Wt  4.0.1
Public Member Functions | Protected Member Functions | List of all members
Wt::WFileUpload Class Reference

A widget that allows a file to be uploaded. More...

#include <Wt/WFileUpload.h>

Inheritance diagram for Wt::WFileUpload:
Inheritance graph
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Public Member Functions

 WFileUpload ()
 Creates a file upload widget.
 
void setMultiple (bool multiple)
 Sets whether the file upload accepts multiple files. More...
 
bool multiple () const
 Returns whether multiple files can be uploaded. More...
 
void setFileTextSize (int chars)
 Sets the size of the file input.
 
int fileTextSize () const
 Returns the size of the file input.
 
std::string spoolFileName () const
 Returns the spooled location of the uploaded file. More...
 
WString clientFileName () const
 Returns the client filename. More...
 
WString contentDescription () const
 Returns the client content description. More...
 
void stealSpooledFile ()
 Steals the spooled file. More...
 
bool empty () const
 Returns whether one or more files have been uploaded.
 
const std::vector< Http::UploadedFile > & uploadedFiles () const
 Returns the uploaded files.
 
bool canUpload () const
 Returns whether upload() will start a new file upload. More...
 
EventSignaluploaded ()
 Signal emitted when a new file was uploaded. More...
 
JSignal<::int64_t > & fileTooLarge ()
 Signal emitted when the user tried to upload a too large file. More...
 
EventSignalchanged ()
 Signal emitted when the user selected a new file. More...
 
void upload ()
 Starts the file upload. More...
 
void setProgressBar (WProgressBar *progressBar)
 Sets a progress bar to indicate upload progress. More...
 
void setProgressBar (std::unique_ptr< WProgressBar > progressBar)
 Sets a progress bar to indicate upload progress. More...
 
WProgressBarprogressBar () const
 Returns the progress bar. More...
 
Signal<::uint64_t,::uint64_t > & dataReceived ()
 Signal emitted while a file is being uploaded. More...
 
virtual void enableAjax () override
 Progresses to an Ajax-enabled widget. More...
 
void setFilters (const std::string &acceptAttributes)
 Sets input accept attributes. More...
 
- Public Member Functions inherited from Wt::WWebWidget
 WWebWidget ()
 Construct a WebWidget.
 
virtual std::vector< WWidget * > children () const override
 Returns child widgets. More...
 
SignalchildrenChanged ()
 Signal emitted when children have been added or removed. More...
 
virtual void setPositionScheme (PositionScheme scheme) override
 Sets the CSS position scheme. More...
 
virtual PositionScheme positionScheme () const override
 Returns the CSS position scheme. More...
 
virtual void setOffsets (const WLength &offset, WFlags< Side > sides=AllSides) override
 Sets CSS offsets for a non-statically positioned widget. More...
 
virtual WLength offset (Side s) const override
 Returns a CSS offset. More...
 
virtual void resize (const WLength &width, const WLength &height) override
 Resizes the widget. More...
 
virtual WLength width () const override
 Returns the width. More...
 
virtual WLength height () const override
 Returns the height. More...
 
virtual void setMinimumSize (const WLength &width, const WLength &height) override
 Sets a minimum size. More...
 
virtual WLength minimumWidth () const override
 Returns the minimum width. More...
 
virtual WLength minimumHeight () const override
 Returns the minimum height. More...
 
virtual void setMaximumSize (const WLength &width, const WLength &height) override
 Sets a maximum size. More...
 
virtual WLength maximumWidth () const override
 Returns the maximum width. More...
 
virtual WLength maximumHeight () const override
 Returns the maximum height. More...
 
virtual void setLineHeight (const WLength &height) override
 Sets the CSS line height for contained text.
 
virtual WLength lineHeight () const override
 Returns the CSS line height for contained text. More...
 
virtual void setFloatSide (Side s) override
 Specifies a CSS float side. More...
 
virtual Side floatSide () const override
 Returns the CSS float side. More...
 
virtual void setClearSides (WFlags< Side > sides) override
 Sets the sides that should be cleared of floats. More...
 
virtual WFlags< SideclearSides () const override
 Returns the sides that should remain empty. More...
 
virtual void setMargin (const WLength &margin, WFlags< Side > sides=AllSides) override
 Sets CSS margins around the widget. More...
 
virtual WLength margin (Side side) const override
 Returns a CSS margin set. More...
 
virtual void setHiddenKeepsGeometry (bool enabled) override
 Sets whether the widget keeps its geometry when hidden. More...
 
