Is it necessary to use bufferInputStream when getting a file from Minio?

Question

I want to know if a buffer is necessary when I receive a input stream from Minio.

I use Minio as my object storage and and have Dropwizard as Backend between client and Minio. now when I use the getObject method from the minio I get a inputStream.

public InputStream getObject(String bucketName, String objectName, long offset)

In my mind it would be something like

@Path("/file")
public class FileResource {

    @GET
    @Produces(MediaType.APPLICATION_OCTET_STREAM)
    public Response getFile() throws Exception {
        InputStream is = minioClient.getObject("mybucket", "myobject");

        return Response.ok(is)
                .header(HttpHeaders.CONTENT_DISPOSITION, 
                        "attachment; filename=\"file.txt\"")
                .build();
    }
}

To my understanding it was possible to just return this input stream as response to the client with the necessary content disposition.

Now is a bufferedInputStream necesairy? And how long does the GET request wait until it is timed out?

Answer 1

I don't have access to Minio. But using a simple local file, your approach works fine.

import com.google.common.net.HttpHeaders;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.nio.file.Paths;
import javax.ws.rs.GET;
import javax.ws.rs.InternalServerErrorException;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

@Path("/file")
@Produces(MediaType.APPLICATION_OCTET_STREAM)
public class FileResource {

    @GET
    public Response getFile() {
        try {
            InputStream is = new FileInputStream(Paths.get("/tmp/foo.txt").toFile());
            return Response.ok(is)
                    .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"file.txt\"")
                    .build();
        } catch (FileNotFoundException ex) {
            throw new InternalServerErrorException(ex.getMessage());
        }

    }
}

A simple file /tmp/foo.txt containing some text is returned with a correct HTTP response. Using curl:

$ curl -v http://localhost:8080/file
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET /file HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.47.0
> Accept: */*
> 
< HTTP/1.1 200 OK
< Date: Wed, 11 Apr 2018 14:15:06 GMT
< Content-Disposition: attachment; filename="file.txt"
< Content-Type: application/octet-stream
< Vary: Accept-Encoding
< Content-Length: 12
< 
foo
bar
baz