fix: Make it more simple solution

Author: brn

src/server/sse.ts

@@ -68,54 +68,33 @@ export class SSEServerTransport implements Transport {
   async handlePostMessage(
     req: IncomingMessage,
     res: ServerResponse,
-    rawBody?: string | Buffer,
-    bodyEncoding?: BufferEncoding
+    rawOrParsedBody?: string | unknown,
   ): Promise<void> {
     if (!this._sseResponse) {
       const message = "SSE connection not established";
       res.writeHead(500).end(message);
       throw new Error(message);
     }
 
-    let body: string;
+    let body: string | unknown;
     try {
       const ct = contentType.parse(req.headers["content-type"] ?? "");
       if (ct.type !== "application/json") {
         throw new Error(`Unsupported content-type: ${ct}`);
       }
 
-      if (rawBody) {
-        if (typeof rawBody === 'string') {
-          body = rawBody;
-        } else if (Buffer.isBuffer(rawBody)) {
-          if (bodyEncoding) {
-            body = rawBody.toString(bodyEncoding);
-          } else if (ct.parameters.charset) {
-            if (Buffer.isEncoding(ct.parameters.charset)) {
-              body = rawBody.toString(ct.parameters.charset as BufferEncoding);
-            } else {
-              throw new Error('Unsupported buffer encoding: ${ct.parameters.charset}')
-            }
-          } else {
-            body = rawBody.toString('utf8');
-          }
-        } else {
-          throw new Error("Unsupported rawBody type. rawBody must be one of 'Buffer' or 'string'");
-        }
-      } else {
-        body = await getRawBody(req, {
-          limit: MAXIMUM_MESSAGE_SIZE,
-          encoding: ct.parameters.charset ?? "utf-8",
-        });
-      }
+      body = rawOrParsedBody ?? await getRawBody(req, {
+        limit: MAXIMUM_MESSAGE_SIZE,
+        encoding: ct.parameters.charset ?? "utf-8",
+      });
     } catch (error) {
       res.writeHead(400).end(String(error));
       this.onerror?.(error as Error);
       return;
     }
 
     try {
-      await this.handleMessage(JSON.parse(body));
+      await this.handleMessage(typeof body === 'string'? JSON.parse(body): body);
     } catch {
       res.writeHead(400).end(`Invalid message: ${body}`);
       return;