build: add api server response envelope helpers

backend-rewrite-tasklist/01_M0_M2_FOUNDATION_AND_AUTH.md

@@ -100,7 +100,8 @@
   交付物：[../server-rs/apps/api-server/src/request_context.rs](../server-rs/apps/api-server/src/request_context.rs)、[../server-rs/apps/api-server/src/app.rs](../server-rs/apps/api-server/src/app.rs)
 - [x] 接入统一错误处理中间件
   交付物：[../server-rs/apps/api-server/src/http_error.rs](../server-rs/apps/api-server/src/http_error.rs)、[../server-rs/apps/api-server/src/error_middleware.rs](../server-rs/apps/api-server/src/error_middleware.rs)、[../server-rs/apps/api-server/src/app.rs](../server-rs/apps/api-server/src/app.rs)
-- [ ] 接入当前项目兼容的 response envelope
+- [x] 接入当前项目兼容的 response envelope
+  交付物：[../server-rs/apps/api-server/src/api_response.rs](../server-rs/apps/api-server/src/api_response.rs)、[../server-rs/apps/api-server/src/request_context.rs](../server-rs/apps/api-server/src/request_context.rs)、[../server-rs/apps/api-server/src/http_error.rs](../server-rs/apps/api-server/src/http_error.rs)
 - [ ] 接入 `x-request-id`
 - [ ] 接入 `x-api-version`
 - [ ] 接入 `x-route-version`

server-rs/Cargo.lock

@@ -24,6 +24,7 @@ dependencies = [
  "axum",
  "serde",
  "serde_json",
+ "time",
  "tokio",
  "tower-http",
  "tracing",
@@ -113,6 +114,15 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "deranged"
+version = "0.5.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7cd812cc2bc1d69d4764bd80df88b4317eaef9e773c75226407d9bc0876b211c"
+dependencies = [
+ "powerfmt",
+]
+
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -386,6 +396,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "num-conv"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6673768db2d862beb9b39a78fdcb1a69439615d5794a1be50caa9bc92c81967"
+
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -404,6 +420,12 @@ version = "0.2.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a89322df9ebe1c1578d689c92318e070967d1042b512afbe49518723f4e6d5cd"
 
+[[package]]
+name = "powerfmt"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"
+
 [[package]]
 name = "prettyplease"
 version = "0.2.37"
@@ -596,6 +618,37 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "time"
+version = "0.3.47"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "743bd48c283afc0388f9b8827b976905fb217ad9e647fae3a379a9283c4def2c"
+dependencies = [
+ "deranged",
+ "itoa",
+ "num-conv",
+ "powerfmt",
+ "serde_core",
+ "time-core",
+ "time-macros",
+]
+
+[[package]]
+name = "time-core"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7694e1cfe791f8d31026952abf09c69ca6f6fa4e1a1229e18988f06a04a12dca"
+
+[[package]]
+name = "time-macros"
+version = "0.2.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e70e4c5a0e0a8a4823ad65dfe1a6930e4f4d756dcd9dd7939022b5e8c501215"
+dependencies = [
+ "num-conv",
+ "time-core",
+]
+
 [[package]]
 name = "tokio"
 version = "1.52.1"

server-rs/apps/api-server/Cargo.toml

@@ -9,6 +9,7 @@ axum = "0.8"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 tokio = { version = "1", features = ["macros", "rt-multi-thread", "net"] }
+time = { version = "0.3", features = ["formatting"] }
 tower-http = { version = "0.6", features = ["trace"] }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter", "fmt"] }

server-rs/apps/api-server/README.md

@@ -30,7 +30,7 @@
 1. [x] 接入统一日志与 tracing
 2. [x] 接入 `request_id`
 3. [x] 接入统一错误处理中间件
-4. [ ] 接入 response envelope
+4. [x] 接入 response envelope
 5. [ ] 接入 `/healthz`
 
