Fix handling of request input that can accept form or json

_examples/advanced-generic-openapi31/_testdata/openapi.json

@@ -161,6 +161,33 @@
     "x-forbid-unknown-query":true
    }
   },
+  "/form-or-json/{path}":{
+   "parameters":[
+    {
+     "name":"X-Umbrella-Header","in":"header","description":"This request header is supported in all operations.",
+     "schema":{"type":"string"}
+    }
+   ],
+   "post":{
+    "tags":["Request"],"summary":"Form Or JSON",
+    "description":"This endpoint can accept both form and json requests with the same input structure.",
+    "operationId":"_examples/advanced-generic-openapi31.formOrJSON",
+    "parameters":[{"name":"path","in":"path","required":true,"schema":{"type":"string"}}],
+    "requestBody":{
+     "content":{
+      "application/json":{"schema":{"$ref":"#/components/schemas/AdvancedFormOrJSONInput"}},
+      "application/x-www-form-urlencoded":{"schema":{"$ref":"#/components/schemas/FormDataAdvancedFormOrJSONInput"}}
+     }
+    },
+    "responses":{
+     "200":{
+      "description":"OK",
+      "content":{"application/json":{"schema":{"$ref":"#/components/schemas/AdvancedFormOrJSONOutput"}}}
+     }
+    },
+    "x-forbid-unknown-path":true
+   }
+  },
   "/gzip-pass-through":{
    "parameters":[
     {
@@ -771,6 +798,11 @@
     "properties":{"bar":{"minLength":3,"type":"string"},"baz":{"minLength":3,"type":["null","string"]}},
     "type":"object"
    },
+   "AdvancedFormOrJSONInput":{
+    "additionalProperties":false,"properties":{"field1":{"type":"string"},"field2":{"type":"integer"}},
+    "required":["field1","field2"],"type":"object"
+   },
+   "AdvancedFormOrJSONOutput":{"properties":{"f1":{"type":"string"},"f2":{"type":"integer"},"f3":{"type":"string"}},"type":"object"},
    "AdvancedGzipPassThroughStruct":{
     "properties":{"id":{"type":"integer"},"text":{"items":{"type":"string"},"type":["array","null"]}},
     "type":"object"
@@ -905,6 +937,10 @@
     "type":"object"
    },
    "FormDataAdvancedForm":{"additionalProperties":false,"properties":{"id":{"type":"integer"},"name":{"type":"string"}},"type":"object"},
+   "FormDataAdvancedFormOrJSONInput":{
+    "additionalProperties":false,"properties":{"field1":{"type":"string"},"field2":{"type":"integer"}},
+    "required":["field1","field2"],"type":"object"
+   },
    "FormDataAdvancedUpload":{
     "additionalProperties":false,
     "properties":{

_examples/advanced-generic-openapi31/form_or_json.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"context"
+
+	"github.com/swaggest/usecase"
+)
+
+type formOrJSONInput struct {
+	Field1 string `json:"field1" formData:"field1" required:"true"`
+	Field2 int    `json:"field2" formData:"field2" required:"true"`
+	Field3 string `path:"path" required:"true"`
+}
+
+func (formOrJSONInput) ForceJSONRequestBody() {}
+
+func formOrJSON() usecase.Interactor {
+	type formOrJSONOutput struct {
+		F1 string `json:"f1"`
+		F2 int    `json:"f2"`
+		F3 string `json:"f3"`
+	}
+
+	u := usecase.NewInteractor(func(ctx context.Context, input formOrJSONInput, output *formOrJSONOutput) error {
+		output.F1 = input.Field1
+		output.F2 = input.Field2
+		output.F3 = input.Field3
+
+		return nil
+	})
+
+	u.SetTags("Request")
+	u.SetDescription("This endpoint can accept both form and json requests with the same input structure.")
+
+	return u
+}

