VILLASnode/lib/api/response.cpp

/* API Response.
 *
 * Author: Steffen Vogel <post@steffenvogel.de>
 * SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
 * SPDX-License-Identifier: Apache-2.0
 */

#include <villas/api/request.hpp>
#include <villas/api/response.hpp>
#include <villas/config.hpp>

using namespace villas::node::api;

Response::Response(Session *s, int c, const std::string &ct, const Buffer &b)
    : session(s), logger(logging.get("api:response")), buffer(b), code(c),
      contentType(ct),
      headers{{"Server:", HTTP_USER_AGENT},
              {"Access-Control-Allow-Origin:", "*"},
              {"Access-Control-Allow-Methods:", "GET, POST, OPTIONS"},
              {"Access-Control-Allow-Headers:", "Content-Type"},
              {"Access-Control-Max-Age:", "86400"}} {}

int Response::writeBody(struct lws *wsi) {
  int ret;

  ret = lws_write(wsi, (unsigned char *)buffer.data(), buffer.size(),
                  LWS_WRITE_HTTP_FINAL);
  if (ret < 0)
    return -1;

  return 1;
}

int Response::writeHeaders(struct lws *wsi) {
  int ret;
  uint8_t headerBuffer[2048], *p = headerBuffer,
                              *end = &headerBuffer[sizeof(headerBuffer) - 1];

  // We need to encode the buffer here for getting the real content length of the response
  encodeBody();

  ret = lws_add_http_common_headers(wsi, code, contentType.c_str(),
                                    buffer.size(), &p, end);
  if (ret)
    return 1;

  for (auto &hdr : headers) {
    ret = lws_add_http_header_by_name(
        wsi, reinterpret_cast<const unsigned char *>(hdr.first.c_str()),
        reinterpret_cast<const unsigned char *>(hdr.second.c_str()),
        hdr.second.size(), &p, end);
    if (ret)
      return -1;
  }

  ret = lws_finalize_write_http_header(wsi, headerBuffer, &p, end);
  if (ret)
    return 1;

  // Do we have a body to send?
  if (buffer.size() > 0)
    lws_callback_on_writable(wsi);

  return 0;
}

JsonResponse::~JsonResponse() {
  if (response)
    json_decref(response);
}

void JsonResponse::encodeBody() { buffer.encode(response, JSON_INDENT(4)); }