 当前 tracing 约定：
@@ -51,6 +51,12 @@
 2. 已经带 `content-type` 的业务错误响应不会被覆盖，避免抢走后续 response envelope 的职责。
 3. 统一错误日志会复用当前请求的 `request_id`，便于后续和响应头、envelope 元信息串联。
 
+当前 response envelope 约定：
+
+1. `RequestContext` 已记录 `request_id`、请求开始时间、默认 `operation` 与 envelope 协商结果。
+2. `json_success_body(...)` / `json_error_body(...)` 会根据 `x-genarrative-response-envelope` 自动在“裸数据 / 标准 envelope / legacy error + meta”之间切换。
+3. `meta.apiVersion`、`meta.requestId`、`meta.routeVersion`、`meta.operation`、`meta.latencyMs`、`meta.timestamp` 已按当前前端契约生成，响应头回写仍留给后续独立任务。
+
 ## 3. 边界约束
 
 1. `api-server` 负责 HTTP、SSE、Cookie、Header、路由与协议装配。

server-rs/apps/api-server/src/api_response.rs

@@ -0,0 +1,129 @@
+use axum::Json;
+use serde::Serialize;
+use serde_json::{json, Value};
+use time::{format_description::well_known::Rfc3339, OffsetDateTime};
+
+use crate::{http_error::ApiErrorPayload, request_context::RequestContext};
+
+pub const API_VERSION: &str = "2026-04-08";
+
+#[derive(Debug, Serialize)]
+struct ApiResponseMeta {
+    #[serde(rename = "apiVersion")]
+    api_version: &'static str,
+    #[serde(rename = "requestId", skip_serializing_if = "Option::is_none")]
+    request_id: Option<String>,
+    #[serde(rename = "routeVersion")]
+    route_version: &'static str,
+    operation: Option<String>,
+    #[serde(rename = "latencyMs")]
+    latency_ms: u64,
+    timestamp: String,
+}
+
+// 当前阶段先把成功响应 envelope helper 准备好，后续 `/healthz` 与业务 handler 会直接复用这里的输出逻辑。
+#[allow(dead_code)]
+pub fn json_success_body<T>(request_context: Option<&RequestContext>, data: T) -> Json<Value>
+where
+    T: Serialize,
+{
+    if let Some(context) = request_context {
+        if context.wants_envelope() {
+            return Json(json!({
+                "ok": true,
+                "data": data,
+                "error": null,
+                "meta": build_api_response_meta(Some(context)),
+            }));
+        }
+    }
+
+    Json(serde_json::to_value(data).unwrap_or(Value::Null))
+}
+
+pub fn json_error_body(
+    request_context: Option<&RequestContext>,
+    error: &ApiErrorPayload,
+) -> Json<Value> {
+    let meta = build_api_response_meta(request_context);
+
+    if request_context.is_some_and(RequestContext::wants_envelope) {
+        return Json(json!({
+            "ok": false,
+            "data": null,
+            "error": error,
+            "meta": meta,
+        }));
+    }
+
+    Json(json!({
+        "error": error,
+        "meta": meta,
+    }))
+}
+
+fn build_api_response_meta(request_context: Option<&RequestContext>) -> ApiResponseMeta {
+    ApiResponseMeta {
+        api_version: API_VERSION,
+        request_id: request_context.map(|context| context.request_id().to_string()),
+        route_version: API_VERSION,
+        operation: request_context.map(|context| context.operation().to_string()),
+        latency_ms: request_context
+            .map(RequestContext::elapsed)
+            .unwrap_or_default(),
+        timestamp: OffsetDateTime::now_utc()
+            .format(&Rfc3339)
+            .unwrap_or_else(|_| "1970-01-01T00:00:00Z".to_string()),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::request_context::RequestContext;
+    use std::time::Duration;
+
+    fn build_request_context(wants_envelope: bool) -> RequestContext {
+        RequestContext::new(
+            "req-test".to_string(),
+            "GET /test".to_string(),
+            Duration::from_millis(12),
+            wants_envelope,
+        )
+    }
+
+    #[test]
+    fn success_body_returns_standard_envelope_when_requested() {
+        let request_context = build_request_context(true);
+        let body = json_success_body(Some(&request_context), json!({ "ok": "value" })).0;
+
+        assert_eq!(body["ok"], Value::Bool(true));
+        assert_eq!(body["data"]["ok"], Value::String("value".to_string()));
+        assert_eq!(body["meta"]["requestId"], Value::String("req-test".to_string()));
+        assert_eq!(body["meta"]["routeVersion"], Value::String(API_VERSION.to_string()));
+    }
+
+    #[test]
+    fn success_body_returns_raw_payload_when_envelope_not_requested() {
+        let request_context = build_request_context(false);
+        let body = json_success_body(Some(&request_context), json!({ "ok": "value" })).0;
+
+        assert_eq!(body["ok"], Value::String("value".to_string()));
+        assert!(body.get("meta").is_none());
+    }
+
+    #[test]
+    fn error_body_returns_legacy_shape_without_envelope_header() {
+        let request_context = build_request_context(false);
+        let error = ApiErrorPayload {
+            code: "NOT_FOUND",
+            message: "资源不存在",
+            details: None,
+        };
+        let body = json_error_body(Some(&request_context), &error).0;
+
+        assert_eq!(body["error"]["code"], Value::String("NOT_FOUND".to_string()));
+        assert_eq!(body["meta"]["requestId"], Value::String("req-test".to_string()));
+        assert!(body.get("ok").is_none());
+    }
+}

