Category: .NET Core

Now, I want to see that I can read from the database the exchange rates. For this, in Azure WebAPP I go to Settings => Configuration and add my connection string.

But now I have a problem: I must read from the configuration.  So back on DI with InMemory class – I inject from ASP.NET Core the Configuration and in the tests I construct directly with null.

IConfiguration configuration;

public InMemoryDB(IConfiguration config)
{
this.configuration = config;

}
private string GetConRead(string name)
{
return configuration?.GetConnectionString(name);
}

Also, for easy retrieving from URL , I modify from

public async Task<ExchangeRates[]> Rates(string bank,string fromDate, string toDate)

( that generates the url : https://infovalutar.azurewebsites.net/api/v1.0/FromDB/Rates?bank=bnr&fromDate=20010101&toDate=20500101 )

to

[HttpGet(“{bank}/{fromDate}/{toDate}”)]
public async Task<ExchangeRates[]> Rates([FromRoute] string bank, [FromRoute]string fromDate, [FromRoute]string toDate)

( that generates the URL: https://infovalutar.azurewebsites.net/api/v1.0/rates/bnr/20010101/20100101 )

( I have also modified the route on the controller to [Route(“api/v{version:apiVersion}/rates”)] )

The modifications are at https://github.com/ignatandrei/InfoValutar/commit/aeda74e071a333e800a36936d2d3fc685b4b3ac8 .

The bad part – the deploy takes now 7 minutes…( running tests first …)

I have to implement now the following (

www.infovalutar.ro/bnr/2004/10/10/EUR

www.infovalutar.ro/bnr/azi/eur

www.infovalutar.ro/2004/6/4/eur.bnr

http://www.infovalutar.ro/bnr/rss

http://infovalutar.ro/curs.asmx?wsdl

I will implement first into the rates API , then I will redirect.

For example, the first one is like this: www.infovalutar.ro/bnr/2004/10/10/EUR and www.infovalutar.ro/2004/6/4/eur.bnr can be implemented like this:

[HttpGet(“{year}/{month}/{day}/{exchange}.{bank}”)]
[HttpGet(“{bank}/{year}/{month}/{day}/{exchange}”)]
public async Task<ExchangeRates> RatesOnDate([FromRoute] string bank,
[FromRoute]int year, [FromRoute]int month,
[FromRoute] int day, [FromRoute] string exchange)

What about the rss ? There is a package called System.ServiceModel.Syndication in .NET Core  – and we can use for RSS like this:

[HttpGet(“{bank}/rss”)]
public async Task<IActionResult> GetRssFeed(string bank)
{
var data= await ret.TodayRates(bank);
var items = data
.Select(it =>
new SyndicationItem(
it.ExchangeTo,
it.ExchangeValue.ToString(),
new Uri($”http://www.infovalutar.ro/bnr/{it.Date.Year}/{it.Date.Month}/{it.Date.Day}/{it.ExchangeTo}”))
)
.ToArray();

var feed = new SyndicationFeed(
“Curs Valutar”,
“CursValutar, case, banci”,
new Uri( “http://www.infovalutar.ro/”),
items
);
feed.Language = “ro-ro”;
feed.TimeToLive = TimeSpan.FromSeconds(30);
using var sw = new StringWriter();
using var rssWriter = XmlWriter.Create(sw);

var rssFormatter = new Rss20FeedFormatter(feed,false);
rssFormatter.WriteTo(rssWriter);
rssWriter.Close();
return Content(sw.ToString(), “text/xml”);
}

What about http://infovalutar.ro/curs.asmx?wsdl ? Found https://devblogs.microsoft.com/dotnet/custom-asp-net-core-middleware-example/ article , that says”it has no support for message security, WSDL generation, duplex channels, non-HTTP transports” – so I do not want to do. Maybe something should be left…

So , now , how I can now intercept calls like

www.infovalutar.ro/bnr/2004/10/10/EUR

www.infovalutar.ro/bnr/azi/eur

www.infovalutar.ro/2004/6/4/eur.bnr

http://www.infovalutar.ro/bnr/rss

? There is no controller ! So – middleware to help!

Infovalutar

Now getting the database – needed for historic data.

When I go to Create New Database in Azure Portal , there are many types of Database (mongo, postgres, many others) – the easy choice, for me, is SqlServer ( even if the tables are not be updated – the exchange rates does not change a lot). There is something that is easy to deploy a WebApp : WebApp + Sql

But I wil create a new one – Azure Sql Managed Instance – the price for 4 vCore is > 400 EUR. Sure do not want this…

So I decided yo have SqlServer, with a database with 2 GB storage  – smaller price, like 4.21 per month– for a normal person.

I can access with SSMS to create tables – and then I generate the script

CREATE TABLE [dbo].[NBR](
[ExchangeFrom] [nvarchar](50) NOT NULL,
[ExchangeTo] [nvarchar](50) NOT NULL,
[Date] [date] NOT NULL,
[ExchangeValue] [decimal](18, 6) NOT NULL,
CONSTRAINT [PK_NBR] PRIMARY KEY CLUSTERED
(
[ExchangeFrom] ASC,
[ExchangeTo] ASC,
[Date] ASC
)WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
GO

Create an ISave interface ( trying to cope with CQRS) .

Now I want to scaffold C# from database like https://docs.microsoft.com/en-us/ef/core/miscellaneous/cli/dotnet

Installing

dotnet tool install –global dotnet-ef

gives error about versioning

dotnet tool install –global dotnet-ef –version 3.0.0

SUccess!

Now trying to scaffold

dotnet ef dbcontext scaffold “Server=(localdb)\mssqllocaldb;Database=Blogging;Trusted_Connection=True;” Microsoft.EntityFrameworkCore.SqlServer -o Models

Error – does not find project

Ok. Run in the folder with the project. Now it does not like .NET Standard – wants .NET Core . Changed in .csproj <TargetFramework>netcoreapp3.0</TargetFramework>

Now it says:

Your startup project ‘InfovalutarDB’ doesn’t reference Microsoft.EntityFrameworkCore.Design.

Adding the NuGet Package

Now the command line

dotnet ef dbcontext scaffold “Server=(localdb)\mssqllocaldb;Database=Blogging;Trusted_Connection=True;” Microsoft.EntityFrameworkCore.SqlServer -o Models

Works!

Reading about storing connection strings safe:

http://go.microsoft.com/fwlink/?LinkId=723263

Figuring a way to use either inmemory database( for fast testing) or sqlserver

var config = ConfigurationManager.ConnectionStrings[“DB”];
var opt= new DbContextOptionsBuilder<InfoValutarContext>();
if (config == null)
{
opt.UseInMemoryDatabase(“write”);
}
else
{
opt.UseSqlServer(config.ConnectionString);
}

var cnt = new InfoValutarContext(opt.Options);

So a new Test created:

ISave s = new SaveSqlServer();
var response = await File.ReadAllTextAsync(Path.Combine(“Data”, “20191020bnr.txt”));
var m = new MockHttpMessageHandler();
m.When(“https://www.bnr.ro/nbrfxrates.xml”)
.Respond(“application/text”, response);

var nbr = new GetNBRExchange(m);
var data = await nbr.GetActualRates().ToArrayAsync();
var nr= await s.Save(data);
Assert.Equal(nr, data.Length);

And modified in the Docker file to restore this new project

Infovalutar