feat(android): implement custom protocol (#527)

* feat(android): implement custom protocol

* add change file

* fix status code, use log::error

* remove println

.changes/android-custom-protocol.md

@@ -0,0 +1,5 @@
+---
+"tao": patch
+---
+
+Implement custom protocol on Android.

Cargo.toml

@@ -52,6 +52,7 @@ ndk-sys = "0.3"
 ndk-context = "0.1"
 once_cell = "1.13"
 paste = "1.0"
+http = "0.2"
 
 [target."cfg(any(target_os = \"ios\", target_os = \"macos\"))".dependencies]
 objc = "0.2"

src/platform_impl/android/ndk_glue.rs

@@ -1,7 +1,12 @@
 use crate::window::Window;
 use crossbeam_channel::*;
+use http::{
+  header::{HeaderMap, HeaderName, HeaderValue},
+  status::StatusCode,
+};
 pub use jni::{
-  objects::{GlobalRef, JClass, JObject, JString},
+  objects::{GlobalRef, JClass, JMap, JObject, JString},
+  sys::jobject,
   JNIEnv,
 };
 use libc::c_void;
@@ -46,20 +51,24 @@ macro_rules! android_fn {
         android_fn!($domain, $package, MainActivity, memory);
         android_fn!($domain, $package, MainActivity, focus, i32);
         android_fn!($domain, $package, RustClient, eval);
+        android_fn!($domain, $package, RustClient, handleRequest, JObject, jobject);
         android_fn!($domain, $package, IpcInterface, ipc, JString);
     }
   };
   ($domain:ident, $package:ident, $class:ident, $function:ident) => {
     android_fn!($domain, $package, $class, $function, JObject)
   };
   ($domain:ident, $package:ident, $class:ident, $function:ident, $arg:ty) => {
+    android_fn!($domain, $package, $class, $function, $arg, ())
+  };
+  ($domain:ident, $package:ident, $class:ident, $function:ident, $arg:ty, $ret: ty) => {
     paste::paste! {
         #[no_mangle]
         unsafe extern "C" fn [< Java_ $domain _ $package _ $class _ $function >](
           env: JNIEnv,
           class: JClass,
           object: $arg,
-        ) {
+        ) -> $ret {
             $function(env, class, object)
         }
     }
@@ -188,6 +197,8 @@ pub enum WebViewMessage {
 }
 
 pub static IPC: OnceCell<UnsafeIpc> = OnceCell::new();
+pub static REQUEST_HANDLER: OnceCell<UnsafeRequestHandler> = OnceCell::new();
+
 pub struct UnsafeIpc(*mut c_void, Rc<Window>);
 impl UnsafeIpc {
   pub fn new(f: *mut c_void, w: Rc<Window>) -> Self {
@@ -197,6 +208,15 @@ impl UnsafeIpc {
 unsafe impl Send for UnsafeIpc {}
 unsafe impl Sync for UnsafeIpc {}
 
+pub struct UnsafeRequestHandler(Box<dyn Fn(WebResourceRequest) -> Option<WebResourceResponse>>);
+impl UnsafeRequestHandler {
+  pub fn new(f: Box<dyn Fn(WebResourceRequest) -> Option<WebResourceResponse>>) -> Self {
+    Self(f)
+  }
+}
+unsafe impl Send for UnsafeRequestHandler {}
+unsafe impl Sync for UnsafeRequestHandler {}
+
 /// `ndk-glue` macros register the reading end of an event pipe with the
 /// main [`ThreadLooper`] under this `ident`.
 /// When returned from [`ThreadLooper::poll_*`](ThreadLooper::poll_once)
@@ -398,6 +418,123 @@ pub unsafe fn eval(_: JNIEnv, _: JClass, _: JObject) {
   MainPipe::send(WebViewMessage::Eval);
 }
 
