Trait actix_web::FromRequest[−][src]

pub trait FromRequest<S>: Sized {
    type Config: Default;
    type Result: Into<AsyncResult<Self>>;
    fn from_request(req: &HttpRequest<S>, cfg: &Self::Config) -> Self::Result;

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

Trait implemented by types that can be extracted from request.

Types that implement this trait can be used with Route::with() method.

Associated Types

`type Config: Default`

Configuration for conversion process

`type Result: Into<AsyncResult<Self>>`

Future that resolves to a Self

Required Methods

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

Convert request to a Self

Provided Methods

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

Convert request to a Self

This method uses default extractor configuration

Implementations on Foreign Types

`impl<S: 'static> FromRequest<S> for Bytes`
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Request payload extractor.

Loads request's payload and construct Bytes instance.

PayloadConfig allows to configure extraction process.

Example

extern crate bytes;
use actix_web::{http, App, Result};

/// extract text data from request
fn index(body: bytes::Bytes) -> Result<String> {
    Ok(format!("Body {:?}!", body))
}

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

`type Config = PayloadConfig`

`type Result = Result<Box<Future<Item = Self, Error = Error>>, Error>`

`fn from_request(req: &HttpRequest<S>, cfg: &Self::Config) -> Self::Result`
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`fn extract(req: &HttpRequest<S>) -> Self::Result`
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`impl<S: 'static> FromRequest<S> for String`
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Extract text information from the request's body.

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

PayloadConfig allows to configure extraction process.

Example

use actix_web::{http, App, Result};

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

fn main() {
    let app = App::new().resource("/index.html", |r| {
        r.method(http::Method::GET)
               .with_config(index, |cfg| { // <- register handler with extractor params
                  cfg.limit(4096);  // <- limit size of the payload
                })
    });
}

`type Config = PayloadConfig`

`type Result = Result<Box<Future<Item = String, Error = Error>>, Error>`

`fn from_request(req: &HttpRequest<S>, cfg: &Self::Config) -> Self::Result`
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`fn extract(req: &HttpRequest<S>) -> Self::Result`
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`impl<T: 'static, S: 'static> FromRequest<S> for Option<T> where T: FromRequest<S>,`
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Optionally extract a field from the request

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

Example

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

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

    }
}

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

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

`type Config = T::Config`

`type Result = Box<Future<Item = Option<T>, Error = Error>>`

`fn from_request(req: &HttpRequest<S>, cfg: &Self::Config) -> Self::Result`
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`fn extract(req: &HttpRequest<S>) -> Self::Result`
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`impl<T: 'static, S: 'static> FromRequest<S> for Result<T, Error> where T: FromRequest<S>,`
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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

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

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

    }
}

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

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

`type Config = T::Config`