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Thread: Qt way of getting/parsing style attributes from html tags? local file batch

  1. #1
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    Thumbs up Qt way of getting/parsing style attributes from html tags? local file batch

    I have this old and dirty code I wrote some years ago that basically parsed css styles from local html documents. That code is really really ugly, and I would like to Qtify it!

    I don't need rendering the webpage at all, just opening local files, reading them and closing them (in batch). How would you guys tackle this?

    I first thought using the webkit somehing like:
    Qt Code:
    1. QWebPage page;
    2. QWebFrame * frame = page.mainFrame();
    3. QUrl fileUrl("localFile.html");
    4. frame->setUrl(fileUrl);
    5. QWebElement document = frame->documentElement();
    6. QWebElementCollection elements = document.findAll("div");
    7. foreach (QWebElement element, elements){
    8. std::cout << element.attribute("style").toStdString() << std::endl;
    9. }
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    That didn't work... Why?

    Can I work with html files like legal xml? In that case, getting the attributes from the styles is going to be somewhat annoying, knowing all the styles are declared in the "head"...

    Any ideas, what Qclasses can be helpful here?
    Last edited by toglia3d; 10th June 2010 at 16:24.

  2. #2
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    Default Re: Qt way of getting/parsing style attributes from html tags? local file batch

    This will get you everything. That may not be what you want. I'm not sure of a way of getting only author specified styles.
    Qt Code:
    1. #include <QtWebKit>
    2. #include <QApplication>
    3. #include <QtCore>
    4. int main(int argc, char * argv[])
    5. {
    6. QApplication a(argc, argv);
    7.  
    8. QWebPage page;
    9. QWebFrame * frame = page.mainFrame();
    10. frame->setHtml("<html><head><style>div { color:blue; }</style><body><div style=\"font-size:120%;\">Hello World!</div></body></html>");
    11. QWebElement document = frame->documentElement();
    12. QWebElementCollection elements = document.findAll("div");
    13. foreach (QWebElement element, elements)
    14. {
    15. QString style = element.evaluateJavaScript("getComputedStyle(this).cssText").toString();
    16. QStringList styles = style.split(';');
    17. foreach(QString pair, styles)
    18. {
    19. QStringList keyvalue = pair.split(':');
    20.  
    21. if (keyvalue.length() == 2)
    22. qDebug() << keyvalue.at(0).trimmed() << " = " << keyvalue.at(1).trimmed();
    23. }
    24. }
    25. }
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  3. #3
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    Default Re: Qt way of getting/parsing style attributes from html tags? local file batch

    Thanks numbat. I will check it out when I get home. Seems like your doing everything I need.

    Another thing, is there a more elegant way of putting the file into a QString than the following?

    Qt Code:
    1. QFile file("local.html");
    2. QTextStream in(&file);
    3. QString completeHtml;
    4. while (!in.atEnd()) {
    5. completeHtml.append(in.readLine());
    6. }
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    Default Re: Qt way of getting/parsing style attributes from html tags? local file batch

    You can use readAll. Here's a way to just get the rules in the style sheets:
    Qt Code:
    1. #include <QtWebKit>
    2. #include <QApplication>
    3. #include <QtCore>
    4. int main(int argc, char * argv[])
    5. {
    6. QApplication a(argc, argv);
    7.  
    8. QWebPage page;
    9. QWebFrame * frame = page.mainFrame();
    10. frame->setHtml("<html><head><style>div { color:blue; } span {font-weight: bold;}</style><body><div style=\"font-size:120%;\">Hello World!</div></body></html>");
    11. QVariant vt = frame->evaluateJavaScript(
    12. "out = []; "
    13. "for (j = 0; j < document.styleSheets.length; j++) { "
    14. "for (i = 0; i < document.styleSheets[j].cssRules.length; i++) { "
    15. "out[i] = document.styleSheets[j].cssRules[i].style.cssText; } } "
    16. "out = out;");
    17. foreach (QVariant v, vt.toList())
    18. {
    19. qDebug() << v.toString();
    20. }
    21. }
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  5. #5
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    Default Re: Qt way of getting/parsing style attributes from html tags? local file batch

    Thanks again.

    Seriously, Qt has all the nutrients and vitamins a young programmer needs to grow healthy.

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    Default Re: Qt way of getting/parsing style attributes from html tags? local file batch

    You don't need QtWebKit just to parse an xml file. Either use one of QXmlStreamReader or QDomDocument or use QtXmlPatterns module to query for specific tags in the file. If you just want contents of all "style" attributes in the file, the last approach will be best. Something like this might work:
    Qt Code:
    1. QXmlQuery qry;
    2. qry.setQuery("doc('file.html')//@style"); // "doc('...')//div@style" will give you all 'style' attrs from all 'div' tags
    3. // or:
    4. // QFile f("file.html");
    5. // f.open(QFile::ReadOnly|QFile::Text);
    6. // qry.setFocus(&f);
    7. // qry.setQuery("//@style");
    8. qry.evaluateTo(&list);
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    Your biological and technological distinctiveness will be added to our own. Resistance is futile.

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  7. #7
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    Default Re: Qt way of getting/parsing style attributes from html tags? local file batch

    Huh? Please excuse me while I pick my jaw up from the ground.
    Thats just beautiful.

  8. #8
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    Default Re: Qt way of getting/parsing style attributes from html tags? local file batch

    Thanks: Found this thread by searching, answered my question.

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