Support for application/grpc-web+[proto, json, thrift]

Is your feature request related to a problem? Please describe. load test a web server that runs on grpc-web+[proto, json, thrift] https://github.com/grpc/grpc-web

Describe the solution you’d like we can use “scalapb-grpcweb” for generating Scala sources needed to implement clients for gRPC-web (similar to “scalapb-runtime-grpc”) Similar structure/template that was used for supporting gRPC over http/2.0 i.e

  grpc("Requests 1")
      .rpc(GrpcWeb.METHOD_AUTH)
      .payload(
        AuthRequest(
          email = "[e-mail]"
        )
      )
      .header(ReqIdHeader)(Random.alphanumeric take 30 mkString "")

[phiSgr]

I’m talking about porting this file.

[UserNoOne]

Finally able to trigger request from Gatling/Scala towards envoy proxy by following procedure mentioned in link

**The body should be the serialized grpc body which is:**
1 byte of zero (not compressed).
network order 4 bytes of proto message length.
serialized proto message.

payload = AuthReq(
        Email="[e-mail]",
        redirectUri="users-login-page/login",
        pass = "$%FDGD"
    )

val bytes = payload .toByteArray
val length = intToNetworkByteOrder(bytes.length)
var data = new Array[Byte](bytes.length + 5)
data(0) = '\u0000'.toByte
System.arraycopy(length, 0, data, 1, length.length)
System.arraycopy(bytes, 0, data, 5, bytes.length)

def intToNetworkByteOrder(num: Int): Array[Byte] = {
    var localNum = num
    val buf = new Array[Byte](4)
    for (i <- 3 to 0 by -1) {
      buf(i) = (localNum & 0xff).toByte
      localNum >>>= 8
    }
    buf
  }

And finally above data variable is used in Gatling http request body