Send body and headers correctly in the wasm backend

Author: FreddieRidell

Cargo.toml

@@ -42,6 +42,7 @@ isahc = { version = "0.9", optional = true, default-features = false, features =
 js-sys = { version = "0.3.25", optional = true }
 wasm-bindgen = { version = "0.2.48", optional = true }
 wasm-bindgen-futures = { version = "0.4.5", optional = true }
+futures-util = "0.3.1"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies.web-sys]
 version = "0.3.25"

src/wasm.rs

@@ -34,7 +34,7 @@ impl HttpClient for WasmClient {
 
     fn send(&self, req: Request) -> BoxFuture<'static, Result<Response, Self::Error>> {
         let fut = Box::pin(async move {
-            let req = fetch::new(req.method(), req.url());
+            let req: fetch::Request = fetch::Request::new(req)?;
             let mut res = req.send().await?;
 
             let body = res.body_bytes();
@@ -56,7 +56,6 @@ impl HttpClient for WasmClient {
     }
 }
 
-// This type e
 struct InnerFuture {
     fut: Pin<Box<dyn Future<Output = Result<Response, io::Error>> + 'static>>,
 }
@@ -77,6 +76,8 @@ impl Future for InnerFuture {
 }
 
 mod fetch {
+    use futures_util::io::AsyncReadExt;
+    use http::request::Parts;
     use js_sys::{Array, ArrayBuffer, Reflect, Uint8Array};
     use wasm_bindgen::JsCast;
     use wasm_bindgen_futures::JsFuture;
@@ -85,27 +86,75 @@ mod fetch {
 
     use std::io;
     use std::iter::{IntoIterator, Iterator};
+    use std::pin::Pin;
 
     /// Create a new fetch request.
-    pub(crate) fn new(method: impl AsRef<str>, url: impl AsRef<str>) -> Request {
-        Request::new(method, url)
-    }
 
     /// An HTTP Fetch Request.
     pub(crate) struct Request {
         init: RequestInit,
         url: String,
+        _body_buf: Pin<Vec<u8>>,
     }
 
     impl Request {
         /// Create a new instance.
-        pub(crate) fn new(method: impl AsRef<str>, url: impl AsRef<str>) -> Self {
+        pub(crate) fn new(req: super::Request) -> Result<Self, io::Error> {
+            let (
+                Parts {
+                    method,
+                    uri,
+                    headers,
+                    ..
+                },
+                mut body,
+            ) = req.into_parts();
+
+            //create a fetch request initaliser
             let mut init = web_sys::RequestInit::new();
+
+            //set the fetch method
             init.method(method.as_ref());
-            Self {
-                init,
-                url: url.as_ref().to_owned(),
+
+            //add any fetch headers
+            let init_headers = web_sys::Headers::new().unwrap();
+            for (name, value) in headers.iter() {
+                init_headers
+                    .append(name.as_str(), value.to_str().unwrap())
+                    .map_err(|_| {
+                        io::Error::new(
+                            io::ErrorKind::Other,
+                            format!(
+                                "could not add header: {} = {}",
+                                name.as_str(),
+                                value.to_str().expect("could not stringify header value")
+                            ),
+                        )
+                    })?;
+            }
+            init.headers(&init_headers);
+
+            //convert the body into a uint8 array
+            // needs to be pinned and retained inside the Request because the Uint8Array passed to
+            // js is just a portal into WASM linear memory, and if the underlying data is moved the
+            // js ref will become silently invalid
+            let mut body_buf = Vec::with_capacity(1024);
+            futures::executor::block_on(body.read_to_end(&mut body_buf)).map_err(|_| {
+                io::Error::new(io::ErrorKind::Other, "could not read body into a buffer")
+            })?;
+            let body_pinned = Pin::new(body_buf);
+            if body_pinned.len() > 0 {
+                unsafe {
+                    let uint_8_array = js_sys::Uint8Array::view(&body_pinned);
+                    init.body(Some(&uint_8_array));
+                }
             }
+
+            Ok(Self {
+                init,
+                url: uri.to_string(),
+                _body_buf: body_pinned,
+            })
         }
 
         /// Submit a request