build: add api server request context middleware

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

@@ -0,0 +1,65 @@
+use axum::{
+    extract::Request,
+    http::{header::HeaderName, HeaderValue, Request as HttpRequest},
+    middleware::Next,
+    response::Response,
+};
+use uuid::Uuid;
+
+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,
+}
+
+impl RequestContext {
+    pub fn new(request_id: String) -> Self {
+        Self { request_id }
+    }
+
+    pub fn request_id(&self) -> &str {
+        &self.request_id
+    }
+}
+
+pub async fn attach_request_context(mut request: Request, next: Next) -> Response {
+    let request_id = request
+        .headers()
+        .get(X_REQUEST_ID_HEADER)
+        .and_then(|value| value.to_str().ok())
+        .map(str::trim)
+        .filter(|value| !value.is_empty())
+        .map(ToOwned::to_owned)
+        .unwrap_or_else(|| Uuid::new_v4().to_string());
+
+    request
+        .extensions_mut()
+        .insert(RequestContext::new(request_id.clone()));
+
+    // 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) {
+        request
+            .headers_mut()
+            .insert(HeaderName::from_static(X_REQUEST_ID_HEADER), header_value);
+    }
+
+    next.run(request).await
+}
+
+pub fn resolve_request_id<B>(request: &HttpRequest<B>) -> Option<String> {
+    request
+        .extensions()
+        .get::<RequestContext>()
+        .map(|context| context.request_id().to_string())
+        .or_else(|| {
+            request
+                .headers()
+                .get(X_REQUEST_ID_HEADER)
+                .and_then(|value| value.to_str().ok())
+                .map(str::trim)
+                .filter(|value| !value.is_empty())
+                .map(ToOwned::to_owned)
+        })
+}