org.webpieces.plugin.grpcjson.GrpcJsonLookup Maven / Gradle / Ivy

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Webpieces plugin that converts between GRPC Protobuf and JSON
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package org.webpieces.plugin.grpcjson;

import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.charset.Charset;

import org.webpieces.ctx.api.RequestContext;
import org.webpieces.httpparser.api.dto.KnownStatusCode;
import org.webpieces.router.api.controller.actions.RenderContent;
import org.webpieces.router.api.extensions.BodyContentBinder;
import org.webpieces.router.api.extensions.ParamMeta;
import org.webpieces.util.exceptions.SneakyThrow;

import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.Message;
import com.google.protobuf.MessageOrBuilder;
import com.google.protobuf.util.JsonFormat;

public class GrpcJsonLookup implements BodyContentBinder {
    @Override
    public  boolean isManaged(Class entityClass, Class paramAnnotation) {
    	//we could detect if the class is a grpc class BUT instead just use annotations for now...
        if(paramAnnotation == GrpcJson.class)
            return true;

        return false;
    }

    @SuppressWarnings("unchecked")
	@Override
    public  T unmarshal(RequestContext ctx, ParamMeta meta, byte[] data) {
        try {

        	Class paramTypeToCreate = (Class) meta.getFieldClass();
        	
            String json = new String(data, Charset.forName("UTF-8"));
            JsonFormat.Parser parser = JsonFormat.parser();

            Method m = paramTypeToCreate.getMethod("newBuilder");
            Message.Builder builder = (Message.Builder) m.invoke(null);
            parser.merge(json, builder);

            return (T) builder.build();
        } catch (IllegalAccessException | InvalidProtocolBufferException | InvocationTargetException | NoSuchMethodException e) {
            throw SneakyThrow.sneak(e);
        }
    }

    @Override
    public  RenderContent marshal(T bean) {
        try {
            JsonFormat.Printer jsonPrinter = JsonFormat.printer();
            String json = jsonPrinter.print((MessageOrBuilder) bean);
            byte[] reqAsBytes = json.getBytes(Charset.forName("UTF-8"));

            return new RenderContent(reqAsBytes, KnownStatusCode.HTTP_200_OK.getCode(), KnownStatusCode.HTTP_200_OK.getReason(), GrpcJsonCatchAllFilter.MIME_TYPE);
        } catch (InvalidProtocolBufferException e) {
            throw new RuntimeException("Could not marshal bean="+bean.getClass(), e);
        }
    }

    @Override
    public Class getAnnotation() {
        return GrpcJson.class;
    }
}