Trait poem::middleware::Middleware

pub trait Middleware<E: Endpoint> {
    type Output: Endpoint;

    // Required method
    fn transform(&self, ep: E) -> Self::Output;
}

Represents a middleware trait.

Create you own middleware

use poem::{
    handler, test::TestClient, web::Data, Endpoint, EndpointExt, Middleware, Request, Result,
};

/// A middleware that extract token from HTTP headers.
struct TokenMiddleware;

impl<E: Endpoint> Middleware<E> for TokenMiddleware {
    type Output = TokenMiddlewareImpl<E>;

    fn transform(&self, ep: E) -> Self::Output {
        TokenMiddlewareImpl { ep }
    }
}

/// The new endpoint type generated by the TokenMiddleware.
struct TokenMiddlewareImpl<E> {
    ep: E,
}

const TOKEN_HEADER: &str = "X-Token";

/// Token data
#[derive(Clone)]
struct Token(String);

impl<E: Endpoint> Endpoint for TokenMiddlewareImpl<E> {
    type Output = E::Output;

    async fn call(&self, mut req: Request) -> Result<Self::Output> {
        if let Some(value) = req
            .headers()
            .get(TOKEN_HEADER)
            .and_then(|value| value.to_str().ok())
        {
            // Insert token data to extensions of request.
            let token = value.to_string();
            req.extensions_mut().insert(Token(token));
        }

        // call the next endpoint.
        self.ep.call(req).await
    }
}

#[handler]
async fn index(Data(token): Data<&Token>) -> String {
    token.0.clone()
}

// Use the `TokenMiddleware` middleware to convert the `index` endpoint.
let ep = index.with(TokenMiddleware);

let mut resp = TestClient::new(ep)
    .get("/")
    .header(TOKEN_HEADER, "abc")
    .send()
    .await;
resp.assert_status_is_ok();
resp.assert_text("abc").await;

Create middleware with functions

use std::sync::Arc;

use poem::{
    handler, test::TestClient, web::Data, Endpoint, EndpointExt, IntoResponse, Request, Result,
};
const TOKEN_HEADER: &str = "X-Token";

#[handler]
async fn index(Data(token): Data<&Token>) -> String {
    token.0.clone()
}

/// Token data
#[derive(Clone)]
struct Token(String);

async fn token_middleware<E: Endpoint>(next: E, mut req: Request) -> Result<E::Output> {
    if let Some(value) = req
        .headers()
        .get(TOKEN_HEADER)
        .and_then(|value| value.to_str().ok())
    {
        // Insert token data to extensions of request.
        let token = value.to_string();
        req.extensions_mut().insert(Token(token));
    }

    // call the next endpoint.
    next.call(req).await
}

let ep = index.around(token_middleware);
let cli = TestClient::new(ep);

let resp = cli.get("/").header(TOKEN_HEADER, "abc").send().await;
resp.assert_status_is_ok();
resp.assert_text("abc").await;

Required Associated Types

type Output: Endpoint

New endpoint type.

If you don’t know what type to use, then you can use BoxEndpoint, which will bring some performance loss, but it is insignificant.

Required Methods

fn transform(&self, ep: E) -> Self::Output

Transform the input Endpoint to another one.

Implementations on Foreign Types

impl<E, T1, T2> Middleware<E> for (T1, T2)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>,

type Output = <T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3> Middleware<E> for (T1, T2, T3)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>,

type Output = <T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4> Middleware<E> for (T1, T2, T3, T4)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>,

type Output = <T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5> Middleware<E> for (T1, T2, T3, T4, T5)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>,

type Output = <T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6> Middleware<E> for (T1, T2, T3, T4, T5, T6)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>,

type Output = <T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>,

type Output = <T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>,

type Output = <T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8, T9> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8, T9)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>, T9: Middleware<T8::Output>,

type Output = <T9 as Middleware<<T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>, T9: Middleware<T8::Output>, T10: Middleware<T9::Output>,

type Output = <T10 as Middleware<<T9 as Middleware<<T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>, T9: Middleware<T8::Output>, T10: Middleware<T9::Output>, T11: Middleware<T10::Output>,

type Output = <T11 as Middleware<<T10 as Middleware<<T9 as Middleware<<T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>, T9: Middleware<T8::Output>, T10: Middleware<T9::Output>, T11: Middleware<T10::Output>, T12: Middleware<T11::Output>,

type Output = <T12 as Middleware<<T11 as Middleware<<T10 as Middleware<<T9 as Middleware<<T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>, T9: Middleware<T8::Output>, T10: Middleware<T9::Output>, T11: Middleware<T10::Output>, T12: Middleware<T11::Output>, T13: Middleware<T12::Output>,

