gdownloader.h

/*
 * File: gdownloader.h
 * -------------------
 * A GDownloader can download data from URLs and save them to files or return
 * the data as a string.
 *
 * Note that because the downloader uses a pure-C++ implementation, your project
 * must include the 'network' component of Qt to function properly.
 * If you get errors when trying to connect to HTTPS URLs, you may also need to
 * install various SSL packages on your system, such as openssl, libssl-dev,
 * libssl1.0, and so on.  This varies by operating system.
 *
 * Based somewhat on this source:
 * https://wiki.qt.io/Download_Data_from_URL
 *
 * @author Marty Stepp
 * @version 2021/04/09
 * - added sgl namespace
 * @version 2021/04/03
 * - removed dependency on custom collections
 * @version 2018/09/18
 * - working version; had to fix various threading / Qt signal issues
 * @version 2018/09/07
 * - added doc comments for new documentation generation
 * @version 2018/08/23
 * - renamed to gdownloader.h to replace Java version
 * @version 2018/08/03
 * - initial version
 */

#ifndef _gdownloader_h
#define _gdownloader_h

#include <map>
#include <string>
#include <QNetworkAccessManager>
#include <QNetworkReply>

namespace sgl {

class GDownloader : public QObject {
    Q_OBJECT

public:
    GDownloader();

    virtual ~GDownloader();

    string downloadAsString(const string& url);

    void downloadToFile(const string& url, const string& file);

    string getErrorMessage() const;

    string getHeader(const string& name) const;

    int getHttpStatusCode() const;

    string getUserAgent() const;

    bool hasError() const;

    void httpGet(const string& url);

    void httpPost(const string& url);

    void setHeader(const string& name, const string& value);

    void setUserAgent(const string& userAgent);

signals:
    void downloaded();

private slots:
    void downloadInternal();
    void fileDownloadError(QNetworkReply::NetworkError);
    void saveDownloadedData(const string& member, const string& filename = "");
    void sslErrors(QList<QSslError>);
    void waitForDownload();

private:
    Q_DISABLE_COPY(GDownloader)

    static string qtNetworkErrorToString(QNetworkReply::NetworkError nerror);

    QNetworkAccessManager* _manager;
    QNetworkReply* _reply;
    std::map<string, string> _headers;   // HTTP headers to send (name => value)
    int _httpStatusCode;
    bool _downloadComplete;
    string _url;
    string _filename;
    string _filedata;
    string _lastErrorMessage;
};

} // namespace sgl

#endif // _gdownloader_h