README.md

@@ -2,7 +2,7 @@
 
 [![Go Reference](https://pkg.go.dev/badge/github.com/z5labs/humus.svg)](https://pkg.go.dev/github.com/z5labs/humus)
 [![Go Report Card](https://goreportcard.com/badge/github.com/z5labs/humus)](https://goreportcard.com/report/github.com/z5labs/humus)
-![Coverage](https://img.shields.io/badge/Coverage-71.5%25-brightgreen)
+![Coverage](https://img.shields.io/badge/Coverage-76.3%25-brightgreen)
 [![build](https://github.com/z5labs/humus/actions/workflows/build.yaml/badge.svg)](https://github.com/z5labs/humus/actions/workflows/build.yaml)
 
 **humus one stop shop framework for all Z5Labs projects in Go.**

rest/rpc/empty_example_test.go

@@ -53,6 +53,9 @@ func ExampleReturnNothing() {
 		fmt.Println("expected HTTP 200 status code but got", resp.StatusCode)
 		return
 	}
+	if resp.Header.Get("Content-Type") != "" {
+		return
+	}
 
 	// Output: hello world
 }
@@ -66,6 +69,7 @@ func (*msgResponse) Spec() (int, *openapi3.Response, error) {
 }
 
 func (mr *msgResponse) WriteResponse(ctx context.Context, w http.ResponseWriter) error {
+	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusOK)
 	enc := json.NewEncoder(w)
 	return enc.Encode(mr)
@@ -95,6 +99,12 @@ func ExampleConsumeNothing() {
 		return
 	}
 
+	contentType := resp.Header.Get("Content-Type")
+	if contentType != "application/json" {
+		fmt.Println("expected Content-Type to be set to application/json instead of:", contentType)
+		return
+	}
+
 	var mr msgResponse
 	dec := json.NewDecoder(resp.Body)
 	err = dec.Decode(&mr)

