Method server_http_proxy

tools/server/server-models.cpp:1129–1253

}

server_http_proxy::server_http_proxy(
        const std::string & method,
        const std::string & scheme,
        const std::string & host,
        int port,
        const std::string & path,
        const std::map<std::string, std::string> & headers,
        const std::string & body,
        const std::function<bool()> should_stop,
        int32_t timeout_read,
        int32_t timeout_write
        ) {
    // shared between reader and writer threads
    auto cli  = std::make_shared<httplib::ClientImpl>(host, port);
    auto pipe = std::make_shared<pipe_t<msg_t>>();

    if (scheme == "https") {
#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
        cli.reset(new httplib::SSLClient(host, port));
#else
        throw std::runtime_error("HTTPS requested but CPPHTTPLIB_OPENSSL_SUPPORT is not defined");
#endif
    }

    // setup Client
    cli->set_follow_location(true);
    cli->set_connection_timeout(timeout_read, 0); // use --timeout value instead of hardcoded 5 s
    cli->set_write_timeout(timeout_read, 0); // reversed for cli (client) vs srv (server)
    cli->set_read_timeout(timeout_write, 0);
    this->status = 500; // to be overwritten upon response
    this->cleanup = [pipe]() {
        pipe->close_read();
        pipe->close_write();
    };

    // wire up the receive end of the pipe
    this->next = [pipe, should_stop](std::string & out) -> bool {
        msg_t msg;
        bool has_next = pipe->read(msg, should_stop);
        if (!msg.data.empty()) {
            out = std::move(msg.data);
        }
        return has_next; // false if EOF or pipe broken
    };

    // wire up the HTTP client
    // note: do NOT capture `this` pointer, as it may be destroyed before the thread ends
    httplib::ResponseHandler response_handler = [pipe, cli](const httplib::Response & response) {
        msg_t msg;
        msg.status = response.status;
        for (const auto & [key, value] : response.headers) {
            const auto lowered = to_lower_copy(key);
            if (should_strip_proxy_header(lowered)) {
                continue;
            }
            if (lowered == "content-type") {
                msg.content_type = value;
                continue;