Trait snafu::futures::TryStreamExt [−][src]
pub trait TryStreamExt: TryStream + Sized { fn context<C, E>(self, context: C) -> Context<Self, C, E>
where
C: IntoError<E, Source = Self::Error> + Clone,
E: Error + ErrorCompat; fn with_context<F, C, E>(self, context: F) -> WithContext<Self, F, E>
where
F: FnMut() -> C,
C: IntoError<E, Source = Self::Error>,
E: Error + ErrorCompat; fn whatever_context<S, E>(self, context: S) -> WhateverContext<Self, S, E>
where
S: Into<String>,
E: FromString; fn with_whatever_context<F, S, E>(
self,
context: F
) -> WithWhateverContext<Self, F, E>
where
F: FnMut(&Self::Error) -> S,
S: Into<String>,
E: FromString; }
Expand description
Additions to TryStream
.
Required methods
Extend a TryStream
’s error with additional context-sensitive
information.
use futures::TryStream; use snafu::{futures::TryStreamExt, Snafu}; #[derive(Debug, Snafu)] enum Error { Authenticating { user_name: String, user_id: i32, source: ApiError, }, } fn example() -> impl TryStream<Ok = i32, Error = Error> { stock_prices().context(AuthenticatingSnafu { user_name: "admin", user_id: 42, }) } fn stock_prices() -> impl TryStream<Ok = i32, Error = ApiError> { /* ... */ }
Note that the context selector will call Into::into
on
each field, so the types are not required to exactly match.
fn with_context<F, C, E>(self, context: F) -> WithContext<Self, F, E> where
F: FnMut() -> C,
C: IntoError<E, Source = Self::Error>,
E: Error + ErrorCompat,
fn with_context<F, C, E>(self, context: F) -> WithContext<Self, F, E> where
F: FnMut() -> C,
C: IntoError<E, Source = Self::Error>,
E: Error + ErrorCompat,
Extend a TryStream
’s error with lazily-generated
context-sensitive information.
use futures::TryStream; use snafu::{futures::TryStreamExt, Snafu}; #[derive(Debug, Snafu)] enum Error { Authenticating { user_name: String, user_id: i32, source: ApiError, }, } fn example() -> impl TryStream<Ok = i32, Error = Error> { stock_prices().with_context(|| AuthenticatingSnafu { user_name: "admin", user_id: 42, }) } fn stock_prices() -> impl TryStream<Ok = i32, Error = ApiError> { /* ... */ }
Note that this may not be needed in many cases because the
context selector will call Into::into
on each field.
fn whatever_context<S, E>(self, context: S) -> WhateverContext<Self, S, E> where
S: Into<String>,
E: FromString,
fn whatever_context<S, E>(self, context: S) -> WhateverContext<Self, S, E> where
S: Into<String>,
E: FromString,
Extend a TryStream
’s error with information from a string.
The target error type must implement FromString
by using
the
#[snafu(whatever)]
attribute. The premade Whatever
type is also available.
In many cases, you will want to use
with_whatever_context
instead
as it is only called in case of error. This method is best
suited for when you have a string literal.
use futures::TryStream; use snafu::{futures::TryStreamExt, Whatever}; fn example() -> impl TryStream<Ok = i32, Error = Whatever> { stock_prices().whatever_context("Couldn't get stock prices") } fn stock_prices() -> impl TryStream<Ok = i32, Error = ApiError> { /* ... */ }
fn with_whatever_context<F, S, E>(
self,
context: F
) -> WithWhateverContext<Self, F, E> where
F: FnMut(&Self::Error) -> S,
S: Into<String>,
E: FromString,
fn with_whatever_context<F, S, E>(
self,
context: F
) -> WithWhateverContext<Self, F, E> where
F: FnMut(&Self::Error) -> S,
S: Into<String>,
E: FromString,
Extend a TryStream
’s error with information from a
lazily-generated string.
The target error type must implement FromString
by using
the
#[snafu(whatever)]
attribute. The premade Whatever
type is also available.
use futures::TryStream; use snafu::{futures::TryStreamExt, Whatever}; fn example(symbol: &'static str) -> impl TryStream<Ok = i32, Error = Whatever> { stock_prices(symbol).with_whatever_context(move |_| { format!("Couldn't get stock prices for {}", symbol) }) } fn stock_prices(symbol: &'static str) -> impl TryStream<Ok = i32, Error = ApiError> { /* ... */ }