Adobe Experience Manager Sites & More

Anoop_Garg · 11/29/23

Hi All,

We have requirement where third party portal want to download assets from Adobe DAM. We have exposed API/Servlet for them listed below . This is working fine if asset size is small in size and getting downloaded but for large asset it's throwing 500 server error on third party portal . Can someone suggest if anything need to be handled from API/Servlet or third Party Portal only ?

https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager-assets/servlet-code-to-dow...

Thanks in advance !

Note: Client don't want to download assets in ZIP format , so using above code in AEM servlet.

Jagadeesh_Prakash · 11/30/23

@Anoop_Garg Let me know if that worked after increase time for timeout. For me with 500 MB of asset below code worked

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
import org.osgi.service.component.annotations.Component;

@Component(
service = { javax.servlet.Servlet.class },
property = {
"sling.servlet.methods=GET",
"sling.servlet.paths=/bin/downloadlargeasset"
}
)
public class DownloadLargeAssetServlet extends SlingSafeMethodsServlet {

@Override
protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response)
throws ServletException, IOException {
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment;filename=largefile.txt");

// Simulating the creation of a large file (500 MB)
InputStream largeFileStream = createLargeFile();

try (ServletOutputStream outputStream = response.getOutputStream()) {
// Stream the content in chunks to avoid loading the entire file into memory
IOUtils.copyLarge(largeFileStream, outputStream);
} finally {
IOUtils.closeQuietly(largeFileStream);
}
}

private InputStream createLargeFile() {
// Simulate creating a large file (500 MB)
byte[] largeFileContent = new byte[500 * 1024 * 1024];
for (int i = 0; i < largeFileContent.length; i++) {
largeFileContent[i] = (byte) (i % 256);
}
return IOUtils.toInputStream(new String(largeFileContent));
}
}

View solution in original post

Jagadeesh_Prakash · 11/29/23

@Anoop_Garg can you try setting below header once and try. Let me know if this is working

response.setHeader("Transfer-Encoding", "chunked");

And also tell me what size of asset is not working for you

Anoop_Garg · 11/30/23

Thanks @Jagadeesh_Prakash ! Issue is happening for assets above 500 MB. I tried to download assets directly from my custom servlet and its working fine. Added above header as well but still same . Might be I need to ask consumer to increase time for timeout as big binary will take time to send the response.

Jagadeesh_Prakash · 11/30/23