feat: dyn middlewares based on js rt

scripts/pre_process.js

@@ -0,0 +1,63 @@
+// 请求预处理
+// 在请求被处理之前执行的函数
+//
+// @param {Object} ctx - 请求上下文对象
+// @returns {Object|undefined} - 返回修改后的请求对象或 undefined
+// 
+// 参考: [JS Rt](./middleware/js_rt.go) 里的 `JSContext`
+function preProcessRequest(ctx) {
+    // 例子：基于数据库的速率限制
+    // if (ctx.url.includes("/v1/chat/completions")) {
+    //     try {
+    //         // Check recent requests from this IP
+    //         var recentRequests = db.Query(
+    //             "SELECT COUNT(*) as count FROM logs WHERE created_at > ? AND ip = ?",
+    //             Math.floor(Date.now() / 1000) - 60, // last minute
+    //             ctx.remoteIP
+    //         );
+
+    //         if (recentRequests && recentRequests.length > 0 && recentRequests[0].count > 10) {
+    //             console.log("速率限制 IP:", ctx.RemoteIP);
+    //             return {
+    //                 block: true,
+    //                 statusCode: 429,
+    //                 message: "超过速率限制"
+    //             };
+    //         }
+    //     } catch (e) {
+    //         console.error("Ratelimit 数据库错误:", e);
+    //     }
+    // }
+
+    // 例子：修改请求
+    if (ctx.URL.includes("/v1/chat/completions")) {
+        try {
+            var bodyObj = ctx.Body;
+
+            let firstMsg = {
+                role: "user",
+                content: "今天天气怎么样"
+            };
+            bodyObj.messages[0] = firstMsg;
+            console.log("Modified first message:", JSON.stringify(firstMsg));
+            console.log("Modified body:", JSON.stringify(bodyObj));
+
+            return {
+                body: bodyObj,
+                headers: {
+                    ...ctx.Headers,
+                    "X-Modified-Body": "true"
+                }
+            };
+        } catch (e) {
+            console.error("Failed to parse/modify request body:", {
+                message: e.message,
+                stack: e.stack,
+                bodyType: typeof ctx.Body,
+                url: ctx.URL
+            });
+        }
+    }
+
+    return undefined; // 跳过处理，继续执行下一个中间件或路由
+}