server-rs/apps/api-server/src/error_middleware.rs

@@ -2,17 +2,18 @@ use axum::{
     extract::Request,
     http::header::CONTENT_TYPE,
     middleware::Next,
-    response::{IntoResponse, Response},
+    response::Response,
 };
 use tracing::{error, warn};
 
 use crate::{
     http_error::AppError,
-    request_context::resolve_request_id,
+    request_context::{resolve_request_id, RequestContext},
 };
 
 pub async fn normalize_error_response(request: Request, next: Next) -> Response {
     let request_id = resolve_request_id(&request);
+    let request_context = request.extensions().get::<RequestContext>().cloned();
     let response = next.run(request).await;
 
     if !should_normalize_error_response(&response) {
@@ -39,7 +40,7 @@ pub async fn normalize_error_response(request: Request, next: Next) -> Response
         );
     }
 
-    app_error.into_response()
+    app_error.into_response_with_context(request_context.as_ref())
 }
 
 fn should_normalize_error_response(response: &Response) -> bool {

server-rs/apps/api-server/src/http_error.rs

@@ -1,11 +1,12 @@
 use axum::{
     http::StatusCode,
     response::{IntoResponse, Response},
-    Json,
 };
 use serde::Serialize;
 use serde_json::Value;
 
+use crate::{api_response::json_error_body, request_context::RequestContext};
+
 #[derive(Debug)]
 pub struct AppError {
     status_code: StatusCode,
@@ -14,17 +15,12 @@ pub struct AppError {
     details: Option<Value>,
 }
 
-#[derive(Debug, Serialize)]
+#[derive(Clone, Debug, Serialize)]
-struct LegacyApiErrorBody {
+pub struct ApiErrorPayload {
-    error: LegacyApiErrorPayload,
+    pub code: &'static str,
-}
+    pub message: &'static str,
-
-#[derive(Debug, Serialize)]
-struct LegacyApiErrorPayload {
-    code: &'static str,
-    message: &'static str,
     #[serde(skip_serializing_if = "Option::is_none")]
-    details: Option<Value>,
+    pub details: Option<Value>,
 }
 
 impl AppError {
@@ -42,19 +38,26 @@ impl AppError {
     pub fn code(&self) -> &'static str {
         self.code
     }
+
+    pub fn into_response_with_context(self, request_context: Option<&RequestContext>) -> Response {
+        let status_code = self.status_code;
+        let payload = self.to_payload();
+
+        (status_code, json_error_body(request_context, &payload)).into_response()
+    }
+
+    fn to_payload(&self) -> ApiErrorPayload {
+        ApiErrorPayload {
+            code: self.code,
+            message: self.message,
+            details: self.details.clone(),
+        }
+    }
 }
 
