Category Archives: Programming

tcpproxy 0.4 released

Posted on by Mahmoud Al-Qudsi
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Image courtesy of Hack A Day

This blog post was a bit delayed in the pipeline, but a new release of tcproxy, our educational async (tokio) rust command line proxy project, is now available for download (precompiled binaries or install via cargo).

I was actually surprised to find that we haven’t written about tcpproxy before (you can see our other rust-related posts here), but it’s a command line tcp proxy “server” written with two purposes in mind: a) serving as a real-world example of an async (tokio-based) rust networking project, and b) serving as a minimal but-still-useful tcp proxy you can run and use directly from the command line, without needing complex installation or configuration procedures. (You can think of it as being like Minix, but for rust and async networking.)

The tcpproxy project has been around for quite some time, originally published in 2017 before rust’s async support was even stabilized. At the time, it manually chained futures to achieve scalability without relying on the thread-per-connection model – but today its codebase is a lot easier to follow and understand thanks to rust’s first-class async/await support.

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CallerArgumentExpression and extension methods don’t mix

Posted on by Mahmoud Al-Qudsi
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This post is for the C# developers out there and takes a look at the interesting conjunction of [CallerArgumentExpression] and static extension methods – a mix that at first seems too convenient to pass up.

A quick recap: [CallerArgumentExpression] landed as part of the C# 10.0 language update and helps to reduce the (often brittle!) boilerplate involved in, among other uses, creating useful error messages capturing the names of variables or the text of expressions. You tag an optional string method parameter with [CallerArgumentExpression("argName")] where argName is the name of the method argument you want stringified, and the compiler does the rest.

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Implementing truly safe semaphores in rust

Posted on by Mahmoud Al-Qudsi
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Discuss this article on r/rust or on Hacker News.

Low-level or systems programming languages generally strive to provide libraries and interfaces that enable developers, boost productivity, enhance safety, provide resistance to misuse, and more — all while trying to reduce the runtime cost of such initiatives. Strong type systems turn runtime safety/sanity checks into compile-time errors, optimizing compilers try to reduce an enforced sequence of api calls into a single instruction, and library developers think up of clever hacks to even completely erase any trace of an abstraction from the resulting binaries. And as anyone that’s familiar with them can tell you, the rust programming language and its developers/community have truly embraced this ethos of zero-cost abstractions, perhaps more so than any others.

I’m not going to go into detail about what the rust language and standard library do to enable zero-cost abstractions or spend a lot of time going over some of the many examples of zero-cost interfaces available to rust programmers, though I’ll just quickly mention a few of my favorites: iterators and all the methods the Iterator trait exposes have to be at the top of every list given the amount of black magic voodoo the compiler has to do to turn these into their loop-based equivalents, zero-sized types make developing embedded firmware in rust a dream and it’s really crazy to see how all the various peripheral abstractions can be completely erased giving you small firmware blobs despite all the safety abstractions, and no list is complete the newest member of the team, async/await and how rust manages to turn an entire web server api into a single state machine and event loop. (And to think this can be used even on embedded without a relatively heavy async framework like tokio and with even zero allocations to boot!)

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C# file size formatting library PrettySize 3.1 released

Posted on by Mahmoud Al-Qudsi
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PrettySizeHot on the heels of an update to our rust port of PrettySize we have a new release of PrettySize.NET that brings new features and capabilities to the best .NET library for formatting file sizes for human-readable output and display.

PrettySize 3.1, available on GitHub and via Nuget, has just been released and contains a number of improvements and requested features and newfound abilities to make handling file sizes (and not just formatting them) easier and more enjoyable.

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PrettySize 0.3 release and a weakness in rust’s type system

Posted on by Mahmoud Al-Qudsi
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PrettySizeI’m happy to announce that a new version of size, the PrettySize.NET port for rust, has been released and includes a number of highly requested features and improvements.

