Public Member Functions | Private Types | Private Member Functions | Private Attributes

SimpleChatWidget Class Reference
[Chat example]

A self-contained chat widget. More...

#include <SimpleChatWidget.h>

Inheritance diagram for SimpleChatWidget:
Inheritance graph
[legend]

List of all members.

Public Member Functions

 SimpleChatWidget (SimpleChatServer &server, Wt::WContainerWidget *parent=0)
 Create a chat widget that will connect to the given server.
 ~SimpleChatWidget ()
 Delete a chat widget.
void letLogin ()
 Show a simple login screen.
bool startChat (const Wt::WString &user)
 Start a chat for the given user.

Private Types

typedef std::map< Wt::WString,
bool > 
UserMap

Private Member Functions

void login ()
void logout ()
void send ()
void updateUsers ()
void updateUser ()
void processChatEvent (const ChatEvent &event)

Private Attributes

UserMap users_
SimpleChatServerserver_
Wt::WApplicationapp_
Wt::JSlot clearInput_
Wt::WString user_
Wt::WLineEdituserNameEdit_
Wt::WTextstatusMsg_
Wt::WContainerWidgetmessages_
Wt::WContainerWidgetmessageEditArea_
Wt::WTextAreamessageEdit_
Wt::WPushButtonsendButton_
Wt::WContainerWidgetuserList_
boost::signals::connection eventConnection_
Wt::WSound messageReceived_

Detailed Description

A self-contained chat widget.

Definition at line 33 of file SimpleChatWidget.h.


Member Typedef Documentation

typedef std::map<Wt::WString, bool> SimpleChatWidget::UserMap [private]

Definition at line 55 of file SimpleChatWidget.h.


Constructor & Destructor Documentation

SimpleChatWidget::SimpleChatWidget ( SimpleChatServer server,
Wt::WContainerWidget parent = 0 
)

Create a chat widget that will connect to the given server.

Definition at line 26 of file SimpleChatWidget.C.

  : WContainerWidget(parent),
    server_(server),
    app_(WApplication::instance()),
    messageReceived_("sounds/message_received.mp3")
{
  user_ = server_.suggestGuest();
  letLogin();

  // this widget supports server-side updates its processChatEvent()
  // method is connected to a slot that is triggered from outside this
  // session's event loop (usually because another user enters text).
  app_->enableUpdates();
}
SimpleChatWidget::~SimpleChatWidget (  )

Delete a chat widget.

Definition at line 42 of file SimpleChatWidget.C.

{
  logout();
}

Member Function Documentation

void SimpleChatWidget::letLogin (  )

Show a simple login screen.

Definition at line 47 of file SimpleChatWidget.C.

{
  clear();

  WVBoxLayout *vLayout = new WVBoxLayout();
  setLayout(vLayout, AlignLeft | AlignTop);

  WHBoxLayout *hLayout = new WHBoxLayout();
  vLayout->addLayout(hLayout);

  hLayout->addWidget(new WLabel("User name:"), 0, AlignMiddle);
  hLayout->addWidget(userNameEdit_ = new WLineEdit(user_), 0, AlignMiddle);
  userNameEdit_->setFocus();

  WPushButton *b = new WPushButton("Login");
  hLayout->addWidget(b, 0, AlignMiddle);
  hLayout->addStretch(1);

  b->clicked().connect(SLOT(this, SimpleChatWidget::login));
  userNameEdit_->enterPressed().connect(SLOT(this, SimpleChatWidget::login));

  vLayout->addWidget(statusMsg_ = new WText());
  statusMsg_->setTextFormat(PlainText);
}
void SimpleChatWidget::login (  ) [private]

Definition at line 72 of file SimpleChatWidget.C.

{
  WString name = WWebWidget::escapeText(userNameEdit_->text());

  if (!startChat(name))
    statusMsg_->setText("Sorry, name '" + name + "' is already taken.");
}
void SimpleChatWidget::logout (  ) [private]

Definition at line 80 of file SimpleChatWidget.C.

