RUST COLOGNE/BONN MEETUP

29. JULY 2015

WEBAPPS WITH NICKEL.RS, GULP, JAVASCRIPT (LINUX)

INTERFACING WITH C UNDER VISUAL STUDIO (WINDOWS)

A FEW THOUGHTS ON COMMUNITY BUILDING

ABOUT ME

• Harris Brakmic

• Software Engineer

• advarics GmbH, Innsbruck ( ) HQ, Bochum ( ) DEV, http://advarics.net

• Tech at work: .NET, Azure Cloud, C#, JavaScript, Backend-to-Frontend dev, mobile Apps

• Tech at home: pretending to learn Rust, claiming to know C, bragging about Linux (Kali, Fedora, Mint)

• http://brakmic.de

• @brakmic

• harris.brakmic

BUILDING WEBAPPS WITH RUST / NICKEL.RS

• OS: Linux Mint (it seems Nickel.rs won‘t compile under Win32)

• Stack: Gulp, NodeJS, RactiveJS (Frontend UI-Library), Nickel.rs

• For faster UI-Development Gulp & NodeJS can be used instead of Nickel.rs

• More info: http://nickel.rs

• Sources: https://github.com/brakmic/nickel-demo

NICKEL.RS

• Framework for Web Apps, written in Rust

• Similar to ExpressJS

• Extensible Architecture (Plugins, Middleware)

• Supports the „usual suspects“: Parameter-Access, Routing, Wildcards etc.

• Templating via Mustache

A VERY SIMPLE WEB SERVER*

#[macro_use] extern crate nickel;

use nickel::{Nickel, HttpRouter};

fn main() {

let mut server = Nickel::new();

server.get("**", middleware!("Hello Rustaceans!"));

server.listen("127.0.0.1:3000");

}

*shamelessly stolen from https://github.com/nickel-org/nickel.rs/blob/master/examples/hello_world.rs

TEMPLATING WITH NICKEL.RS

src/templates/hello.tpl

<div>

Hello {{ name }}

</div>

src/main.rs

server.get("/", middleware! { |_, res|

let mut data = HashMap::<&str, &str>::new();

data.insert("name", "Rustaceans");

return res.render(„src/templates/hello.tpl", &data)

});

RUST UNDER WIN32 WITH VS2013 + VISUALRUST

• OS: Windows 8.1x64 + Visual Studio 2013

• VisualRust Addin from https://github.com/PistonDevelopers/VisualRust

• Development still in early phase!

• Some tweaks needed! (Cargo.toml not available by default)

• Pro-Tip: add two new entries (Cargo Build / Run) under Tools/External Tools

• Sources: https://github.com/brakmic/IHaveNoClue

PREPARATIONS: EXPORT, ADAPT, LINK• All function exports must be extern “C“ because Rust can‘t use C++ DLLs (name mangling, vptr etc.)

extern "C" IAMALIBRARY_API int SampleFunction(int a, int b);

extern "C" IAMALIBRARY_API void WriteContent(CarrierObject* obj);

• Implement proper mappings of C-structs

#[repr(C)]

pub struct CarrierObject{

pub a_value: int32_t}

• Link the library

#[link(name = "IAmALibrary")]

extern "C" {

fn SampleFunction(a: i32, b: i32) -> i32;

fn WriteContent(obj: *mut CarrierObject);

}

USAGE IN UNSAFE BLOCKS

• No Rust, no Safety!

• Therefore, when executing „unsafe“ operations like pointer arithmetic or calling C-DLLs, such calls must be packed into unsafe-blocks.

fn main() { Safely allocate the object on heap

let mut an_object = Box::new(CarrierObject{ a_value: 100 });

unsafe { WriteContent(&mut *an_object); }; Forward raw object-pointer to unsafe function

let answer = unsafe { SampleFunction(40,2) };

println!("The ultimate answer is {}", answer);

}

A FEW THOUGHTS ON COMMUNITY BUILDING

• Two new domains: http://rustaceans.de & http://rustaceans.cologne

• Some unfair criticism:

http://users.rust-lang.org is full of excellent material but relatively hard to search / filter.

Only a few general categories exist: announcements, help, „uncategorized“ and meta

A beginner (like me) quickly gets lost in the uncategorized sea of questions/answers.

• A possible alternative?

What about a new forum with better structure, easier information retrieval and (optionally)

German language?

• Forum example: http://forum.rustaceans.de

• What about establishing a frequent Rust meetup in the Cologne/Bonn area?

• Do we need a website?