addonovan/mwf

My Web Framework. I'm bad at names.

mwf

General

My Web Framework. (Great name, I know)

This project was inspired by Gary Bernhardt's screencast on Destroy All Software about making a webframework from scratch.

This is not intended to be used in a production or production-like setting, so please don't even try to do so.

About

This is a backend web framework, like ASP.NET. The most important part of this is the router and route resolvers, which take in a route that has been requested from the server and try to find the handler which should accept it.

Examples

Examples can be found in the examples directory.

Here is a simple "Hello World" server:

struct HelloWorld;
impl RequestHandler for HelloWorld
{
    fn handle(&self, _route_map: RouteMap) -> mwf::Result<View>
    {
        Ok(View::raw("Hello world!"))
    }
}

fn main()
{
    ServerBuilder::new()
        .bind("/", HelloWorld)
        .start();
}

Routing

The Resolver trait, whose definition (as well as related one) is listed below, will simply take in a URL which has been split up along the slashes, and return None if the path isn't accepted by the resolver, or Some(RouteMap) if the route was accepted.

pub type RouteMap = HashMap<String, String>;

pub struct ResolveParams<'a>
{
    pub method: Method,
    pub route: Vec<&'a str>,
}

pub trait Resolver
    where Self: Send + Sync
{
    fn resolve(&self, params: &ResolveParams) -> Option<RouteMap>;
}

The standard resolver (which is the default one enabled) has three path tokens:

• a literal token (/foo)
  • This matches text exactly as it appears in a URL
• a variable token (/:foo)
  • This matches any text in the same position, and the text it matched will be stored in the RouteMap under the variable's name
  • Variables must begin with a leading : which is used in its name in the RouteMap.
• an optional variable token (/:foo?)
  • This matches anything in the same position (including nothing).
  • The matched text will be stored in the RouteMap under the variable's name ("" if it matched nothing)
  • Like variables, optional variables must begin with a : and must also end with a ?. Both of these characters are part of the variable's name in the RouteMap.

Using these tokens, you can build route handlers for a lot of things.

Request Handlers

On the other side of request resolution, is the actual handler itself. Handler is also a trait (shown below), but a much simpler one. This receives the RouteMap generated by its corresponding Resolver and then serves a View of the content which is meant to be at the URL. Because generating the page might cause an error (who hasn't seen a 500 Internal Service Error before?), we don't want the entire server to crash on such a problem. For this reason, the handler must actually return a mwf::Result.

pub trait RequestHandler
    where Self: Send + Sync
{
    fn handle(&self, route_map: RouteMap) -> mwf::Result<View>;
}

Using the ServerBuilder interface, handlers are attached to the server by using the ServerBuilder.bind(method, route_spec, handler) method, as shown above in the hello world example.