Struct rocket_contrib::Json[][src]

pub struct Json<T = Value>(pub T);

The JSON type: implements FromData and Responder, allowing you to easily consume and respond with JSON.

Receiving JSON

If you're receiving JSON data, simply add a data parameter to your route arguments and ensure the type of the parameter is a Json<T>, where T is some type you'd like to parse from JSON. T must implement Deserialize or DeserializeOwned from Serde. The data is parsed from the HTTP request body.

This example is not tested
#[post("/users/", format = "application/json", data = "<user>")]
fn new_user(user: Json<User>) {

You don't need to use format = "application/json", but it may be what you want. Using format = application/json means that any request that doesn't specify "application/json" as its Content-Type header value will not be routed to the handler.

Sending JSON

If you're responding with JSON data, return a Json<T> type, where T implements Serialize from Serde. The content type of the response is set to application/json automatically.

This example is not tested
fn user(id: usize) -> Json<User> {
    let user_from_id = User::from(id);

Incoming Data Limits

The default size limit for incoming JSON data is 1MiB. Setting a limit protects your application from denial of service (DOS) attacks and from resource exhaustion through high memory consumption. The limit can be increased by setting the limits.json configuration parameter. For instance, to increase the JSON limit to 5MiB for all environments, you may add the following to your Rocket.toml:

json = 5242880


impl<T> Json<T>

Consumes the JSON wrapper and returns the wrapped item.


let string = "Hello".to_string();
let my_json = Json(string);
assert_eq!(my_json.into_inner(), "Hello".to_string());

Trait Implementations

impl<T: Debug> Debug for Json<T>

Formats the value using the given formatter. Read more

impl<T: DeserializeOwned> FromData for Json<T>

The associated error to be returned when the guard fails.

Validates, parses, and converts an instance of Self from the incoming request body data. Read more

impl<T: Serialize> Responder<'static> for Json<T>

Serializes the wrapped value into JSON. Returns a response with Content-Type JSON and a fixed-size body with the serialized value. If serialization fails, an Err of Status::InternalServerError is returned.

Returns Ok if a Response could be generated successfully. Otherwise, returns an Err with a failing Status. Read more

impl<T> Deref for Json<T>

The resulting type after dereferencing.

Important traits for &'a mut R

Dereferences the value.

impl<T> DerefMut for Json<T>

Important traits for &'a mut R

Mutably dereferences the value.

Auto Trait Implementations

impl<T> Send for Json<T> where
    T: Send

impl<T> Sync for Json<T> where
    T: Sync