The last major release of the size crate was 0.1.2, released in December of 2018. It was feature complete with regards to its original purpose: the (automatic) textual formatting of file sizes for human-readable printing/display purposes. It would automatically take a file size, pick the appropriate unit (KB, MB, GB, etc) to display the final result in, and choose a suitable precision for the floating numeric component. It had support for both base-10 (KB, MB, GB, etc) and base-2 (KiB, MiB, GiB, etc) types, and the user could choose between them as well as override how the unit was formatted. In short, it did one thing and did it right.

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Using SIMD acceleration in rust to create the world’s fastest tac

Posted on by Mahmoud Al-Qudsi
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NeoSmart Technologies’ open source (MIT-licensed), cross-platform tac (written in rust) has been updated to version 2.0 (GitHub link). This is a major release with enormous performance improvements under-the-hood, primarily featuring handwritten SIMD acceleration of the core logic that allows it to process input up to three times faster than its GNU Coreutils counterpart. (For those that aren’t familiar with it, tac is a command-line utility to reverse the contents of a file.)

This release has been a long time in the making. I had the initial idea of utilizing vectorized instructions to speed up the core line ending search logic during the initial development of tac in 2017, but was put off by the complete lack of stabilized SIMD support in rust at the time. In 2019, after attempting to process a few log files – each of which were over 100 GiB – I decided to revisit the subject and implemented a proof-of-concept shortly thereafter… and that’s when things stalled for a number of reasons.

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AsyncLock 3.0 for .NET 5.0 Released

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An updated version of AsyncLock has just been released on GitHub and Nuget with improved support for reentrancy detection.

AsyncLock is a async/await-native anonymous lock for .NET and .NET Core that allows safely using async/await while holding a lock, for example:

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Scripting in rust with self-interpreting source code

Posted on by Mahmoud Al-Qudsi
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I have a soft spot in my heart for rust and a passionate distrust (that has slowly turned into hatred) for interpreted, loosely typed languages, but it’s hard to deny the convenience of being able to bang out a bash script you can literally just write and run without having to deal with the edit-compile-run loop, let alone create a new project, worry about whether or not you’re going to check it into version control, and everything else that somehow tends to go hand-in-hand with modern strongly typed languages.

A nifty but scarcely known rust feature is that the language parser will ignore a shebang at the start of the source code file, meaning you can install an interpreter that will compile and run your rust code when you execute the .rs file – without losing the ability to compile it normally. cargo-script is one such interpreter, meaning you can cargo install cargo-script then execute your source code (after making it executable, :! chmod +x %) with something like this:

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SecureStore: the open secrets container format

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It’s been a while since we first released our SecureStore.NET library for C# and ASP.NET developers back in 2017, as a solution for developers looking for an uncomplicated way of safely and securely storing secrets without needing to build and maintain an entire infrastructure catering to that end. Originally built way back in 2015 to support secrets storage in legacy ASP.NET applications, SecureStore.NET has been since updated for ASP.NET Core and UWP desktop application development, and now we’re proud to announce the release of SecureStore 1.0 with multi-platform and cross-framework support, with an updated schema making a few more features possible and official implementations in C#/.NET and Rust.

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Adding a Razor Pages ModelBindingProvider in ASP.NET Core

Posted on by Mahmoud Al-Qudsi
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Microsoft’s official documentation on adding custom model binding providers to convert between (typically) a string and a custom type for complex model binding in ASP.NET Core as of .NET Core 3.1 goes something like this:

  • Create an IModelBinder for your class and use [ModelBinder(BinderType = typeof(MyModelEntityBinder)] to decorate each and every binding site, e.g.
    public async Task<IActionResult> OnPost([ModelBinder(BinderType = typeof(MyModelEntityBinder)]) MyModel model), which provides the runtime with the type information it needs to instantiate the model binding provider and convert the input to a model.
  • Optionally create an IModelBinderProvider class and register it with the ASP.NET Core host to provide the type information ahead-of-time (once and for all), so that you can instead use the barebones and much shorter decoration at each model binding site instead:
    public async Task<IActionResult> OnPost([ModelBinder] MyModel model)

The latter is significantly easier on the eyes and far less error prone… but where does the type registration take place? Per the linked documentation, the recommendation is the following in Startup.cs:

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