The User-Agent HTTP header is hardcoded/overwritten to libhttpclient/1.0.0.0 regardless of custom settings.

Description

When making HTTP requests using the internal HTTP client libraries, the User-Agent header cannot be customized. Even if a custom User-Agent is explicitly defined in the code, it is overwritten or ignored during the final transmission, resulting in all requests being sent with User-Agent: libhttpclient/1.0.0.0.

This behavior prevents proper identification of specific services or versions and departs from the expected behavior of a standard HTTP client implementation.

Steps to Reproduce

1. Initialize an HTTP request using the internal library.

2. Set a custom string for the User-Agent header (e.g., "MyCustomClient/1.0").

3. Execute the request to a destination that logs incoming headers (e.g., a local mock server or a service like Webhook.site).

4. Inspect the received HTTP headers.

Observed Results

The received User-Agent is always libhttpclient/1.0.0.0.

Expected Results

The received User-Agent should match the custom string set in the code.

Environment & Platform

• OS: Observed on both Windows and Linux.

• Impact: Cross-platform consistency suggests this is a hardcoded value within the common library logic.

• Version: 1.26.20-beta26

• Build ID: 43049666

• Branch: r/26_u2

• Commit ID: 7c7f24697370a34623235a6a0dfeb6bf59e3c3f4

• Configuration: Publish

• Required Permissions: @minecraft/server-net enabled in permissions.json.

Code Snippet

import { http, HttpHeader, HttpRequest, HttpRequestMethod, } from "@minecraft/server-net";
import { system } from "@minecraft/server";
export const URL = "http://127.0.0.1:1080";

export async function call() {

    const req = new HttpRequest(URL);
    req.method = HttpRequestMethod.Post;
    const User_agent = new HttpHeader("User-Agent", "RooCode/1.0");
    const Content_Type = new HttpHeader("Content-Type", "application/json");
    const Authorization = new HttpHeader("Authorization", `Bearer xxx`);


    req.headers = [
        User_agent,
        Content_Type,
        Authorization,
    ];


    console.log(req.headers)
    req.headers.forEach(header => {
        console.log(`${header.key}: ${header.value}`);
    });


    req.body = JSON.stringify({
        nothing: "nonono"
    });
    req.timeout = 30*1000;

    const resp = await http.request(req);
    if (resp.status !== 200) {
        throw new Error(`${resp.status}: ${resp.body}`);
    }
    console.log(`Response: ${resp.body}`);
    return resp.body
}

system.run(() => {
    call()
});

console.log("Hello, World!");

The following is the actual packet received by the local mock server, showing the overwritten header.

POST / HTTP/1.1
Connection: Keep-Alive
Content-Type: application/json
Authorization: Bearer xxx
User-Agent: libhttpclient/1.0.0.0
Content-Length: 20
Host: 127.0.0.1:1080

{"nothing":"nonono"}

Key Finding: As shown above, while other headers like Authorization and Content-Type are correctly processed, the User-Agent remains libhttpclient/1.0.0.0 despite being set differently in the application code.