modest.

 

Amazing multi-platform Asteroids in C#

Amazing multi-platform Asteroids in C#

Android asteroidsAsteroids was the first full arcade game I ever wrote in C. Asteroids in C# takes things to a whole new level.  The solution contains 12 projects in all: Three Blazor projects, a WinForms version, a WPF version, a UWP (Universal Windows Platform) and a Xamarin Android Forms version (shown).

You can compile and run any of the projects though you will need to install and setup a suitable SDK and emulated (or a real device) for the Android.

Written by Howard Uman and ported by Ernie Salazar, this is a wireframe asteroids, more true to the original than my own raster version. Out of curiosity, I created an Android 9.0 emulator (I don’t have a recent Android phone) and compiled then deployed it to the emulator. The screenshot is grabbed directly from the emulator which has a less than ideal screen ratio. This would work better on a tablet.

The structure of the C# Solution is interesting. All of the game code is in the Base project. All of the other platforms just host the main game window. The game uses the SkiaSharp graphics framework for Android Forms.

This is a very nice open source project and an excellent way to see how Blazor works in both Wasm and Server mode, not to mention the Android, WinForms/WPF and UWP versions.

I have an interest in Blazor which lets you write C# code that runs in the browser very easily.  With a bit of workj, this should be runnable on a Linux webserver as well. Something for me to try…

 

 

A newish game platform

A newish game platform

Blazor DungoonWeb games have been largely Flash in the past though that took a nosedive in the ‘tens (2010 onwards) and Flash is officially no more as of 2021. The spirit lives on in JavaScript games and there are innumerable games in JavaScript. That said, I’ve never been that keen on JavaScript. I talked about Web games in a post back in December and particularly that I saw Blazor as a possible game platform.

Today though I discovered Awesome Blazor on GitHub and it includes 18 Blazor web games including a multiplayer dungeon which is shown (I think it looks like a bit Pacmanish personally) . Most of these are ASP .NET Core 3.1 (which became .NET 5 late last year).

Some games will use wasm (Web Assembly) while other use C# in a terminal. As a simple proof of concept but nicely done, have a look at the virtual train set online.  You can lay track and then run one or more trains along it. Impressive as a demonstration of what you can do with C# and Blazor in a browser.

Time to upgrade Visual Studio?

Time to upgrade Visual Studio?

>NET 5
Visual Studio assembly versions

It’s more relevant if you are a .NET developer ie C# or VB.NET, but .NET 5.0 (including C# 9) has just been released. It was an almost 4 GB download and followed by a reboot but I’m now on .NET 5. No more .NET Core or .NET Framework unless you are developing GUI applications on Windows.

But you can also develop on Linux or Mac, but not using WinForms or WPF. Those are Windows only.  This page has downloads, or you can do what I did and upgrade through the Visual Studio Installer.

Also if you are on C (on Windows) you get C11 and C17 if you specify a compiler flag. You’ll see this on the Visual Studio 16.8 release notes.  I like to be on the (bleeding) edge of things. Maybe it’s FOMO (Fear of Missing Out). But I do find it interesting to see where the Linux support is going.

My other side project continues

My other side project continues

Smartphone
Image by Gerd Altmann from Pixabay

This is the social mobile multiplayer game I have mentioned before. The initial game creation program is mostly working. I say mostly because I will still be adding to it. It does however create all of the game data in about 30 seconds for a game that can hold up to 10,000 players. It then creates the output files which are read by the mobile apps. These apps have yet to be created but I’ve decided to do some early testing using non-mobile apps that I’m working on.

What I want to do is prototype the mobile app, not particularly visually but functionally. To this end I’m creating a C# client desktop app that does everything that the mobile app will do. It can read the data (directly rather than via a webserver) and let me create new orders and upload them back to the server (or in this case my development PC).

This client will be crude and not great looking but lets me test that data is coming and going correctly. I use JSON for everything, as a data transfer format as well as storing all game data at rest as opposed to a database. It lets me hold all game data in dictionaries (with a bit of tweaking it is possible to save/load lists of objects to JSON. After loading I convert them to Dictionaries using an Id field.

                var bytes = File.ReadAllText(Lib.PeopleFilename);
                var list = new List();                
                list = JsonSerializer.Deserialize<List>(bytes);
                persons = list.ToDictionary(x => x.Id);

It works and is quick. The downside of using a Dictionary is that it occupies more bytes per element than a List. How many? Well it’s never easy to figure. .NET does not really encourage discovering how things are implemented. This GitHub project by developer Ludovit Scholtz shows the memory used by various .NET Generic Collection Types (HashTable,  Dictionary, ConcurrentDictionary, HashSet, ConcurrentBag, Queue and ConcurrentQueue) with various string lengths in a TestObject which as string, an int and a DateTimeOffset.

Storing a million objects in a Dictionary <int,TestObject> with a null string occupies 48,222,240 bytes so roughly 48 bytes per entry. I believe a List is closer to 20 bytes overhead per element. So for slightly more than double the memory use, using a Dictionary gives a tangible performance yield.

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