Struct actix_web::Json

[+] Show declaration

pub struct Json<T>(pub T);

[−] Expand description

Json helper

Json can be used for two different purpose. First is for json response generation and second is for extracting 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

#[macro_use] extern crate serde_derive;
use actix_web::{App, Json, Result, http};

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

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

fn main() {
    let app = App::new().resource(
       "/index.html",
       |r| r.method(http::Method::POST).with(index));  // <- use `with` extractor
}

The Json type allows you to respond with well-formed JSON data: simply return a value of type Json where T is the type of a structure to serialize into JSON. The type T must implement the Serialize trait from serde.

#[derive(Serialize)]
struct MyObj {
    name: String,
}

fn index(req: HttpRequest) -> Result<Json<MyObj>> {
    Ok(Json(MyObj {
        name: req.match_info().query("name")?,
    }))
}

Methods

impl<T> Json<T>

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pub fn into_inner(self) -> T

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Deconstruct to an inner value

Trait Implementations

impl<T> Deref for Json<T>

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type Target = T

The resulting type after dereferencing.

Important traits for &'a mut R

impl<'a, R> Read for &'a mut R where
    R: Read + ?Sized, impl<'a, W> Write for &'a mut W where
    W: Write + ?Sized, impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn deref(&self) -> &T

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Dereferences the value.

impl<T> DerefMut for Json<T>

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Important traits for &'a mut R

impl<'a, R> Read for &'a mut R where
    R: Read + ?Sized, impl<'a, W> Write for &'a mut W where
    W: Write + ?Sized, impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn deref_mut(&mut self) -> &mut T

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Mutably dereferences the value.

impl<T> Debug for Json<T> where     T: Debug,

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

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Formats the value using the given formatter.

impl<T> Display for Json<T> where     T: Display,

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

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Formats the value using the given formatter.

impl<T: Serialize> Responder for Json<T>

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type Item = HttpResponse

The associated item which can be returned.

type Error = Error

The associated error which can be returned.

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

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Convert itself to AsyncResult or Error.

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

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type Config = JsonConfig<S>

Configuration for conversion process

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

Future that resolves to a Self

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

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Convert request to a Self

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

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Convert request to a Self