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pub struct Capped<T> {
    pub value: T,
    pub n: N,
}
Expand description

Encapsulates a value capped to a data limit.

A Capped<T> type represents a T that has been limited (capped) to some number of bytes. The internal N specifies whether the value is complete (also Capped::is_complete()) or whether it was capped prematurely. A Capped is returned by various methods of DataStream. Some Capped<T> types, like Capped<String> and Capped<TempFile>, implement traits like FromData and FromForm.

Example

Since Capped<TempFile> implements FromData, it can be used as a data guard. The following Rocket route accepts a raw upload and stores the upload in a different directory depending on whether the file exceeded the data limit or not. See TempFile for details on temporary file storage locations and limits.

use rocket::data::Capped;
use rocket::fs::TempFile;

#[post("/upload", data = "<file>")]
async fn upload(mut file: Capped<TempFile<'_>>) -> std::io::Result<()> {
    if file.is_complete() {
        file.persist_to("/tmp/complete/file.txt").await?;
    } else {
        file.persist_to("/tmp/incomplete/file.txt").await?;
    }

    Ok(())
}

Fields

value: T

The capped value itself.

n: N

The number of bytes written and whether value is complete.

Implementations

Creates a new Capped from a value and an n. Prefer to use Capped::from() when possible.

Example
use rocket::data::{Capped, N};

let n = N { written: 2, complete: true };
let capped = Capped::new("hi".to_string(), n);

Creates a new Capped from a value and the length of value n, marking value as complete. Prefer to use Capped::from() when possible.

Example
use rocket::data::{Capped, N};

let string = "hi";
let capped = Capped::complete("hi", string.len());

Converts a Capped<T> to Capped<U> by applying f to the contained value.

Example
use rocket::data::{Capped, N};

let n = N { written: 2, complete: true };
let capped: Capped<usize> = Capped::new(10usize, n);
let mapped: Capped<String> = capped.map(|n| n.to_string());

Returns true if self.n.written is 0, that is, no bytes were written to value.

Example
use rocket::data::{Capped, N};

let n = N { written: 2, complete: true };
let capped = Capped::new("hi".to_string(), n);
assert!(!capped.is_empty());

let n = N { written: 0, complete: true };
let capped = Capped::new("".to_string(), n);
assert!(capped.is_empty());

Returns true if self.n.complete, that is, value represents the entire data stream.

Example
use rocket::data::{Capped, N};

let n = N { written: 2, complete: true };
let capped = Capped::new("hi".to_string(), n);
assert!(capped.is_complete());

let n = N { written: 4, complete: false };
let capped = Capped::new("hell".to_string(), n);
assert!(!capped.is_complete());

Returns the internal value.

Example
use rocket::data::{Capped, N};

let n = N { written: 2, complete: true };
let capped = Capped::new("hi".to_string(), n);
assert_eq!(capped.into_inner(), "hi");

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

The resulting type after dereferencing.

Dereferences the value.

Mutably dereferences the value.

Creates a Capped<T> from a value, setting complete to true.

The associated error to be returned when the guard fails.

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

The associated error to be returned when the guard fails.

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

The associated error to be returned when the guard fails.

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

The associated error to be returned when the guard fails.

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

The associated error to be returned when the guard fails.

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

The associated error to be returned when the guard fails.

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

The associated error to be returned when the guard fails.

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

Parse a value of T from a form value field. Read more

Parse a value of T from a form data field. Read more

Returns a default value, if any exists, to be used during lenient parsing when the form field is missing. Read more

Parse a value of T from a form value field. Read more

Parse a value of T from a form data field. Read more

Returns a default value, if any exists, to be used during lenient parsing when the form field is missing. Read more

Parse a value of T from a form value field. Read more

Parse a value of T from a form data field. Read more

Returns a default value, if any exists, to be used during lenient parsing when the form field is missing. Read more

Parse a value of T from a form value field. Read more

Parse a value of T from a form data field. Read more

Returns a default value, if any exists, to be used during lenient parsing when the form field is missing. Read more

The length of the value.

Convert len into u64.

The zero value for L.

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

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Converts self into a collection.

Should always be Self

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more