Category: exchange rates

In order to see the WebAPI, Swagger is a default technology. Reading https://docs.microsoft.com/en-us/aspnet/core/tutorials/web-api-help-pages-using-swagger?view=aspnetcore-3.0 , seems to have 2 options: Swashbuckle and NSwag. Looking at github repositories, both have > 2k stars, active development, tutorials. The only thing that I see more at NSwag are generators for Angular.

Integrated NSwag as for the tutorial from https://docs.microsoft.com/en-us/aspnet/core/tutorials/getting-started-with-nswag?view=aspnetcore-3.0&tabs=visual-studio . There is a small problem – when I try the swagger , I should put explicit the version. However, a not experienced user can not see this value.

Trying to put documentation : when I go to Project=>Properties=>Build and click the XML documentation, shows the full path to the XML. I do not need this!  So I edit the .csproj directly and change from full path to file

Also, because I want to be sure to have documentation, I change “warnings to errors”.

So now I must document Program and main(removed public from startup.cs and createwebhost – to not document)

Total: 6 changes , https://github.com/ignatandrei/InfoValutar/commit/4fbff903c4510acbcb219d0263ae89736e9f2d8d

So now I can browse to swagger

However, I should indicate to people that swagger is enabled to invite them browse to this – and this is easy to do in Kestrel, right ? Just take the address of the url …

So, trying in Program.cs to find the adresses:

var build = CreateHostBuilder(args).Build();
var s = build.Services.GetService(typeof(KestrelServerOptions));
var s1 = build.Services.GetService(typeof(IServer));
var s2 = build.Services.GetService(typeof(IServerAddressesFeature));
build.Run();

Not a chance – not yet configured. So , next chance is in Startup.cs

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
//other code
var sa = app.ServerFeatures.Get<IServerAddressesFeature>();
var urls =string.Join(",", sa.Addresses.Select(it => it + "swagger"));
Console.WriteLine("please use " + urls);

( for this, you must not use IIS Express, but rather the project)

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Now , after copy the plugins, the build is not working.

Thnking about the build events, I realize that to find same copy command on Linux and Windows is difficult – so Windows it is.

( and, BTW , In LInux the macro $(SolutionDir ) does not work use  repoRoot

https://docs.microsoft.com/en-us/visualstudio/msbuild/customize-your-build?view=vs-2019

https://github.com/Microsoft/msbuild/issues/2397

)

Switch windows-latest on https://help.github.com/en/actions/automating-your-workflow-with-github-actions/workflow-syntax-for-github-actions#jobsjob_idruns-on 

Now tests are failing – repairing the tests.

I realize that I cannot build just the csproj – the solution sln knows the order in which to build the projects- but the .csproj does not. So now building the sln and then publish

Now giving error in Github, but not on local. More, there was a not repeatable . I figured was because of the parallel builds so this is the final line

dotnet build –configuration Release InfoValutar/InfoValutar.sln /m:1

Now it works!

The only programming thing that I have done is to add versioning , https://github.com/microsoft/aspnet-api-versioning/wiki/How-to-Version-Your-Service . I do tend to say that the URL is a Unique Identifier – so I want the versioning be part of the URL.

As advised by https://github.com/microsoft/aspnet-api-versioning/wiki/Versioning-via-the-URL-Path

I added the pacakage Microsoft.AspNetCore.Mvc.Versioning and

services.AddApiVersioning();

and on the controller

[ApiVersion( “1.0” )]

[Route(“api/v{version:apiVersion}/[controller]/[action]”)]

and now I can access

api/v1.0/TodayRates/banks

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I have had 2 problems to solve

1. How to put the plugins for the console and web api ?
2. How to cache the data  ? ( plugins / exchange rates)

The solution for the first problem should be easy for the programmer PC, and for the deploying the application ( console/ web api/ etc )There are several solutions :

1. Each plugin knows where to copy the dll ( console/web api)
2. The application ( console / webapi) knows a special place from which to copy the plugin definition

I tend to agree with both – but mostly with the second. So … the idea is as follows:

The plugin builds and copy the output to a special folder, named “plugins” ( what a surprise, righyt?)

The console /webapi copies the folder plugins under his directory

The only problem here is that we should ensure that plugins are build first, even if the application does NOT have reference to them.

