HttpClient support for pluggable back-ends (#532)

refactored HttpClient to separate out cpr implementation into separate classes, with an abstract base class to allow plugging in multiple implementations in the future

1 files changed, 147 insertions, 0 deletions

diff --git a/src/zenhttp/clients/httpclientcommon.h b/src/zenhttp/clients/httpclientcommon.h
new file mode 100644
index 000000000..9060cde48
--- /dev/null
+++ b/src/zenhttp/clients/httpclientcommon.h
@@ -0,0 +1,147 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zencore/compositebuffer.h>
+#include <zencore/trace.h>
+
+#include <zenhttp/httpclient.h>
+
+namespace zen {
+
+using namespace std::literals;
+
+class HttpClientBase
+{
+public:
+	HttpClientBase(std::string_view BaseUri, const HttpClientSettings& Connectionsettings = {});
+	virtual ~HttpClientBase() = 0;
+
+	using Response	  = HttpClient::Response;
+	using KeyValueMap = HttpClient::KeyValueMap;
+
+	[[nodiscard]] virtual Response Put(std::string_view Url, const IoBuffer& Payload, const KeyValueMap& AdditionalHeader = {})	   = 0;
+	[[nodiscard]] virtual Response Put(std::string_view Url, const KeyValueMap& Parameters = {})								   = 0;
+	[[nodiscard]] virtual Response Get(std::string_view	  Url,
+									   const KeyValueMap& AdditionalHeader = {},
+									   const KeyValueMap& Parameters	   = {})														   = 0;
+	[[nodiscard]] virtual Response Head(std::string_view Url, const KeyValueMap& AdditionalHeader = {})							   = 0;
+	[[nodiscard]] virtual Response Delete(std::string_view Url, const KeyValueMap& AdditionalHeader = {})						   = 0;
+	[[nodiscard]] virtual Response Post(std::string_view   Url,
+										const KeyValueMap& AdditionalHeader = {},
+										const KeyValueMap& Parameters		= {})														   = 0;
+	[[nodiscard]] virtual Response Post(std::string_view Url, const IoBuffer& Payload, const KeyValueMap& AdditionalHeader = {})   = 0;
+	[[nodiscard]] virtual Response Post(std::string_view   Url,
+										const IoBuffer&	   Payload,
+										ZenContentType	   ContentType,
+										const KeyValueMap& AdditionalHeader = {})												   = 0;
+	[[nodiscard]] virtual Response Post(std::string_view Url, CbObject Payload, const KeyValueMap& AdditionalHeader = {})		   = 0;
+	[[nodiscard]] virtual Response Post(std::string_view Url, CbPackage Payload, const KeyValueMap& AdditionalHeader = {})		   = 0;
+	[[nodiscard]] virtual Response Post(std::string_view	   Url,
+										const CompositeBuffer& Payload,
+										ZenContentType		   ContentType,
+										const KeyValueMap&	   AdditionalHeader = {})												   = 0;
+	[[nodiscard]] virtual Response Upload(std::string_view Url, const IoBuffer& Payload, const KeyValueMap& AdditionalHeader = {}) = 0;
+	[[nodiscard]] virtual Response Upload(std::string_view		 Url,
+										  const CompositeBuffer& Payload,
+										  ZenContentType		 ContentType,
+										  const KeyValueMap&	 AdditionalHeader = {})												   = 0;
+
+	[[nodiscard]] virtual Response Download(std::string_view			 Url,
+											const std::filesystem::path& TempFolderPath,
+											const KeyValueMap&			 AdditionalHeader = {}) = 0;
+
+	[[nodiscard]] virtual Response TransactPackage(std::string_view Url, CbPackage Package, const KeyValueMap& AdditionalHeader = {}) = 0;
+
+	LoggerRef		 Log() { return m_Log; }
+	std::string_view GetBaseUri() const { return m_BaseUri; }
+	std::string_view GetSessionId() const { return m_SessionId; }
+
+	bool Authenticate();
+
+protected:
+	LoggerRef				 m_Log;
+	std::string				 m_BaseUri;
+	std::string				 m_SessionId;
+	const HttpClientSettings m_ConnectionSettings;
+
+	const std::optional<HttpClientAccessToken> GetAccessToken();
+
+	RwLock				  m_AccessTokenLock;
+	HttpClientAccessToken m_CachedAccessToken;
+};
+
+namespace detail {
+
+	class TempPayloadFile
+	{
+	public:
+		TempPayloadFile(const TempPayloadFile&) = delete;
+		TempPayloadFile& operator=(const TempPayloadFile&) = delete;
+
+		TempPayloadFile();
+		~TempPayloadFile();
+
+		std::error_code Open(const std::filesystem::path& TempFolderPath, uint64_t FinalSize);
+		std::error_code Write(std::string_view DataString);
+		IoBuffer		DetachToIoBuffer();
+		IoBuffer		BorrowIoBuffer();
+		inline uint64_t GetSize() const { return m_WriteOffset; }
+		void			ResetWritePos(uint64_t WriteOffset);
+
+	private:
+		std::error_code Flush();
+		std::error_code AppendData(const void* Data, uint64_t Size);
+
+		void*					  m_FileHandle;
+		std::uint64_t			  m_WriteOffset;
+		static constexpr uint64_t CacheBufferSize = 512u * 1024u;
+		uint8_t					  m_CacheBuffer[CacheBufferSize];
+		std::uint64_t			  m_CacheBufferOffset = 0;
+	};
+
+	class BufferedReadFileStream
+	{
+	public:
+		BufferedReadFileStream(const BufferedReadFileStream&) = delete;
+		BufferedReadFileStream& operator=(const BufferedReadFileStream&) = delete;
+
+		BufferedReadFileStream(void* FileHandle, uint64_t FileOffset, uint64_t FileSize, uint64_t BufferSize);
+		~BufferedReadFileStream();
+
+		void Read(void* Data, uint64_t Size);
+
+	private:
+		void Read(void* Data, uint64_t BytesToRead, uint64_t FileOffset);
+
+		void*		   m_FileHandle	 = nullptr;
+		const uint64_t m_FileSize	 = 0;
+		const uint64_t m_FileEnd	 = 0;
+		uint64_t	   m_BufferSize	 = 0;
+		uint8_t*	   m_Buffer		 = nullptr;
+		uint64_t	   m_BufferStart = 0;
+		uint64_t	   m_BufferEnd	 = 0;
+		uint64_t	   m_FileOffset	 = 0;
+	};
+
+	class CompositeBufferReadStream
+	{
+	public:
+		CompositeBufferReadStream(const CompositeBufferReadStream&) = delete;
+		CompositeBufferReadStream& operator=(const CompositeBufferReadStream&) = delete;
+
+		CompositeBufferReadStream(const CompositeBuffer& Data, uint64_t BufferSize);
+		uint64_t Read(void* Data, uint64_t Size);
+
+	private:
+		const CompositeBuffer&					m_Data;
+		const uint64_t							m_BufferSize;
+		size_t									m_SegmentIndex;
+		std::unique_ptr<BufferedReadFileStream> m_SegmentDiskBuffer;
+		MemoryView								m_SegmentMemoryBuffer;
+		uint64_t								m_BytesLeftInSegment;
+	};
+
+}  // namespace detail
+
+}  // namespace zen