cpp/http_helpers.cpp

#include "http_helpers.h"

#include <boost/asio.hpp>
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>

#include <ctime>
#include <iomanip>
#include <iostream>
#include <sstream>

namespace asio = boost::asio;
namespace beast = boost::beast;
namespace http = beast::http;

std::string now_utc_iso() {
    std::time_t t = std::time(nullptr);
    std::tm tm{};
    gmtime_r(&t, &tm);
    std::ostringstream oss;
    oss << std::put_time(&tm, "%Y-%m-%dT%H:%M:%SZ");
    return oss.str();
}

void log_line(const std::string &line) {
    std::cout << "[" << now_utc_iso() << "] " << line << std::endl;
}

std::string truncate_body(const std::string &body, size_t max_len) {
    if (body.size() <= max_len) return body;
    return body.substr(0, max_len) + "...[truncated]";
}

std::optional<std::string> extract_cancel_request_id(const std::string &path) {
    const std::string prefix = "/requests/";
    const std::string suffix = "/cancel";
    if (path.size() <= prefix.size() + suffix.size()) return std::nullopt;
    if (path.rfind(prefix, 0) != 0) return std::nullopt;
    if (path.substr(path.size() - suffix.size()) != suffix) return std::nullopt;
    const std::string request_id = path.substr(prefix.size(), path.size() - prefix.size() - suffix.size());
    if (request_id.empty()) return std::nullopt;
    return request_id;
}

std::pair<int, std::string> forward_chat(const WorkerInfo &worker, const std::string &body) {
    asio::io_context ioc;
    asio::ip::tcp::resolver resolver(ioc);
    beast::tcp_stream stream(ioc);
    auto const results = resolver.resolve("127.0.0.1", std::to_string(worker.port));
    stream.connect(results);

    http::request<http::string_body> req{http::verb::post, "/v1/chat/completions", 11};
    req.set(http::field::host, "127.0.0.1");
    req.set(http::field::content_type, "application/json");
    req.set(http::field::user_agent, "llm-manager");
    req.body() = body;
    req.prepare_payload();
    http::write(stream, req);

    beast::flat_buffer buffer;
    http::response<http::string_body> res;
    http::read(stream, buffer, res);
    beast::error_code ec;
    stream.socket().shutdown(asio::ip::tcp::socket::shutdown_both, ec);
    return {res.result_int(), res.body()};
}

ProxiedGetResult forward_get_to_worker(const WorkerInfo &worker, const std::string &target) {
    asio::io_context ioc;
    asio::ip::tcp::resolver resolver(ioc);
    beast::tcp_stream stream(ioc);
    auto const results = resolver.resolve("127.0.0.1", std::to_string(worker.port));
    stream.connect(results);

    http::request<http::string_body> req{http::verb::get, target, 11};
    req.set(http::field::host, "127.0.0.1");
    req.set(http::field::user_agent, "llm-manager");
    req.set(http::field::accept_encoding, "gzip, identity");
    http::write(stream, req);

    beast::flat_buffer buffer;
    http::response<http::string_body> res;
    http::read(stream, buffer, res);
    beast::error_code ec;
    stream.socket().shutdown(asio::ip::tcp::socket::shutdown_both, ec);

    ProxiedGetResult out;
    out.status = res.result_int();
    out.body = res.body();
    if (res.base().find(http::field::content_type) != res.base().end()) {
        out.content_type = res.base()[http::field::content_type].to_string();
    }
    if (res.base().find(http::field::content_encoding) != res.base().end()) {
        out.content_encoding = res.base()[http::field::content_encoding].to_string();
    }
    return out;
}