public static async Task HandleGrpcRequestAsync(this DownstreamContext context, Func <Task> next, SslCredentials secureCredentials = null)
{
// ignore if the request is not a gRPC content type
if (!context.HttpContext.Request.Headers.Any(h => h.Key.ToLowerInvariant() == "content-type" && h.Value == "application/grpc"))
{
await next.Invoke();
}
else
{
var methodPath = context.DownstreamReRoute.DownstreamPathTemplate.Value;
var grpcAssemblyResolver = context.HttpContext.RequestServices.GetService <GrpcAssemblyResolver>();
var methodDescriptor = grpcAssemblyResolver.FindMethodDescriptor(methodPath.Split('/').Last().ToUpperInvariant());
if (methodDescriptor == null)
{
await next.Invoke();
}
else
{
string requestData;
var upstreamHeaders = new Dictionary <string, string>
{
{ "x-grpc-route-data", JsonConvert.SerializeObject(context.TemplatePlaceholderNameAndValues.Select(x => new { x.Name, x.Value })) },
{ "x-grpc-body-data", await context.DownstreamRequest.Content.ReadAsStringAsync() }
};
if (context.HttpContext.Request.Method.ToLowerInvariant() == "get")
{
requestData = context.HttpContext.ParseGetJsonRequest(upstreamHeaders);
}
else
{
requestData = context.HttpContext.ParseOtherJsonRequest(upstreamHeaders);
}
var loadBalancerFactory = context.HttpContext.RequestServices.GetService <ILoadBalancerFactory>();
var loadBalancerResponse = await loadBalancerFactory.Get(context.DownstreamReRoute, context.Configuration.ServiceProviderConfiguration);
var serviceHostPort = await loadBalancerResponse.Data.Lease(context);
var downstreamAddress = context.DownstreamReRoute.DownstreamAddresses.FirstOrDefault();
var downstreamHost = $"{serviceHostPort.Data.DownstreamHost}:{serviceHostPort.Data.DownstreamPort}";
var channel = new Channel(downstreamHost, secureCredentials ?? ChannelCredentials.Insecure);
var client = new MethodDescriptorCaller(channel);
var requestObject = JsonConvert.DeserializeObject(requestData, methodDescriptor.InputType.ClrType);
var result = await client.InvokeAsync(methodDescriptor, context.HttpContext.GetRequestHeaders(), requestObject);
var response = new OkResponse <GrpcHttpContent>(new GrpcHttpContent(JsonConvert.SerializeObject(result)));
var httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK)
{
Content = response.Data
};
context.HttpContext.Response.ContentType = "application/json";
context.DownstreamResponse = new DownstreamResponse(httpResponseMessage);
}
}
}
public static async Task HandleGrpcRequestAsync(this DownstreamContext context, Func <Task> next)
{
// ignore if the request is not a gRPC content type
if (!context.HttpContext.Request.Headers.Any(h => h.Key.ToLowerInvariant() == "content-type" && h.Value == "application/grpc"))
{
await next.Invoke();
}
else
{
var methodPath = context.DownstreamReRoute.DownstreamPathTemplate.Value;
var grpcAssemblyResolver = context.HttpContext.RequestServices.GetService <GrpcAssemblyResolver>();
var methodDescriptor = grpcAssemblyResolver.FindMethodDescriptor(methodPath.Split('/').Last().ToUpperInvariant());
if (methodDescriptor == null)
{
await next.Invoke();
}
else
{
string requestData;
var upstreamHeaders = new Dictionary <string, string>
{
{ "x-grpc-route-data", JsonConvert.SerializeObject(context.TemplatePlaceholderNameAndValues.Select(x => new { x.Name, x.Value })) },
{ "x-grpc-body-data", await context.DownstreamRequest.Content.ReadAsStringAsync() }
};
if (context.HttpContext.Request.Method.ToLowerInvariant() == "get")
{
requestData = context.HttpContext.ParseGetJsonRequest(upstreamHeaders);
}
else
{
requestData = context.HttpContext.ParseOtherJsonRequest(upstreamHeaders);
}
// todo: only get the first one, currently we use service mesh to LB the downstream gRPC services
// but we open to support it with manually LB such as Consult
var downstreamAddress = context.DownstreamReRoute.DownstreamAddresses.FirstOrDefault();
var downstreamHost = $"{downstreamAddress.Host}:{downstreamAddress.Port}";
var channel = new Channel(downstreamHost, ChannelCredentials.Insecure); //todo: handle TLS with certs later
var client = new MethodDescriptorCaller(channel);
var requestObject = JsonConvert.DeserializeObject(requestData, methodDescriptor.InputType.ClrType);
var result = await client.InvokeAsync(methodDescriptor, context.HttpContext.GetRequestHeaders(), requestObject);
var response = new OkResponse <GrpcHttpContent>(new GrpcHttpContent(JsonConvert.SerializeObject(result)));
var httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK)
{
Content = response.Data
};
context.HttpContext.Response.ContentType = "application/json";
context.DownstreamResponse = new DownstreamResponse(httpResponseMessage);
}
}
}
public async Task Invoke(HttpContext context, GrpcAssemblyResolver grpcAssemblyResolver, IOptions <GrpcMapperOptions> options)
{
if (!context.Request.Headers.Any(h => h.Key.ToLowerInvariant() == "content-type" && h.Value == "application/grpc"))
{
await _next(context);
}
else
{
var path = context.Request.Path.Value;
var methodDescriptor = grpcAssemblyResolver.FindMethodDescriptor(path.Split('/').Last().ToUpperInvariant());
if (methodDescriptor == null)
{
await _next(context);
}
else
{
string requestData;
if (context.Request.Method.ToLowerInvariant() == "get")
{
requestData = context.ParseGetJsonRequestOnAggregateService();
}
else
{
requestData = await context.ParseOtherJsonRequestOnAggregateService();
}
var grpcLookupTable = options.Value.GrpcMappers;
var grpcClient = grpcLookupTable.FirstOrDefault(x => x.GrpcMethod == path).GrpcHost; //todo: should catch object to throw exception
var channel = new Channel(grpcClient, ChannelCredentials.Insecure);
var client = new MethodDescriptorCaller(channel);
var requestObject = JsonConvert.DeserializeObject(requestData, methodDescriptor.InputType.ClrType);
var result = await client.InvokeAsync(methodDescriptor, context.GetRequestHeaders(), requestObject);
await context.Response.WriteAsync(JsonConvert.SerializeObject(result));
}
}
}