{
  if (eventConnection_.connected()) {
    eventConnection_.disconnect(); // do not listen for more events
    server_.logout(user_);

    letLogin();
  }
}
void SimpleChatWidget::processChatEvent ( const ChatEvent event ) [private]

Definition at line 249 of file SimpleChatWidget.C.

{
  /*
   * This is where the "server-push" happens. This method is called
   * when a new event or message needs to be notified to the user. In
   * general, it is called from another session.
   */

  /*
   * First, take the lock to safely manipulate the UI outside of the
   * normal event loop, by having exclusive access to the session.
   */
  WApplication::UpdateLock lock = app_->getUpdateLock();

  /*
   * Format and append the line to the conversation.
   *
   * This is also the step where the automatic XSS filtering will kick in:
   * - if another user tried to pass on some JavaScript, it is filtered away.
   * - if another user did not provide valid XHTML, the text is automatically
   *   interpreted as PlainText
   */
  bool needPush = false;

  /*
   * If it is not a normal message, also update the user list.
   */
  if (event.type() != ChatEvent::Message) {
    needPush = true;
    updateUsers();
  }

  bool display = event.type() != ChatEvent::Message
    || (users_.find(event.user()) != users_.end() && users_[event.user()]);

  if (display) {
    needPush = true;

    WText *w = new WText(event.formattedHTML(user_), messages_);
    w->setInline(false);
    w->setStyleClass("chat-msg");

    /*
     * Leave not more than 100 messages in the back-log
     */
    if (messages_->count() > 100)
      delete messages_->children()[0];

    /*
     * Little javascript trick to make sure we scroll along with new content
     */
    app_->doJavaScript(messages_->jsRef() + ".scrollTop += "
                       + messages_->jsRef() + ".scrollHeight;");

    /* If this message belongs to another user, play a received sound */
    if (event.user() != user_)
      messageReceived_.play();
  }

  if (needPush)
    app_->triggerUpdate();
}
void SimpleChatWidget::send (  ) [private]

Definition at line 204 of file SimpleChatWidget.C.

{
  if (!messageEdit_->text().empty()) {
    server_.sendMessage(user_, messageEdit_->text());
    if (!WApplication::instance()->environment().ajax())
      messageEdit_->setText(WString::Empty);
  }

  messageEdit_->setFocus();
}
bool SimpleChatWidget::startChat ( const Wt::WString user )

Start a chat for the given user.

Returns false if the user could not login.

Definition at line 90 of file SimpleChatWidget.C.

{
  if (server_.login(user)) {
    eventConnection_
      = server_.chatEvent().connect(SLOT(this,
                                       SimpleChatWidget::processChatEvent));
    user_ = user;    

    clear();

    /*
     * Create a vertical layout, which will hold 3 rows,
     * organized like this:
     *
     * WVBoxLayout
     * --------------------------------------------
     * | nested WHBoxLayout (vertical stretch=1)  |
     * |                              |           |
     * |  messages                    | userslist |
     * |   (horizontal stretch=1)     |           |
     * |                              |           |
     * --------------------------------------------
     * | message edit area                        |
     * --------------------------------------------
     * | WHBoxLayout                              |
     * | send | logout |       stretch = 1        |
     * --------------------------------------------
     */
    WVBoxLayout *vLayout = new WVBoxLayout();

    // Create a horizontal layout for the messages | userslist.
    WHBoxLayout *hLayout = new WHBoxLayout();

    // Add widget to horizontal layout with stretch = 1
    hLayout->addWidget(messages_ = new WContainerWidget(), 1);
    messages_->setStyleClass("chat-msgs");
    // Display scroll bars if contents overflows
    messages_->setOverflow(WContainerWidget::OverflowAuto);

    // Add another widget to hirozontal layout with stretch = 0
    hLayout->addWidget(userList_ = new WContainerWidget());
    userList_->setStyleClass("chat-users");
    userList_->setOverflow(WContainerWidget::OverflowAuto);

    hLayout->setResizable(0, true);

    // Add nested layout to vertical layout with stretch = 1
    vLayout->addLayout(hLayout, 1);