rest/rpc/json.go

@@ -0,0 +1,149 @@
+// Copyright (c) 2025 Z5Labs and Contributors
+//
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+package rpc
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+
+	"github.com/z5labs/humus/internal/ptr"
+	"github.com/z5labs/humus/internal/try"
+
+	"github.com/swaggest/jsonschema-go"
+	"github.com/swaggest/openapi-go/openapi3"
+	"go.opentelemetry.io/otel"
+)
+
+// ReturnJsonHandler
+type ReturnJsonHandler[Req, Resp any] struct {
+	inner Handler[Req, Resp]
+}
+
+// ReturnJson initializes a [ReturnJsonHandler].
+func ReturnJson[Req, Resp any](h Handler[Req, Resp]) *ReturnJsonHandler[Req, Resp] {
+	return &ReturnJsonHandler[Req, Resp]{
+		inner: h,
+	}
+}
+
+// JsonResponse
+type JsonResponse[T any] struct {
+	inner *T
+}
+
+// Spec implements the [TypedResponse] interface.
+func (*JsonResponse[T]) Spec() (int, *openapi3.Response, error) {
+	var t T
+	var reflector jsonschema.Reflector
+
+	jsonSchema, err := reflector.Reflect(t, jsonschema.InlineRefs)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	var schemaOrRef openapi3.SchemaOrRef
+	schemaOrRef.FromJSONSchema(jsonSchema.ToSchemaOrBool())
+
+	spec := &openapi3.Response{
+		Content: map[string]openapi3.MediaType{
+			"application/json": {
+				Schema: &schemaOrRef,
+			},
+		},
+	}
+	return http.StatusOK, spec, nil
+}
+
+// WriteResponse implements the [ResponseWriter] interface.
+func (jr *JsonResponse[T]) WriteResponse(ctx context.Context, w http.ResponseWriter) error {
+	_, span := otel.Tracer("rpc").Start(ctx, "JsonResponse.WriteResponse")
+	defer span.End()
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+
+	enc := json.NewEncoder(w)
+	return enc.Encode(jr.inner)
+}
+
+// Handle implements the [Handler] interface.
+func (h *ReturnJsonHandler[Req, Resp]) Handle(ctx context.Context, req *Req) (*JsonResponse[Resp], error) {
+	spanCtx, span := otel.Tracer("rpc").Start(ctx, "ReturnJsonHandler.Handle")
+	defer span.End()
+
+	resp, err := h.inner.Handle(spanCtx, req)
+	if err != nil {
+		return nil, err
+	}
+	return &JsonResponse[Resp]{inner: resp}, nil
+}
+
+// ConsumeJsonHandler
+type ConsumeJsonHandler[Req, Resp any] struct {
+	inner Handler[Req, Resp]
+}
+
+// ConsumeJson initializes a [ConsumeJsonHandler].
+func ConsumeJson[Req, Resp any](h Handler[Req, Resp]) *ConsumeJsonHandler[Req, Resp] {
+	return &ConsumeJsonHandler[Req, Resp]{
+		inner: h,
+	}
+}
+
+// JsonRequest
+type JsonRequest[T any] struct {
+	inner T
+}
+
+// Spec implements the [TypedRequest] interface.
+func (*JsonRequest[T]) Spec() (*openapi3.RequestBody, error) {
+	var t T
+	var reflector jsonschema.Reflector
+
+	jsonSchema, err := reflector.Reflect(t, jsonschema.InlineRefs)
+	if err != nil {
+		return nil, err
+	}
+
+	var schemaOrRef openapi3.SchemaOrRef
+	schemaOrRef.FromJSONSchema(jsonSchema.ToSchemaOrBool())
+
+	spec := &openapi3.RequestBody{
+		Required: ptr.Ref(true),
+		Content: map[string]openapi3.MediaType{
+			"application/json": {
+				Schema: &schemaOrRef,
+			},
+		},
+	}
+	return spec, nil
+}
+
+// ReadRequest implements the [RequestReader] interface.
+func (jr *JsonRequest[T]) ReadRequest(ctx context.Context, r *http.Request) (err error) {
+	_, span := otel.Tracer("rpc").Start(ctx, "JsonRequest.ReadRequest")
+	defer span.End()
+	defer try.Close(&err, r.Body)
+
+	contentType := r.Header.Get("Content-Type")
+	if contentType != "application/json" {
+		return InvalidContentTypeError{
+			ContentType: contentType,
+		}
+	}
+
+	dec := json.NewDecoder(r.Body)
+	return dec.Decode(&jr.inner)
+}
+
+// Handle implements the [Handler] interface.
+func (h *ConsumeJsonHandler[Req, Resp]) Handle(ctx context.Context, req *JsonRequest[Req]) (*Resp, error) {
+	spanCtx, span := otel.Tracer("rpc").Start(ctx, "ConsumeJsonHandler.Handle")
+	defer span.End()
+
+	return h.inner.Handle(spanCtx, &req.inner)
+}

rest/rpc/json_example_test.go

@@ -0,0 +1,86 @@
+// Copyright (c) 2025 Z5Labs and Contributors
+//
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+package rpc
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+)
+
+func ExampleReturnJson() {
+	p := ProducerFunc[msgResponse](func(_ context.Context) (*msgResponse, error) {
+		return &msgResponse{Msg: "hello world"}, nil
+	})
+
+	h := ReturnJson(ConsumeNothing(p))
+
+	op := NewOperation(h)
+
+	srv := httptest.NewServer(op)
+	defer srv.Close()
+
+	resp, err := http.Get(srv.URL)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		fmt.Println("expected HTTP 200 status code but got", resp.StatusCode)
+		return
+	}
+
+	contentType := resp.Header.Get("Content-Type")
+	if contentType != "application/json" {
+		fmt.Println("expected Content-Type to be set to application/json instead of:", contentType)
+		return
+	}
+
+	var mr msgResponse
+	dec := json.NewDecoder(resp.Body)
+	err = dec.Decode(&mr)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	fmt.Println(mr.Msg)
+	// Output: hello world
+}
+
+func ExampleConsumeJson() {
+	c := ConsumerFunc[msgRequest](func(_ context.Context, req *msgRequest) error {
+		fmt.Println(req.Msg)
+		return nil
+	})
+
+	h := ConsumeJson(ReturnNothing(c))
+
+	op := NewOperation(h)
+
+	srv := httptest.NewServer(op)
+	defer srv.Close()
+
+	resp, err := http.Post(srv.URL, "application/json", strings.NewReader(`{"msg":"hello world"}`))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	if resp.StatusCode != http.StatusOK {
+		fmt.Println("expected HTTP 200 status code but got", resp.StatusCode)
+		return
+	}
+	if resp.Header.Get("Content-Type") != "" {
+		return
+	}
+
+	// Output: hello world
+}