EzyHTTP upload file

Same as every HTTP server framewords, EzyHttp allows you upload file, too. And we recommend you let's use asynchronous API, to know why, please take a look the explanation here.

1. FileUploader

EzyHTTP provides to you an convenient FileUploader class. It wraps ResourceUploadManager, an event loop like below:

And the event loop will do like this:

loop:
    take a inputstream/outputstream pair from the queue:
        take 1024 bytes from the inputstream of the requested file and push to client's outputstream
        if there is no remain data in the inputstream
            then response to the client: call to the callback and done
        else
            push the the inputstream/outputstream pair back to the queue

2. Enable file upload configuration

To enable file upload, you can add the configuration to your application.properties file like this:

resources.upload.enable=true

If you want to set queue capacity and thread pool size, buffer size, you can setup:

resources.upload.capacity=[an integer value]
resources.upload.thread_pool_size=[an integer value]
resources.upload.buffer_size=[an integer value]

3. Upload file asynchronously

To upload a file asynchronously with FilerUploader, you can do like this:

@Controller("/api/v1")
@AllArgsConstructor
public class FileController {

    private final FileUploadService fileUploadService;

    @Async
    @DoPost("/files/upload")
    public void uploadPost(
        RequestArguments requestArguments
    ) throws Exception {
        fileUploadService.accept(requestArguments.getRequest());
    }
}

@EzySingleton
@AllArgsConstructor
public class FileUploadService {

    private final FileUploader fileUploader;
    
    public void accept(HttpServletRequest request) throws Exception {
        accept(
            request,
            request.getPart("file"),
            () -> System.out.println("Upload finished")
        );
    }

    public void accept(
        HttpServletRequest request,
        Part part,
        EzyExceptionVoid callback
    ) {
        String fileName = part.getSubmittedFileName();
        File file = new File("files/" + fileName);
        AsyncContext asyncContext = request.getAsyncContext();
        fileUploader.accept(asyncContext, part, file, callback);
    }   
}

4. Upload file Synchronously

To upload a file synchronously, you can do like this:

@Controller("/api/v1")
public class FileController {

    @DoPost("/files/upload-sync")
    public ResponseEntity uploadSyncPost(
        HttpServletRequest request
    ) throws Exception {
        Part part = request.getPart("file");
        String fileName = part.getSubmittedFileName();
        File file = new File("files/" + fileName);
        InputStream inputStream = part.getInputStream();
        byte[] buffer = new byte[1024];
        try (OutputStream outputStream = new FileOutputStream(file)) {
            while (true) {
                int read = inputStream.read(buffer);
                if (read > 0) {
                    outputStream.write(buffer, 0, read);
                } else {
                    break;
                }
            }
        }
        return ResponseEntity.noContent();
    }
}

Next step

You can see How to download a file