HTTP override fix (envoyproxy#240)

* HTTP override fix

* Code clean up and fix a test.

* Address code review comments.

* Code comment.

* Style formatting

contrib/endpoints/src/api_manager/check_auth_test.cc

@@ -348,6 +348,8 @@ class CheckAuthTest : public ::testing::Test {
           *apikey = "apikey";
           return true;
         }));
+    EXPECT_CALL(*raw_request_, FindHeader("X-HTTP-Method-Override", _))
+        .Times(1);
     EXPECT_CALL(*raw_request_, FindHeader("referer", _))
         .WillOnce(Invoke([](const std::string &, std::string *http_referer) {
           *http_referer = "";

contrib/endpoints/src/api_manager/check_service_control.cc

@@ -31,7 +31,7 @@ void CheckServiceControl(std::shared_ptr<context::RequestContext> context,
   // If the method is not configured from the service config.
   // or if not need to check service control, skip it.
   if (!context->method()) {
-    if (context->request()->GetRequestHTTPMethod() == "OPTIONS") {
+    if (context->GetRequestHTTPMethodWithOverride() == "OPTIONS") {
       TRACE(trace_span) << "OPTIONS request is rejected";
       continuation(Status(Code::PERMISSION_DENIED,
                           "The service does not allow CORS traffic.",

contrib/endpoints/src/api_manager/context/request_context.cc

@@ -31,6 +31,9 @@ namespace {
 // Cloud Trace Context Header
 const char kCloudTraceContextHeader[] = "X-Cloud-Trace-Context";
 
+// HTTP Method Override Header
+const char kHttpMethodOverrideHeader[] = "X-HTTP-Method-Override";
+
 // Log message prefix for a success method.
 const char kMessage[] = "Method: ";
 // Log message prefix for an ignored method.
@@ -87,7 +90,7 @@ RequestContext::RequestContext(std::shared_ptr<ServiceContext> service_context,
   start_time_ = std::chrono::system_clock::now();
   last_report_time_ = std::chrono::steady_clock::now();
   operation_id_ = GenerateUUID();
-  const std::string &method = request_->GetRequestHTTPMethod();
+  const std::string &method = GetRequestHTTPMethodWithOverride();
   const std::string &path = request_->GetUnparsedRequestPath();
   std::string query_params = request_->GetQueryParameters();
 
@@ -100,6 +103,7 @@ RequestContext::RequestContext(std::shared_ptr<ServiceContext> service_context,
   // 2) Store all the pieces needed for extracting variable bindings (such as
   //    http template variables, url path parts) in MethodCallInfo and extract
   //    variables lazily when needed.
+
   method_call_ =
       service_context_->GetMethodCallInfo(method, path, query_params);
 
@@ -126,6 +130,19 @@ RequestContext::RequestContext(std::shared_ptr<ServiceContext> service_context,
   }
 }
 
+std::string RequestContext::GetRequestHTTPMethodWithOverride() {
+  std::string method;
+
+  if (!request_->FindHeader(kHttpMethodOverrideHeader, &method)) {
+    method = request()->GetRequestHTTPMethod();
+  }
+
+  service_context()->env()->LogDebug(std::string("Request method SET TO: ") +
+                                     method);
+
+  return method;
+}
+
 void RequestContext::ExtractApiKey() {
   bool api_key_defined = false;
   auto url_queries = method()->api_key_url_query_parameters();
@@ -260,7 +277,7 @@ void RequestContext::FillReportRequestInfo(
   FillComputePlatform(info);
 
   info->url = request_->GetUnparsedRequestPath();
-  info->method = request_->GetRequestHTTPMethod();
+  info->method = GetRequestHTTPMethodWithOverride();
 
   info->protocol = request_->GetRequestProtocol();
   info->check_response_info = check_response_info_;

contrib/endpoints/src/api_manager/context/request_context.h

@@ -115,6 +115,12 @@ class RequestContext {
     last_report_time_ = tp;
   }
 
+  // Get the HTTP method to be used for the request. This method understands the
+  // X-Http-Method-Override header and if present, returns the
+  // X-Http-Method-Override method. Otherwise, the actual HTTP method is
+  // returned.
+  std::string GetRequestHTTPMethodWithOverride();
+
  private:
   // Fill OperationInfo
   void FillOperationInfo(service_control::OperationInfo *info);