Wt

I found 3 problems while trying to send changes to WCssStyleSheet. All 3 problems can be reproduced with the C file and config file included. I simply edited hello.C.

I also included a function to post new WText widget to all open sessions to test if push is working properly.

1. WServer::post() WCssStyleSheet changes do not get pushed. Only the session that sent the changes is successfully updated.¶

To reproduce

1. Compile with bool USE_INLINE_WCSSSTYLESHEET = true;
   
2. Open 2 or more sessions, use any combination of browsers(I used Chrome, Firefox and Safari iOS)
   

3. Press the 'toggle styleSheet() rules' button
   
   You will see that the session that you clicked the button from will be updated perfectly, however, the other open sessions gets the changes post()ed, however, the are not 'pushed' to the browser. If you refresh the session from the browser refresh button, first the page will, for a fraction of a second, change color but it will go back to white. If you refresh again then only the changes will become permanent.

2. External stylesheets do not link properly after a refresh¶

To reproduce

1. Compile with bool USE_INLINE_WCSSSTYLESHEET = false;
   
2. Open a session
   

3. Press the browser refresh button
   
   You will that the html has a background colour, however, after you refresh the page the background colour will be gone and it'll be plain white.

3. Problem clearing/deleting CssRules from UserStyleSheet¶

To reproduce

1. Compile with bool USE_INLINE_WCSSSTYLESHEET = false;
   
2. Open 2 or more sessions
   
3. Press the 'toggle styleSheet() rules' two times
   I get an unhandled exception error in 'void WCssStyleSheet::clear()' 2nd line 'delete rules_.back();'

wt_config.xml

<server>
    <application-settings location="*">
        <session-management>
            <tracking>URL</tracking>
            <reload-is-new-session>false</reload-is-new-session>
        </session-management>
        <log-config>* -debug -info</log-config>
    </application-settings>
</server>

hello.C

#include <Wt/WApplication>
#include <Wt/WBreak>
#include <Wt/WContainerWidget>
#include <Wt/WPushButton>
#include <Wt/WServer>
#include <Wt/WCssStyleSheet>

using namespace Wt;

bool USE_INLINE_WCSSSTYLESHEET = false;

class HelloApplication : public WApplication
{
public:
    HelloApplication(const WEnvironment& env);
    ~HelloApplication();

    void ResetCssRules(WCssTextRule *rule);
    void Listen(const std::string &sessionId);

private:
    bool S;
    WCssStyleSheet UserStyleSheet;
};

typedef std::set<HelloApplication *> AppSetType;
AppSetType AppSet;

HelloApplication::HelloApplication(const WEnvironment& env)
    : WApplication(env), S(false)
{
    setTitle("WCssStyleSheet update test");

    //initial html css rule
    if(USE_INLINE_WCSSSTYLESHEET)
        styleSheet().addRule(new WCssTextRule("html", "background:#FFEE00;"));
    else
        UserStyleSheet.addRule(new WCssTextRule("html", "background:#FFEE00;"));

    useStyleSheet(UserStyleSheet);

    auto button = new WPushButton("Toggle styleSheet() rules", root());
    button->setFocus();
    button->clicked().connect(boost::bind<void>([this](){
        WCssTextRule *NewCssRule;
        if(S)
        {
            NewCssRule = new WCssTextRule("html", "background:#FFEE00;");
        }
        else
        {
            NewCssRule = new WCssTextRule("html", "background:#123456;");
        }

        for(AppSetType::iterator itr = AppSet.begin();
            itr != AppSet.end();
            ++itr)
        {
            if(*itr == this) //Call function directly if its the same app
                ResetCssRules(NewCssRule);
            else
                WServer::instance()->post((*itr)->sessionId(), boost::bind(&HelloApplication::ResetCssRules, *itr, NewCssRule));
        }

        S = !S;
    }));

    auto sayHiButton = new WPushButton("Say Hi to every one", root());
    sayHiButton->clicked().connect(boost::bind<void>([this](){
        for(AppSetType::iterator itr = AppSet.begin();
            itr != AppSet.end();
            ++itr)
        {
            if(*itr == this) //Call function directly if its the same app
                Listen(sessionId());
            else
                WServer::instance()->post((*itr)->sessionId(), boost::bind(&HelloApplication::Listen, *itr, sessionId()));
        }
    }));

    //I use mutex, but I don't believe it would be a problem for testing
    AppSet.insert(this);

    enableUpdates();
}

HelloApplication::~HelloApplication()
{
    //I use mutex, but I don't believe it would be a problem for testing
    AppSet.erase(this);
}

void HelloApplication::ResetCssRules(WCssTextRule *rule)
{
    if(USE_INLINE_WCSSSTYLESHEET)
    {
        styleSheet().clear();
        styleSheet().addRule(rule);
    }
    else
    {
        UserStyleSheet.clear();
        UserStyleSheet.addRule(rule);
    }
    triggerUpdate();
}

void HelloApplication::Listen(const std::string &sessionId)
{
    new WBreak(root());
    new WText(std::string("Session ") + sessionId + " said hi", root());
    triggerUpdate();
}

WApplication *createApplication(const WEnvironment& env)
{
    return new HelloApplication(env);
}

int main(int argc, char **argv)
{
    return WRun(argc, argv, &createApplication);
}