Merge pull request #206 from stackia/patch-2

fix(response-stream): fix response with no content doesn't correctly end the writable stream
H4ad · Feb 29, 2024 · 115628a · 115628a
2 parents 250221f + bded8cf
commit 115628a
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Showing 2 changed files with 9 additions and 14 deletions.
diff --git a/src/handlers/aws/aws-stream.handler.ts b/src/handlers/aws/aws-stream.handler.ts
@@ -296,19 +296,9 @@ export class AwsStreamHandler<TApp> extends BaseHandler<
           awsMetadata,
         );
 
-        // some status do not return body, and
-        // for some unknown reason, we cannot finish the stream without writing at least once
-        // so I have this thing just to fix this issue
-        // ref: https://stackoverflow.com/a/37303151
-        const isHundreadStatus = status >= 100 && status < 200;
-        const isNoContentStatus = status === 304 || status === 204;
-        const isHeadRequest = requestValues.method === 'HEAD';
-
-        if (isHundreadStatus || isNoContentStatus || isHeadRequest) {
-          finalResponse.write('');
-          // end the response to avoid waiting for nothing
-          response.end();
-        }
+        // We must call write with an empty string to trigger the awsMetadata to be sent
+        // https://github.com/aws/aws-lambda-nodejs-runtime-interface-client/blob/2ce88619fd176a5823bc5f38c5484d1cbdf95717/src/HttpResponseStream.js#L22
+        finalResponse.write('');
 
         return finalResponse;
       },

diff --git a/src/network/response-stream.ts b/src/network/response-stream.ts
@@ -106,10 +106,11 @@ export class ServerlessStreamResponse extends ServerResponse {
           const stringData = getString(data);
           const endStatusIndex = stringData.indexOf(endStatusSeparator);
           const status = +stringData.slice(0, endStatusIndex).split(' ')[1];
+          const endHeaderIndex = stringData.indexOf(headerEnd);
 
           const headerData = stringData.slice(
             endStatusIndex + 2,
-            stringData.indexOf(headerEnd),
+            endHeaderIndex,
           );
           const headers = parseHeaders(headerData);
           log.debug('SERVERLESS_ADAPTER:RESPONSE_STREAM:FRAMEWORK_HEADERS', {
@@ -118,6 +119,10 @@ export class ServerlessStreamResponse extends ServerResponse {
 
           writesToIgnore = 1;
           internalWritable = onReceiveHeaders(status, headers);
+
+          // If we get an endChunked right after header which means the response body is empty, we need to immediately end the writable
+          if (stringData.substring(endHeaderIndex + 4) === endChunked)
+            internalWritable.end();
         }
 
         return true;