[QUESTION] What is Endian of Message Length

[lykhouzov]

Hi, I am trying to repeat the examples but in Rust an faced a little issue that i cannot find following.
In tutorial it is said that message frame structure is following

 +--------------------------+-----------------------------------------+  
 | Message Length (4 bytes) | Serialized ProtoMessage object (byte[]) |  
 +--------------------------+-----------------------------------------+  
                            |<---------- Message Length ------------->|

But i cannot find is method length is Big or Little Endian.
I've tried both variant and both gives me empty response
for example i am sending following message

let msg = ProtoOAGetAccountListByAccessTokenReq{
        payloadType: ProtoOAPayloadType::PROTO_OA_GET_ACCOUNTS_BY_ACCESS_TOKEN_REQ,
        accessToken: Cow::from(ACCESS_TOKEN),
    };

and then i can get a response and decode it but a structure has empty(default) fields

ProtoOAGetAccountListByAccessTokenRes {
    payloadType: PROTO_OA_GET_ACCOUNTS_BY_ACCESS_TOKEN_RES,
    accessToken: "",
    permissionScope: None,
    ctidTraderAccount: [],
}

when I read from stream

let mut length: [u8; 4] = [0x00; 4];
    stream.read_exact(&mut length)?;
    println!("received bytes = {:?}, length = {:?}", length, i32::from_le_bytes(length));

I get following bytes and converted into length

received bytes = [21, 3, 1, 0], length = 66325

that is i am receiving some response, but it looks like it is empty(default) response message

could you help me with this?
Thank you.

[LeoSko]

@lykhouzov, I know this is old, but if you haven't resolved it yet, here it is: we use big endian. :) And could you try out the other message, e.g. ProtoOAApplicationAuthReq - does it work for you?