Send excel files from micro to micro

Question

I am trying to establish a communication between two micros, where the first one receives a petition from the frontend and contacts with another micro, which creates an excel file and sends it back to the first micro, starting the download of the file.

First, I tried to print a simple String response to check the communication between micros and that worked correctly, but the same thing for files didn't work.

Here is the code that I am following: For Controller A:

    @GetMapping(path="/test")
    public void getEntities2(HttpServletRequest request, HttpServletResponse response) throws IOException {   

        ResponseEntity<Workbook> responseEntity = new RestTemplate()
                .getForEntity("http://localhost:8080/proceso/excel", Workbook.class);
        assertThat(responseEntity.getStatusCode(), equalTo(HttpStatus.OK));
        response.setHeader("Content-disposition", "attachment; filename=" + "test.xls");
        Workbook workbook = responseEntity.getBody();
        workbook.write(response.getOutputStream());
        workbook.close();       
    }

The second Controller (Excel file generator):

@GetMapping(path="/excel")
    public ResponseEntity<Workbook> test3(HttpServletResponse response) throws Exception {
        HashMap<String, ArrayList<String>> test = new HashMap<String, ArrayList<String>>();
        Workbook workbook =  CreateExcel.excelCreator(test);

        Workbook responseFile = workbook;
        return ResponseEntity.ok()
                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=" + "test.xls")
                .contentType(MediaType.MULTIPART_FORM_DATA)
                .body(responseFile);
    }

And then the following error appears:

org.springframework.web.client.HttpClientErrorException$NotAcceptable: 406 null

I just want to receive the file in the first controller and download the Excel from localhost. Is there any way to do it? Thanks all.

Answer 1

I discovered the problem. The excel file is a octet-stream file so it needs to be received as a byte[] array. This is the Controller A:

    @GetMapping(path="/")
public ResponseEntity<byte[]> getEntities() throws IOException {   
ResponseEntity<byte[]> responseEntity = new RestTemplate()
.getForEntity("http://localhost:8080/excel", byte[].class);
assertThat(responseEntity.getStatusCode(), equalTo(HttpStatus.OK));

return responseEntity;
}

And Controller B:

@GetMapping(path="/excel")
public void getExcel(HttpServletResponse response) throws Exception {

Iterable<InstancesAggregate> list = instancesAggregate.myfindAll(); //Creating a list
HashMap<String, ArrayList<String>> test = CreateExcel.setExcelProceso(list);
Workbook workbook =  CreateExcel.excelCreator(test);
response.setHeader("Content-disposition", "attachment; filename=" + "test.xls");
   workbook.write(response.getOutputStream());
   workbook.close();    

}

This works fine for me, hope someone find the info useful.