switch to a Document trait and introduce Script/Head/Style/Meta components (#2635)

* switch to a Document trait and introduce Script/Head/Style/Meta components

* Fix desktop title

* Insert special elements into the head during the inital SSR render

* Make all head component attributes optional

* hydrate head elements

* improve the server streaming head warning

* Document fullstack head hydration approach

* deduplicate head elements by href

* move Link into head::Link

* document head components

* add meta and title examples

* Fix a few doc examples

* fix formatting

* Add title to playwright tests

* serde is optional on web, but it is enabled by hydrate

* remove leftover console log

packages/fullstack/src/render.rs

@@ -160,8 +160,34 @@ impl SsrRendererPool {
 
         let join_handle = spawn_platform(move || async move {
             let mut virtual_dom = virtual_dom_factory();
+            #[cfg(feature = "document")]
+            let document = std::rc::Rc::new(crate::document::server::ServerDocument::default());
+            #[cfg(feature = "document")]
+            virtual_dom.provide_root_context(document.clone() as std::rc::Rc<dyn Document>);
+
+            // poll the future, which may call server_context()
+            tracing::info!("Rebuilding vdom");
+            with_server_context(server_context.clone(), || virtual_dom.rebuild_in_place());
 
             let mut pre_body = String::new();
+
+            if let Err(err) = wrapper.render_head(&mut pre_body) {
+                _ = into.start_send(Err(err));
+                return;
+            }
+
+            #[cfg(feature = "document")]
+            {
+                // Collect any head content from the document provider and inject that into the head
+                if let Err(err) = document.render(&mut pre_body, &mut renderer) {
+                    _ = into.start_send(Err(err.into()));
+                    return;
+                }
+
+                // Enable a warning when inserting contents into the head during streaming
+                document.start_streaming();
+            }
+
             if let Err(err) = wrapper.render_before_body(&mut pre_body) {
                 _ = into.start_send(Err(err));
                 return;
@@ -206,10 +232,6 @@ impl SsrRendererPool {
                 };
             }
 
-            // poll the future, which may call server_context()
-            tracing::info!("Rebuilding vdom");
-            with_server_context(server_context.clone(), || virtual_dom.rebuild_in_place());
-
             // Render the initial frame with loading placeholders
             let mut initial_frame = renderer.render(&virtual_dom);
 
@@ -364,6 +386,18 @@ impl FullstackHTMLTemplate {
 }
 
 impl FullstackHTMLTemplate {
+    /// Render any content before the head of the page.
+    pub fn render_head<R: std::fmt::Write>(
+        &self,
+        to: &mut R,
+    ) -> Result<(), dioxus_ssr::incremental::IncrementalRendererError> {
+        let ServeConfig { index, .. } = &self.cfg;
+
+        to.write_str(&index.head)?;
+
+        Ok(())
+    }
+
     /// Render any content before the body of the page.
     pub fn render_before_body<R: std::fmt::Write>(
         &self,
@@ -371,7 +405,7 @@ impl FullstackHTMLTemplate {
     ) -> Result<(), dioxus_ssr::incremental::IncrementalRendererError> {
         let ServeConfig { index, .. } = &self.cfg;
 
-        to.write_str(&index.pre_main)?;
+        to.write_str(&index.close_head)?;
 
         Ok(())
     }