Supporting Multiple Microsoft Teams Bots in One ASP.NET Core Application

Since the advent of Large Language Models (LLMs), we have been leveraging the technology to streamline processes and improve staff efficiency. One of the things LLMs are good at is coming up with coherent text based on a given context. Leveraging this strength, we have applied the Retrieval Augmented Generation (RAG) pattern to build chatbots that help staff across different areas, including human resources, contract management, and other department-specific procedures. For the user interface of the chatbots, we use Microsoft Teams, as it’s our primary communication platform. The bots’ functionalities are quite similar in nature, in the sense that they all pull data from a data store by calling APIs, sending the user’s chat message, and replying to messages in Microsoft Teams. However, because each bot requires a different category of data for use as the LLM’s context, we need a separate Microsoft Teams app for each bot. Behind the scenes, the Teams app calls the corresponding web API, which is an ASP.NET Core application, to send and receive messages. The ASP.NET Core applications are very similar in nature, in that they all call APIs to get the LLM’s response for a user’s request. As such, we were thinking of ways to minimize code duplication and the infrastructure needed to support multiple bots. In the web API, we follow a clean architecture with infrastructure, a shared kernel, a domain layer, and other typical layers. One approach I thought of was that we could reuse all the layers except for the web API. We would have one web API project for each bot we want to support. However, that approach still requires separate infrastructure for each bot—things like Key Vault, App Insights, Blob Storage, etc.—since each bot is a separate app that serves a different domain. Luckily, after some back-and-forth discussions with GitHub Copilot and reading sample code, I tested and found a way to support multiple bots using the same codebase and infrastructure.

Building a fully multitenant system using Microsoft Identity Framework and SQL Row Level Security

This post was written a while ago, but I’ve never published it.

In this post, I show an example of using SQL row level security to isolate data among different organizations in a same database using row level security. In that post, I show an example of reading a value in the database session context as part of the filtering logic. In this post, I show an example of how to preset a value in the database session context from ASP.NET core application, and also how to authenticate users from multiple tenants using Microsoft Identity Framework.

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Analyzing a rental property through automation

In this post, I write about building an API to help me analyze real estate properties.

Web scraping in C# using HtmlAgilityPack

In this post, I show an example of scraping data in C# using HtmlAgilityPack. I come across HtmlAgilityPack because I need to get data from Zillow to analyze properties deals. I was able to scrape the data I want without much trouble using HtmlAgilityPack with a bit of XPath, LINQ and regular expression.

Building multitenant application – Part 2: Storing value into database session context from ASP.NET core web API

In the previous post about row level security in SQL server, I gave an example of reading a value from the database session context to feed into the security function for filtering data. In this post, I show examples of calling the sp_set_session_context store procedure from an ASP.NET core web API to store a value into the session context.

Build and deploy a WebJob alongside web app using azure pipelines

In this post, I’m going to share some of the issues, misunderstandings I ran into when trying to setup and deploy a WebJob alongside a web application using azure pipelines. The WebJob is a console application, and the web app is an ASP.NET core. Both the WebJob and web app target .NET 5.

Authenticate against azure ad using certificate in a client credentials flow

I have an API which needs to authenticate against azure ad to obtain an access token for calling another downstream API. When registering an application in azure AD for the caller API, I could either setup a shared secret or a certificate for the API to use as part of its credentials in a client credentials flow . In the past, I had always used a shared secret as it was more convenient and easier to setup. However, using certificate provides stronger security. After spending a few hours of googling and hacking, I was able to setup and use a certificate instead of a shared secret as credentials for the caller API to authenticate against azure AD.

Notes on The Clean Architecture

In this post, I’m going to share my understanding of clean architecture after reading about it in the book “Clean Architecture” and other posts, as well as how I implement the clean architecture in an ASP.NET core project.

Three essential libraries for unit testing a .NET project

In this post, I share the three libraries I find useful for unit testing a .NET project: EF Core SQLite Database Provider, Bogus and Moq.

How to retrieve connection strings in azure key vault from ASP.NET using configuration builders, XML transformation and azure devops.

Configuration builders are mechanisms to retrieve connection strings from external sources. Using configuration builders, you may not have to do much codings besides installing packages and providing XML configurations for connecting to popular sources. In this post, I share with you my experience in using configuration builders for .NET to securely retrieve connection strings from an azure key vault. I’ll go over the setup and share some of the issues I face while integrating my app with azure key vault.