AwsProxyHttpServletResponseWriter

[argenstijn]

• Framework version: XX
• Implementations: Jersey / Spring / Spring Boot / Spark

Scenario

Lambda in combination with ALB should not use base 64 RFC2045 for encoding binary content

Expected behavior

responseString = Base64.getEncoder().encodeToString(containerResponse.getAwsResponseBodyBytes());
awsProxyResponse.setBase64Encoded(true);

Actual behavior

Base64.getMimeEncoder().encodeToString(containerResponse.getAwsResponseBodyBytes());
awsProxyResponse.setBase64Encoded(true);

It;s possible to configure the base 64 encoder to use for creating the response?

[sapessi]

Hi @argenstijn - it is not possible today. However, we can add this as a fix for the next release. What is the issue you are running into? What's the output from the ALB?

[argenstijn]

you will receive a 502 Bad Gateway.

[argenstijn]

by the ALB

[sapessi]

I have tested this and for some reason I cannot seem to return binary content from an ALB no matter what I do - even without using the MIME encoder. This works fine with API Gateway. I will check-in with the ALB team to dive deeper on the issue

[argenstijn]

Hi, i have a working version. Will add it IT tomorrow. Cheers mark Get Outlook for Android<https://aka.ms/ghei36>

…

________________________________ From: Stefano Buliani <notifications@github.com> Sent: Wednesday, July 15, 2020 10:05:48 PM To: awslabs/aws-serverless-java-container <aws-serverless-java-container@noreply.github.com> Cc: argenstijn <argenstijn@hotmail.com>; Mention <mention@noreply.github.com> Subject: Re: [awslabs/aws-serverless-java-container] AwsProxyHttpServletResponseWriter (#339) I have tested this and for some reason I cannot seem to return binary content from an ALB no matter what I do - even without using the MIME encoder. This works fine with API Gateway. I will check-in with the ALB team to dive deeper on the issue — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#339 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AAA75LG4JXNLMIOOIXPYAU3R3YDZZANCNFSM4MNF77XA>.

[argenstijn]

See config below:

/**

• Same functionality as {@link AwsProxyHttpServletResponseWriter} but uses
• the default BASE64 encoder when detecting binary data.

*/
public class DefaultBase64EncoderAwsProxyHttpServletResponseWriter extends ResponseWriter<AwsHttpServletResponse, AwsProxyResponse> {

@Override
public AwsProxyResponse writeResponse(AwsHttpServletResponse containerResponse, Context lambdaContext)
        throws InvalidResponseObjectException {
   
    AwsProxyResponse awsProxyResponse = new AwsProxyResponse();
    if (containerResponse.getAwsResponseBodyString() != null) {
        String responseString;

        if (!isBinary(containerResponse.getContentType()) && isValidUtf8(containerResponse.getAwsResponseBodyBytes())) {
            responseString = containerResponse.getAwsResponseBodyString();
        } else {
            responseString = Base64.getEncoder().encodeToString(containerResponse.getAwsResponseBodyBytes());
            awsProxyResponse.setBase64Encoded(true);
        }

        awsProxyResponse.setBody(responseString);
    }
    awsProxyResponse.setMultiValueHeaders(containerResponse.getAwsResponseHeaders());

    awsProxyResponse.setStatusCode(containerResponse.getStatus());

    if (containerResponse.getAwsProxyRequest().getRequestSource() == AwsProxyRequest.RequestSource.ALB) {
        awsProxyResponse.setStatusDescription(containerResponse.getStatus() + " " + Response.Status.fromStatusCode(containerResponse.getStatus()).getReasonPhrase());
    }
   
    return awsProxyResponse;
}

private boolean isBinary(String contentType) {
        
    if(contentType != null) {
        int semidx = contentType.indexOf(';');
        if(semidx >= 0) {
            return LambdaContainerHandler.getContainerConfig().isBinaryContentType(contentType.substring(0, semidx));
        }
        else {
            return LambdaContainerHandler.getContainerConfig().isBinaryContentType(contentType);
        }
    }
    return false;
}

}

Then you should use this class and make sure that you also add the binary you try to send:

 JerseyLambdaContainerHandler<AwsProxyRequest, AwsProxyResponse> newHandler =
        new JerseyLambdaContainerHandler<>(AwsProxyRequest.class, AwsProxyResponse.class,
            new AwsProxyHttpServletRequestReader(),
            new DefaultBase64EncoderAwsProxyHttpServletResponseWriter(),
            new AwsProxySecurityContextWriter(), new AwsProxyExceptionHandler(), app);

 
    newHandler.initialize();  
String[] BINARTY_CONTENT_TYPES = {"application/pdf"};  
    LambdaContainerHandler.getContainerConfig().addBinaryContentTypes(BINARTY_CONTENT_TYPES});    

In this example you should be able to download a PDF

[sapessi]

1.5.2 has now hit maven central. Closing this issue.

[swagsb]

Hi,

I am still facing this issue using 1.5.2 . My scenario :

I am simply trying to download a zip which has an xml file. My controller

@GetMapping("/downloadZip")
public void downloadFile(HttpServletResponse response) {

    response.setContentType("application/octet-stream");
    response.setHeader("Content-Disposition", "attachment;filename=download.zip");
    response.setStatus(HttpServletResponse.SC_OK);

    try (ZipOutputStream zippedOut = new ZipOutputStream(response.getOutputStream())) {
            Resource resource = new ClassPathResource("logback.xml");
            ZipEntry e = new ZipEntry(resource.getFilename());
            e.setSize(resource.contentLength());
            e.setTime(System.currentTimeMillis());
            // etc.
            zippedOut.putNextEntry(e);
            // And the content of the resource:
            StreamUtils.copy(resource.getInputStream(), zippedOut);
            zippedOut.closeEntry();

        zippedOut.finish();
    } catch (Exception e) {
        // Exception handling goes here
    }
}

This downloads the zip fine on local. On aws , it downloads the zip , but cant extract it . Its corrupted. Windows says invalid.
I tested it by putting breakpoint on AwsProxyHttpServletResponseWriter , line no 38 , here :
if (!this.isBinary(containerResponse.getContentType()) && this.isValidUtf8(containerResponse.getAwsResponseBodyBytes())) {
responseString = containerResponse.getAwsResponseBodyString();
} else {
responseString = Base64.getEncoder().encodeToString(containerResponse.getAwsResponseBodyBytes());
awsProxyResponse.setBase64Encoded(true);
}

I can see that its going to the else block and using Base 64 encoder.
Any idea why this still doesnt work on ALB ? Should I check this with AWS then ?