codify "platform" into resolution logic, server-fn/fullstack overhaul (#4596)

overhaul dioxus fullstack using a new implementation of server_fn

This PR is a complete rewrite of dioxus fullstack designed to improve compatibility with axum and to fix a number of compilation errors based on feature flag unification plumbing through macros.

examples/01-app-demos/hotdog/src/backend.rs

@@ -0,0 +1,41 @@
+use anyhow::Result;
+use dioxus::prelude::*;
+
+#[cfg(feature = "server")]
+thread_local! {
+    static DB: std::sync::LazyLock<rusqlite::Connection> = std::sync::LazyLock::new(|| {
+        let conn = rusqlite::Connection::open("hotdogdb/hotdog.db").expect("Failed to open database");
+
+        conn.execute_batch(
+            "CREATE TABLE IF NOT EXISTS dogs (
+                id INTEGER PRIMARY KEY,
+                url TEXT NOT NULL
+            );",
+        )
+        .unwrap();
+
+        conn
+    });
+}
+
+#[get("/api/dogs")]
+pub async fn list_dogs() -> Result<Vec<(usize, String)>> {
+    DB.with(|db| {
+        Ok(db
+            .prepare("SELECT id, url FROM dogs ORDER BY id DESC LIMIT 10")?
+            .query_map([], |row| Ok((row.get(0)?, row.get(1)?)))?
+            .collect::<Result<Vec<(usize, String)>, rusqlite::Error>>()?)
+    })
+}
+
+#[delete("/api/dogs/{id}")]
+pub async fn remove_dog(id: usize) -> Result<()> {
+    DB.with(|db| db.execute("DELETE FROM dogs WHERE id = ?1", [id]))?;
+    Ok(())
+}
+
+#[post("/api/dogs")]
+pub async fn save_dog(image: String) -> Result<()> {
+    DB.with(|db| db.execute("INSERT INTO dogs (url) VALUES (?1)", [&image]))?;
+    Ok(())
+}

examples/01-app-demos/hotdog/src/frontend.rs

@@ -0,0 +1,71 @@
+use dioxus::prelude::*;
+
+use crate::{
+    backend::{list_dogs, remove_dog, save_dog},
+    Route,
+};
+
+#[component]
+pub fn Favorites() -> Element {
+    let mut favorites = use_loader(list_dogs)?;
+
+    rsx! {
+        div { id: "favorites",
+            for (id , url) in favorites.cloned() {
+                div { class: "favorite-dog", key: "{id}",
+                    img { src: "{url}" }
+                    button {
+                        onclick: move |_| async move {
+                            _ = remove_dog(id).await;
+                            favorites.restart();
+                        },
+                        "❌"
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[component]
+pub fn NavBar() -> Element {
+    rsx! {
+        div { id: "title",
+            span {}
+            Link { to: Route::DogView, h1 { "🌭 HotDog! " } }
+            Link { to: Route::Favorites, id: "heart", "♥️" }
+        }
+        Outlet::<Route> {}
+    }
+}
+
+#[component]
+pub fn DogView() -> Element {
+    let mut img_src = use_loader(|| async move {
+        anyhow::Ok(
+            reqwest::get("https://dog.ceo/api/breeds/image/random")
+                .await?
+                .json::<serde_json::Value>()
+                .await?["message"]
+                .to_string(),
+        )
+    })?;
+
+    rsx! {
+        div { id: "dogview",
+            img { id: "dogimg", src: "{img_src}" }
+        }
+        div { id: "buttons",
+            button {
+                id: "skip",
+                onclick: move |_| img_src.restart(),
+                "skip"
+            }
+            button {
+                id: "save",
+                onclick: move |_| async move { _ = save_dog(img_src()).await },
+                "save!"
+            }
+        }
+    }
+}

examples/01-app-demos/hotdog/src/main.rs

@@ -0,0 +1,29 @@
+mod backend;
+mod frontend;
+
+use dioxus::prelude::*;
+use frontend::*;
+
+#[derive(Routable, PartialEq, Clone)]
+enum Route {
+    #[layout(NavBar)]
+    #[route("/")]
+    DogView,
+
+    #[route("/favorites")]
+    Favorites,
+}
+
+fn main() {
+    #[cfg(not(feature = "server"))]
+    dioxus::fullstack::set_server_url("https://hot-dog.fly.dev");
+
+    dioxus::launch(app);
+}
+
+fn app() -> Element {
+    rsx! {
+        Stylesheet { href: asset!("/assets/main.css") }
+        Router::<Route> {}
+    }
+}