Searching for information on internal website is often not an easy task. Indeed, you can't use your favorite search engine to find information. So, you need to provide your own solution. Of course, you can't rebuild Google or Bing 😦 But, you can still provide a sufficient search engine. In this serie, I'll show how to quickly create a search engine for your internal websites using Playwright and… [read more]

Recently I needed to create a new unique index on a MongoDB collection. However, there were some duplicate data... so I got the following error: E11000 duplicate key error collection: db.collection index: index_name dup key: { key: "duplicate value" } The error message lists the first duplicated value, but they may be more duplicates. Instead of fixing them one by one, I used the aggregation pipeline to… [read more]

I recently needed to set up an alert when a certificate expires soon or when it uses an insecure signature algorithm. The first step is to get the certificate. In .NET you can use the SslStream class to do the hard job. Then, you can set up a recurring task using Azure Pipelines or GitHub Actions to validate certificates every day, but this is not part of this post. static class CertificateDownloader { //… [read more]

The more code you write, the more bugs you create. Indeed, this is a known fact that almost all applications are buggy! This means that as a software developer, you must spend a part of your time debugging applications. There are a few common steps when debugging an application: Getting all the needed information to understand the issue (reproduction steps, call stack, logs, etc.) Reproducing the problem… [read more]

There are many ways to generate PDF files. You can use a PDF library, but generating a PDF manually is not trivial. You can use a report library, but they are often paid solution and not trivial to use for simple needs. In this post, we'll use an html template and Playwright to generate a PDF file. Using a browser to convert an html file to a PDF file is very convenient as it allows to use all html/CSS… [read more]

I recently had to investigate an infinite loop in an application. A simplified version of the buggy code is like that: static void Main() { bool isReady = false; var thread = new Thread(_ => { // ... (initialization) isReady = true; // ... (code after initialization) }); thread.Start(); // wait for the other thread to do some initialization while (!isReady) { // code omitted for brevity }… [read more]

This post is the result of a code review. The code I'll show is a simplified version of the original code, so the bug is easier to spot (or not). The goal of the code is to read a UTF-8 encoded string from a stream. In the actual context, the stream is a named pipe and there are a few more things to do with the stream. string ReadString(Stream stream) { var sb = new StringBuilder(); var buffer = new… [read more]

We often use NuGet through Visual Studio or dotnet CLI, but you can also use the same using your own application. In this post, I'm going to show multiple examples of using the .NET client library for NuGet. To start using the NuGet client library, you need to add a reference to the NuGet packages: <ItemGroup> <PackageReference Include="NuGet.Protocol" Version="5.10.0" /> <PackageReference… [read more]

Reproducible builds are important when building NuGet packages from public sources. Indeed, it gives your consumers confidence in your packages by allowing them to validate the package has actually been built using the public sources. To be able to reproduce a build, you need the source files, the referenced DLLs, the compiler version, and the compiler options (language version, defines, nullables, etc.)… [read more]

If you want to improve the performance of a Blazor application, you may want to reduce the number of time the UI is recomputed. In Blazor, this means reducing the number of time the StateHasChanged method is called. This method needs to be called only when the state has changed and the UI needs to be updated. However, there are multiple ways to implicitly call it. One of them is to handle an event such as… [read more]