From cd06adf6c894094f2ae9e1ffe0daab0d665df3bd Mon Sep 17 00:00:00 2001
From: Afonso Lage <lage.afonso@gmail.com>
Date: Tue, 13 Feb 2024 09:31:25 -0300
Subject: [PATCH] Added CORS `Mode` property to `Request` on web (#52)

Closes #51

- Add `Mode` to `Request` on wasm builds;
- Add `Mode::Cors` as default;

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
---
 ehttp/src/lib.rs   |  3 +++
 ehttp/src/types.rs | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 ehttp/src/web.rs   |  2 +-
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/ehttp/src/lib.rs b/ehttp/src/lib.rs
index 96a5796..550b96e 100644
--- a/ehttp/src/lib.rs
+++ b/ehttp/src/lib.rs
@@ -75,6 +75,9 @@ pub async fn fetch_async(request: Request) -> Result<Response> {
 mod types;
 pub use types::{Error, Headers, PartialResponse, Request, Response, Result};
 
+#[cfg(target_arch = "wasm32")]
+pub use types::Mode;
+
 #[cfg(not(target_arch = "wasm32"))]
 mod native;
 #[cfg(not(target_arch = "wasm32"))]
diff --git a/ehttp/src/types.rs b/ehttp/src/types.rs
index 729a851..ed3febd 100644
--- a/ehttp/src/types.rs
+++ b/ehttp/src/types.rs
@@ -93,6 +93,39 @@ impl<'h> IntoIterator for &'h Headers {
 
 // ----------------------------------------------------------------------------
 
+/// Determine if cross-origin requests lead to valid responses.
+/// Based on <https://developer.mozilla.org/en-US/docs/Web/API/Request/mode>
+#[cfg(target_arch = "wasm32")]
+#[derive(Default, Clone, Copy, Debug)]
+pub enum Mode {
+    /// If a request is made to another origin with this mode set, the result is an error.
+    SameOrigin = 0,
+
+    /// The request will not include the Origin header in a request.
+    /// The server's response will be opaque, meaning that JavaScript code cannot access its contents
+    NoCors = 1,
+
+    /// Includes an Origin header in the request and expects the server to respond with an
+    /// "Access-Control-Allow-Origin" header that indicates whether the request is allowed.
+    #[default]
+    Cors = 2,
+
+    /// A mode for supporting navigation
+    Navigate = 3,
+}
+
+#[cfg(target_arch = "wasm32")]
+impl From<Mode> for web_sys::RequestMode {
+    fn from(mode: Mode) -> Self {
+        match mode {
+            Mode::SameOrigin => web_sys::RequestMode::SameOrigin,
+            Mode::NoCors => web_sys::RequestMode::NoCors,
+            Mode::Cors => web_sys::RequestMode::Cors,
+            Mode::Navigate => web_sys::RequestMode::Navigate,
+        }
+    }
+}
+
 /// A simple HTTP request.
 #[derive(Clone, Debug)]
 pub struct Request {
@@ -107,6 +140,10 @@ pub struct Request {
 
     /// ("Accept", "*/*"), …
     pub headers: Headers,
+
+    /// Request mode used on fetch. Only available on wasm builds
+    #[cfg(target_arch = "wasm32")]
+    pub mode: Mode,
 }
 
 impl Request {
@@ -118,6 +155,8 @@ impl Request {
             url: url.to_string(),
             body: vec![],
             headers: Headers::new(&[("Accept", "*/*")]),
+            #[cfg(target_arch = "wasm32")]
+            mode: Mode::default(),
         }
     }
 
@@ -129,6 +168,8 @@ impl Request {
             url: url.to_string(),
             body: vec![],
             headers: Headers::new(&[("Accept", "*/*")]),
+            #[cfg(target_arch = "wasm32")]
+            mode: Mode::default(),
         }
     }
 
@@ -143,6 +184,8 @@ impl Request {
                 ("Accept", "*/*"),
                 ("Content-Type", "text/plain; charset=utf-8"),
             ]),
+            #[cfg(target_arch = "wasm32")]
+            mode: Mode::default(),
         }
     }
 
@@ -176,6 +219,8 @@ impl Request {
             url: url.to_string(),
             body: data,
             headers: Headers::new(&[("Accept", "*/*"), ("Content-Type", content_type.as_str())]),
+            #[cfg(target_arch = "wasm32")]
+            mode: Mode::default(),
         }
     }
 
@@ -191,6 +236,8 @@ impl Request {
             url: url.to_string(),
             body: serde_json::to_string(body)?.into_bytes(),
             headers: Headers::new(&[("Accept", "*/*"), ("Content-Type", "application/json")]),
+            #[cfg(target_arch = "wasm32")]
+            mode: Mode::default(),
         })
     }
 }
diff --git a/ehttp/src/web.rs b/ehttp/src/web.rs
index 94871dd..cb7d4c3 100644
--- a/ehttp/src/web.rs
+++ b/ehttp/src/web.rs
@@ -42,7 +42,7 @@ pub(crate) fn string_from_fetch_error(value: JsValue) -> String {
 pub(crate) async fn fetch_base(request: &Request) -> Result<web_sys::Response, JsValue> {
     let mut opts = web_sys::RequestInit::new();
     opts.method(&request.method);
-    opts.mode(web_sys::RequestMode::Cors);
+    opts.mode(request.mode.into());
 
     if !request.body.is_empty() {
         let body_bytes: &[u8] = &request.body;