Struct Query 

pub struct Query<T>(pub T);

Query string extractor.

Extracts and deserializes query string parameters into a typed struct. This extractor uses serde for deserialization, so the target type must implement DeserializeOwned.

Features

• Optional fields: Use Option<T> for optional parameters
• Multi-value: Use Vec<T> for parameters that appear multiple times
• Default values: Use #[serde(default)] for default values
• Percent-decoding: Values are automatically percent-decoded

Example

use fastapi_core::Query;
use serde::Deserialize;

#[derive(Deserialize)]
struct SearchParams {
    q: String,                      // Required
    page: Option<i32>,              // Optional
    #[serde(default)]
    limit: i32,                     // Default (0)
    tags: Vec<String>,              // Multi-value: ?tags=a&tags=b
}

#[get("/search")]
async fn search(cx: &Cx, params: Query<SearchParams>) -> impl IntoResponse {
    // Access the inner value via params.0 or *params
    let query = &params.q;
    // ...
}

Error Handling

Returns HTTP 422 (Unprocessable Entity) when:

• Required fields are missing
• Type conversion fails (e.g., “abc” to i32)
• Serde deserialization fails

Tuple Fields

0: T

Implementations

impl<T> Query<T>

pub fn new(value: T) -> Self

Create a new Query extractor with the given value.

pub fn into_inner(self) -> T

Consume the extractor and return the inner value.

Trait Implementations

impl<T: Clone> Clone for Query<T>

fn clone(&self) -> Query<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for Query<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for Query<T>

fn default() -> Query<T>

Returns the “default value” for a type.

impl<T> Deref for Query<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T> DerefMut for Query<T>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<T: DeserializeOwned> FromRequest for Query<T>

type Error = QueryExtractError

Error type when extraction fails.

async fn from_request( _ctx: &RequestContext, req: &mut Request, ) -> Result<Self, Self::Error>

Extract a value from the request.

impl<T: Copy> Copy for Query<T>