Trait actix_web::FromRequest

pub trait FromRequest: Sized {
    type Error: Into<Error>;
    type Future: Future<Output = Result<Self, Self::Error>>;
    type Config: Default + 'static;
    pub fn from_request(
        req: &HttpRequest, 
        payload: &mut Payload
    ) -> Self::Future;

    pub fn extract(req: &HttpRequest) -> Self::Future { ... }
    pub fn configure<F>(f: F) -> Self::Config
    where
        F: FnOnce(Self::Config) -> Self::Config,
    { ... }
}

Trait implemented by types that can be extracted from request.

Types that implement this trait can be used with Route handlers.

Associated Types

type Error: Into<Error>

The associated error which can be returned.

type Future: Future<Output = Result<Self, Self::Error>>

Future that resolves to a Self

type Config: Default + 'static

Configuration for this extractor

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Required methods

pub fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future

Convert request to a Self

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Provided methods

pub fn extract(req: &HttpRequest) -> Self::Future

Convert request to a Self

This method uses Payload::None as payload stream.

pub fn configure<F>(f: F) -> Self::Config where
    F: FnOnce(Self::Config) -> Self::Config, 

Create and configure config instance.

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Implementations on Foreign Types

impl<T: 'static> FromRequest for Option<T> where
    T: FromRequest,
    T::Future: 'static, 

Optionally extract a field from the request

If the FromRequest for T fails, return None rather than returning an error response

Example

use actix_web::{web, dev, App, Error, HttpRequest, FromRequest};
use actix_web::error::ErrorBadRequest;
use futures_util::future::{ok, err, Ready};
use serde_derive::Deserialize;
use rand;

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

impl FromRequest for Thing {
    type Error = Error;
    type Future = Ready<Result<Self, Self::Error>>;
    type Config = ();

    fn from_request(req: &HttpRequest, payload: &mut dev::Payload) -> Self::Future {
        if rand::random() {
            ok(Thing { name: "thingy".into() })
        } else {
            err(ErrorBadRequest("no luck"))
        }

    }
}

/// extract `Thing` from request
async fn index(supplied_thing: Option<Thing>) -> String {
    match supplied_thing {
        // Puns not intended
        Some(thing) => format!("Got something: {:?}", thing),
        None => format!("No thing!")
    }
}

fn main() {
    let app = App::new().service(
        web::resource("/users/:first").route(
            web::post().to(index))
    );
}

type Config = T::Config

type Error = Error

type Future = LocalBoxFuture<'static, Result<Option<T>, Error>>

pub fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future

impl<T> FromRequest for Result<T, T::Error> where
    T: FromRequest + 'static,
    T::Error: 'static,
    T::Future: 'static, 

Optionally extract a field from the request or extract the Error if unsuccessful

If the FromRequest for T fails, inject Err into handler rather than returning an error response

Example

use actix_web::{web, dev, App, Result, Error, HttpRequest, FromRequest};
use actix_web::error::ErrorBadRequest;
use futures_util::future::{ok, err, Ready};
use serde_derive::Deserialize;
use rand;

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

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

    fn from_request(req: &HttpRequest, payload: &mut dev::Payload) -> Self::Future {
        if rand::random() {
            ok(Thing { name: "thingy".into() })
        } else {
            err(ErrorBadRequest("no luck"))
        }
    }
}

/// extract `Thing` from request
async fn index(supplied_thing: Result<Thing>) -> String {
    match supplied_thing {
        Ok(thing) => format!("Got thing: {:?}", thing),
        Err(e) => format!("Error extracting thing: {}", e)
    }
}

fn main() {
    let app = App::new().service(
        web::resource("/users/:first").route(web::post().to(index))
    );
}

type Config = T::Config

type Error = Error

type Future = LocalBoxFuture<'static, Result<Result<T, T::Error>, Error>>

pub fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future

impl FromRequest for String

Extract text information from a request's body.

Text extractor automatically decode body according to the request's charset.

PayloadConfig allows to configure extraction process.

Example

use actix_web::{web, App, FromRequest};

/// extract text data from request
async fn index(text: String) -> String {
    format!("Body {}!", text)
}

fn main() {
    let app = App::new().service(
        web::resource("/index.html")
            .app_data(String::configure(|cfg| {  // <- limit size of the payload
                cfg.limit(4096)
            }))
            .route(web::get().to(index))  // <- register handler with extractor params
    );
}

type Config = PayloadConfig

type Error = Error

type Future = Either<LocalBoxFuture<'static, Result<String, Error>>, Ready<Result<String, Error>>>

pub fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future

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Implementors

impl FromRequest for Bytes

Request binary data from a request's payload.

Loads request's payload and construct Bytes instance.

PayloadConfig allows to configure extraction process.

