正则表达式自动提取网页内容

使用正则表达式自动提取网页内容。

lesson learn：

1.  处理前替换掉页面中的回车换行，以便执行第2步
2.  使用 ".*?" 进行非贪婪匹配，结合正则表达式尾部的 "(?.*)"，反复对剩余内容进行匹配，直至没有匹配内容
3.  尖括号（< >），双引号( " ) 等特殊字符需要注意添加反斜杠（ \ ）转义
4.  使用正则表达式方法 reInfo.patternErrorOffset() 来确认正则方法是否正确；
5.  使用 QtConcurrent::run( this, &DataSource::fetch, 7 ) 线程化耗时操作

#define DIV_BGN  "\\.*?"
#define ITEM_CLS    "class=\\\"item\\\".*?"
#define NAME_CLS    "class=\\\"name\\\".*?"
#define LINK_NAME_ELEM      "\\.*?.html)\\\"\\s+?title=\\\"(?.*?)\\\"\\s.*?class=\\\"name\\-text\\\".*?"

#define INFO_CLS     "class=\\\"info\\\".*?"
#define DESC_ELEM    "\\.*?)\\\"\\s.*?class=\\\"text\\\".*?"

#define OTHER_CLS   "class=\\\"other\\\".*?"
#define SIZE_ELEM    "\\大小:(?.*?)\\.*?"
#define SEED_ELEM   DIV_BGN \
                        "class=\\\"seed-down\\\".*?href=\\\"(?http.*?\\.torrent)\\\".*?" \
                    DIV_END
#define MAGNET_ELEM  DIV_BGN \
                        "\\s*class=\\\"magnet\\\".*?href=\\\"(?magnet.*?)\\\".*?" \
                     DIV_END
#define REST_DATA    "(?.*)"

const QRegularExpression  reInfo(
                        DIV_BGN ITEM_CLS
                            DIV_BGN NAME_CLS
                                LINK_NAME_ELEM
                            DIV_END
                            DIV_BGN INFO_CLS
                                DESC_ELEM
                                DIV_BGN OTHER_CLS
                                    SIZE_ELEM
                                    SEED_ELEM
                                    MAGNET_ELEM
                                DIV_END
                            DIV_END
                        DIV_END
                        REST_DATA
            );

void DataSource::fetch( int idx)
{

    qint64  i=0;
    QRegularExpressionMatch match;

    for( int k=1 ; k< 240 ; k++ )
    {
        int try_cnt = 0;
        TinyCurl  curl;
        QEventLoop  evtLoop;
        QByteArray replyData;
        QUrl url = QString("https://hide-the-real-url/sort-%1-%2.html").arg(idx).arg(k);

        QNetworkReply::NetworkError err =  QNetworkReply::UnknownNetworkError;
        for( try_cnt=0 ; (try_cnt<3) && ( QNetworkReply::NoError != err ) ; try_cnt++ );
        {
            err = curl.get( url, replyData, evtLoop );
        }
        if( QNetworkReply::NoError != err )
        {
            continue;
        }
        QString data(replyData);
        data.replace("\r", "").replace("\n", "");

//        if( reInfo.patternErrorOffset() >= 0 )
//        {
//            qDebug() << "reInfo.patternErrorOffset : "  << reInfo.patternErrorOffset();
//        }

        while( ( match = reInfo.match( data ) ).hasMatch() )
        {
            qDebug() << "Name" << match.captured("name");
            qDebug() << "Page" <<  match.captured("link");
            qDebug() << "Desc" <<  match.captured("desc");
            qDebug() << "Size" <<  match.captured("size");
            qDebug() << "Magnet" <<  match.captured("magnet");
            qDebug() << "seed" <<  match.captured("seed");

            data = match.captured("rest");
        }
    }
}


void DataSource::start()
{
    craber = QtConcurrent::run( this, &DataSource::fetch, 7 );
}