LINQ DistinctBy on a property for .NET Standard and older .NET versions

Today I learned how to implement a custom Enumerable.DistinctBy extension method that returns distinct elements from a sequence according to a specified key selector function. .NET 6 and its successors have the method built in within LINQ, but I needed it in a .NET Standard 2.0 class library, so I was out of luck. My implementation is simple, not different from others I found online, and should also work fine with old ....

October 25, 2023

rsync with a different user

Today I learned how to rsync with a user different than the one connected to the remote. Why would one want to do such a thing? The data I need to download from that server is owned by ‘backup,’ a different, service-only user. I wanted to avoid going the change-permissions slippery route and allow my user direct access to the data. Looking at the rsync documentation, I learned about the nifty --rsync-path=PROGRAM option:...

August 23, 2023

Homebrew and .NET 8 Preview don't like each other

Today I learned that .NET 8 Preview could play better with Homebrew (or vice-versa). I’m working on a C# 12 presentation for our local developer meetup, and for that, I wanted .NET 8 Preview to run side by side with version 7 on my Mac. As version 7 was initially installed with Homebrew, I also wanted to install version 8 Preview with Homebrew, but that recipe was unavailable. Not perfectly happy with that, I fell back to the stand-alone installer, expecting problems....

June 13, 2023

Python `decimal.getcontext` does not work with bpython

I have been working on a side project for which I’m using bpython, a “fancy interface to the Python interpreter.” If you use the Python REPL often, you should check it out. It offers unique features like in-line syntax highlighting, readline-like autocomplete, a “rewind” function to pop the last line of code from memory, auto-indentation and more. Anyway, today I found a bug in bpython, and that’s that Python’s decimal.getcontext() does not work with it....

June 6, 2023

macOS networkQuality tool

Today I learned about a precious little macOS command line tool, networkQuality. The networkQuality tool is a built-in tool released in macOS Monterey that can help diagnose network issues and measure network performance. Usage: networkQuality -v Example output: ==== SUMMARY ==== Uplink capacity: 44.448 Mbps (Accuracy: High) Downlink capacity: 162.135 Mbps (Accuracy: High) Responsiveness: Low (73 RPM) (Accuracy: High) Idle Latency: 50.125 milliseconds (Accuracy: High) Interface: en0 Uplink bytes transferred: 69....

May 15, 2023

The real cost of interruption

I’m just back from reading Programmer Interrupted: The Real Cost of Interruption and Context Switching, an interesting short piece in which I learned about at least two new things. First, The Parable of the Two Watchmakers, introduced by Nobel Prize winner Herbert Simon, describes the complex relationship between sub-systems and their larger wholes. In the context of the article, it helps explain, even for non-programmers, the cost of an interruption. It also hints at a possible mitigation technique:...

April 7, 2023

Hand dryers

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February 28, 2023

Awesome psql tips

Today I learned about psql-tips.org by Lætitia Avrot, an excellent repository of psql (the CLI tool, not the database itself) tips. I like how one randomized tip is playfully served on the home page while the complete list is always at hand.

February 23, 2023

Making the latest C# language features available in older .NET versions

In a C# library I’ve been working on, I wanted to use C# 9.0’s init keyword. Quoting the documentation: The init keyword defines an accessor method in a property or indexer. An init-only setter assigns a value to the property or the indexer element only during object construction. This enforces immutability so that once the object is initialized, it can’t be changed again. Consider the following class: public class Person { public string FirstName { get; init; } } You can initialize it like this:...

February 4, 2023

On implementing the ASP.NET Core 7 rate-limiting middleware

Today, my last self-assigned duty before the Christmas break was to migrate our in-house rate-limiting implementation (based on the AspNetCoreRateLimiting third-party package) to the new, shiny rate-limiting middleware introduced by ASP.NET Core 7. While the process was relatively straightforward, I stumbled upon a few quirks I want to annotate here. Our use case is simple. We use what the ASP.NET Core 7 documentation defines as a “fixed window limiter.” It uses a specified time window to limit requests....

December 23, 2022