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/08-apis/form.rs

@@ -0,0 +1,142 @@
+//! Forms
+//!
+//! Dioxus forms deviate slightly from html, automatically returning all named inputs
+//! in the "values" field.
+
+use dioxus::prelude::*;
+use std::collections::HashMap;
+
+fn main() {
+    dioxus::launch(app);
+}
+
+fn app() -> Element {
+    let mut values = use_signal(HashMap::new);
+    let mut submitted_values = use_signal(HashMap::new);
+
+    rsx! {
+        div { style: "display: flex",
+            div { style: "width: 50%",
+                h1 { "Form" }
+
+                if !submitted_values.read().is_empty() {
+                    h2 { "Submitted! ✅" }
+                }
+
+                // The form element is used to create an HTML form for user input
+                // You can attach regular attributes to it
+                form {
+                    id: "cool-form",
+                    style: "display: flex; flex-direction: column;",
+
+                    // You can attach a handler to the entire form
+                    oninput: move |ev| {
+                        println!("Input event: {:#?}", ev);
+                        values.set(ev.values());
+                    },
+
+                    // On desktop/liveview, the form will not navigate the page - the expectation is that you handle
+                    // The form event.
+                    // However, if your form doesn't have a submit handler, it might navigate the page depending on the webview.
+                    // We suggest always attaching a submit handler to the form.
+                    onsubmit: move |ev| {
+                        println!("Submit event: {:#?}", ev);
+                        submitted_values.set(ev.values());
+                    },
+
+                    // Regular text inputs with handlers
+                    label { r#for: "username", "Username" }
+                    input {
+                        r#type: "text",
+                        name: "username",
+                        oninput: move |ev| {
+                            println!("setting username");
+                            values.set(ev.values());
+                        }
+                    }
+
+                    // And then the various inputs that might exist
+                    // Note for a value to be returned in .values(), it must be named!
+
+                    label { r#for: "full-name", "Full Name" }
+                    input { r#type: "text", name: "full-name" }
+                    input { r#type: "text", name: "full-name" }
+
+                    label { r#for: "email", "Email (matching <name>@example.com)" }
+                    input { r#type: "email", pattern: ".+@example\\.com", size: "30", required: "true", id: "email", name: "email" }
+
+                    label { r#for: "password", "Password" }
+                    input { r#type: "password", name: "password" }
+
+                    label { r#for: "color", "Color" }
+                    input { r#type: "radio", checked: true, name: "color", value: "red" }
+                    input { r#type: "radio", name: "color", value: "blue" }
+                    input { r#type: "radio", name: "color", value: "green" }
+
+                    // Select multiple comes in as a comma separated list of selected values
+                    // You should split them on the comma to get the values manually
+                    label { r#for: "country", "Country" }
+                    select {
+                        name: "country",
+                        multiple: true,
+                        oninput: move |ev| {
+                            println!("Input event: {:#?}", ev);
+                            println!("Values: {:#?}", ev.value().split(',').collect::<Vec<_>>());
+                        },
+                        option { value: "usa",  "USA" }
+                        option { value: "canada",  "Canada" }
+                        option { value: "mexico",  "Mexico" }
+                    }
+
+                    // Safari can be quirky with color inputs on mac.
+                    // We recommend always providing a text input for color as a fallback.
+                    label { r#for: "color", "Color" }
+                    input { r#type: "color", value: "#000002", name: "head", id: "head" }
+
+                    // Dates!
+                    input {
+                        min: "2018-01-01",
+                        value: "2018-07-22",
+                        r#type: "date",
+                        name: "trip-start",
+                        max: "2025-12-31",
+                        id: "start"
+                    }
+
+                    // CHekcboxes
+                    label { r#for: "cbox", "Color" }
+                    div {
+                        label { r#for: "cbox-red", "red" }
+                        input { r#type: "checkbox", checked: true, name: "cbox", value: "red", id: "cbox-red" }
+                    }
+                    div {
+                        label { r#for: "cbox-blue", "blue" }
+                        input { r#type: "checkbox", name: "cbox", value: "blue", id: "cbox-blue" }
+                    }
+                    div {
+                        label { r#for: "cbox-green", "green" }
+                        input { r#type: "checkbox", name: "cbox", value: "green", id: "cbox-green" }
+                    }
+                    div {
+                        label { r#for: "cbox-yellow", "yellow" }
+                        input { r#type: "checkbox", name: "cbox", value: "yellow", id: "cbox-yellow" }
+                    }
+
+
+                    // Buttons will submit your form by default.
+                    button { r#type: "submit", value: "Submit", "Submit the form" }
+                }
+            }
+            div { style: "width: 50%",
+                h1 { "Oninput Values" }
+                pre { "{values:#?}" }
+            }
+        }
+        button {
+            onclick: move |_| {
+                println!("Values: {:#?}", values.read());
+            },
+            "Log values"
+        }
+    }
+}