SendFaxMessage does not support sending without files.

[grokify]

When sending without a file the following error is encountered:

$ go run fax_send.go -to=+16505550100
panic: Status: 400 Bad Request, Body: {
  "message" : "Bad Request",
  "errors" : [ ]
}

This is handled by MessagesApi.SendFaxMessage:

https://github.com/grokify/go-ringcentral/blob/master/client/messages_api.go#L530

func (a *MessagesApiService) SendFaxMessage(ctx context.Context, accountId string, extensionId string, localVarFile *os.File, faxResolution string, to []string, localVarOptionals map[string]interface{}) (FaxResponse, *http.Response, error) {

It sets up the following vars.

	var (
		localVarHttpMethod = strings.ToUpper("Post")
		localVarPostBody   interface{}
		localVarFileName   string
		localVarFileBytes  []byte
		successPayload     FaxResponse
	)

localVarFileName and localVarFileBytes are not populated when localVarFile is nil, however it is still sent to prepareRequest:

https://github.com/grokify/go-ringcentral/blob/master/client/messages_api.go#L600

r, err := a.client.prepareRequest(ctx, localVarPath, localVarHttpMethod, localVarPostBody, localVarHeaderParams, localVarQueryParams, localVarFormParams, localVarFileName, localVarFileBytes)

Need to investigate what happens in client.prepareRequest with empty localVarFileName and localVarFileBytes.

[grokify]

For testing purposes, try sending with a file. I will investigate how to send without a file using Swagger Codegen.

$ go run fax_send.go -to=+16505550100 -file=$GOPATH/src/github.com/grokify/go-ringcentral/examples/fax_send/test_file.pdf