How to reuse a db client and modularize handlers?

[scorphus]

Hi! This is what I tried to do:

extern crate chill;
extern crate pencil;

use pencil::Pencil;
use pencil::{Request, PencilResult, Response};
use pencil::method::Get;
use pencil::helpers;

use chill::Client;


struct Handlers {
    db: Client,
}

impl Handlers {
    fn hello(&self, _: &mut Request) -> PencilResult {
        Ok(Response::from("Hello World!"))
    }
}


fn main() {
    let mut app = Pencil::new("/web/hello");
    let mut handlers = Handlers{db: Client::new("http://0.0.0.0:5984/").unwrap()};
    app.route("/", &[Get], "hello", handlers.hello);
    app.run("0.0.0.0:5000");
}

I can't pass handlers.hello as a ViewFunc to app.route(). How could I do what I just meant by this code? As you can see, I'm pretty new to Rust.

Thanks.

[scorphus]

After applying #14 – actually rebasing on top of master and solving a conflict – I managed to do this:

extern crate chill;
extern crate pencil;

use pencil::Pencil;
use pencil::{Request, PencilResult, Response};
use pencil::method::Get;
use pencil::helpers;

use chill::Client;


struct Handlers {
    db: Client,
}

impl Handlers {
    fn hello(&self, _: &mut Request) -> PencilResult {
        Ok(Response::from("Hello World!"))
    }

}


fn main() {
    let mut app = Pencil::new("/web/hello");
    let handlers = Handlers{db: Client::new("http://0.0.0.0:5984/").unwrap()};
    app.route("/", &[Get], "hello", move |resp| handlers.hello(resp));
    app.run("0.0.0.0:5000");
}

So far so good. But no DB connections yet. So I tried:

extern crate chill;
extern crate pencil;

use pencil::Pencil;
use pencil::{Request, PencilResult, Response};
use pencil::method::Get;
use pencil::helpers;

use chill::Client;


struct Handlers {
    db: Client,
}

impl Handlers {
    fn hello(&self, _: &mut Request) -> PencilResult {
        Ok(Response::from("Hello World!"))
    }

    fn logo(&self, req: &mut Request) -> PencilResult {
        println!("From {}", req.remote_addr());
        println!("Headers {}", req.headers());
        Ok(helpers::send_file("./static/logo.png", "image/png".parse().unwrap(), false).unwrap())
    }

}


fn main() {
    let mut app = Pencil::new("/web/hello");
    let handlers = Handlers{db: Client::new("http://0.0.0.0:5984/").unwrap()};
    app.route("/", &[Get], "hello", move |resp| handlers.hello(resp));
    app.route("/logo.png", &[Get], "logo", move |resp| handlers.logo(resp));
    app.run("0.0.0.0:5000");
}

Which obviously failed:

   Compiling handers v0.1.0 (file:///Users/pablo/Workspace/handers)
src/main.rs:34:56: 34:64 error: capture of moved value: `handlers` [E0382]
src/main.rs:34     app.route("/logo.png", &[Get], "logo", move |resp| handlers.logo(resp));
                                                                      ^~~~~~~~
src/main.rs:33:37: 33:48 note: value moved (into closure) here
src/main.rs:33     app.route("/", &[Get], "hello", move |resp| handlers.hello(resp));
                                                   ^~~~~~~~~~~
src/main.rs:34:56: 34:64 help: run `rustc --explain E0382` to see a detailed explanation
src/main.rs:34:56: 34:64 note: move occurs because `handlers` has type `Handlers`, which does not implement the `Copy` trait
error: aborting due to previous error
error: Could not compile `handers`.

And, finally, I gave up:

extern crate chill;
extern crate pencil;

use pencil::Pencil;
use pencil::{Request, PencilResult, Response};
use pencil::method::Get;
use pencil::helpers;

use chill::Client;


#[derive(Copy, Clone)]
struct Handlers {
    db: Client,
}

impl Handlers {
    fn hello(&self, _: &mut Request) -> PencilResult {
        Ok(Response::from("Hello World!"))
    }

    fn logo(&self, req: &mut Request) -> PencilResult {
        println!("From {}", req.remote_addr());
        println!("Headers {}", req.headers());
        Ok(helpers::send_file("./static/logo.png", "image/png".parse().unwrap(), false).unwrap())
    }

}


fn main() {
    let mut app = Pencil::new("/web/hello");
    let handlers = Handlers{db: Client::new("http://0.0.0.0:5984/").unwrap()};
    app.route("/", &[Get], "hello", move |resp| handlers.hello(resp));
    app.route("/logo.png", &[Get], "logo", move |resp| handlers.logo(resp));
    app.run("0.0.0.0:5000");
}

Because of:

   Compiling handlers v0.1.0 (file:///.../handlers)
src/main.rs:12:10: 12:14 error: the trait `Copy` may not be implemented for this type; field `db` does not implement `Copy` [E0204]
src/main.rs:12 #[derive(Copy, Clone)]
                        ^~~~
src/main.rs:12:10: 12:14 note: in this expansion of #[derive(Copy)] (defined in src/main.rs)
src/main.rs:12:10: 12:14 help: run `rustc --explain E0204` to see a detailed explanation
error: aborting due to previous error
error: Could not compile `handlers`.

@fengsp: Can you please help me achieve what I meant by this code? Thank you!