If we're receiving a response slowly and the user aborts, we need to note this and not record the truncated resource to cache.

Fixes #1081

Nginx side of the change: apache/incubator-pagespeed-ngx#966

Author: jeffkaufman

net/instaweb/apache/mod_instaweb.cc

@@ -818,7 +818,9 @@ apr_status_t instaweb_in_place_check_headers_filter(ap_filter_t* filter,
       // We now have the final headers.  If they don't let us cache then we'll
       // abort even though we've already buffered up the whole resource.
       InstawebHandler::AboutToBeDoneWithRecorder(request, recorder);
-      recorder->DoneAndSetHeaders(&response_headers);  // Deletes recorder.
+      // Deletes recorder
+      recorder->DoneAndSetHeaders(&response_headers,
+                                  !request->connection->aborted);
     }
   }
 

net/instaweb/system/in_place_resource_recorder.cc

@@ -208,7 +208,13 @@ void InPlaceResourceRecorder::DroppedDueToSize() {
 }
 
 void InPlaceResourceRecorder::DoneAndSetHeaders(
-    ResponseHeaders* response_headers) {
+    ResponseHeaders* response_headers, bool entire_response_received) {
+  if (!entire_response_received) {
+    // To record successfully, we must have a complete response.  Otherwise you
+    // get https://github.com/pagespeed/mod_pagespeed/issues/1081.
+    Fail();
+  }
+
   if (!failure_ && !full_response_headers_considered_) {
     ConsiderResponseHeaders(kFullHeaders, response_headers);
   }

net/instaweb/system/in_place_resource_recorder_test.cc

@@ -97,7 +97,8 @@ class InPlaceResourceRecorderTest : public RewriteTestBase {
     StringPiece gzipped(reinterpret_cast<const char*>(&kGzippedData[0]),
                         STATIC_STRLEN(kGzippedData));
     recorder->Write(gzipped, message_handler());
-    recorder.release()->DoneAndSetHeaders(&final_headers);
+    recorder.release()->DoneAndSetHeaders(
+        &final_headers, true /* complete response */);
 
     HTTPValue value_out;
     ResponseHeaders headers_out;
@@ -160,7 +161,8 @@ TEST_F(InPlaceResourceRecorderTest, BasicOperation) {
       InPlaceResourceRecorder::kPreliminaryHeaders, &prelim_headers);
   recorder->Write(kHello, message_handler());
   recorder->Write(kBye, message_handler());
-  recorder.release()->DoneAndSetHeaders(&ok_headers);
+  recorder.release()->DoneAndSetHeaders(
+      &ok_headers, true /* complete response */);
 
   HTTPValue value_out;
   ResponseHeaders headers_out;
@@ -171,6 +173,26 @@ TEST_F(InPlaceResourceRecorderTest, BasicOperation) {
   EXPECT_EQ(StrCat(kHello, kBye), contents);
 }
 
+TEST_F(InPlaceResourceRecorderTest, IncompleteResponse) {
+  ResponseHeaders prelim_headers;
+  prelim_headers.set_status_code(HttpStatus::kOK);
+
+  ResponseHeaders ok_headers;
+  SetDefaultLongCacheHeaders(&kContentTypeCss, &ok_headers);
+
+  scoped_ptr<InPlaceResourceRecorder> recorder(MakeRecorder(kTestUrl));
+  recorder->ConsiderResponseHeaders(
+      InPlaceResourceRecorder::kPreliminaryHeaders, &prelim_headers);
+  recorder->Write(kHello, message_handler());
+  recorder.release()->DoneAndSetHeaders(
+      &ok_headers, false /* incomplete response */);
+
+  HTTPValue value_out;
+  ResponseHeaders headers_out;
+  EXPECT_EQ(HTTPCache::kNotFound,
+            HttpBlockingFind(kTestUrl, http_cache(), &value_out, &headers_out));
+}
+
 TEST_F(InPlaceResourceRecorderTest, CheckCacheableContentTypes) {
   CheckCacheableContentType(&kContentTypeJpeg);
   CheckCacheableContentType(&kContentTypeCss);
@@ -192,7 +214,8 @@ TEST_F(InPlaceResourceRecorderTest, BasicOperationFullHeaders) {
       InPlaceResourceRecorder::kFullHeaders, &ok_headers);
   recorder->Write(kHello, message_handler());
   recorder->Write(kBye, message_handler());
-  recorder.release()->DoneAndSetHeaders(&ok_headers);
+  recorder.release()->DoneAndSetHeaders(
+      &ok_headers, true /* complete response */);
 
   HTTPValue value_out;
   ResponseHeaders headers_out;
@@ -216,7 +239,8 @@ TEST_F(InPlaceResourceRecorderTest, DontRemember304) {
   scoped_ptr<InPlaceResourceRecorder> recorder(MakeRecorder(kTestUrl));
   recorder->ConsiderResponseHeaders(
       InPlaceResourceRecorder::kPreliminaryHeaders, &prelim_headers);
-  recorder.release()->DoneAndSetHeaders(&not_modified_headers);
+  recorder.release()->DoneAndSetHeaders(
+      &not_modified_headers, true /* complete response */);
 
   HTTPValue value_out;
   ResponseHeaders headers_out;
@@ -237,7 +261,8 @@ TEST_F(InPlaceResourceRecorderTest, Remember500AsFetchFailed) {
   scoped_ptr<InPlaceResourceRecorder> recorder(MakeRecorder(kTestUrl));
   recorder->ConsiderResponseHeaders(
       InPlaceResourceRecorder::kPreliminaryHeaders, &prelim_headers);
-  recorder.release()->DoneAndSetHeaders(&error_headers);
+  recorder.release()->DoneAndSetHeaders(
+      &error_headers, true /* complete response */);
 
   HTTPValue value_out;
   ResponseHeaders headers_out;
@@ -252,7 +277,8 @@ TEST_F(InPlaceResourceRecorderTest, RememberEmpty) {
 
   scoped_ptr<InPlaceResourceRecorder> recorder(MakeRecorder(kTestUrl));
   // No contents written.
-  recorder.release()->DoneAndSetHeaders(&ok_headers);
+  recorder.release()->DoneAndSetHeaders(
+      &ok_headers, true /* complete response */);
 
   HTTPValue value_out;
   ResponseHeaders headers_out;

net/instaweb/system/public/in_place_resource_recorder.h

@@ -109,10 +109,16 @@ class InPlaceResourceRecorder : public Writer {
   // Because of Apache's quirky filter order, we cannot get both the
   // uncompressed final contents and the complete headers at the same time.
   //
+  // Set entire_response_received to true if you know that the response data fed
+  // into Write() is complete.  For example, if the browser cancelled the
+  // download and so this is a partial response, set entire_response_received to
+  // false so we know not to cache it.
+  //
   // Does not take ownership of response_headers.
   //
   // Deletes itself. Do not use object after calling DoneAndSetHeaders().
-  void DoneAndSetHeaders(ResponseHeaders* response_headers);
+  void DoneAndSetHeaders(ResponseHeaders* response_headers,
+                         bool entire_response_received);
 
   const GoogleString& url() const { return url_; }
   MessageHandler* handler() { return handler_; }