How to pass the value @Body MultipartBody from curl or postman or swagger Micronaut

Question

I have a simple below post method in Micronaut, which sends the image to the controller as shown below

@Controller("/product")
public class ProductController {

    @Post(consumes = MediaType.MULTIPART_FORM_DATA, produces = MediaType.MULTIPART_FORM_DATA)
    public String post(@Body MultipartBody file){
        return "This is multipost";
    }
}

How can I pass the value of file to the controller from the postman, curl or swagger?

I tried the below things

curl --location --request POST 'http://localhost:8080/product' \
--form 'file=@"/Users/macbook/Downloads/anand 001.jpg"'

I get the error as Required Body [file] not specified. How do we pass the value?

Answer 1

Change signature of post() method to use @Part instead of @Body and use directly byte array instead of MultipartBody. You can also define the part name in @Part annotation, which is file in your case.

It can look like this:

@Controller("/products")
public class ProductController {

    @Post(consumes = MediaType.MULTIPART_FORM_DATA)
    public String post(@Part("file") byte[] file) {
        return "Received: " + new String(file, StandardCharsets.UTF_8);
    }

}

And example curl call:

curl -X POST 'http://localhost:8080/products' -F 'file=@/home/cgrim/tmp/test.txt'

... with response:

Received: Some dummy data in text file.

So the problem is not in your curl command or call from Postman but in the controller implementation.

---

Here is an example of declarative client for that operation:

@Client("/products")
public interface ProductClient {
    @Post(produces = MULTIPART_FORM_DATA)
    HttpResponse<String> createProduct(@Body MultipartBody body);
}

And that client can be used like this:

var requestBody = MultipartBody.builder()
    .addPart("file", file.getName(), TEXT_PLAIN_TYPE, file)
    .build();
var response = client.createProduct(requestBody);