fix: use signals rather than Action::new_local() (closes #3746) (#3749)

Author: gbj

examples/server_fns_axum/src/app.rs

@@ -363,10 +363,8 @@ pub fn FileUpload() -> impl IntoView {
         Ok(count)
     }
 
-    let upload_action = Action::new_local(|data: &FormData| {
-        // `MultipartData` implements `From<FormData>`
-        file_length(data.clone().into())
-    });
+    let pending = RwSignal::new(false);
+    let result = RwSignal::new(None);
 
     view! {
         <h3>File Upload</h3>
@@ -375,22 +373,26 @@ pub fn FileUpload() -> impl IntoView {
             ev.prevent_default();
             let target = ev.target().unwrap().unchecked_into::<HtmlFormElement>();
             let form_data = FormData::new_with_form(&target).unwrap();
-            upload_action.dispatch_local(form_data);
+            pending.set(true);
+            spawn_local(async move {
+                result.set(Some(file_length(form_data.into()).await));
+                pending.set(false);
+            });
         }>
             <input type="file" name="file_to_upload"/>
             <input type="submit"/>
         </form>
         <p>
             {move || {
-                if upload_action.input_local().read().is_none() && upload_action.value().read().is_none()
+                if !pending.get() && result.read().is_none()
                 {
                     "Upload a file.".to_string()
-                } else if upload_action.pending().get() {
+                } else if pending.get() {
                     "Uploading...".to_string()
-                } else if let Some(Ok(value)) = upload_action.value().get() {
+                } else if let Some(Ok(value)) = result.get() {
                     value.to_string()
                 } else {
-                    format!("{:?}", upload_action.value().get())
+                    format!("{:?}", result.get())
                 }
             }}