 impl IntoResponse for AppError {
     fn into_response(self) -> Response {
-        let body = LegacyApiErrorBody {
+        self.into_response_with_context(None)
-            error: LegacyApiErrorPayload {
-                code: self.code,
-                message: self.message,
-                details: self.details,
-            },
-        };
-
-        (self.status_code, Json(body)).into_response()
     }
 }
 

server-rs/apps/api-server/src/main.rs

@@ -1,4 +1,5 @@
 mod app;
+mod api_response;
 mod config;
 mod error_middleware;
 mod http_error;

server-rs/apps/api-server/src/request_context.rs

@@ -1,3 +1,5 @@
+use std::time::{Duration, Instant};
+
 use axum::{
     extract::Request,
     http::{header::HeaderName, HeaderValue, Request as HttpRequest},
@@ -6,25 +8,57 @@ use axum::{
 };
 use uuid::Uuid;
 
+pub const API_RESPONSE_ENVELOPE_HEADER: &str = "x-genarrative-response-envelope";
 pub const X_REQUEST_ID_HEADER: &str = "x-request-id";
 
 // 当前阶段先把请求级元信息统一挂到 extensions，后续响应头、envelope 与错误处理中间件继续复用。
 #[derive(Clone, Debug)]
 pub struct RequestContext {
     request_id: String,
+    operation: String,
+    request_started_at: Instant,
+    wants_envelope: bool,
 }
 
 impl RequestContext {
-    pub fn new(request_id: String) -> Self {
+    pub fn new(
-        Self { request_id }
+        request_id: String,
+        operation: String,
+        elapsed_seed: Duration,
+        wants_envelope: bool,
+    ) -> Self {
+        Self {
+            request_id,
+            operation,
+            request_started_at: Instant::now()
+                .checked_sub(elapsed_seed)
+                .unwrap_or_else(Instant::now),
+            wants_envelope,
+        }
     }
 
     pub fn request_id(&self) -> &str {
         &self.request_id
     }
+
+    pub fn operation(&self) -> &str {
+        &self.operation
+    }
+
+    pub fn wants_envelope(&self) -> bool {
+        self.wants_envelope
+    }
+
+    pub fn elapsed(&self) -> u64 {
+        self.request_started_at
+            .elapsed()
+            .as_millis()
+            .min(u64::MAX as u128) as u64
+    }
 }
 
 pub async fn attach_request_context(mut request: Request, next: Next) -> Response {
+    let wants_envelope = wants_api_envelope(&request);
     let request_id = request
         .headers()
         .get(X_REQUEST_ID_HEADER)
@@ -33,10 +67,14 @@ pub async fn attach_request_context(mut request: Request, next: Next) -> Respons
         .filter(|value| !value.is_empty())
         .map(ToOwned::to_owned)
         .unwrap_or_else(|| Uuid::new_v4().to_string());
+    let operation = format!("{} {}", request.method(), request.uri());
 
-    request
+    request.extensions_mut().insert(RequestContext::new(
-        .extensions_mut()
+        request_id.clone(),
-        .insert(RequestContext::new(request_id.clone()));
+        operation,
+        Duration::ZERO,
+        wants_envelope,
+    ));
 
     // 统一把 request_id 写回请求头，方便后续 tracing、响应头与 envelope 层读取同一来源。
     if let Ok(header_value) = HeaderValue::from_str(&request_id) {
@@ -63,3 +101,13 @@ pub fn resolve_request_id<B>(request: &HttpRequest<B>) -> Option<String> {
                 .map(ToOwned::to_owned)
         })
 }
+
+fn wants_api_envelope<B>(request: &HttpRequest<B>) -> bool {
+    request
+        .headers()
+        .get(API_RESPONSE_ENVELOPE_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .map(str::trim)
+        .map(str::to_lowercase)
+        .is_some_and(|value| matches!(value.as_str(), "1" | "true" | "v1" | "envelope"))
+}