Example

use bytes::Bytes;
use actix_web::{web, App};

/// extract binary data from request
async fn index(body: Bytes) -> String {
    format!("Body {:?}!", body)
}

fn main() {
    let app = App::new().service(
        web::resource("/index.html").route(
            web::get().to(index))
    );
}

type Config = PayloadConfig

type Error = Error

type Future = Either<LocalBoxFuture<'static, Result<Bytes, Error>>, Ready<Result<Bytes, Error>>>

pub fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future

impl FromRequest for HttpRequest

It is possible to get HttpRequest as an extractor handler parameter

Example

use actix_web::{web, App, HttpRequest};
use serde_derive::Deserialize;

/// extract `Thing` from request
async fn index(req: HttpRequest) -> String {
   format!("Got thing: {:?}", req)
}

fn main() {
    let app = App::new().service(
        web::resource("/users/{first}").route(
            web::get().to(index))
    );
}

type Config = ()

type Error = Error

type Future = Ready<Result<Self, Error>>

pub fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future

impl FromRequest for Payload

Get request's payload stream

Example

use actix_web::{web, error, App, Error, HttpResponse};
use std::future::Future;
use futures_core::stream::Stream;
use futures_util::StreamExt;

/// extract binary data from request
async fn index(mut body: web::Payload) -> Result<HttpResponse, Error>
{
    let mut bytes = web::BytesMut::new();
    while let Some(item) = body.next().await {
        bytes.extend_from_slice(&item?);
    }

    format!("Body {:?}!", bytes);
    Ok(HttpResponse::Ok().finish())
}

fn main() {
    let app = App::new().service(
        web::resource("/index.html").route(
            web::get().to(index))
    );
}

type Config = PayloadConfig

type Error = Error

type Future = Ready<Result<Payload, Error>>

pub fn from_request(_: &HttpRequest, payload: &mut Payload) -> Self::Future

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

Provides a mechanism for trying two extractors, a primary and a fallback. Useful for "polymorphic payloads" where, for example, a form might be JSON or URL encoded.

It is important to note that this extractor, by necessity, buffers the entire request payload as part of its implementation. Though, it does respect a PayloadConfig's maximum size limit.

type Error = EitherExtractError<A::Error, B::Error>

type Future = LocalBoxFuture<'static, Result<Self, Self::Error>>

type Config = ()

pub fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future

impl<T> FromRequest for Form<T> where
    T: DeserializeOwned + 'static, 

type Config = FormConfig

type Error = Error

type Future = LocalBoxFuture<'static, Result<Self, Error>>

pub fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future

impl<T> FromRequest for Json<T> where
    T: DeserializeOwned + 'static, 

Json extractor. Allow to extract typed information from request's payload.

To extract typed information from request's body, the type T must implement the Deserialize trait from serde.

JsonConfig allows to configure extraction process.

Example

use actix_web::{web, App};
use serde_derive::Deserialize;

#[derive(Deserialize)]
struct Info {
    username: String,
}

/// deserialize `Info` from request's body
async fn index(info: web::Json<Info>) -> String {
    format!("Welcome {}!", info.username)
}

fn main() {
    let app = App::new().service(
        web::resource("/index.html").route(
           web::post().to(index))
    );
}

type Error = Error

type Future = LocalBoxFuture<'static, Result<Self, Error>>

type Config = JsonConfig

pub fn from_request(req: &HttpRequest, payload: &mut Payload) -> Self::Future

impl<T> FromRequest for Path<T> where
    T: DeserializeOwned, 

Extract typed information from the request's path.

Example

use actix_web::{web, App};

/// extract path info from "/{username}/{count}/index.html" url
/// {username} - deserializes to a String
/// {count} -  - deserializes to a u32
async fn index(web::Path((username, count)): web::Path<(String, u32)>) -> String {
    format!("Welcome {}! {}", username, count)
}

fn main() {
    let app = App::new().service(
        web::resource("/{username}/{count}/index.html") // <- define path parameters
             .route(web::get().to(index)) // <- register handler with `Path` extractor
    );
}

It is possible to extract path information to a specific type that implements Deserialize trait from serde.

use actix_web::{web, App, Error};
use serde_derive::Deserialize;

#[derive(Deserialize)]
struct Info {
    username: String,
}

/// extract `Info` from a path using serde
async fn index(info: web::Path<Info>) -> Result<String, Error> {
    Ok(format!("Welcome {}!", info.username))
}

fn main() {
    let app = App::new().service(
        web::resource("/{username}/index.html") // <- define path parameters
             .route(web::get().to(index)) // <- use handler with Path` extractor
    );
}

type Error = Error

type Future = Ready<Result<Self, Error>>

type Config = PathConfig

pub fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future

impl<T> FromRequest for Query<T> where
    T: DeserializeOwned, 

Extract typed information from the request's query.

Example

use actix_web::{web, App};
use serde_derive::Deserialize;

#[derive(Debug, Deserialize)]
pub enum ResponseType {
   Token,
   Code
}

#[derive(Deserialize)]
pub struct AuthRequest {
   id: u64,
   response_type: ResponseType,
}

// Use `Query` extractor for query information.
// This handler get called only if request's query contains `id` and `response_type` fields.
// The correct request for this handler would be `/index.html?id=64&response_type=Code"`
async fn index(info: web::Query<AuthRequest>) -> String {
    format!("Authorization request for client with id={} and type={:?}!", info.id, info.response_type)
}

fn main() {
    let app = App::new().service(
       web::resource("/index.html")
           .route(web::get().to(index))); // <- use `Query` extractor
}

type Error = Error

type Future = Ready<Result<Self, Error>>

type Config = QueryConfig

pub fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future

impl<T: Clone + 'static> FromRequest for ReqData<T>

type Config = ()

type Error = Error

type Future = Ready<Result<Self, Error>>

pub fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future

impl<T: ?Sized + 'static> FromRequest for Data<T>

type Config = ()

type Error = Error

type Future = Ready<Result<Self, Error>>

pub fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future

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