virtual bool hiddenKeepsGeometry () const override
 Returns whether the widget keeps its geometry when hidden. More...
 
virtual void setHidden (bool hidden, const WAnimation &animation=WAnimation()) override
 Hides or shows the widget. More...
 
virtual bool isHidden () const override
 Returns whether the widget is set hidden. More...
 
virtual bool isVisible () const override
 Returns whether the widget is visible. More...
 
virtual void setDisabled (bool disabled) override
 Sets whether the widget is disabled. More...
 
virtual bool isDisabled () const override
 Returns whether the widget is set disabled. More...
 
virtual bool isEnabled () const override
 Returns whether the widget is enabled. More...
 
virtual void setPopup (bool popup) override
 Lets the widget overlay over other sibling widgets. More...
 
virtual bool isPopup () const override
 Returns whether the widget is overlayed. More...
 
virtual void setInline (bool isInline) override
 Sets whether the widget is displayed inline or as a block. More...
 
virtual bool isInline () const override
 Returns whether the widget is displayed inline or as block. More...
 
virtual void setDecorationStyle (const WCssDecorationStyle &style) override
 Sets a CSS decoration style. More...
 
virtual WCssDecorationStyledecorationStyle () override
 Returns the decoration style of this widget. More...
 
virtual void setStyleClass (const WString &styleClass) override
 Sets (one or more) CSS style classes. More...
 
virtual WString styleClass () const override
 Returns the CSS style class. More...
 
virtual void addStyleClass (const WString &styleClass, bool force=false) override
 Adds a CSS style class. More...
 
virtual void removeStyleClass (const WString &styleClass, bool force=false) override
 Removes a CSS style class. More...
 
virtual bool hasStyleClass (const WString &styleClass) const override
 Returns whether the widget has a style class.
 
virtual void setVerticalAlignment (AlignmentFlag alignment, const WLength &length=WLength()) override
 Sets the vertical alignment. More...
 
virtual AlignmentFlag verticalAlignment () const override
 Returns the vertical alignment. More...
 
virtual WLength verticalAlignmentLength () const override
 Returns the fixed vertical alignment that was set. More...
 
virtual void setToolTip (const WString &text, TextFormat textFormat=TextFormat::Plain) override
 Sets a tooltip. More...
 
virtual void setDeferredToolTip (bool enable, TextFormat textFormat=TextFormat::Plain) override
 Enable deferred tooltip. More...
 
virtual WString toolTip () const override
 Returns the tooltip.
 
virtual void refresh () override
 Refresh the widget. More...
 
virtual void setAttributeValue (const std::string &name, const WString &value) override
 Sets an attribute value. More...
 
virtual WString attributeValue (const std::string &name) const override
 Returns an attribute value. More...
 
virtual void setJavaScriptMember (const std::string &name, const std::string &value) override
 Sets a JavaScript member. More...
 
virtual std::string javaScriptMember (const std::string &name) const override
 Returns the value of a JavaScript member. More...
 
virtual void callJavaScriptMember (const std::string &name, const std::string &args) override
 Calls a JavaScript member. More...
 
virtual void load () override
 Loads content just before the widget is used. More...
 
virtual bool loaded () const override
 Returns whether this widget has been loaded. More...
 
virtual void setId (const std::string &id) override
 Sets the CSS Id. More...
 
virtual WWidgetfind (const std::string &name) override
 Finds a descendent widget by name. More...
 
virtual WWidgetfindById (const std::string &id) override
 Finds a descendent widget by id.
 
virtual void setSelectable (bool selectable) override
 Sets as selectable. More...
 
virtual void doJavaScript (const std::string &javascript) override
 Executes the given JavaScript statements when the widget is rendered or updated. More...
 
virtual const std::string id () const override
 Returns the (unique) identifier for this object. More...
 
void setLoadLaterWhenInvisible (bool)
 Change the way the widget is loaded when invisible. More...
 
std::string htmlTagName () const
 returns the current html tag name More...
 
void setHtmlTagName (const std::string &tag)
 set the custom HTML tag name More...
 
virtual void setCanReceiveFocus (bool enabled) override
 Sets whether the widget can receive focus. More...
 
virtual bool canReceiveFocus () const override
 Returns whether the widget can receive focus. More...
 
virtual bool setFirstFocus () override
 Set focus on the widget's first descendant. More...
 
virtual void setFocus (bool focus) override
 Sets focus. More...
 
virtual bool hasFocus () const override
 Returns whether the widget currently has the focus.
 
virtual void setTabIndex (int index) override
 Sets the tab index. More...
 
virtual int tabIndex () const override
 Returns the tab index. More...
 
