Streaming

examples/streaming/README.md

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+OpenAPI Code Generation Example - Streaming
+-------------------------------------------
+
+This directory contains an example server using our code generator which implements
+a simple streaming API with a single endpoint.
+
+This is the structure:
+- `sse.yaml`: Contains the OpenAPI 3.0 specification
+- `stdhttp/`: Contains the written and generated code for the server using the standard http package
+

examples/streaming/sse.yaml

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+openapi: 3.0.0
+info:
+  title: Simple SSE Service
+  version: 1.0.0
+paths:
+  /:
+    get:
+      summary: Server-Sent Events Stream
+      description: Provides a stream of JSON documents containing a timestamp and sequence number.
+      operationId: getStream
+      responses:
+        200:
+          description: SSE Stream
+          content:
+            text/event-stream:
+              schema:
+                type: object
+                properties:
+                  time:
+                    type: string
+                    format: date-time
+                    description: Timestamp of the event.
+                  sequence:
+                    type: integer
+                    description: Sequence number of the event.
+              example:
+                time: "2023-11-20T10:30:00Z"
+                sequence: 1

examples/streaming/stdhttp/Makefile

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+SHELL:=/bin/bash
+
+YELLOW := \e[0;33m
+RESET := \e[0;0m
+
+GOVER := $(shell go env GOVERSION)
+GOMINOR := $(shell bash -c "cut -f2 -d. <<< $(GOVER)")
+
+define execute-if-go-122
+@{ \
+if [[ 22 -le $(GOMINOR) ]]; then \
+	$1; \
+else \
+	echo -e "$(YELLOW)Skipping task as you're running Go v1.$(GOMINOR).x which is < Go 1.22, which this module requires$(RESET)"; \
+fi \
+}
+endef
+
+lint:
+	$(call execute-if-go-122,$(GOBIN)/golangci-lint run ./...)
+
+lint-ci:
+
+	$(call execute-if-go-122,$(GOBIN)/golangci-lint run ./... --out-format=colored-line-number --timeout=5m)
+
+generate:
+	$(call execute-if-go-122,go generate ./...)
+
+test:
+	$(call execute-if-go-122,go test -cover ./...)
+
+tidy:
+	$(call execute-if-go-122,go mod tidy)
+
+tidy-ci:
+	$(call execute-if-go-122,tidied -verbose)

examples/streaming/stdhttp/go.mod

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+module github.com/oapi-codegen/oapi-codegen/v2/examples/streaming/stdhttp
+
+go 1.21.13
+
+replace github.com/oapi-codegen/oapi-codegen/v2 => ../../../
+
+require (
+	github.com/getkin/kin-openapi v0.127.0
+	github.com/oapi-codegen/oapi-codegen/v2 v2.0.0-00010101000000-000000000000
+	github.com/oapi-codegen/runtime v1.1.1
+)
+
+require (
+	github.com/dprotaso/go-yit v0.0.0-20220510233725-9ba8df137936 // indirect
+	github.com/go-openapi/jsonpointer v0.21.0 // indirect
+	github.com/go-openapi/swag v0.23.0 // indirect
+	github.com/invopop/yaml v0.3.1 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/mohae/deepcopy v0.0.0-20170929034955-c48cc78d4826 // indirect
+	github.com/perimeterx/marshmallow v1.1.5 // indirect
+	github.com/speakeasy-api/openapi-overlay v0.9.0 // indirect
+	github.com/vmware-labs/yaml-jsonpath v0.3.2 // indirect
+	golang.org/x/mod v0.17.0 // indirect
+	golang.org/x/text v0.18.0 // indirect
+	golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

examples/streaming/stdhttp/main.go

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+package main
+
+import (
+	"context"
+	"github.com/oapi-codegen/oapi-codegen/v2/examples/streaming/stdhttp/sse"
+	"log/slog"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+func main() {
+	server := sse.NewServer()
+	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer cancel()
+	err := server.Run(ctx)
+	if err != nil {
+		slog.Error("server run failed", "error:", err)
+		os.Exit(1)
+	}
+}

examples/streaming/stdhttp/sse/cfg.yaml

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+# yaml-language-server: $schema=../../../../configuration-schema.json
+package: sse
+output: streaming.gen.go
+generate:
+  std-http-server: true
+  strict-server: true
+  models: true
+  embedded-spec: true

examples/streaming/stdhttp/sse/generate.go

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+package sse
+
+//go:generate go run github.com/oapi-codegen/oapi-codegen/v2/cmd/oapi-codegen -config cfg.yaml ../../sse.yaml

examples/streaming/stdhttp/sse/impl.go

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+package sse
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"time"
+)
+
+type Server struct {
+	httpServer *http.Server
+}
+
+func NewServer() *Server {
+	s := &Server{}
+	strictHandler := NewStrictHandler(s, nil)
+	handler := Handler(strictHandler)
+	s.httpServer = &http.Server{
+		Handler: handler,
+		Addr:    ":8080",
+	}
+	return s
+}
+func (s Server) Run(ctx context.Context) error {
+	go func() {
+		<-ctx.Done()
+		slog.Warn("context cancelled, shutting down")
+		ctxTimeout, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		err := s.httpServer.Shutdown(ctxTimeout)
+		cancel()
+		if err != nil {
+			slog.Error("httpServer.Shutdown() error", "error", err)
+		}
+	}()
+
+	err := s.httpServer.ListenAndServe()
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
+		return fmt.Errorf("httpServer.ListenAndServe() error: %w", err)
+	}
+	return nil
+}
+
+type SObject struct {
+	Time     time.Time `json:"time"`
+	Sequence int       `json:"sequence"`
+}
+
+// GetStream handles GET / and will stream a JSON object every second.
+func (Server) GetStream(ctx context.Context, _ GetStreamRequestObject) (GetStreamResponseObject, error) {
+	r, w := io.Pipe() // creates a pipe so that we can write to the response body asynchronously
+	go func() {
+		defer w.Close()
+		seq := 1
+		ticker := time.NewTicker(time.Second)
+		for {
+			select {
+			case <-ctx.Done():
+				slog.Info("request context done, closing stream")
+				return
+			case <-ticker.C:
+				content := getContent(seq)
+				if _, err := w.Write(content); err != nil {
+					return
+				}
+				if _, err := w.Write([]byte("\n")); err != nil {
+					return
+				}
+				seq++
+			}
+		}
+	}()
+	return GetStream200TexteventStreamResponse{
+		Body:          r,
+		ContentLength: 0,
+	}, nil
+}
+
+func getContent(seq int) []byte {
+	streamObject := SObject{
+		Time:     time.Now(),
+		Sequence: seq,
+	}
+	bytes, _ := json.Marshal(streamObject)
+	return bytes
+}