sgcHTTP: HTTP Server, HTTP/2, gRPC & Google Cloud Components for Delphi & C++ Builder

TsgcHTTPServer turns your Delphi or C++ Builder application into an HTTP server. Set Port, handle OnCommandGet, set Active to true, and every request reaches your code with its request and response objects, while OnCommandOther covers verbs such as PUT and DELETE. Point DocumentRoot at a folder and the server returns static files from it. HTTPCompression compresses responses, KeepAlive reuses connections, SessionState with OnSessionStart and OnSessionEnd tracks sessions, MaxRequestBodySize caps request bodies and HTTPUploadFiles saves uploaded files to disk. For production, SSL and SSLOptions enable TLS, Authentication and OnAuthentication protect your endpoints, and ThreadPool and MaxConnections control how it scales. It is the same engine as the sgcWebSockets WebSocket server without the WebSocket part, and it ships with the bundled Core runtime.

TsgcHTTP2Client speaks HTTP/2 (RFC 9113): multiple requests share a single TCP connection as independent streams, so one slow response does not block the others behind it. Headers are compressed with HPACK, and the h2 protocol is negotiated during the TLS handshake through ALPN, the reason the component is built on sgcCustomIndy rather than the standard Indy library. Every verb is covered, Connect, Get, Post, Put, Patch, Delete and Options, each with a synchronous call and an Async twin. Events surface the connection lifecycle: OnHTTP2Connect, OnHTTP2Response, OnHTTP2ResponseFragment for chunked bodies, OnHTTP2PushPromise for server push, OnHTTP2GoAway and OnHTTP2Disconnect. HTTP2Options configures the local settings frame, and TLSOptions and Authentication carry over from the rest of the sgc HTTP stack.

TsgcGRPCClient is built on the HTTP/2 client, so it inherits the multiplexed connection and adds the gRPC wire format on top: length-prefixed Protocol Buffers messages over HTTP/2 streams. Call and CallAsync cover unary RPCs, ServerStreamingCall handles a stream of responses to one request, and OpenClientStream/SendStreamMessage/CloseClientStream plus OpenBidiStream/SendBidiMessage/CloseBidiStream cover client-streaming and bidirectional-streaming RPCs. OnGRPCResponse, OnGRPCStreamMessage and OnGRPCStreamEnd deliver the traffic, and RetryPolicy, Interceptors and ServiceConfig add retry behavior, cross-cutting logic and service configuration without touching the call sites. Like the HTTP/2 client it is built on, it needs sgcCustomIndy for ALPN.

Three more classes reach Google Cloud services over plain HTTPS, authenticated with a Google service account, and none of them need sgcCustomIndy. TsgcHTTPGoogleCloud_PubSub_Client publishes and pulls messages and manages topics, subscriptions and snapshots: Publish, Pull, Acknowledge, CreateTopic, CreateSubscription and the rest of the Pub/Sub REST surface. TsgcHTTPGoogleCloud_Calendar_Client wraps the Google Calendar API v3: NewCalendar, NewEvent, LoadEvents and LoadCalendars, with OnGetCalendar and OnGetCalendarEvent events for synchronization. TsgcHTTPGoogleCloud_FCM_Client sends a push notification payload to a Firebase project with one call, SendMessage. All three are code-only classes: create one, set GoogleCloudOptions, call the methods.