Sebuf

Quick Task 260416-eht: Implement SSE Streaming Support

What Was Done#

Added Server-Sent Events (SSE) streaming support across all 5 sebuf protoc generators, enabling real-time streaming HTTP APIs from protobuf definitions.

Changes#

  1. Proto annotation (proto/sebuf/http/annotations.proto): Added bool stream = 3 to HttpConfig message, regenerated Go proto code
  2. Shared annotations (internal/annotations/http_config.go): Added Stream bool field to HTTPConfig struct, populated from proto
  3. Go HTTP server (internal/httpgen/generator.go): Added SSESender interface, sseSender struct, and SSEHandler[Req] generic handler with text/event-stream headers, http.Flusher support, and request binding (path params, query params, body, validation)
  4. Go HTTP client (internal/clientgen/generator.go): Added EventStream[T] generic type with Next(T) bool / Err() / Close() following bufio.Scanner pattern, and SSE-specific method generation
  5. TS client (internal/tsclientgen/generator.go): Added async *method() returning AsyncGenerator<T> with ReadableStream SSE parsing
  6. TS server (internal/tsservergen/generator.go): Added SSE route generation where handler returns ReadableStream<T>, route wraps into SSE-formatted Response
  7. OpenAPI (internal/openapiv3/generator.go): Added text/event-stream content type with x-sse-event-schema vendor extension for SSE operations

Test Coverage#

  • SSE test proto covers: standard unary RPC + SSE streaming + SSE with path params + SSE with query params (all in same service)
  • Golden tests pass for all 5 generators (14 test cases each for tsclientgen/tsservergen, 9+ for others)
  • Non-SSE methods verified unchanged across all generators
  • All 8 test packages pass, 0 lint issues

Outcome#

SSE streaming is now a first-class feature in sebuf. Users can annotate RPCs with stream: true on sebuf.http.config to generate streaming endpoints across all supported languages and documentation formats.