Crate salvo_flash 

Flash messages middleware for the Salvo web framework.

Flash messages are temporary notifications that persist across a single redirect, commonly used to display success, error, or info messages after form submissions.

How It Works

1. A handler sets flash messages before redirecting
2. The middleware stores them (in cookies or session)
3. On the next request, the messages are available and then cleared

Storage Options

Store	Feature	Description
CookieStore	cookie-store	Stores messages in a cookie
SessionStore	session-store	Stores messages in the session

Message Levels

Messages have severity levels for appropriate UI styling:

• Debug - Debugging information
• Info - General information
• Success - Operation completed successfully
• Warning - Warning that doesn’t prevent operation
• Error - Error that needs attention

Example

use salvo_flash::{FlashDepotExt, CookieStore};
use salvo_core::prelude::*;

#[handler]
async fn submit_form(depot: &mut Depot, res: &mut Response) {
    // Set flash message before redirect
    depot.outgoing_flash_mut().success("Form submitted successfully!");
    res.render(Redirect::other("/result"));
}

#[handler]
async fn show_result(depot: &mut Depot, res: &mut Response) {
    if let Some(flash) = depot.incoming_flash() {
        for msg in flash.iter() {
            println!("{}: {}", msg.level, msg.value);
        }
    }
    res.render("Result page");
}

// Setup router with flash middleware
let router = Router::new()
    .hoop(CookieStore::new().into_handler())
    .push(Router::with_path("submit").post(submit_form))
    .push(Router::with_path("result").get(show_result));

Filtering by Level

Use minimum_level() to filter out lower-priority messages:

let mut handler = FlashHandler::new(CookieStore::new());
handler.minimum_level(FlashLevel::Warning);  // Only show Warning and Error

Read more: https://salvo.rs

Structs

CookieStorecookie-store

CookieStore is a FlashStore implementation that stores the flash messages in a cookie.

Flash

A flash is a list of messages.

FlashHandler

FlashHandler is a middleware for flash messages.

FlashMessage

A flash message.

SessionStoresession-store

SessionStore is a FlashStore implementation that stores the flash messages in a session.

Enums

FlashLevel

Verbosity level of a flash message.

Constants

INCOMING_FLASH_KEY

Key for incoming flash messages in depot.

OUTGOING_FLASH_KEY

Key for outgoing flash messages in depot.

Traits

FlashDepotExt

A trait for Depot to get flash messages.

FlashStore

FlashStore is for stores flash messages.

Functions

cookie_storecookie-store

Helper function to create a CookieStore.

session_storesession-store

Helper function to create a SessionStore.