EventSignalblurred ()
 Signal emitted when the widget lost focus. More...
 
EventSignalfocussed ()
 Signal emitted when the widget recieved focus. More...
 
virtual bool scrollVisibilityEnabled () const finaloverride
 Returns whether scroll visibility detection is enabled for this widget. More...
 
virtual void setScrollVisibilityEnabled (bool enabled) finaloverride
 Sets whether scroll visibility detection is enabled for this widget. More...
 
virtual int scrollVisibilityMargin () const finaloverride
 Returns the margin around the viewport within which the widget is considered visible. More...
 
virtual void setScrollVisibilityMargin (int margin) finaloverride
 Sets the margin around the viewport within which the widget is considered visible. More...
 
virtual Signal< bool > & scrollVisibilityChanged () finaloverride
 Signal triggered when the scroll visibility of this widget changes. More...
 
virtual bool isScrollVisible () const finaloverride
 Returns whether this widget is currently considered scroll visible. More...
 
virtual void setThemeStyleEnabled (bool enabled) finaloverride
 Sets whether theme styling for a widget is enabled or disabled. More...
 
virtual bool isThemeStyleEnabled () const finaloverride
 Returns whether this widget is currently styled by the chosen theme. More...
 
virtual void setObjectName (const std::string &name) override
 Sets an object name. More...
 
- Public Member Functions inherited from Wt::WWidget
virtual ~WWidget ()
 Destructor. More...
 
WWidgetparent () const
 Returns the parent widget.
 
virtual std::unique_ptr< WWidgetremoveWidget (WWidget *widget)
 Removes a child widget.
 
std::unique_ptr< WWidgetremoveFromParent ()
 Removes the widget from its parent. More...
 
void setWidth (const WLength &width)
 Sets the width. More...
 
void setHeight (const WLength &height)
 Sets the height. More...
 
virtual void positionAt (const WWidget *widget, Orientation orientation=Orientation::Vertical)
 Positions a widget next to another widget. More...
 
virtual void toggleStyleClass (const WString &styleClass, bool add, bool force=false)
 Toggles a CSS style class.
 
std::string jsRef () const
 Returns a JavaScript expression to the corresponding DOM node. More...
 
void setFocus ()
 Sets focus. More...
 
virtual void acceptDrops (const std::string &mimeType, const WString &hoverStyleClass=WString())
 Sets a mime type to be accepted for dropping. More...
 
virtual void stopAcceptDrops (const std::string &mimeType)
 Indicates that a mime type is no longer accepted for dropping. More...
 
virtual void htmlText (std::ostream &out)
 Streams the (X)HTML representation. More...
 
bool isRendered () const
 Returns whether the widget is rendered. More...
 
void hide ()
 Hides the widget. More...
 
void animateHide (const WAnimation &animation)
 Hides the widget using an animation. More...
 
void show ()
 Shows the widget. More...
 
void animateShow (const WAnimation &animation)
 Shows the widget using an animation. More...
 
void enable ()
 Enables the widget. More...
 
void disable ()
 Disable thes widget. More...
 
bool layoutSizeAware () const
 Returns whether the widget is layout size aware. More...
 
- Public Member Functions inherited from Wt::WObject
void addChild (std::unique_ptr< WObject > child)
 Add a child WObject whose lifetime is determined by this WObject.
 
template<typename Child >
Child * addChild (std::unique_ptr< Child > child)
 Add a child WObject, returning a raw pointer. More...
 
std::unique_ptr< WObjectremoveChild (WObject *child)
 Remove a child WObject, so its lifetime is no longer determined by this WObject.
 
virtual std::string objectName () const
 Returns the object name. More...
 
void resetLearnedSlots ()
 Resets learned stateless slot implementations. More...
 
template<class T >
void resetLearnedSlot (void(T::*method)())
 Resets a learned stateless slot implementation. More...
 
template<class T >
WStatelessSlot * implementStateless (void(T::*method)())
 Declares a slot to be stateless and learn client-side behaviour on first invocation. More...
 
template<class T >
WStatelessSlot * implementStateless (void(T::*method)(), void(T::*undoMethod)())
 Declares a slot to be stateless and learn client-side behaviour in advance. More...
 
void isNotStateless ()
 Marks the current function as not stateless. More...
 
template<class T >
WStatelessSlot * implementJavaScript (void(T::*method)(), const std::string &jsCode)
 Provides a JavaScript implementation for a method. More...
 