_examples/advanced-generic-openapi31/form_or_json_test.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/bool64/httptestbench"
+	"github.com/valyala/fasthttp"
+)
+
+func Benchmark_formOrJSON(b *testing.B) {
+	r := NewRouter()
+
+	srv := httptest.NewServer(r)
+	defer srv.Close()
+
+	b.Run("form", func(b *testing.B) {
+		httptestbench.RoundTrip(b, 50, func(i int, req *fasthttp.Request) {
+			req.Header.SetMethod(http.MethodPost)
+			req.SetRequestURI(srv.URL + "/form-or-json/abc")
+			req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+			req.SetBody([]byte(`field1=def&field2=123`))
+		}, func(i int, resp *fasthttp.Response) bool {
+			return resp.StatusCode() == http.StatusOK
+		})
+	})
+
+	b.Run("json", func(b *testing.B) {
+		httptestbench.RoundTrip(b, 50, func(i int, req *fasthttp.Request) {
+			req.Header.SetMethod(http.MethodPost)
+			req.SetRequestURI(srv.URL + "/form-or-json/abc")
+			req.Header.Set("Content-Type", "application/json")
+			req.SetBody([]byte(`{"field1":"string","field2":0}`))
+		}, func(i int, resp *fasthttp.Response) bool {
+			return resp.StatusCode() == http.StatusOK
+		})
+	})
+}

_examples/advanced-generic-openapi31/router.go

@@ -1,4 +1,4 @@
 //go:build go1.18
 
 package main
 
@@ -204,6 +204,8 @@
 	s.Post("/text-req-body/{path}", textReqBody(), nethttp.RequestBodyContent("text/csv"))
 	s.Post("/text-req-body-ptr/{path}", textReqBodyPtr(), nethttp.RequestBodyContent("text/csv"))
 
+	s.Post("/form-or-json/{path}", formOrJSON())
+
 	// Security middlewares.
 	//  - sessMW is the actual request-level processor,
 	//  - sessDoc is a handler-level wrapper to expose docs.

request/decoder.go

@@ -77,6 +77,11 @@ func decodeValidate(d *form.Decoder, v interface{}, p url.Values, in rest.ParamI
 
 func makeDecoder(in rest.ParamIn, formDecoder *form.Decoder, decoderFunc decoderFunc) valueDecoderFunc {
 	return func(r *http.Request, v interface{}, validator rest.Validator) error {
+		ct := r.Header.Get("Content-Type")
+		if in == rest.ParamInFormData && ct != "" && ct != "multipart/form-data" && ct != "application/x-www-form-urlencoded" {
+			return nil
+		}
+
 		values, err := decoderFunc(r)
 		if err != nil {
 			return err

request/decoder_test.go

@@ -1,6 +1,7 @@
 package request_test
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"net/http"
@@ -566,3 +567,39 @@ func TestDecoderFactory_MakeDecoder_default_unexported(t *testing.T) {
 	dec := f.MakeDecoder(http.MethodGet, showImageInput{}, nil)
 	assert.NotNil(t, dec)
 }
+
+type formOrJSONInput struct {
+	Field1 string `json:"field1" formData:"field1" required:"true"`
+	Field2 int    `json:"field2" formData:"field2" required:"true"`
+}
+
+func (formOrJSONInput) ForceJSONRequestBody() {}
+
+func TestDecoderFactory_MakeDecoder_formOrJSON(t *testing.T) {
+	var in formOrJSONInput
+
+	dec := request.NewDecoderFactory().MakeDecoder(http.MethodPost, in, nil)
+
+	validator := jsonschema.NewFactory(&openapi.Collector{}, &openapi.Collector{}).
+		MakeRequestValidator(http.MethodPost, in, nil)
+
+	req, err := http.NewRequestWithContext(context.Background(), http.MethodPost,
+		"/", bytes.NewReader([]byte(`{"field1":"abc","field2":123}`)))
+	assert.NoError(t, err)
+
+	req.Header.Set("Content-Type", "application/json")
+
+	require.NoError(t, dec.Decode(req, &in, validator))
+	assert.Equal(t, "abc", in.Field1)
+	assert.Equal(t, 123, in.Field2)
+
+	in = formOrJSONInput{}
+	req, err = http.NewRequestWithContext(context.Background(), http.MethodPost,
+		"/", bytes.NewReader([]byte(`field1=abc&field2=123`)))
+	assert.NoError(t, err)
+
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	require.NoError(t, dec.Decode(req, &in, validator))
+	assert.Equal(t, "abc", in.Field1)
+	assert.Equal(t, 123, in.Field2)
+}