How to use spring's MockMultipartHttpServletRequest? Getting "no multipart boundary was found"

Question

Clearly I'm not using this test fixture right. My servlet works just fine in tomcat, but when I try to use this mock, the multi-part boundary is not found. "the request was rejected because no multipart boundary was found".

There is an answer here that shows how to use this using a text file, but that answer sets the boundary string explicitly and embeds the file as test. I would think I would not need to do with by hand with methods like mockrequest.addFile(...)

What am I not setting here or how I am doing this wrong?

@org.testng.annotations.Test
public void testDoPost() throws Exception
{
    MockMultipartFile file = new MockMultipartFile("test.zip", "test.zip", "application/zip", MyServletTest.class.getResourceAsStream("/test.zip"));
    MockMultipartHttpServletRequest mockRequest = new MockMultipartHttpServletRequest();
    mockRequest.addFile(file);
    mockRequest.set
    mockRequest.setMethod("POST");
    mockRequest.setParameter("variant", "php");
    mockRequest.setParameter("os", "mac");
    mockRequest.setParameter("version", "3.4");
    MockHttpServletResponse response = new MockHttpServletResponse();
    new MyServletTest().doPost(mockRequest, response);
    //  BOOM !
}

Here is the exception

Caused by: blablah:   the request was rejected because no multipart boundary was found

Answer 1

You need to set the boundary.

Here there is a good explanations about what is the boundary https://stackoverflow.com/a/10932533/2762092

To solve your problem try this code.

    import java.io.IOException;
    import java.nio.file.Files;
    import java.nio.file.Path;
    import java.nio.file.Paths;

    import org.apache.commons.lang.ArrayUtils;
    import org.springframework.mock.web.MockHttpServletResponse;
    import org.springframework.mock.web.MockMultipartFile;
    import org.springframework.mock.web.MockMultipartHttpServletRequest;


public class FileUploadTest {

    public void testDoPost() throws IOException {
            Path path = Paths.get("c:\\temp\\test.zip");
            byte[] data = Files.readAllBytes(path);
            MockMultipartFile file = new MockMultipartFile("test.zip", "test.zip",
                    "application/zip", data);
            MockMultipartHttpServletRequest mockRequest = new MockMultipartHttpServletRequest();
            String boundary = "q1w2e3r4t5y6u7i8o9";
            mockRequest.setContentType("multipart/form-data; boundary="+boundary);
            mockRequest.setContent(createFileContent(data,boundary,"application/zip","test.zip"));
            mockRequest.addFile(file);
            mockRequest.setMethod("POST");
            mockRequest.setParameter("variant", "php");
            mockRequest.setParameter("os", "mac");
            mockRequest.setParameter("version", "3.4");
            MockHttpServletResponse response = new MockHttpServletResponse();
            new FileUpload().doPost(mockRequest, response);
        }

        public byte[] createFileContent(byte[] data, String boundary, String contentType, String fileName){
            String start = "--" + boundary + "\r\n Content-Disposition: form-data; name=\"file\"; filename=\""+fileName+"\"\r\n"
                     + "Content-type: "+contentType+"\r\n\r\n";;

            String end = "\r\n--" + boundary + "--"; // correction suggested @butfly 
            return ArrayUtils.addAll(start.getBytes(),ArrayUtils.addAll(data,end.getBytes()));
        }
}

Answer 2

Vote up for Samuel. Though spent one day trying to make it working. The problem was in:

String end = "--" + boundary + "--";

Should be:

String end = "\r\n--" + boundary + "--";

Answer 3

Great answer for Samuel, but a bug:

        String end = "\r\n"+ boundary + "--";

should be:

        String end = "--"+ boundary + "--";

Thanks for his work very much.

Answer 4

Able to add multiple fields ,

   private byte[] createFileContents(String requestId, String date, String image, String invoiceNumber,String imageFile) {

    String requestIdField = "--" + BOUNDARY + "\r\n Content-Disposition: form-data; name=\"" + REQUEST_ID_KEY
            + "\";" + "Content-type: " + CONTENT_TYPE + "\r\n value=\"12345\"" + "\r\n\r\n";
    String requestIdValue = requestId + "\r\n";
    String numberFiledField = "--" + BOUNDARY + "\r\n Content-Disposition: form-data; name=\"" + NUMBER_KEY + "\";"
            + "Content-type: " + CONTENT_TYPE + "\r\n value=\"12345\"" + "\r\n\r\n";
    String invoiceValue = invoiceNumber + "\r\n";
    String dateField = "--" + BOUNDARY + "\r\n Content-Disposition: form-data; name=\"" + DATE_KEY + "\";"
            + "Content-type: " + CONTENT_TYPE + "\r\n value=\"12345\"" + "\r\n\r\n";
    String dateValue = date + "\r\n";
    String imageField = "--" + BOUNDARY + "\r\n Content-Disposition: form-data; name=\"" + IMAGE_KEY
            + "\"; filename=\"" + imageFile + "\"\r\n" + "Content-type: " + CONTENT_TYPE + "\r\n\r\n";
    String imageValue = image + "\r\n";
    String end = "\r\n--" + BOUNDARY + "--";
    return ArrayUtils.addAll((requestIdField + requestIdValue + numberFiledField + invoiceValue + dateField
            + dateValue + imageField + imageValue).getBytes(), ArrayUtils.addAll(data, end.getBytes()));
}

Answer 5

My way to test multipart/form-data via mock MVC sending params and files is the following:

    @Test
void testSendFeedback() throws Exception {
    var builder = MockMvcRequestBuilders.multipart(URL_PATH);

    Path path = Files.createTempFile("test-file", "tmp");
    builder = builder.part(new MockPart("image", path.toFile().getName(), Files.readAllBytes(path)));

    builder.param("field1", "value1")
        .param("fields2", "value2");

    mockMvc.perform(builder.header(HttpHeaders.AUTHORIZATION, YOUR_AUTH_VALUE).contentType(MediaType.MULTIPART_FORM_DATA_VALUE))
        .andDo(print())
        .andExpect(status().isNoContent());
}