Runtime does not allow raw bytes to be returned over http

[roastario]

Returning a byte[] from a HttpTriggered function seems to format as JSON string, and the content type is set to application/json.

Using the HttpResponseMessage does not seem to currently work due to: #69

This breaks a lot of applications which are expecting binary data.

[roastario]

Just a follow up, I've tested all the combinations of return types possible:

package com.r3.networkmap.azure;

import com.microsoft.azure.serverless.functions.HttpRequestMessage;
import com.microsoft.azure.serverless.functions.HttpResponseMessage;
import com.microsoft.azure.serverless.functions.annotation.*;

import java.nio.ByteBuffer;

public class DelegatedToJavaFunctions {


    @FunctionName("getNetworkMapBA")
    @HttpOutput(name = "$return", dataType = "binary")
    public HttpResponseMessage<byte[]> getNetworkMapArray(
            @HttpTrigger(methods = {"get"}, dataType = "binary", authLevel = AuthorizationLevel.ANONYMOUS, route = "network-mapBA", name = "in") HttpRequestMessage<String> token,
            @BlobInput(name = "serialisedNetworkMap", dataType = "binary", connection = "AzureWebJobsStorage", path = "networkmap/network-map.ser") byte[] networkMap) {
        HttpResponseMessage<byte[]> response = token.createResponse(200, (networkMap));
//        response.addHeader("Content-Length", "${networkMap!!.size}");
//        response.addHeader("Content-Type", "application/octet-stream");
        return response;
    }

    @FunctionName("getNetworkMapBB")
    @HttpOutput(name = "$return", dataType = "binary")
    public HttpResponseMessage<ByteBuffer> getNetworkMapBuffer(
            @HttpTrigger(methods = {"get"}, dataType = "binary", authLevel = AuthorizationLevel.ANONYMOUS, route = "network-mapBB", name = "in") HttpRequestMessage<String> token,
            @BlobInput(name = "serialisedNetworkMap", dataType = "binary", connection = "AzureWebJobsStorage", path = "networkmap/network-map.ser") byte[] networkMap) {
        HttpResponseMessage<ByteBuffer> response = token.createResponse(200, ByteBuffer.wrap(networkMap));
//        response.addHeader("Content-Length", "${networkMap!!.size}");
//        response.addHeader("Content-Type", "application/octet-stream");
        return response;
    }

    @FunctionName("getNetworkMapBBNoWrapper")
    @HttpOutput(name = "$return", dataType = "binary")
    public ByteBuffer getNetworkMapBBNoWrapper(
            @HttpTrigger(methods = {"get"}, dataType = "binary", authLevel = AuthorizationLevel.ANONYMOUS, route = "network-mapBBNW", name = "in") HttpRequestMessage<String> token,
            @BlobInput(name = "serialisedNetworkMap", dataType = "binary", connection = "AzureWebJobsStorage", path = "networkmap/network-map.ser") byte[] networkMap) {
//        response.addHeader("Content-Length", "${networkMap!!.size}");
//        response.addHeader("Content-Type", "application/octet-stream");
        return ByteBuffer.wrap(networkMap);
    }

    @FunctionName("getNetworkMapBANoWrapper")
    @HttpOutput(name = "$return", dataType = "binary")
    public byte[] getNetworkMapBANoWrapper(
            @HttpTrigger(methods = {"get"}, dataType = "binary", authLevel = AuthorizationLevel.ANONYMOUS, route = "network-mapBANW", name = "in") HttpRequestMessage<String> token,
            @BlobInput(name = "serialisedNetworkMap", dataType = "binary", connection = "AzureWebJobsStorage", path = "networkmap/network-map.ser") byte[] networkMap) {
//        response.addHeader("Content-Length", "${networkMap!!.size}");
//        response.addHeader("Content-Type", "application/octet-stream");
        return (networkMap);
    }


}

ByteBuffer (Wrapped or unwrapped) - Always returns plain text as it's content type (and mangles the binary response)
byte[] (Wrapped or unwrapped) - Always returns application/json as it's content type (and mangles the binary response)

Adding Content-Length header causes a 500
Adding Content-Type header causes a 406

[JunyiYi]

Worker should set corresponding fields (such as "is_raw", "Content-Type") after receiving HTTP Response from client code, and pass them to the Host.

[JunyiYi]

Azure functions host will update the grpc protocol to resolve this issue at the host side: Azure/azure-functions-host#2552

[mhoeger]

^note: content-type should still be set by the worker, the change will essentially make "is_raw" default to true instead of false.

[paulbatum]

@pragnagopa i think this is addressed... can you verify?

[pragnagopa]

This has been addressed as part of Azure/azure-functions-host#2552