fix: fix bug with customheadersoption, added and integrated CustomHeaders class

Author: eliekozah

google/cloud/storage/internal/generic_request.h

@@ -317,12 +317,12 @@ class GenericRequestBase<Derived, OverrideDefaultProject, Options...>
  */
 template <typename Derived, typename... Options>
 class GenericRequest
-    : public GenericRequestBase<Derived, CustomHeader, Fields, IfMatchEtag,
+    : public GenericRequestBase<Derived, CustomHeader, CustomHeaders, Fields, IfMatchEtag,
                                 IfNoneMatchEtag, QuotaUser, UserIp,
                                 Options...> {
  public:
   using Super =
-      GenericRequestBase<Derived, CustomHeader, Fields, IfMatchEtag,
+      GenericRequestBase<Derived, CustomHeader, CustomHeaders, Fields, IfMatchEtag,
                          IfNoneMatchEtag, QuotaUser, UserIp, Options...>;
 
   template <typename H, typename... T>

google/cloud/storage/internal/rest/request_builder.cc

@@ -32,6 +32,15 @@ RestRequestBuilder& RestRequestBuilder::AddOption(CustomHeader const& p) {
   return *this;
 }
 
+RestRequestBuilder& RestRequestBuilder::AddOption(CustomHeaders const& p) {
+  if (!p.headers().empty()) {
+    for (const auto& header : p.headers()) {
+      request_.AddHeader(header.first, header.second);
+    }
+  }
+  return *this;
+}
+
 RestRequestBuilder& RestRequestBuilder::AddOption(EncryptionKey const& p) {
   if (p.has_value()) {
     request_.AddHeader(std::string(EncryptionKey::prefix()) + "algorithm",

google/cloud/storage/internal/rest/request_builder.h

@@ -95,6 +95,9 @@ class RestRequestBuilder {
   /// Adds a custom header to the request.
   RestRequestBuilder& AddOption(CustomHeader const& p);
 
+  /// Adds custom headers to the request.
+  RestRequestBuilder& AddOption(CustomHeaders const& p);
+
   /// Adds one of the well-known encryption header groups to the request.
   RestRequestBuilder& AddOption(EncryptionKey const& p);
 

google/cloud/storage/tests/CMakeLists.txt

@@ -16,6 +16,7 @@
 
 set(storage_client_integration_tests
     # cmake-format : sort
+    elie_test.cc
     async_client_integration_test.cc
     auto_finalize_integration_test.cc
     bucket_integration_test.cc

google/cloud/storage/tests/storage_client_integration_tests.bzl

@@ -26,6 +26,7 @@ storage_client_integration_tests = [
     "curl_sign_blob_integration_test.cc",
     "decompressive_transcoding_integration_test.cc",
     "default_object_acl_integration_test.cc",
+    "elie_test.cc",
     "error_injection_integration_test.cc",
     "error_parsing_integration_test.cc",
     "grpc_bucket_metadata_integration_test.cc",

google/cloud/storage/well_known_headers.cc

@@ -31,6 +31,16 @@ std::ostream& operator<<(std::ostream& os, CustomHeader const& rhs) {
   return os << rhs.custom_header_name() << ": " << rhs.value();
 }
 
+std::ostream& operator<<(std::ostream& os, const CustomHeaders& rhs) {
+  if (rhs.headers().empty()) {
+    return os;
+  }
+  for (const auto& header : rhs.headers()) {
+      os << header.first << ": " << header.second << "\n";
+  }
+  return os;
+}
+
 EncryptionKeyData EncryptionDataFromBinaryKey(std::string const& key) {
   return EncryptionKeyData{
       "AES256", internal::Base64Encode(key),

google/cloud/storage/well_known_headers.h

@@ -98,6 +98,34 @@ class CustomHeader
 
 std::ostream& operator<<(std::ostream& os, CustomHeader const& rhs);
 
+/**
+ * An option to inject multiplecustom headers at once into the request.
+ *
+ * In some cases it is necessary to inject custom headers into the request. For
+ * example, because the protocol has added new headers and the library has not
+ * been updated to support them, or because
+ */
+class CustomHeaders    
+    : public internal::WellKnownHeader<CustomHeaders, std::string> {
+  public:
+      using Type = std::unordered_multimap<std::string, std::string>;
+  
+      CustomHeaders() = default;
+      CustomHeaders(std::initializer_list<Type::value_type> headers) 
+      : headers_(std::move(headers)) {}
+  
+      void add(const std::string& name, const std::string& value) {
+          headers_.insert({name, value});
+      }
+  
+      const Type& headers() const { return headers_; }
+  
+  private:
+      Type headers_;
+  };
+
+  std::ostream& operator<<(std::ostream& os, const CustomHeaders& rhs);
+
 /**
  * A pre-condition: apply this operation only if the HTTP Entity Tag matches.
  *