Enum actix_web::Either

pub enum Either<A, B> {
    A(A),
    B(B),
}

Combines two different responder types into a single type

use actix_web::{AsyncResponder, Either, Error, HttpRequest, HttpResponse};
use futures::future::result;

type RegisterResult =
    Either<HttpResponse, Box<Future<Item = HttpResponse, Error = Error>>>;

fn index(req: HttpRequest) -> RegisterResult {
    if is_a_variant() {
        // <- choose variant A
        Either::A(HttpResponse::BadRequest().body("Bad data"))
    } else {
        Either::B(
            // <- variant B
            result(Ok(HttpResponse::Ok()
                .content_type("text/html")
                .body("Hello!")))
                .responder(),
        )
    }
}

Variants

A(A)

First branch of the type

B(B)

Second branch of the type

Trait Implementations

impl<A, B> Responder for Either<A, B> where
    A: Responder,
    B: Responder, 

type Item = AsyncResult<HttpResponse>

The associated item which can be returned.

type Error = Error

The associated error which can be returned.

fn respond_to<S: 'static>(
    self,
    req: &HttpRequest<S>
) -> Result<AsyncResult<HttpResponse>, Error>

Convert itself to AsyncResult or Error.

impl<A: 'static, B: 'static, S: 'static> FromRequest<S> for Either<A, B> where
    A: FromRequest<S>,
    B: FromRequest<S>, 

Extract either one of two fields from the request.

If both or none of the fields can be extracted, the default behaviour is to prefer the first successful, last that failed. The behaviour can be changed by setting the appropriate EitherCollisionStrategy.

CAVEAT: Most of the time both extractors will be run. Make sure that the extractors you specify can be run one after another (or in parallel). This will always fail for extractors that modify the request state (such as the Form extractors that read in the body stream). So Either<Form, Form> will not work correctly - it will only succeed if it matches the first option, but will always fail to match the second (since the body stream will be at the end, and appear to be empty).

Example

extern crate rand;
#[macro_use] extern crate serde_derive;
use actix_web::{http, App, Result, HttpRequest, Error, FromRequest};
use actix_web::error::ErrorBadRequest;
use actix_web::Either;

#[derive(Debug, Deserialize)]
struct Thing { name: String }

#[derive(Debug, Deserialize)]
struct OtherThing { id: String }

impl<S> FromRequest<S> for Thing {
    type Config = ();
    type Result = Result<Thing, Error>;

    #[inline]
    fn from_request(req: &HttpRequest<S>, _cfg: &Self::Config) -> Self::Result {
        if rand::random() {
            Ok(Thing { name: "thingy".into() })
        } else {
            Err(ErrorBadRequest("no luck"))
        }
    }
}

impl<S> FromRequest<S> for OtherThing {
    type Config = ();
    type Result = Result<OtherThing, Error>;

    #[inline]
    fn from_request(req: &HttpRequest<S>, _cfg: &Self::Config) -> Self::Result {
        if rand::random() {
            Ok(OtherThing { id: "otherthingy".into() })
        } else {
            Err(ErrorBadRequest("no luck"))
        }
    }
}

/// extract text data from request
fn index(supplied_thing: Either<Thing, OtherThing>) -> Result<String> {
    match supplied_thing {
        Either::A(thing) => Ok(format!("Got something: {:?}", thing)),
        Either::B(other_thing) => Ok(format!("Got anotherthing: {:?}", other_thing))
    }
}

fn main() {
    let app = App::new().resource("/users/:first", |r| {
        r.method(http::Method::POST).with(index)
    });
}

type Config = EitherConfig<A, B, S>

Configuration for conversion process

type Result = AsyncResult<Either<A, B>>

Future that resolves to a Self

fn from_request(req: &HttpRequest<S>, cfg: &Self::Config) -> Self::Result

Convert request to a Self

fn extract(req: &HttpRequest<S>) -> Self::Result

Convert request to a Self

impl<A: PartialEq, B: PartialEq> PartialEq<Either<A, B>> for Either<A, B>

fn eq(&self, other: &Either<A, B>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Either<A, B>) -> bool

This method tests for !=.

impl<A: Debug, B: Debug> Debug for Either<A, B>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<A, B, I, E> Future for Either<A, B> where
    A: Future<Item = I, Error = E>,
    B: Future<Item = I, Error = E>, 

type Item = I

The type of value that this future will resolved with if it is successful.