+pub struct WebResourceRequest {
+  /// The request url.
+  pub url: String,
+  /// The request method.
+  pub method: String,
+  /// The request headers.
+  pub headers: HeaderMap<HeaderValue>,
+}
+
+pub struct WebResourceResponse {
+  /// The response's status
+  pub status: StatusCode,
+
+  /// The response's headers
+  pub headers: HeaderMap<HeaderValue>,
+
+  /// The response's mimetype type
+  pub mimetype: Option<String>,
+
+  /// The response body.
+  pub body: Vec<u8>,
+}
+
+fn handle_request(env: JNIEnv, request: JObject) -> Result<jobject, jni::errors::Error> {
+  let uri = env
+    .call_method(request, "getUrl", "()Landroid/net/Uri;", &[])?
+    .l()?;
+  let url: JString = env
+    .call_method(uri, "toString", "()Ljava/lang/String;", &[])?
+    .l()?
+    .into();
+  let url = env.get_string(url)?.to_string_lossy().to_string();
+
+  let method: JString = env
+    .call_method(request, "getMethod", "()Ljava/lang/String;", &[])?
+    .l()?
+    .into();
+  let method = env.get_string(method)?.to_string_lossy().to_string();
+
+  let request_headers = env
+    .call_method(request, "getRequestHeaders", "()Ljava/util/Map;", &[])?
+    .l()?;
+  let request_headers = JMap::from_env(&env, request_headers)?;
+  let mut headers = HeaderMap::new();
+  for (header, value) in request_headers.iter()? {
+    let header = env.get_string(header.into())?;
+    let value = env.get_string(value.into())?;
+    if let (Ok(header), Ok(value)) = (
+      HeaderName::from_bytes(header.to_bytes()),
+      HeaderValue::from_bytes(value.to_bytes()),
+    ) {
+      headers.insert(header, value);
+    }
+  }
+
+  if let Some(handler) = REQUEST_HANDLER.get() {
+    let response = (handler.0)(WebResourceRequest {
+      url,
+      method,
+      headers,
+    });
+    if let Some(response) = response {
+      let status_code = response.status.as_u16() as i32;
+      let reason_phrase = "OK";
+      let encoding = "UTF-8";
+      let mime_type = if let Some(mime) = response.mimetype {
+        env.new_string(mime)?.into()
+      } else {
+        JObject::null()
+      };
+      let bytes = response.body;
+
+      let hashmap = env.find_class("java/util/HashMap")?;
+      let response_headers = env.new_object(hashmap, "()V", &[])?;
+      for (key, value) in response.headers.iter() {
+        env.call_method(
+          response_headers,
+          "put",
+          "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;",
+          &[
+            env.new_string(key.as_str())?.into(),
+            // TODO can we handle this better?
+            env
+              .new_string(String::from_utf8_lossy(value.as_bytes()))?
+              .into(),
+          ],
+        )?;
+      }
+
+      let byte_array_input_stream = env.find_class("java/io/ByteArrayInputStream")?;
+      let byte_array = env.byte_array_from_slice(&bytes)?;
+      let stream = env.new_object(byte_array_input_stream, "([B)V", &[byte_array.into()])?;
+
+      let web_resource_response_class = env.find_class("android/webkit/WebResourceResponse")?;
+      let web_resource_response = env.new_object(
+        web_resource_response_class,
+        "(Ljava/lang/String;Ljava/lang/String;ILjava/lang/String;Ljava/util/Map;Ljava/io/InputStream;)V",
+        &[mime_type.into(), env.new_string(encoding)?.into(), status_code.into(), env.new_string(reason_phrase)?.into(), response_headers.into(), stream.into()],
+      )?;
+
+      return Ok(*web_resource_response);
+    }
+  }
+  Ok(*JObject::null())
+}
+
+#[allow(non_snake_case)]
+pub unsafe fn handleRequest(env: JNIEnv, _: JClass, request: JObject) -> jobject {
+  match handle_request(env, request) {
+    Ok(response) => response,
+    Err(e) => {
+      log::error!("Failed to handle request: {}", e);
+      *JObject::null()
+    }
+  }
+}
+
 pub unsafe fn ipc(env: JNIEnv, _: JClass, arg: JString) {
   match env.get_string(arg) {
     Ok(arg) => {