allow web worker resource to be relative (#2086)

* allow web worker resource to be relative

fixes #2056

* make backwards compatible with rust < 1.52

* fix clippy warning

* Apply suggestions from code review

Co-authored-by: mc1098 <m.cripps1@uni.brighton.ac.uk>

* do not reimplement stdlib function

* fixup previous

* improve docstring

Co-authored-by: mc1098 <m.cripps1@uni.brighton.ac.uk>

packages/yew-agent/src/lib.rs

@@ -55,6 +55,15 @@ pub trait Agent: Sized + 'static {
         "main.js"
     }
 
+    /// Indicates whether the name of the resource is relative.
+    ///
+    /// The default implementation returns `false`, which will cause the result
+    /// returned by [`Self::name_of_resource`] to be interpreted as an absolute
+    /// URL. If `true` is returned, it will be interpreted as a relative URL.
+    fn resource_path_is_relative() -> bool {
+        false
+    }
+
     /// Signifies if resource is a module.
     /// This has pending browser support.
     fn is_module() -> bool {

packages/yew-agent/src/worker/mod.rs

@@ -69,15 +69,29 @@ where
     let msg = msg.pack();
     worker.post_message_vec(msg);
 }
-
-fn worker_new(name_of_resource: &str, is_module: bool) -> Worker {
+fn worker_new(name_of_resource: &str, resource_is_relative: bool, is_module: bool) -> Worker {
     let origin = gloo_utils::document()
         .location()
         .unwrap_throw()
         .origin()
         .unwrap_throw();
-    let script_url = format!("{}/{}", origin, name_of_resource);
-    let wasm_url = format!("{}/{}", origin, name_of_resource.replace(".js", "_bg.wasm"));
+    let pathname = gloo_utils::window().location().pathname().unwrap_throw();
+
+    let prefix = if resource_is_relative {
+        pathname
+            .rfind(|c| c == '/')
+            .map(|i| &pathname[..i])
+            .unwrap_or_default()
+    } else {
+        ""
+    };
+    let script_url = format!("{}{}/{}", origin, prefix, name_of_resource);
+    let wasm_url = format!(
+        "{}{}/{}",
+        origin,
+        prefix,
+        name_of_resource.replace(".js", "_bg.wasm")
+    );
     let array = Array::new();
     array.push(
         &format!(

packages/yew-agent/src/worker/private.rs

@@ -54,11 +54,12 @@ where
         };
 
         let name_of_resource = AGN::name_of_resource();
+        let is_relative = AGN::resource_path_is_relative();
         let handler_cell = Rc::new(RefCell::new(Some(handler)));
 
         let worker = {
             let handler_cell = handler_cell.clone();
-            let worker = worker_new(name_of_resource, AGN::is_module());
+            let worker = worker_new(name_of_resource, is_relative, AGN::is_module());
             let worker_clone = worker.clone();
             worker.set_onmessage_closure(move |data: Vec<u8>| {
                 if let Some(handler) = handler_cell.borrow().as_ref() {

packages/yew-agent/src/worker/public.rs

@@ -64,8 +64,9 @@ where
                         }
                     };
                     let name_of_resource = AGN::name_of_resource();
+                    let is_relative = AGN::resource_path_is_relative();
                     let worker = {
-                        let worker = worker_new(name_of_resource, AGN::is_module());
+                        let worker = worker_new(name_of_resource, is_relative, AGN::is_module());
                         let worker_clone = worker.clone();
                         worker.set_onmessage_closure(move |data: Vec<u8>| {
                             handler(data, &worker_clone);