bevy/examples/remote/server.rs
Liam Gallagher f1fbb668f9
Watching versions of bevy/get and bevy/list with HTTP SSE (#15608)
## Objective

Add a way to stream BRP requests when the data changes.

## Solution

#### BRP Side (reusable for other transports)

Add a new method handler type that returns a optional value. This
handler is run in update and if a value is returned it will be sent on
the message channel. Custom watching handlers can be added with
`RemotePlugin::with_watching_method`.

#### HTTP Side

If a request comes in with `+watch` in the method, it will respond with
`text/event-stream` rather than a single response.

## Testing

I tested with the podman HTTP client. This client has good support for
SSE's if you want to test it too.

## Parts I want some opinions on

- For separating watching methods I chose to add a `+watch` suffix to
the end kind of like `content-type` headers. A get would be
`bevy/get+watch`.
- Should watching methods send an initial response with everything or
only respond when a change happens? Currently the later is what happens.

## Future work

- The `bevy/query` method would also benefit from this but that
condition will be quite complex so I will leave that to later.

---------

Co-authored-by: Zachary Harrold <zac@harrold.com.au>
2024-10-08 16:21:46 +00:00

71 lines
2 KiB
Rust

//! A Bevy app that you can connect to with the BRP and edit.
use bevy::math::ops::cos;
use bevy::{
input::common_conditions::input_just_pressed,
prelude::*,
remote::{http::RemoteHttpPlugin, RemotePlugin},
};
use serde::{Deserialize, Serialize};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_plugins(RemotePlugin::default())
.add_plugins(RemoteHttpPlugin::default())
.add_systems(Startup, setup)
.add_systems(Update, remove.run_if(input_just_pressed(KeyCode::Space)))
.add_systems(Update, move_cube)
.register_type::<Cube>()
.run();
}
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
// circular base
commands.spawn((
Mesh3d(meshes.add(Circle::new(4.0))),
MeshMaterial3d(materials.add(Color::WHITE)),
Transform::from_rotation(Quat::from_rotation_x(-std::f32::consts::FRAC_PI_2)),
));
// cube
commands.spawn((
Mesh3d(meshes.add(Cuboid::new(1.0, 1.0, 1.0))),
MeshMaterial3d(materials.add(Color::srgb_u8(124, 144, 255))),
Transform::from_xyz(0.0, 0.5, 0.0),
Cube(1.0),
));
// light
commands.spawn((
PointLight {
shadows_enabled: true,
..default()
},
Transform::from_xyz(4.0, 8.0, 4.0),
));
// camera
commands.spawn((
Camera3d::default(),
Transform::from_xyz(-2.5, 4.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y),
));
}
fn move_cube(mut query: Query<&mut Transform, With<Cube>>, time: Res<Time>) {
for mut transform in &mut query {
transform.translation.y = -cos(time.elapsed_seconds()) + 1.5;
}
}
fn remove(mut commands: Commands, query: Query<Entity, With<Cube>>) {
commands.entity(query.single()).remove::<Cube>();
}
#[derive(Component, Reflect, Serialize, Deserialize)]
#[reflect(Component, Serialize, Deserialize)]
struct Cube(f32);