Crate actix_web_flash_messages
source ·Expand description
§Flash Messages for actix-web
Web applications sometimes need to show a one-time notification to the user - e.g. an error message after having failed to login.
These notifications are commonly called flash messages.
actix-web-flash-messages
provides a framework to work with flash messages in actix-web
, closely modeled after Django’s message framework.
use actix_web::{Responder, HttpResponse, get,http};
use actix_web_flash_messages::{
FlashMessage, IncomingFlashMessages,
};
use std::fmt::Write;
/// Attach two flash messages to the outgoing response,
/// a redirect.
#[get("/set")]
async fn set() -> impl Responder {
FlashMessage::info("Hey there!").send();
FlashMessage::debug("How is it going?").send();
// Redirect to /show
HttpResponse::TemporaryRedirect()
.insert_header((http::header::LOCATION, "/show"))
.finish()
}
/// Pick up the flash messages attached to the request, showing
/// them to the user via the request body.
#[get("/show")]
async fn show(messages: IncomingFlashMessages) -> impl Responder {
let mut body = String::new();
for message in messages.iter() {
writeln!(body, "{} - {}", message.content(), message.level()).unwrap();
}
HttpResponse::Ok().body(body)
}
§How to install
Add actix-web-flash-messages
to your dependencies:
[dependencies]
# ...
actix-web = "4"
actix-web-flash-messages = "0.4"
By default, actix-web-flash-messages
does not provide any storage backend to receive and send flash messages.
You can enable:
- a cookie-based one,
storage::CookieMessageStore
, using thecookies
feature flag. The cookie store uses a signed cookie to store and retrieve messages;
[dependencies]
# ...
actix-web-flash-messages = { version = "0.4", features = ["cookies"] }
- a session-based one,
storage::SessionMessageStore
, using thesessions
feature flag. The session store attaches flash messages to the current session.
[dependencies]
# ...
actix-web-flash-messages = { version = "0.4", features = ["sessions"] }
You can provide a different message store by implementing the storage::FlashMessageStore
trait.
§Examples
You can find examples of application using actix-web-flash-messages
on GitHub:
§The Structure of a Flash Message
FlashMessage
s are made of a Level
and a string of content.
The message level can be used for filtering and rendering - for example:
- Only show flash messages at
info
level or above in a production environment, while retainingdebug
level messages for local development; - Use different colours, in the UI, to display messages (e.g. red for errors, orange for warnings, etc.);
You can build a FlashMessage
via FlashMessage::new
by specifying its content and Level
.
You can also use the shorter level-based constructors - e.g. FlashMessage::info
.
§Enabling Flash Messages
To start sending and receiving flash messages you need to register FlashMessagesFramework
as a middleware on your actix_web
’s App
:
use actix_web_flash_messages::{FlashMessagesFramework, storage::CookieMessageStore};
use actix_web::{HttpServer, App, web};
use actix_web::cookie::Key;
#[actix_web::main]
async fn main() {
let signing_key = Key::generate(); // This will usually come from configuration!
let message_store = CookieMessageStore::builder(signing_key).build();
let message_framework = FlashMessagesFramework::builder(message_store).build();
HttpServer::new(move || {
App::new()
.wrap(message_framework.clone())
// [...] your endpoints
})
}
You will then be able to:
- extract
FlashMessage
s from incoming requests using theIncomingFlashMessages
extractor; - send
FlashMessage
s alongside the outgoing response usingFlashMessage::send
.
use actix_web::{Responder, HttpResponse, get};
use actix_web_flash_messages::{
FlashMessage, IncomingFlashMessages,
};
/// Send a flash messages alongside the outgoing response, a redirect.
#[get("/set")]
async fn set() -> impl Responder {
FlashMessage::info("Hey there!").send();
// [...]
}
/// Extract the flash message from the incoming request.
#[get("/show")]
async fn show(_messages: IncomingFlashMessages) -> impl Responder {
// [...]
}
§Framework Configuration
There are a few knobs that you can tweak when it comes to FlashMessagesFramework
.
Use FlashMessagesFramework::builder
to get access to its fluent configuration API, built around FlashMessagesFrameworkBuilder
.
§Minimum Level
By default, FlashMessagesFramework
will only dispatch messages at info
-level or above, discarding debug
-level messages.
You can change this setting using FlashMessagesFrameworkBuilder::minimum_level
.
use actix_web_flash_messages::{FlashMessagesFramework, Level, storage::CookieMessageStore};
use actix_web::{HttpServer, App, web};
fn get_message_store() -> CookieMessageStore {
// [...]
}
#[actix_web::main]
async fn main() {
// Show debug-level messages when developing locally
let minimum_level = match std::env::var("APP_ENV") {
Ok(s) if &s == "local" => Level::Debug,
_ => Level::Info,
};
let message_framework = FlashMessagesFramework::builder(get_message_store())
.minimum_level(minimum_level)
.build();
HttpServer::new(move || {
App::new()
.wrap(message_framework.clone())
// [...] Your endpoints
})
}
§License
Licensed under either of Apache License, Version 2.0 or MIT license at your option. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
Re-exports§
pub use middleware::FlashMessagesMiddleware;
Modules§
- Pluggable storage backends for flash messages.
Structs§
- A one-time user notification.
actix-web
middleware providing support for sending and receivingFlashMessage
s.- A fluent builder to construct a
FlashMessagesFramework
instance. - An
actix-web
extractor to retrieveFlashMessage
s attached to an incoming request.
Enums§
- The severity level of a
FlashMessage
.