enhancement: make content-type header optional for json payloads

server/src/errors.rs

@@ -119,8 +119,8 @@ pub fn custom_json_error_handler(
 ) -> actix_web::Error {
     let (error_message, solution) = match &err {
                 JsonPayloadError::ContentType => (
-                    "Content type error",
-                    "Ensure that the content type of the request body is set to application/json."
+                    "Content type header error",
+                    "Ensure the content type request header of the HTTP request is set as `Content-Type: application/json`."
                 ),
                 JsonPayloadError::Payload(_) => (
                     "Payload error",

server/src/lib.rs

@@ -595,6 +595,7 @@ pub fn main() -> std::io::Result<()> {
             App::new()
                 .wrap(Cors::permissive())
                 .app_data(PayloadConfig::new(134200000))
+                .wrap(middleware::json_middleware::JsonMiddlewareFactory)
                 .app_data(json_cfg.clone())
                 .app_data(
                     web::PathConfig::default()

server/src/middleware/json_middleware.rs

@@ -0,0 +1,66 @@
+use actix_http::header::HeaderValue;
+use actix_web::{
+    dev::{forward_ready, Service, ServiceRequest, ServiceResponse, Transform},
+    Error,
+};
+use futures_util::future::LocalBoxFuture;
+use std::{
+    future::{ready, Ready},
+    rc::Rc,
+};
+
+pub struct JsonMiddleware<S> {
+    service: Rc<S>,
+}
+
+impl<S, B> Service<ServiceRequest> for JsonMiddleware<S>
+where
+    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error> + 'static,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Response = ServiceResponse<B>;
+    type Error = Error;
+    type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+    forward_ready!(service);
+    fn call(&self, mut req: ServiceRequest) -> Self::Future {
+        // Clone the Rc pointers so we can move them into the async block.
+        let srv = self.service.clone();
+        Box::pin(async move {
+            if req
+                .headers()
+                .get(actix_http::header::CONTENT_TYPE)
+                .is_none()
+            {
+                req.headers_mut().insert(
+                    actix_http::header::CONTENT_TYPE,
+                    HeaderValue::from_static("application/json"),
+                );
+            }
+            let res = srv.call(req).await?;
+            Ok(res)
+        })
+    }
+}
+
+pub struct JsonMiddlewareFactory;
+
+impl<S, B> Transform<S, ServiceRequest> for JsonMiddlewareFactory
+where
+    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error> + 'static,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Response = ServiceResponse<B>;
+    type Error = Error;
+    type InitError = ();
+    type Transform = JsonMiddleware<S>;
+    type Future = Ready<Result<Self::Transform, Self::InitError>>;
+
+    fn new_transform(&self, service: S) -> Self::Future {
+        ready(Ok(JsonMiddleware {
+            service: Rc::new(service),
+        }))
+    }
+}

server/src/middleware/mod.rs

@@ -1,2 +1,3 @@
 pub mod api_version;
 pub mod auth_middleware;
+pub mod json_middleware;