Struct Data

pub struct Data<'r> { /* private fields */ }

Type representing the body data of a request.

This type is the only means by which the body of a request can be retrieved. This type is not usually used directly. Instead, data guards (types that implement FromData) are created indirectly via code generation by specifying the data = "<var>" route parameter as follows:

#[post("/submit", data = "<var>")]
fn submit(var: DataGuard) { /* ... */ }

Above, DataGuard can be any type that implements FromData. Note that Data itself implements FromData.

Reading Data

Data may be read from a Data object by calling either the open() or peek() methods.

The open method consumes the Data object and returns the raw data stream. The Data object is consumed for safety reasons: consuming the object ensures that holding a Data object means that all of the data is available for reading.

The peek method returns a slice containing at most 512 bytes of buffered body data. This enables partially or fully reading from a Data object without consuming the Data object.

Implementations

impl<'r> Data<'r>

pub fn open(self, limit: ByteUnit) -> DataStream<'r>

Returns the raw data stream, limited to limit bytes.

The stream contains all of the data in the body of the request, including that in the peek buffer. The method consumes the Data instance. This ensures that a Data type always represents all of the data in a request.

Example

use rocket::data::{Data, ToByteUnit};

fn handler(data: Data<'_>) {
    let stream = data.open(2.mebibytes());
}

pub async fn peek(&mut self, num: usize) -> &[u8]

Retrieve at most num bytes from the peek buffer without consuming self.

The peek buffer contains at most 512 bytes of the body of the request. The actual size of the returned buffer is the min of the request’s body, num and 512. The peek_complete method can be used to determine if this buffer contains all of the data in the body of the request.

Examples

In a data guard:

use rocket::request::{self, Request, FromRequest};
use rocket::data::{Data, FromData, Outcome};
use rocket::http::Status;

#[rocket::async_trait]
impl<'r> FromData<'r> for MyType {
    type Error = MyError;

    async fn from_data(r: &'r Request<'_>, mut data: Data<'r>) -> Outcome<'r, Self> {
        if data.peek(2).await != b"hi" {
            return Outcome::Forward((data, Status::BadRequest))
        }

        /* .. */
    }
}

In a fairing:

use rocket::{Rocket, Request, Data, Response};
use rocket::fairing::{Fairing, Info, Kind};

#[rocket::async_trait]
impl Fairing for MyType {
    fn info(&self) -> Info {
        Info {
            name: "Data Peeker",
            kind: Kind::Request
        }
    }

    async fn on_request(&self, req: &mut Request<'_>, data: &mut Data<'_>) {
        if data.peek(2).await == b"hi" {
            /* do something; body data starts with `"hi"` */
        }

        /* .. */
    }
}

pub fn peek_complete(&self) -> bool

Returns true if the peek buffer contains all of the data in the body of the request. Returns false if it does not or if it is not known if it does.

Example

use rocket::data::Data;

async fn handler(mut data: Data<'_>) {
    if data.peek_complete() {
        println!("All of the data: {:?}", data.peek(512).await);
    }
}

Trait Implementations

impl<'r> FromData<'r> for Data<'r>

type Error = Infallible

The associated error to be returned when the guard fails.

fn from_data<'life0, 'async_trait>( _: &'r Request<'life0>, data: Data<'r>, ) -> Pin<Box<dyn Future<Output = Outcome<'r, Self>> + Send + 'async_trait>>

where Self: 'async_trait, 'r: 'async_trait, 'life0: 'async_trait,

Asynchronously validates, parses, and converts an instance of Self from the incoming request body data.