For this, there is a special menu in VS for solution, namely “build order” – you go to this –and after to the second tab, project dependencies. For the console and web I select as dependency the two loading projects – InfoValutarNBR and InfoValutarECB. The changes are reflected into the sln file

I could have done this on just the InfoValutarLoadingLibs project – but maybe I can have another way to load the libraries ( not so much for the moment )

So now I begin to modify what happens

after build events for InfoValutarNBR and InfoValutarECB

xcopy “$(TargetDir)*.*” “$(SolutionDir)plugins\$(ProjectName)” /E /F /I /Y /R

and pre build events for InfoValutarDOS and InfoValutarWebAPI.

Now, there are several things to do:

1. Add to .gitignore the plugins folder to not put into the source control( ok)
2. Write some documentation about the process
3. Think about linux/docker compiling – there is a xcopy there  ?

About the documentation –  I just did. More, I create a InfoValutarPluginStarter , in order for others to copy this project and make a new plugin.

Realized also that the WebAPI could be simpler

[HttpGet(“{bank}”)]
public IAsyncEnumerable<ExchangeRates> Rates([FromRoute] string bank)

And also that I should throw another exception if Bank is null or empty:

if(string.IsNullOrWhiteSpace(bank))
throw new ArgumentNullException($”{nameof(bank)} cannot be empty”);

For docker compiling – next time

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I realized that will be no documentation for plugins – until I create one .

Figured also that each plugin should have a name  -to understand from where he grabs data – so some code involved code.

Asking when and if the plugins are copied to the application  – not found yet an answer…

Now the user can choose what bank he wants to see data ? We could do this for the console application –  and I think that is the moment to play with Icaza  Gui Terminal https://github.com/migueldeicaza/gui.cs  – Created buttons to display plugins (NBR and ECB ). Will not work if many plugins will come – but it is ok for the moment.

Discovered the window for code coverage – read https://github.com/tonerdo/coverlet/blob/master/Documentation/VSTestIntegration.md

Some error when writing the .runsettings file – discovered from command line ( GUI does not show)

Reading the docs , https://docs.microsoft.com/en-us/visualstudio/test/using-code-coverage-to-determine-how-much-code-is-being-tested?view=vs-2019#analyze-code-coverage , it says that is not available for community…

Back to square 1 after 1 hour- just made documentation.

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Modified project – instead of one project that have the NBR and ECB exchange rates,I have now 4
1. Common interfaces / classes

2 NBR loading( first plugin)

3 ECB loading ( second plugin)

4 plugin loading project

Going to .NET Standard 2.1 and trying to load the NuGet https://github.com/natemcmaster/DotNetCorePlugins/blob/master/docs/what-are-shared-types.md .

Does not load. Going back to .NET Core 2.0  – some result.

RTFM – not supported .NET Standard  https://github.com/natemcmaster/DotNetCorePlugins/issues/24

So created a .NET Standard dll and changed from

<TargetFramework>netstandard2.0</TargetFramework>

to

<TargetFramework>netcoreapp3.0</TargetFramework>

Copied the code from https://github.com/natemcmaster/DotNetCorePlugins/blob/master/samples/hello-world/HostApp/Program.cs .

Loaded 0 plugins.

Put plugins in plugins directory – again 0 plugins.

Read the code copied – I must create separate folders for each plugin – makes sense, because we can have plugin diamond dependency – see here https://github.com/natemcmaster/DotNetCorePlugins/blob/master/docs/what-are-shared-types.md

Put in separate folder – error in this line

// This assumes the implementation of IPlugin has a parameterless constructor
var plugin = Activator.CreateInstance(pluginType) as BankGetExchange;

Apparently , this code does NOT mean to have a parameterless contructor – even if seems from the code

public class GetNBRExchange: BankGetExchange
{
private readonly HttpClient httpClient;

public GetNBRExchange(HttpMessageHandler handler = null)
{
if (handler != null)
httpClient = new HttpClient(handler, disposeHandler: false);
else
httpClient = new HttpClient();
}

So small modification to preserve tests and default code:

public class GetNBRExchange: BankGetExchange
{
private readonly HttpClient httpClient;
public GetNBRExchange() : this(null)
{

}
public GetNBRExchange(HttpMessageHandler handler)
{
if (handler != null)
httpClient = new HttpClient(handler, disposeHandler: false);
else
httpClient = new HttpClient();
}

Now it works …

You can find modifications here

https://github.com/ignatandrei/InfoValutar/commit/0e4cf6b83bb5f4cbab71e9e8c96ae719771fcae1 – total 13 changed files….

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