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use crate::api::conn::Command;
use crate::api::method::BoxFuture;
use crate::api::method::OnceLockExt;
use crate::api::opt::Resource;
use crate::api::Connection;
use crate::api::Result;
use crate::method::Live;
use crate::opt::KeyRange;
use crate::Surreal;
use crate::Value;
use serde::de::DeserializeOwned;
use std::borrow::Cow;
use std::future::IntoFuture;
use std::marker::PhantomData;
/// A select future
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct Select<'r, C: Connection, R, T = ()> {
pub(super) client: Cow<'r, Surreal<C>>,
pub(super) resource: Result<Resource>,
pub(super) response_type: PhantomData<R>,
pub(super) query_type: PhantomData<T>,
}
impl<C, R, T> Select<'_, C, R, T>
where
C: Connection,
{
/// Converts to an owned type which can easily be moved to a different thread
pub fn into_owned(self) -> Select<'static, C, R, T> {
Select {
client: Cow::Owned(self.client.into_owned()),
..self
}
}
}
macro_rules! into_future {
($method:ident) => {
fn into_future(self) -> Self::IntoFuture {
let Select {
client,
resource,
..
} = self;
Box::pin(async move {
let router = client.router.extract()?;
router
.$method(Command::Select {
what: resource?,
})
.await
})
}
};
}
impl<'r, Client> IntoFuture for Select<'r, Client, Value>
where
Client: Connection,
{
type Output = Result<Value>;
type IntoFuture = BoxFuture<'r, Self::Output>;
into_future! {execute_value}
}
impl<'r, Client, R> IntoFuture for Select<'r, Client, Option<R>>
where
Client: Connection,
R: DeserializeOwned,
{
type Output = Result<Option<R>>;
type IntoFuture = BoxFuture<'r, Self::Output>;
into_future! {execute_opt}
}
impl<'r, Client, R> IntoFuture for Select<'r, Client, Vec<R>>
where
Client: Connection,
R: DeserializeOwned,
{
type Output = Result<Vec<R>>;
type IntoFuture = BoxFuture<'r, Self::Output>;
into_future! {execute_vec}
}
impl<C> Select<'_, C, Value>
where
C: Connection,
{
/// Restricts the records selected to those in the specified range
pub fn range(mut self, range: impl Into<KeyRange>) -> Self {
self.resource = self.resource.and_then(|x| x.with_range(range.into()));
self
}
}
impl<C, R> Select<'_, C, Vec<R>>
where
C: Connection,
{
/// Restricts the records selected to those in the specified range
pub fn range(mut self, range: impl Into<KeyRange>) -> Self {
self.resource = self.resource.and_then(|x| x.with_range(range.into()));
self
}
}
impl<'r, C, R> Select<'r, C, R>
where
C: Connection,
R: DeserializeOwned,
{
/// Turns a normal select query into a live query
///
/// # Examples
///
/// ```no_run
/// # use futures::StreamExt;
/// # use surrealdb::opt::Resource;
/// # use surrealdb::Result;
/// # use surrealdb::Notification;
/// # #[derive(Debug, serde::Deserialize)]
/// # struct Person;
/// #
/// # #[tokio::main]
/// # async fn main() -> surrealdb::Result<()> {
/// # let db = surrealdb::engine::any::connect("mem://").await?;
/// #
/// // Select the namespace/database to use
/// db.use_ns("namespace").use_db("database").await?;
///
/// // Listen to all updates on a table
/// let mut stream = db.select("person").live().await?;
/// # let _: Option<Result<Notification<Person>>> = stream.next().await;
///
/// // Listen to updates on a range of records
/// let mut stream = db.select("person").range("jane".."john").live().await?;
/// # let _: Option<Result<Notification<Person>>> = stream.next().await;
///
/// // Listen to updates on a specific record
/// let mut stream = db.select(("person", "h5wxrf2ewk8xjxosxtyc")).live().await?;
///
/// // The returned stream implements `futures::Stream` so we can
/// // use it with `futures::StreamExt`, for example.
/// while let Some(result) = stream.next().await {
/// handle(result);
/// }
///
/// // Handle the result of the live query notification
/// fn handle(result: Result<Notification<Person>>) {
/// match result {
/// Ok(notification) => println!("{notification:?}"),
/// Err(error) => eprintln!("{error}"),
/// }
/// }
/// #
/// # Ok(())
/// # }
/// ```
pub fn live(self) -> Select<'r, C, R, Live> {
Select {
client: self.client,
resource: self.resource,
response_type: self.response_type,
query_type: PhantomData,
}
}
}