type Output = <T13 as Middleware<<T12 as Middleware<<T11 as Middleware<<T10 as Middleware<<T9 as Middleware<<T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>, T9: Middleware<T8::Output>, T10: Middleware<T9::Output>, T11: Middleware<T10::Output>, T12: Middleware<T11::Output>, T13: Middleware<T12::Output>, T14: Middleware<T13::Output>,

type Output = <T14 as Middleware<<T13 as Middleware<<T12 as Middleware<<T11 as Middleware<<T10 as Middleware<<T9 as Middleware<<T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>, T9: Middleware<T8::Output>, T10: Middleware<T9::Output>, T11: Middleware<T10::Output>, T12: Middleware<T11::Output>, T13: Middleware<T12::Output>, T14: Middleware<T13::Output>, T15: Middleware<T14::Output>,

type Output = <T15 as Middleware<<T14 as Middleware<<T13 as Middleware<<T12 as Middleware<<T11 as Middleware<<T10 as Middleware<<T9 as Middleware<<T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

impl<E, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16> Middleware<E> for (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16)

where E: Endpoint, T1: Middleware<E>, T2: Middleware<T1::Output>, T3: Middleware<T2::Output>, T4: Middleware<T3::Output>, T5: Middleware<T4::Output>, T6: Middleware<T5::Output>, T7: Middleware<T6::Output>, T8: Middleware<T7::Output>, T9: Middleware<T8::Output>, T10: Middleware<T9::Output>, T11: Middleware<T10::Output>, T12: Middleware<T11::Output>, T13: Middleware<T12::Output>, T14: Middleware<T13::Output>, T15: Middleware<T14::Output>, T16: Middleware<T15::Output>,

type Output = <T16 as Middleware<<T15 as Middleware<<T14 as Middleware<<T13 as Middleware<<T12 as Middleware<<T11 as Middleware<<T10 as Middleware<<T9 as Middleware<<T8 as Middleware<<T7 as Middleware<<T6 as Middleware<<T5 as Middleware<<T4 as Middleware<<T3 as Middleware<<T2 as Middleware<<T1 as Middleware<E>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output>>::Output

fn transform(&self, ep: E) -> Self::Output

Implementors

impl<E> Middleware<E> for CookieJarManager

where E: Endpoint,

type Output = CookieJarManagerEndpoint<E>

impl<E> Middleware<E> for ForceHttps

where E: Endpoint,

type Output = ForceHttpsEndpoint<E>

impl<E, T> Middleware<E> for AddData<T>

where E: Endpoint, T: Clone + Send + Sync + 'static,

type Output = AddDataEndpoint<E, T>

impl<E: Endpoint> Middleware<E> for CookieSession

Available on crate feature session only.

type Output = CookieJarManagerEndpoint<CookieSessionEndpoint<E>>

impl<E: Endpoint> Middleware<E> for Compression

type Output = CompressionEndpoint<E>

impl<E: Endpoint> Middleware<E> for Cors

type Output = CorsEndpoint<E>

impl<E: Endpoint> Middleware<E> for Csrf

type Output = CookieJarManagerEndpoint<CsrfEndpoint<E>>

impl<E: Endpoint> Middleware<E> for NormalizePath

type Output = NormalizePathEndpoint<E>

impl<E: Endpoint> Middleware<E> for OpenTelemetryMetrics

type Output = OpenTelemetryMetricsEndpoint<E>

impl<E: Endpoint> Middleware<E> for PropagateHeader

type Output = PropagateHeaderEndpoint<E>

impl<E: Endpoint> Middleware<E> for SensitiveHeader

type Output = SensitiveHeaderEndpoint<E>

impl<E: Endpoint> Middleware<E> for SetHeader

type Output = SetHeaderEndpoint<E>

impl<E: Endpoint> Middleware<E> for SizeLimit

type Output = SizeLimitEndpoint<E>

impl<E: Endpoint> Middleware<E> for TokioMetrics

type Output = TokioMetricsEndpoint<E>

impl<E: Endpoint> Middleware<E> for Tracing

type Output = TracingEndpoint<E>

impl<E: Endpoint, H: PanicHandler> Middleware<E> for CatchPanic<H>

type Output = CatchPanicEndpoint<E, H>

impl<T, E> Middleware<E> for OpenTelemetryTracing<T>

where T: Tracer + Send + Sync, T::Span: Send + Sync + 'static, E: Endpoint,

type Output = OpenTelemetryTracingEndpoint<T, E>

impl<T, E, E2> Middleware<E> for FnMiddleware<T>

where T: Fn(E) -> E2, E: Endpoint, E2: Endpoint,

type Output = E2

impl<T: SessionStorage, E: Endpoint> Middleware<E> for ServerSession<T>

Available on crate feature session only.

type Output = CookieJarManagerEndpoint<ServerSessionEndpoint<T, E>>