Add typed WebSocket handler errors and public error metadata (#33)

Author: Handy-caT

Cargo.lock

@@ -114,6 +114,7 @@ ws-wtx-http2 = ["ws-wtx", "wtx/http2"]
 serde = { version = "1.0", features = ["derive"] }
 serde_json = { version = "1.0", features = ["raw_value"] }
 eyre = "0.6"
+derive_more = { version = "2.1.1", features = ["display"] }
 convert_case = "0.6"
 itertools = "0.12"
 clap = { version = "4.5", features = ["derive", "env"] }

Cargo.toml

@@ -31,8 +31,8 @@ declare -a FULL_DESC=(
     "ReceiveUserInfo: with appPubId"
     "ReceiveUserInfo: with token"
     "ReceiveUserInfo: with appPubId and token"
-    "ReceiveUserInfo: error code is 100400 (BAD_REQUEST)"
-    "ReceiveUserInfo: username appears in error message"
+    "ReceiveUserInfo: code and kind match"
+    "ReceiveUserInfo: fixed message"
     "Error: unknown method returns error"
     "Error: missing params field (no response expected)"
     "Error: wrong params type"
@@ -63,12 +63,12 @@ declare -a FULL_ASSERT=(
     '.type == "Immediate"'
     '.params.message == "echo: "'
     '.params.message == "echo: hello world! @#$%"'
-    '.type == "Error" and (.params | test("Test passed"))'
-    '.type == "Error" and (.params | test("Test passed"))'
-    '.type == "Error" and (.params | test("Test passed"))'
-    '.type == "Error" and (.params | test("Test passed"))'
-    '.code == 100400'
-    '.params | test("bob")'
+    '.type == "Error" and .kind == "BadRequest"'
+    '.type == "Error" and .kind == "BadRequest"'
+    '.type == "Error" and .kind == "BadRequest"'
+    '.type == "Error" and .kind == "BadRequest"'
+    '.code == 100400 and .kind == "BadRequest"'
+    '.params == "ReceiveUserInfo is not processed by this test server"'
     '.type == "Error"'
     '.type == "Error"'
     '.type == "Error"'

examples/test_ws_echo.sh

@@ -28,7 +28,7 @@ Messages follow the library's JSON envelope format:
 {"method": 211, "seq": 2, "params": {"userPubId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890", "username": "alice"}}
 
 // server → client (always an error — test server)
-{"type":"Error","method":211,"seq":2,"params":"Test passed: received ReceiveUserInfo for user 'alice' (id: a1b2c3d4-e5f6-7890-abcd-ef1234567890) — this is a test server and will not process the request","error_code":{"code":100400},"log_id":"..."}
+{"type":"Error","method":211,"code":100400,"kind":"BadRequest","seq":2,"log_id":"...","params":"ReceiveUserInfo is not processed by this test server"}
 ```
 
 The optional fields `appPubId` and `token` can also be included:
@@ -76,7 +76,7 @@ With optional fields:
 Expected response (error confirming the test passed):
 
 ```
-{"type":"Error","method":211,"seq":2,"params":"Test passed: received ReceiveUserInfo for user 'alice' (id: a1b2c3d4-e5f6-7890-abcd-ef1234567890) — this is a test server and will not process the request","error_code":{"code":100400},"log_id":"..."}
+{"type":"Error","method":211,"code":100400,"kind":"BadRequest","seq":2,"log_id":"...","params":"ReceiveUserInfo is not processed by this test server"}
 ```
 
 ## Run with Cloudflare Containers (wrangler dev)
@@ -115,5 +115,5 @@ Or call `ReceiveUserInfo`:
 Expected response:
 
 ```
-{"type":"Error","method":211,"seq":2,"params":"Test passed: received ReceiveUserInfo for user 'alice' (id: a1b2c3d4-e5f6-7890-abcd-ef1234567890) — this is a test server and will not process the request","error_code":{"code":100400},"log_id":"..."}
+{"type":"Error","method":211,"code":100400,"kind":"BadRequest","seq":2,"log_id":"...","params":"ReceiveUserInfo is not processed by this test server"}
 ```

examples/ws-echo/README.md

@@ -1,8 +1,9 @@
 use std::sync::Arc;
 
 use async_trait::async_trait;
+use derive_more::Display;
 use endpoint_libs::libs::error_code::ErrorCode;
-use endpoint_libs::libs::handler::RequestHandler;
+use endpoint_libs::libs::handler::{RequestHandler, Response};
 #[cfg(feature = "error_aggregation")]
 use endpoint_libs::libs::log::error_aggregation::ErrorAggregationConfig;
 use endpoint_libs::libs::log::{LogLevel, LoggingConfig, OtelConfig, setup_logging};
@@ -95,8 +96,9 @@ pub struct MethodEcho;
 #[async_trait(?Send)]
 impl RequestHandler for MethodEcho {
     type Request = EchoRequest;
+    type Error = CustomError;
 
-    async fn handle(&self, ctx: RequestContext, req: EchoRequest) -> Result<EchoResponse> {
+    async fn handle(&self, ctx: RequestContext, req: EchoRequest) -> Response<EchoRequest> {
         tracing::info!(
             conn_id = %ctx.connection_id,
             message = %req.message,
@@ -116,15 +118,32 @@ impl RequestHandler for MethodEcho {
 
 pub struct MethodReceiveUserInfo;
 
+#[derive(Debug, Display)]
+pub enum ReceiveUserInfoError {
+    #[display("ReceiveUserInfo is not processed by this test server")]
+    Rejected,
+}
+
+impl From<ReceiveUserInfoError> for CustomError {
+    fn from(err: ReceiveUserInfoError) -> Self {
+        match err {
+            ReceiveUserInfoError::Rejected => {
+                CustomError::new(ErrorCode::BAD_REQUEST, err.to_string())
+            }
+        }
+    }
+}
+
 #[async_trait(?Send)]
 impl RequestHandler for MethodReceiveUserInfo {
     type Request = HoneyReceiveUserInfoRequest;
+    type Error = ReceiveUserInfoError;
 
     async fn handle(
         &self,
         ctx: RequestContext,
         req: HoneyReceiveUserInfoRequest,
-    ) -> Result<HoneyReceiveUserInfoResponse> {
+    ) -> Response<HoneyReceiveUserInfoRequest, ReceiveUserInfoError> {
         tracing::info!(
             conn_id = %ctx.connection_id,
             user_pub_id = %req.user_pub_id,
@@ -133,21 +152,12 @@ impl RequestHandler for MethodReceiveUserInfo {
             has_token = req.token.is_some(),
             "ReceiveUserInfo request received (test server — will reject)"
         );
-        let msg = format!(
-            "Test passed: received ReceiveUserInfo for user '{}' (id: {}){} — \
-             this is a test server and will not process the request",
-            req.username,
-            req.user_pub_id,
-            req.app_pub_id
-                .map(|id| format!(", app: {id}"))
-                .unwrap_or_default(),
-        );
         tracing::info!(
             conn_id = %ctx.connection_id,
             user_pub_id = %req.user_pub_id,
             "Rejecting ReceiveUserInfo with BAD_REQUEST"
         );
-        Err(CustomError::new(ErrorCode::BAD_REQUEST, msg).into())
+        Err(ReceiveUserInfoError::Rejected.into())
     }
 }