I've recently been working on building retrieval augmented generation (RAG) experiences into applications; building systems where large language models (LLMs) can query documents. To achieve this, we first need a strategy to chunk those documents and make them LLM-friendly. Kernel Memory, a sister project of Semantic Kernel supports this.
Generating a Word document in the context of an ASP.NET controller is quite simple to do. However, it took me a little experimentation to work out just what was required. This post documents (pun very much intended) what we need to do.
Writing tests is important. The easier it is to write tests, the more likely they'll be written. I've long loved snapshot testing for this reason. Snapshot testing takes away the need to manually write verification code in your tests. Instead, you write tests that compare the output of a call to your method with JSON serialised output you've generated on a previous occasion. This approach takes less time to write, less time to maintain, and the solid readability of JSON makes it more likely you'll pick up on bugs. It's so much easier to scan JSON than it is a list of assertions.
Loving snapshot testing as I do, I want to show you how to write high quality and low effort log assertions using snapshot testing. The behaviour of logging code is really important; it's this that we tend to rely upon when debugging production issues. But how do you test logging code? Well, you could write a bunch of assertions that check how your logger is used. But that's a lot of work, it's not super readable and it's not fun. (Always remember: if it's not fun, you're doing it wrong.)
Instead, we'll achieve this using snapshot testing.
The Graph API is a great way to get information about users in Azure Active Directory. I recently needed to get the names and ids of the Active Directory groups that a user was a member of. Here's how to do it with the C# SDK.
I'm writing this post as, whilst it ends up being a relatively small amount of code and configuration required, if you don't know what that is, you can end up somewhat stuck. This should hopefully unstick you.
Easy Auth is a great way to authenticate your users. However, when used in the context of Azure Container Apps, .NET applications do not, by default, recognise that Easy Auth is in place. You might be authenticated but .NET will still act as if you aren't. builder.Services.AddAuthentication() and app.UseAuthentication() doesn't change that. This post explains the issue and solves it through the implementation of an AuthenticationHandler.
ESLint provides a great linting experience for TypeScript and JavaScript in VS Code. The suggestions, fixes and ignore options make creating clean code a joy. A similar experience is available for C# in VS Code through Roslyn Analyzers - this post tells us more.
Private Azure Artifact feeds in in Azure DevOps can be used to serve NuGet packages. To build applications both locally and in an Azure Pipeline using those packages, there are a few steps to follow which this post will demonstrate.
For API endpoints that return multiple types, you can use inheritance with Swashbuckle to get create a Swagger / Open API definition featuring the variety of available types. Serving all these types is not the default behaviour. This post shows you how to opt in.
.NET Core can make use of C# 9 by making some changes to your .csproj files. There is a way to opt all projects in a solution into this behaviour in a single place, through using a Directory.Build.props file and / or a Directory.Build.targets file. Here's how to do it.
C# 9 has some amazing features. Azure Functions are have two modes: isolated and in-process. Whilst isolated supports .NET 5 (and hence C# 9), in-process supports .NET Core 3.1 (C# 8). This post shows how we can use C# 9 with in-process Azure Functions running on .NET Core 3.1.
The upgrade of Azure Functions from .NET Core 3.1 to .NET 5 is significant. There's an excellent guide for the general steps required to perform the upgrade. However there's a number of (unrelated) items which are not covered by that post:
I've written lately about zero downtime releases with Azure App Service. Zero downtime releases are only successful if your authentication mechanism survives a new deployment. We looked in my last post at how to achieve this with Azure's in-built authentication mechanism; Easy Auth.
I wrote recently about zero downtime deployments on Azure App Service. Many applications require authentication, and ours is no exception. In our case we're using Azure Active Directory facilitated by "Easy Auth" which provides authentication to our App Service.
If you're deploying an ASP.NET application to Azure App Services / Azure Container Apps or similar, there's a decent chance you'll also be using the fantastic Serilog and will want to plug it into Azure's Application Insights.
I wrote recently about how to get Azure App Service Easy Auth to work with roles. This involved borrowing the approach used by MaximeRouiller.Azure.AppService.EasyAuth.
As a consequence of writing that post I came to learn that official support for Azure Easy Auth had landed in October 2020 in v1.2 of Microsoft.Identity.Web. This was great news; I was delighted.
However, it turns out that the same authorization issue that MaximeRouiller.Azure.AppService.EasyAuth suffers from, is visited upon Microsoft.Identity.Web as well. This post shows hoew to resolve it with IClaimsTransformation.
By default Microsoft.Identity.Web responds to unauthorized requests with a 302 (redirect). Do you want a 403 (forbidden) instead? Here's how.
I blogged a little while ago around to support integration tests using Autofac. This was specific to Autofac but documented a workaround for a long standing issue with ConfigureTestContainer that was introduced into .NET core 3.0 which affects all third-party containers that use ConfigureTestContainer in their tests.
Updated 2nd Oct 2020: for an approach that works with Autofac 6 and ConfigureTestContainer see this post.
This last four months has been quite the departure for me. Most typically I find myself building applications; for this last period of time I've been taking the platform that I work on, and been migrating it from running on our on premise servers to running in the cloud.
This is a post about having two kinds of authentication working at the same time in ASP.Net Core. But choosing which authentication method to use dynamically at runtime; based upon the criteria of your choice.