Use and update GetBody() member of request (#704)

Author: ShouheiNishi

openapi3filter/validate_request.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"sort"
@@ -216,7 +217,19 @@ func ValidateRequestBody(ctx context.Context, input *RequestValidationInput, req
 			}
 		}
 		// Put the data back into the input
-		req.Body = ioutil.NopCloser(bytes.NewReader(data))
+		req.Body = nil
+		if req.GetBody != nil {
+			if req.Body, err = req.GetBody(); err != nil {
+				req.Body = nil
+			}
+		}
+		if req.Body == nil {
+			req.ContentLength = int64(len(data))
+			req.GetBody = func() (io.ReadCloser, error) {
+				return io.NopCloser(bytes.NewReader(data)), nil
+			}
+			req.Body, _ = req.GetBody() // no error return
+		}
 	}
 
 	if len(data) == 0 {
@@ -292,8 +305,14 @@ func ValidateRequestBody(ctx context.Context, input *RequestValidationInput, req
 			}
 		}
 		// Put the data back into the input
-		req.Body = ioutil.NopCloser(bytes.NewReader(data))
+		if req.Body != nil {
+			req.Body.Close()
+		}
 		req.ContentLength = int64(len(data))
+		req.GetBody = func() (io.ReadCloser, error) {
+			return io.NopCloser(bytes.NewReader(data)), nil
+		}
+		req.Body, _ = req.GetBody() // no error return
 	}
 
 	return nil

openapi3filter/validate_request_test.go

@@ -212,6 +212,12 @@ components:
 			assert.Equal(t, contentLen, bodySize, "expect ContentLength %d to equal body size %d", contentLen, bodySize)
 			bodyModified := originalBodySize != bodySize
 			assert.Equal(t, bodyModified, tc.expectedModification, "expect request body modification happened: %t, expected %t", bodyModified, tc.expectedModification)
+
+			validationInput.Request.Body, err = validationInput.Request.GetBody()
+			assert.NoError(t, err, "unable to re-generate body by GetBody(): %v", err)
+			body2, err := io.ReadAll(validationInput.Request.Body)
+			assert.NoError(t, err, "unable to read request body: %v", err)
+			assert.Equal(t, body, body2, "body by GetBody() is not matched")
 		})
 	}
 }