More fullstack fixes (#4737)

* allow `--server` only builds!

* rollback example

* capture `/:route` routes

* fix: properly implement file uploads in forms

* implement desktop form uploads

* Performant serialization of form bytes

* finish up file stuff

* cleanups

* add request headers to streaming context

* remove some unwraps

examples/07-fullstack/multipart_form.rs

@@ -52,11 +52,14 @@ fn app() -> Element {
 #[post("/api/upload-multipart")]
 async fn upload(mut form: MultipartFormData) -> Result<()> {
     while let Ok(Some(field)) = form.next_field().await {
+        let name = field.name().unwrap_or("<none>").to_string();
+        let file_name = field.file_name().unwrap_or("<none>").to_string();
+        let content_type = field.content_type().unwrap_or("<none>").to_string();
+        let size = field.bytes().await.unwrap().len();
+
         info!(
-            "Field name: {:?}, filename: {:?}, content_type: {:?}",
-            field.name().to_owned(),
-            field.file_name(),
-            field.content_type(),
+            "Field name: {:?}, filename: {:?}, content_type: {:?}, size: {:?}",
+            name, file_name, content_type, size
         );
     }
 

examples/07-fullstack/server_state.rs

@@ -17,6 +17,7 @@ Option 1:
 For simple, synchronous, thread-safe data, we can use statics with atomic types or mutexes.
 The `LazyLock` type from the standard library is a great choice for simple, synchronous data
 */
+#[cfg(feature = "server")]
 static MESSAGES: LazyLock<Mutex<Vec<String>>> = LazyLock::new(|| Mutex::new(Vec::new()));
 
 #[post("/api/messages")]