Trait xitca_web::handler::FromRequest
source · pub trait FromRequest<'a, Req>: Sized {
type Type<'b>: FromRequest<'b, Req, Error = Self::Error>;
type Error;
// Required method
fn from_request(
req: &'a Req,
) -> impl Future<Output = Result<Self, Self::Error>>;
}Expand description
Extract type from Req asynchronously and receive them with function passed to handler_service.
'a is the lifetime of the extracted type.
When Req is also a borrowed type, the lifetimes of Req type and of the extracted type should
be kept separate. See example below of extracting &str from &String:
§Examples
// new type for implementing FromRequest trait to &str.
struct Str<'a>(&'a str);
// borrowed Req type has a named lifetime of it self while trait implementor has the same lifetime
// from FromRequest's lifetime param.
impl<'a, 'r> FromRequest<'a, &'r String> for Str<'a> {
type Type<'b> = Str<'b>; // use GAT lifetime to output a named lifetime instance of implementor.
type Error = ();
async fn from_request(req: &'a &'r String) -> Result<Self, Self::Error> {
Ok(Str(req))
}
}
let input = &String::from("996");
let extract = Str::from_request(&input).await.unwrap();
assert_eq!(extract.0, input.as_str());Required Associated Types§
Required Methods§
Object Safety§
This trait is not object safe.