Struct Query

pub struct Query<T>(pub T);

Extract typed information from the request’s query.

To extract typed data from the URL query string, the inner type T must implement the DeserializeOwned trait.

Differences From actix_web::web::Query

This extractor uses serde_html_form under-the-hood which supports multi-value items. These are sent by HTML select inputs when multiple options are chosen and can be collected into a Vec.

This version also removes the custom error handler config; users should instead prefer to handle errors using the explicit Result<Query<T>, E> extractor in their handlers.

Panics

A query string consists of unordered key=value pairs, therefore it cannot be decoded into any type which depends upon data ordering (eg. tuples). Trying to do so will result in a panic.

Examples

use actix_web::{Responder, get};
use actix_web_lab::extract::Query;
use serde::Deserialize;

#[derive(Debug, Deserialize)]
#[serde(rename_all = "lowercase")]
enum LogType {
    Reports,
    Actions,
}

#[derive(Debug, Deserialize)]
pub struct LogsParams {
    #[serde(rename = "type")]
    log_type: u64,

    #[serde(rename = "user")]
    users: Vec<String>,
}

// Deserialize `LogsParams` struct from query string.
// This handler gets called only if the request's query parameters contain both fields.
// A valid request path for this handler would be `/logs?type=reports&user=foo&user=bar"`.
#[get("/logs")]
async fn index(info: Query<LogsParams>) -> impl Responder {
    let LogsParams { log_type, users } = info.into_inner();
    format!("Logs request for type={log_type} and user list={users:?}!")
}

// Or use destructuring, which is equivalent to `.into_inner()`.
#[get("/debug2")]
async fn debug2(Query(info): Query<LogsParams>) -> impl Responder {
    dbg!("Authorization object = {info:?}");
    "OK"
}

Tuple Fields

0: T

Implementations

impl<T> Query<T>

pub fn into_inner(self) -> T

Unwrap into inner T value.

impl<T: DeserializeOwned> Query<T>

pub fn from_query(query_str: &str) -> Result<Self, QueryDeserializeError>

Deserialize a T from the URL encoded query parameter string.

let numbers = Query::<HashMap<String, u32>>::from_query("one=1&two=2").unwrap();

assert_eq!(numbers.get("one"), Some(&1));
assert_eq!(numbers.get("two"), Some(&2));
assert!(numbers.get("three").is_none());

Trait Implementations

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

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

Returns a duplicate of the value.

const 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> 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: Display> Display for Query<T>

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

Formats the value using the given formatter.

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

See here for example of usage as an extractor.

type Error = QueryDeserializeError

The associated error which can be returned.

type Future = Ready<Result<Query<T>, <Query<T> as FromRequest>::Error>>

Future that resolves to a Self.

fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future

Create a Self from request parts asynchronously.

fn extract(req: &HttpRequest) -> Self::Future

Create a Self from request head asynchronously.

impl<T: Ord> Ord for Query<T>

fn cmp(&self, other: &Query<T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<T: PartialEq> PartialEq for Query<T>

fn eq(&self, other: &Query<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

const fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: PartialOrd> PartialOrd for Query<T>

fn partial_cmp(&self, other: &Query<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: Eq> Eq for Query<T>

impl<T> StructuralPartialEq for Query<T>