Struct rocket::response::Flash [−][src]
Sets a "flash" cookie that will be removed when it is accessed. The anologous request type is FlashMessage.
This type makes it easy to send messages across requests. It is typically used for "status" messages after redirects. For instance, if a user attempts to visit a page he/she does not have access to, you may want to redirect the user to a safe place and show a message indicating what happened on the redirected page. The message should only persist for a single request. This can be accomplished with this type.
Usage
Each Flash
message consists of a name
and some msg
contents. A generic
constructor (new) can be used to construct a message with any
name, while the warning, success, and
error constructors create messages with the corresponding
names.
Messages can be retrieved on the request side via the FlashMessage type and the name and msg methods.
Response
The Responder
implementation for Flash
sets the message cookie and then
uses the passed in responder res
to complete the response. In other words,
it simply sets a cookie and delagates the rest of the response handling to
the wrapped responder.
Example
The following complete Rocket application illustrates the use of a Flash
message on both the request and response sides.
use rocket::response::{Flash, Redirect}; use rocket::request::FlashMessage; use rocket::http::RawStr; #[post("/login/<name>")] fn login(name: &RawStr) -> Result<&'static str, Flash<Redirect>> { if name == "special_user" { Ok("Hello, special user!") } else { Err(Flash::error(Redirect::to("/"), "Invalid username.")) } } #[get("/")] fn index(flash: Option<FlashMessage>) -> String { flash.map(|msg| format!("{}: {}", msg.name(), msg.msg())) .unwrap_or_else(|| "Welcome!".to_string()) } fn main() { rocket::ignite().mount("/", routes![login, index]).launch(); }
On the response side (in login
), a Flash
error message is set if some
fictional authentication failed, and the user is redirected to "/"
. On the
request side (in index
), the handler emits the flash message if there is
one and otherwise emits a standard welcome message. Note that if the user
were to refresh the index page after viewing a flash message, the user would
receive the standard welcome message.
Methods
impl<'r, R: Responder<'r>> Flash<R>
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impl<'r, R: Responder<'r>> Flash<R>
pub fn new<N: AsRef<str>, M: AsRef<str>>(res: R, name: N, msg: M) -> Flash<R>
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pub fn new<N: AsRef<str>, M: AsRef<str>>(res: R, name: N, msg: M) -> Flash<R>
Constructs a new Flash
message with the given name
, msg
, and
underlying responder
.
Examples
Construct a "suggestion" message with contents "Try this out!" that redirects to "/".
use rocket::response::{Redirect, Flash}; let msg = Flash::new(Redirect::to("/"), "suggestion", "Try this out!");
pub fn success<S: AsRef<str>>(responder: R, msg: S) -> Flash<R>
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pub fn success<S: AsRef<str>>(responder: R, msg: S) -> Flash<R>
Constructs a "success" Flash
message with the given responder
and
msg
.
Examples
Construct a "success" message with contents "It worked!" that redirects to "/".
use rocket::response::{Redirect, Flash}; let msg = Flash::success(Redirect::to("/"), "It worked!");
pub fn warning<S: AsRef<str>>(responder: R, msg: S) -> Flash<R>
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pub fn warning<S: AsRef<str>>(responder: R, msg: S) -> Flash<R>
Constructs a "warning" Flash
message with the given responder
and
msg
.
Examples
Construct a "warning" message with contents "Watch out!" that redirects to "/".
use rocket::response::{Redirect, Flash}; let msg = Flash::warning(Redirect::to("/"), "Watch out!");
pub fn error<S: AsRef<str>>(responder: R, msg: S) -> Flash<R>
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pub fn error<S: AsRef<str>>(responder: R, msg: S) -> Flash<R>
Constructs an "error" Flash
message with the given responder
and
msg
.
Examples
Construct an "error" message with contents "Whoops!" that redirects to "/".
use rocket::response::{Redirect, Flash}; let msg = Flash::error(Redirect::to("/"), "Whoops!");
impl Flash<()>
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impl Flash<()>
pub fn name(&self) -> &str
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pub fn name(&self) -> &str
Returns the name
of this message.
pub fn msg(&self) -> &str
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pub fn msg(&self) -> &str
Returns the msg
contents of this message.
Trait Implementations
impl<R: Debug> Debug for Flash<R>
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impl<R: Debug> Debug for Flash<R>
impl<'r, R: Responder<'r>> Responder<'r> for Flash<R>
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impl<'r, R: Responder<'r>> Responder<'r> for Flash<R>
impl<'a, 'r> FromRequest<'a, 'r> for Flash<()>
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impl<'a, 'r> FromRequest<'a, 'r> for Flash<()>