type Error = E

The type of error that this future will resolve with if it fails in a normal fashion.

fn poll(&mut self) -> Poll<I, E>

Query this future to see if its value has become available, registering interest if it is not.

fn wait(self) -> Result<Self::Item, Self::Error>

Block the current thread until this future is resolved.

fn map<F, U>(self, f: F) -> Map<Self, F> where
    F: FnOnce(Self::Item) -> U, 

Map this future's result to a different type, returning a new future of the resulting type.

fn map_err<F, E>(self, f: F) -> MapErr<Self, F> where
    F: FnOnce(Self::Error) -> E, 

Map this future's error to a different error, returning a new future.

fn from_err<E>(self) -> FromErr<Self, E> where
    E: From<Self::Error>, 

Map this future's error to any error implementing From for this future's Error, returning a new future.

fn then<F, B>(self, f: F) -> Then<Self, B, F> where
    B: IntoFuture,
    F: FnOnce(Result<Self::Item, Self::Error>) -> B, 

Chain on a computation for when a future finished, passing the result of the future to the provided closure f.

fn and_then<F, B>(self, f: F) -> AndThen<Self, B, F> where
    B: IntoFuture<Error = Self::Error>,
    F: FnOnce(Self::Item) -> B, 

Execute another future after this one has resolved successfully.

fn or_else<F, B>(self, f: F) -> OrElse<Self, B, F> where
    B: IntoFuture<Item = Self::Item>,
    F: FnOnce(Self::Error) -> B, 

Execute another future if this one resolves with an error.

fn select<B>(self, other: B) -> Select<Self, <B as IntoFuture>::Future> where
    B: IntoFuture<Item = Self::Item, Error = Self::Error>, 

Waits for either one of two futures to complete.

fn select2<B>(self, other: B) -> Select2<Self, <B as IntoFuture>::Future> where
    B: IntoFuture, 

Waits for either one of two differently-typed futures to complete.

fn join<B>(self, other: B) -> Join<Self, <B as IntoFuture>::Future> where
    B: IntoFuture<Error = Self::Error>, 

Joins the result of two futures, waiting for them both to complete.

fn join3<B, C>(
    self,
    b: B,
    c: C
) -> Join3<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future> where
    B: IntoFuture<Error = Self::Error>,
    C: IntoFuture<Error = Self::Error>, 

Same as join, but with more futures.

fn join4<B, C, D>(
    self,
    b: B,
    c: C,
    d: D
) -> Join4<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future, <D as IntoFuture>::Future> where
    B: IntoFuture<Error = Self::Error>,
    C: IntoFuture<Error = Self::Error>,
    D: IntoFuture<Error = Self::Error>, 

Same as join, but with more futures.

fn join5<B, C, D, E>(
    self,
    b: B,
    c: C,
    d: D,
    e: E
) -> Join5<Self, <B as IntoFuture>::Future, <C as IntoFuture>::Future, <D as IntoFuture>::Future, <E as IntoFuture>::Future> where
    B: IntoFuture<Error = Self::Error>,
    C: IntoFuture<Error = Self::Error>,
    D: IntoFuture<Error = Self::Error>,
    E: IntoFuture<Error = Self::Error>, 

Same as join, but with more futures.

fn into_stream(self) -> IntoStream<Self>

Convert this future into a single element stream.

fn flatten(self) -> Flatten<Self> where
    Self::Item: IntoFuture,
    <Self::Item as IntoFuture>::Error: From<Self::Error>, 

Flatten the execution of this future when the successful result of this future is itself another future.

fn flatten_stream(self) -> FlattenStream<Self> where
    Self::Item: Stream,
    <Self::Item as Stream>::Error == Self::Error, 

Flatten the execution of this future when the successful result of this future is a stream.

fn fuse(self) -> Fuse<Self>

Fuse a future such that poll will never again be called once it has completed.

fn inspect<F>(self, f: F) -> Inspect<Self, F> where
    F: FnOnce(&Self::Item), 

Do something with the item of a future, passing it on.

fn catch_unwind(self) -> CatchUnwind<Self> where
    Self: UnwindSafe, 

Catches unwinding panics while polling the future.

fn shared(self) -> Shared<Self>

Create a cloneable handle to this future where all handles will resolve to the same result.