- Public Member Functions inherited from Wt::Core::observable
 observable ()
 Default constructor.
 
virtual ~observable ()
 Destructor. More...
 
template<typename... Args, typename C >
auto bindSafe (void(C::*method)(Args...))
 Protects a method call against object destruction. More...
 
template<typename... Args, typename C >
auto bindSafe (void(C::*method)(Args...) const) const
 Protects a const method call against object destruction. More...
 
template<typename Function >
auto bindSafe (const Function &function)
 Protects a function against object destruction. More...
 

Protected Member Functions

virtual void propagateSetEnabled (bool enabled) override
 Propagates that a widget was enabled or disabled through children. More...
 
- Protected Member Functions inherited from Wt::WWebWidget
virtual WStatelessSlot * getStateless (Method method) override
 On-demand stateless slot implementation. More...
 
virtual void render (WFlags< RenderFlag > flags) override
 Renders the widget. More...
 
- Protected Member Functions inherited from Wt::WWidget
void setLayoutSizeAware (bool sizeAware)
 Sets the widget to be aware of its size set by a layout manager. More...
 
virtual void layoutSizeChanged (int width, int height)
 Virtual method that indicates a size change. More...
 
 WWidget ()
 Creates a widget.
 
virtual void dropEvent (WDropEvent dropEvent)
 Handles a drop event. More...
 
virtual int boxPadding (Orientation orientation) const
 Returns the widget's built-in padding. More...
 
virtual int boxBorder (Orientation orientation) const
 Returns the widget's built-in border width. More...
 
void scheduleRender (WFlags< RepaintFlag > flags=None)
 Schedules rerendering of the widget. More...
 

Additional Inherited Members

- Public Types inherited from Wt::WObject
typedef void(WObject::* Method) ()
 Typedef for a WObject method without arguments.
 
- Static Public Member Functions inherited from Wt::WWebWidget
static std::string jsStringLiteral (const std::string &v, char delimiter= '\'')
 Turn a CharEncoding::UTF8 encoded string into a JavaScript string literal. More...
 
- Static Public Member Functions inherited from Wt::WWidget
static WString tr (const char *key)
 Short hand for WString::tr() More...
 

Detailed Description

A widget that allows a file to be uploaded.

This widget is displayed as a box in which a filename can be entered and a browse button.

Depending on availability of JavaScript, the behaviour of the widget is different, but the API is designed in a way which facilitates a portable use.

When JavaScript is available, the file will not be uploaded until upload() is called. This will start an asynchronous upload (and thus return immediately). While the file is being uploaded, the dataReceived() signal is emitted when data is being received and if the connector library provides support (see also WResource::setUploadProgress() for a more detailed discussion). Although you can modify the GUI from this signal, you still need to have a mechanism in place to update the client interface (using a WTimer or using server-push). When the file has been uploaded, the uploaded() signal is emitted, or if the file was too large, the fileTooLarge() signal is emitted. You may configure a progress bar that is used to show the upload progress using setProgressBar(). When no JavaScript is available, the file will be uploaded with the next click event. Thus, upload() has no effect – the file will already be uploaded, and the corresponding signals will already be emitted. To test if upload() will start an upload, you may check using the canUpload() call.

Thus, to properly use the widget, one needs to follow these rules:

The WFileUpload widget must be hidden or deleted when a file is received. In addition it is wise to prevent the user from uploading the file twice as in the example below.

The uploaded file is automatically spooled to a local temporary file which will be deleted together with the WFileUpload widget, unless stealSpooledFile() is called.

Usage example:

Wt::WFileUpload *upload = addWidget(std::make_unique<Wt::WFileUpload>());
upload->setFileTextSize(40);
// Provide a button
Wt::WPushButton *uploadButton =
addWidget(std::make_unique<Wt::WPushButton>("Send"));
// Upload when the button is clicked.
uploadButton->clicked().connect(upload, &Wt::WFileUpload::upload);
uploadButton->clicked().connect(uploadButton, &Wt::WPushButton::disable);
// Upload automatically when the user entered a file.
upload->changed().connect(upload, &WFileUpload::upload);
upload->changed().connect(uploadButton, &Wt::WPushButton::disable);
// React to a succesfull upload.
upload->uploaded().connect(this, &MyWidget::fileUploaded);
// React to a fileupload problem.
upload->fileTooLarge().connect(this, &MyWidget::fileTooLarge);

WFileUpload is an inline widget.

