qt5-legatus-legacy/Lts/Common/LtsRestClient/lts_rest_client.cpp

/**
 * Lightweight REST Client Framework
 * $Id$
 * $HeadURL$
 * $Author$
 * Created by Hannes Fritsche, ESZS, 2026-08-21
 */

#include "lts_rest_client.h"
#include <QTimer>
#include <QUrl>
#include <QtNetwork/QNetworkAccessManager>
#include <QtNetwork/QNetworkReply>
#include <QtNetwork/QNetworkRequest>

namespace LtsCommon
{

LtsRestClient::LtsRestClient(const QString &baseUrl, QObject *parent)
  : QObject(parent)
  , m_baseUrl(baseUrl)
  , m_manager(new QNetworkAccessManager(this))
{
}

void LtsRestClient::ping(PingSuccessCallback onSuccess, ErrorCallback onError, int timeoutMs)
{
  const QNetworkRequest request((QUrl(m_baseUrl)));
  QNetworkReply *reply = m_manager->head(request);

  if (!reply)
  {
    if (onError)
      onError(QStringLiteral("Failed to initiate ping."));

    return;
  }

  // 1. Setup the timer (parented to reply for auto-cleanup)
  QTimer *timeoutTimer = new QTimer(reply);
  timeoutTimer->setSingleShot(true);

  // 2. Connect the timeout signal to abort the request
  connect(timeoutTimer, &QTimer::timeout, this, [reply]()
  {
    if (reply && reply->isRunning())
      reply->abort(); // Triggers finished() with OperationCanceledError
  });

  // 3. Connect the finished signal to handle the response
  connect(reply,
          &QNetworkReply::finished,
          this,
          [reply, timeoutTimer, onSuccess, onError]()
  {
    timeoutTimer->stop();
    reply->deleteLater();

    if (reply->error() != QNetworkReply::NoError)
    {
      if (onError)
      {
        if (reply->error() == QNetworkReply::OperationCanceledError)
          onError(QStringLiteral("Ping timed out."));
        else
          onError(reply->errorString());
      }

      return;
    }

    const int statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();

    if (onSuccess)
      onSuccess(statusCode);
  });

  // 4. Start the timer only after all connections are successfully established
  timeoutTimer->start(timeoutMs);
}

void LtsRestClient::get(const QString &endpoint, SuccessCallback onSuccess, ErrorCallback onError)
{
  sendRequest(QStringLiteral("GET"), endpoint, QByteArray(), onSuccess, onError);
}

void LtsRestClient::post(const QString &endpoint, const QJsonDocument &json, SuccessCallback onSuccess, ErrorCallback onError)
{
  sendRequest(QStringLiteral("POST"), endpoint, json.toJson(), onSuccess, onError);
}

void LtsRestClient::put(const QString &endpoint, const QJsonDocument &json, SuccessCallback onSuccess, ErrorCallback onError)
{
  sendRequest(QStringLiteral("PUT"), endpoint, json.toJson(), onSuccess, onError);
}

void LtsRestClient::del(const QString &endpoint, SuccessCallback onSuccess, ErrorCallback onError)
{
  sendRequest(QStringLiteral("DELETE"), endpoint, QByteArray(), onSuccess, onError);
}

void LtsRestClient::sendRequest(const QString &method, const QString &endpoint, const QByteArray &data, SuccessCallback onSuccess, ErrorCallback onError)
{
  QUrl url(m_baseUrl);
  url.setPath(url.path() + endpoint);

  QNetworkRequest request(url);
  request.setHeader(QNetworkRequest::ContentTypeHeader, QStringLiteral("application/json"));

  QNetworkReply *reply = nullptr;

  if (method == QStringLiteral("GET"))
    reply = m_manager->get(request);
  else if (method == QStringLiteral("POST"))
    reply = m_manager->post(request, data);
  else if (method == QStringLiteral("PUT"))
    reply = m_manager->put(request, data);
  else if (method == QStringLiteral("DELETE"))
    reply = m_manager->deleteResource(request);

  if (!reply)
  {
    if (onError)
      onError(QStringLiteral("Failed to initiate request."));

    return;
  }

  connect(reply,
          &QNetworkReply::finished,
          this,
          [reply, onSuccess, onError]()
  {
    reply->deleteLater();

    // Handle network errors
    if (reply->error() != QNetworkReply::NoError)
    {
      if (onError)
        onError(reply->errorString());

      return;
    }

    // Handle HTTP errors
    const int statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
    if (statusCode >= 400)
    {
      if (onError)
        onError(QStringLiteral("HTTP Error %1").arg(statusCode));

      return;
    }

    // Parse JSON safely
    QJsonParseError parseError;
    const QJsonDocument doc = QJsonDocument::fromJson(reply->readAll(), &parseError);

    if (parseError.error != QJsonParseError::NoError)
    {
      if (onError)
        onError(QStringLiteral("JSON Parse Error: ") + parseError.errorString());

      return;
    }

    if (onSuccess)
      onSuccess(doc);
  });
}

} // namespace LtsCommon