George Kosmidis

Microsoft MVP | Cloud Solutions Architect | .NET Software Engineer | Organizer of Munich .NET Meetup | Speaker
IdentityServer4, ASP.NET Core API and a client with username/password

IdentityServer4, ASP.NET Core API and a client with username/password

This is an end-to-end guide on how to quickly setup IdentityServer4, use it in your ASP.NET Core API for authentication, and finally login to your API from a client by asking a user for their username and password. It is divided in three parts that describe respectively the configuration of each one of the following three systems:

Modified 2 years and 4 months ago

My next events!

Mindspace Salvatorplatz (Salvatorplatz 3, München, BY, Germany 80333)
Online
Microsoft MVP - George Kosmidis
Writing a custom OutputFormatter to return an Excel (.xlsx) from an action in ASP.NET Core API

Writing a custom OutputFormatter to return an Excel (.xlsx) from an action in ASP.NET Core API

As most of us, I already know my next week work schedule. It includes writing some actions in respond to a requirement for excel exports. It’s nothing new and its’s relatively easy with libraries like NPOI: you just create your excel on the fly and return a FileResult.

Modified 2 years and 4 months ago

Handling, serializing and returning exceptions with a middleware in an ASP.NET Core API

ASP.NET Core offers a very cool way to avoid all that boring boilerplate exception handling code, just by intercepting all requests. It is called Middleware and actually, ASP.NET Core is full of built-in middlewares!

Modified 3 years and 4 months ago
Publishing ASP.NET Core: An error occurred while starting the application

Publishing ASP.NET Core: An error occurred while starting the application

Have you seen this error?
An error occurred while starting the application.
.NET Core <version> | Microsoft.AspNetCore.Hosting <version> | Microsoft Windows <version> | Need help?

Modified 2 years and 4 months ago

Parameterized Raw SQL Queries with Entity Framework: How to Unit Test with SQLite

Entity Framework Core allows you to drop down to raw SQL queries when working with a relational database. This can be useful, because raw SQL queries can return entity types or, starting with EF Core 2.1, query types that are part of your model, but it could also be a problem when it comes down to Unit Testing.

Modified 2 years and 4 months ago

Thread synchronisation with SemaphoreSlim and async delegate calls

Although running a parallel foreach that makes async calls is a pretty usual task, I found my self in a complicated situation, when async delegate calls got in the way!

Modified 1 year ago

Mocking expected behaviour of SQL functions for Unit Testing with SQLite

While unit testing, I came across a method in an SQL repository class that was using a raw SQL query, and along with that, SQL Server’s newid() function. Since the complicated reason behind this decision was out of scope, I had to find a way to unit test that method…

SQLite was -of course- the first approach, but any attempt to actually test the method would nevertheless fail with the exception Microsoft.Data.Sqlite.SqliteException: 'SQLite Error 1: 'no such function: newid'.'.

Modified 3 years and 4 months ago