The gateway cannot handle the form parameters correctly

[gongluck]

Gateway configuration parameters:

Name: demo-gateway
Host: localhost
Port: 8889
Log:
  Level: debug
Upstreams:
  - Grpc:
      Target:
        127.0.0.1:8081
    ProtoSets:
      - hello.pb
    Mappings:
      - Method: post
        Path: /ping
        RpcPath: hello.Hello/Ping

Test with postman:

Cause of the problem

// NewRequestParser creates a new request parser from the given http.Request and resolver.
func NewRequestParser(r *http.Request, resolver jsonpb.AnyResolver) (grpcurl.RequestParser, error) {
	vars := pathvar.Vars(r)
	params, err := httpx.GetFormValues(r)
	if err != nil {
		return nil, err
	}

	for k, v := range vars {
		params[k] = v
	}

	body, ok := getBody(r)
	if !ok {
		return buildJsonRequestParser(params, resolver)
	}

	if len(params) == 0 {
		return grpcurl.NewJSONRequestParser(body, resolver), nil
	}

	m := make(map[string]any)
	if err := json.NewDecoder(body).Decode(&m); err != nil {
                // here return io.EOF
                // Because the body's data has already been read by the above call to function GetFormValues？
                // Even though there's an error, but params maybe have data!
		return nil, err
	}

	for k, v := range params {
		m[k] = v
	}

	return buildJsonRequestParser(m, resolver)
}

My solution

// NewRequestParser creates a new request parser from the given http.Request and resolver.
func NewRequestParser(r *http.Request, resolver jsonpb.AnyResolver) (grpcurl.RequestParser, error) {
	vars := pathvar.Vars(r)
	params, err := httpx.GetFormValues(r)
	if err != nil {
		return nil, err
	}

	for k, v := range vars {
		params[k] = v
	}

	body, ok := getBody(r)
	if !ok {
		return buildJsonRequestParser(params, resolver)
	}

	if len(params) == 0 {
		return grpcurl.NewJSONRequestParser(body, resolver), nil
	}

	m := make(map[string]any)
	if err := json.NewDecoder(body).Decode(&m); err != nil && err != io.EOF { // skip eof
		return nil, err
	}

	for k, v := range params {
		m[k] = v
	}

	return buildJsonRequestParser(m, resolver)
}

End

If my changes are accepted, I can initiate a pr, or do you have a better way?