Awesome

tide-flash

http-rs/tide flash messages middleware with support for configurable flash storage through Cookies. Extensible to allow other storage mechanisms such as sessions. Primarily a mechanism for sending one time log messages to the client that may not maintain the state on redirects (such as on request logins). This is commonly used for authentication requests where the login is on an HTTP POST and a response will need to both: return a redirect as well as one time log messages to render.

Examples

To setup flash middleware with the configured CookieStore use the defaults below:

use tide::log::LogMiddleware;
use tide_flash::{cookies::CookieStore, FlashMiddleware};

mod routes;

#[async_std::main]
async fn main() -> tide::Result<()> {
    let mut app = tide::new();
    dotenv::dotenv().ok();
    env_logger::init();

    app.with(LogMiddleware::new());
    app.with(FlashMiddleware::new(CookieStore::default()));

    routes::configure(&mut app);

    let host = std::env::var("HOST").unwrap_or(String::from("0.0.0.0"));
    let port: u16 = std::env::var("PORT")?.parse()?;
    app.listen((host, port)).await?;

    Ok(())
}

Defaults for the CookieStore are:

impl Default for CookieConfig {
    fn default() -> Self {
        Self {
            max_age: time::Duration::seconds(60),
            site: SameSite::Lax,
            http_only: true,
            path: String::from("/"),
        }
    }
}

Now to simply use it you can import the response extensions through:

use tide_flash::ext::*;
use tide::{Response, Request, Redirect};

pub async fn authenticate(mut req: Request<State>) -> tide::Result {
    match req.body_form::<UserForm>().await {
        Ok(form) => {
            if form.username == "foo" && form.password == "bar" {
                let claims = Claims {
                    username: String::from("foo"),
                    exp: 10000000000,
                    sub: String::from("asdf"),
                    uid: 1,
                };
                req.login(claims)?;
                Ok(Redirect::new("/").into())
            } else {
                let mut res: Response = Redirect::new("/").into();
                res.flash_error("invalid credentials");
                Ok(res)
            }
        }
        Err(e) => {
            let mut res: Response = Redirect::new("/").into();
            res.flash_error(e.to_string());
            Ok(res)
        }
    }
}

There are a number of simple response extension utilities you can use here including:

pub trait ResponseFlashExt {
    fn flash(&mut self, level: &str, msg: String);
    fn flash_success<S: Into<String>>(&mut self, msg: S);
    fn flash_info<S: Into<String>>(&mut self, msg: S);
    fn flash_warn<S: Into<String>>(&mut self, msg: S);
    fn flash_error<S: Into<String>>(&mut self, msg: S);
    fn flash_debug<S: Into<String>>(&mut self, msg: S);
}

To obtain the corresponding flash messages from the tide::Request use the flash function on the request extension:

impl<'request, T: Serialize> Context<'request, T> {
    pub fn with_data(request: &'request Request<State>, data: T) -> Self {
        Self {
            request,
            flash: request.flash(),
            claims: request.claims(),
            data: Some(data),
        }
    }

    pub fn render(self, template: &str) -> Result<String, handlebars::RenderError> {
        self.request.state().render(
            template,
            &serde_json::json!({
                "flash": self.flash,
                "claims": self.claims,
                "data": self.data
            }),
        )
    }
}