    // Add widget to vertical layout with stretch = 0
    vLayout->addWidget(messageEdit_ = new WTextArea());
    messageEdit_->setStyleClass("chat-noedit");
    messageEdit_->setRows(2);
    messageEdit_->setFocus();

    // Create a horizontal layout for the buttons.
    hLayout = new WHBoxLayout();

    // Add button to horizontal layout with stretch = 0
    hLayout->addWidget(sendButton_ = new WPushButton("Send"));
    WPushButton *b;

    // Add button to horizontal layout with stretch = 0
    hLayout->addWidget(b = new WPushButton("Logout"));

    // Add stretching spacer to horizontal layout
    hLayout->addStretch(1);

    // Add nested layout to vertical layout with stretch = 0
    vLayout->addLayout(hLayout);

    setLayout(vLayout);

    /*
     * Connect event handlers:
     *  - click on button
     *  - enter in text area
     *
     * We will clear the input field using a small custom client-side
     * JavaScript invocation.
     */

    // Create a JavaScript 'slot' (JSlot). The JavaScript slot always takes
    // 2 arguments: the originator of the event (in our case the
    // button or text area), and the JavaScript event object.
    clearInput_.setJavaScript
      ("function(o, e) {"
       "" + messageEdit_->jsRef() + ".value='';"
       "}");

    // Bind the C++ and JavaScript event handlers.
    sendButton_->clicked().connect(SLOT(this, SimpleChatWidget::send));
    messageEdit_->enterPressed().connect(SLOT(this, SimpleChatWidget::send));
    sendButton_->clicked().connect(clearInput_);
    messageEdit_->enterPressed().connect(clearInput_);

    // Prevent the enter from generating a new line, which is its
    // default function
    messageEdit_->enterPressed().setPreventDefault(true);

    b->clicked().connect(SLOT(this, SimpleChatWidget::logout));

    WText *msg = new WText
      ("<div><span class='chat-info'>You are joining the conversation as "
       + user_ + "</span></div>", messages_);
    msg->setStyleClass("chat-msg");

    updateUsers();
    
    return true;
  } else
    return false;
}
void SimpleChatWidget::updateUser (  ) [private]

Definition at line 243 of file SimpleChatWidget.C.

{
  WCheckBox *b = dynamic_cast<WCheckBox *>(sender());
  users_[b->text()] = b->isChecked();
}
void SimpleChatWidget::updateUsers (  ) [private]

Definition at line 215 of file SimpleChatWidget.C.

{
  userList_->clear();

  SimpleChatServer::UserSet users = server_.users();

  UserMap oldUsers = users_;
  users_.clear();

  for (SimpleChatServer::UserSet::iterator i = users.begin();
       i != users.end(); ++i) {
    WCheckBox *w = new WCheckBox(*i, userList_);
    w->setInline(false);

    UserMap::const_iterator j = oldUsers.find(*i);
    if (j != oldUsers.end())
      w->setChecked(j->second);
    else
      w->setChecked(true);

    users_[*i] = w->isChecked();
    w->changed().connect(SLOT(this, SimpleChatWidget::updateUser));

    if (*i == user_)
      w->setStyleClass("chat-self");
  }
}

Member Data Documentation

Definition at line 59 of file SimpleChatWidget.h.

Definition at line 61 of file SimpleChatWidget.h.

boost::signals::connection SimpleChatWidget::eventConnection_ [private]

Definition at line 74 of file SimpleChatWidget.h.

Definition at line 70 of file SimpleChatWidget.h.

Definition at line 69 of file SimpleChatWidget.h.

Definition at line 76 of file SimpleChatWidget.h.

Definition at line 68 of file SimpleChatWidget.h.

Definition at line 71 of file SimpleChatWidget.h.

Definition at line 58 of file SimpleChatWidget.h.

Definition at line 66 of file SimpleChatWidget.h.

Definition at line 63 of file SimpleChatWidget.h.

Definition at line 72 of file SimpleChatWidget.h.

Definition at line 65 of file SimpleChatWidget.h.

Definition at line 56 of file SimpleChatWidget.h.


The documentation for this class was generated from the following files:

Generated on Sat Dec 4 2010 06:32:32 for Wt by doxygen 1.7.2