feat(api): expose transport config snapshot

Co-Authored-By: Virgil <virgil@lethean.io>

spec_builder_helper.go

@@ -4,7 +4,6 @@ package api
 
 import (
 	"slices"
-	"strings"
 )
 
 // OpenAPISpecBuilder returns a SpecBuilder populated from the engine's current
@@ -18,6 +17,7 @@ func (e *Engine) OpenAPISpecBuilder() *SpecBuilder {
 		return &SpecBuilder{}
 	}
 
+	transport := e.TransportConfig()
 	builder := &SpecBuilder{
 		Title:                   e.swaggerTitle,
 		Description:             e.swaggerDesc,
@@ -33,22 +33,13 @@ func (e *Engine) OpenAPISpecBuilder() *SpecBuilder {
 		ExternalDocsURL:         e.swaggerExternalDocsURL,
 	}
 
-	if e.swaggerEnabled || strings.TrimSpace(e.swaggerPath) != "" {
-		builder.SwaggerPath = resolveSwaggerPath(e.swaggerPath)
-	}
-
-	if e.graphql != nil {
-		builder.GraphQLPath = e.graphql.path
-		builder.GraphQLPlayground = e.graphql.playground
-	}
-	if e.wsHandler != nil || strings.TrimSpace(e.wsPath) != "" {
-		builder.WSPath = resolveWSPath(e.wsPath)
-	}
-	if e.sseBroker != nil || strings.TrimSpace(e.ssePath) != "" {
-		builder.SSEPath = resolveSSEPath(e.ssePath)
-	}
-	builder.PprofEnabled = e.pprofEnabled
-	builder.ExpvarEnabled = e.expvarEnabled
+	builder.SwaggerPath = transport.SwaggerPath
+	builder.GraphQLPath = transport.GraphQLPath
+	builder.GraphQLPlayground = transport.GraphQLPlayground
+	builder.WSPath = transport.WSPath
+	builder.SSEPath = transport.SSEPath
+	builder.PprofEnabled = transport.PprofEnabled
+	builder.ExpvarEnabled = transport.ExpvarEnabled
 
 	return builder
 }

spec_builder_helper_test.go

@@ -149,6 +149,49 @@ func TestEngine_Good_OpenAPISpecBuilderCarriesEngineMetadata(t *testing.T) {
 	}
 }
 
+func TestEngine_Good_TransportConfigCarriesEngineMetadata(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	broker := api.NewSSEBroker()
+	e, err := api.New(
+		api.WithSwagger("Engine API", "Engine metadata", "2.0.0"),
+		api.WithSwaggerPath("/docs"),
+		api.WithWSPath("/socket"),
+		api.WithWSHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {})),
+		api.WithGraphQL(newTestSchema(), api.WithPlayground(), api.WithGraphQLPath("/gql")),
+		api.WithSSE(broker),
+		api.WithSSEPath("/events"),
+		api.WithPprof(),
+		api.WithExpvar(),
+	)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	cfg := e.TransportConfig()
+	if cfg.SwaggerPath != "/docs" {
+		t.Fatalf("expected swagger path /docs, got %q", cfg.SwaggerPath)
+	}
+	if cfg.GraphQLPath != "/gql" {
+		t.Fatalf("expected graphql path /gql, got %q", cfg.GraphQLPath)
+	}
+	if !cfg.GraphQLPlayground {
+		t.Fatal("expected GraphQL playground to be enabled")
+	}
+	if cfg.WSPath != "/socket" {
+		t.Fatalf("expected ws path /socket, got %q", cfg.WSPath)
+	}
+	if cfg.SSEPath != "/events" {
+		t.Fatalf("expected sse path /events, got %q", cfg.SSEPath)
+	}
+	if !cfg.PprofEnabled {
+		t.Fatal("expected pprof to be enabled")
+	}
+	if !cfg.ExpvarEnabled {
+		t.Fatal("expected expvar to be enabled")
+	}
+}
+
 func TestEngine_Good_OpenAPISpecBuilderExportsDefaultSwaggerPath(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 

transport.go

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: EUPL-1.2
+
+package api
+
+import "strings"
+
+// TransportConfig captures the configured transport endpoints and flags for an Engine.
+//
+// It is intentionally small and serialisable so callers can inspect the active HTTP
+// surface without rebuilding an OpenAPI document.
+type TransportConfig struct {
+	SwaggerPath       string
+	GraphQLPath       string
+	GraphQLPlayground bool
+	WSPath            string
+	SSEPath           string
+	PprofEnabled      bool
+	ExpvarEnabled     bool
+}
+
+// TransportConfig returns the currently configured transport metadata for the engine.
+//
+// The result snapshots the Engine state at call time and normalises any configured
+// URL paths using the same rules as the runtime handlers.
+func (e *Engine) TransportConfig() TransportConfig {
+	if e == nil {
+		return TransportConfig{}
+	}
+
+	cfg := TransportConfig{
+		GraphQLPlayground: e.graphql != nil && e.graphql.playground,
+		PprofEnabled:      e.pprofEnabled,
+		ExpvarEnabled:     e.expvarEnabled,
+	}
+
+	if e.swaggerEnabled || strings.TrimSpace(e.swaggerPath) != "" {
+		cfg.SwaggerPath = resolveSwaggerPath(e.swaggerPath)
+	}
+	if e.graphql != nil {
+		cfg.GraphQLPath = e.graphql.path
+	}
+	if e.wsHandler != nil || strings.TrimSpace(e.wsPath) != "" {
+		cfg.WSPath = resolveWSPath(e.wsPath)
+	}
+	if e.sseBroker != nil || strings.TrimSpace(e.ssePath) != "" {
+		cfg.SSEPath = resolveSSEPath(e.ssePath)
+	}
+
+	return cfg
+}