CSS

The file upload itself corresponds to a <input type="file"> tag, but may be wrapped in a <form> tag for an Ajax session to implement the asynchronous upload action. This widget does not provide styling, and styling through CSS is not well supported across browsers.

Member Function Documentation

bool Wt::WFileUpload::canUpload ( ) const

Returns whether upload() will start a new file upload.

A call to upload() will only start a new file upload if there is no JavaScript support. Otherwise, the most recent file will already be uploaded.

EventSignal & Wt::WFileUpload::changed ( )

Signal emitted when the user selected a new file.

One could react on the user selecting a (new) file, by uploading the file immediately.

Caveat: this signal is not emitted with konqueror and possibly other browsers. Thus, in the above scenario you should still provide an alternative way to call the upload() method.

WString Wt::WFileUpload::clientFileName ( ) const

Returns the client filename.

When multiple files were uploaded, this returns the information from the first file.

WString Wt::WFileUpload::contentDescription ( ) const

Returns the client content description.

When multiple files were uploaded, this returns the information from the first file.

Signal<::uint64_t, ::uint64_t>& Wt::WFileUpload::dataReceived ( )

Signal emitted while a file is being uploaded.

When supported by the connector library, you can track the progress of the file upload by listening to this signal.

void Wt::WFileUpload::enableAjax ( )
overridevirtual

Progresses to an Ajax-enabled widget.

This method is called when the progressive bootstrap method is used, and support for AJAX has been detected. The default behavior will upgrade the widget's event handling to use AJAX instead of full page reloads, and propagate the call to its children.

You may want to reimplement this method if you want to make changes to widget when AJAX is enabled. You should always call the base implementation.

See also
WApplication::enableAjax()

Reimplemented from Wt::WWebWidget.

JSignal<::int64_t>& Wt::WFileUpload::fileTooLarge ( )

Signal emitted when the user tried to upload a too large file.

The parameter is the (approximate) size of the file the user tried to upload.

The maximum file size is determined by the maximum request size, which may be configured in the configuration file (<max-request-size>).

See also
uploaded()
WApplication::requestTooLarge()
bool Wt::WFileUpload::multiple ( ) const

Returns whether multiple files can be uploaded.

See also
setMultiple()
WProgressBar* Wt::WFileUpload::progressBar ( ) const

Returns the progress bar.

See also
setProgressBar()
void Wt::WFileUpload::propagateSetEnabled ( bool  enabled)
overrideprotectedvirtual

Propagates that a widget was enabled or disabled through children.

When enabling or disabling a widget, you usually also want to disable contained children. This method is called by setDisabled() to propagate its state to all children.

You may want to reimplement this method if they wish to render differently when a widget is disabled. The default implementation will propagate the signal to all children.

Reimplemented from Wt::WWebWidget.

void Wt::WFileUpload::setFilters ( const std::string &  acceptAttributes)

Sets input accept attributes.

The accept attribute may be specified to provide user agents with a hint of what file types will be accepted. Use html input accept attributes as input.

WFileUpload *fu = new WFileUpload(root());
fu->setFilters("image/*");
*
void Wt::WFileUpload::setMultiple ( bool  multiple)

Sets whether the file upload accepts multiple files.

In browsers which support the "multiple" attribute for the file upload (to be part of HTML5) control, this will allow the user to select multiple files at once.

All uploaded files are available from uploadedFiles(). The single-file API will return only information on the first uploaded file.

The default value is false.

void Wt::WFileUpload::setProgressBar ( WProgressBar progressBar)

Sets a progress bar to indicate upload progress.

When the file is being uploaded, upload progress is indicated using the provided progress bar. Both the progress bar range and values are configured when the upload starts.

The file upload itself is hidden as soon as the upload starts.

The default progress bar is 0 (no upload progress is indicated).

See also
dataReceived()
void Wt::WFileUpload::setProgressBar ( std::unique_ptr< WProgressBar progressBar)

Sets a progress bar to indicate upload progress.

When the file is being uploaded, upload progress is indicated using the provided progress bar. Both the progress bar range and values are configured when the upload starts.

The bar becomes part of the file upload, and replaces the file prompt when the upload is started.

The default progress bar is 0 (no upload progress is indicated).

See also
dataReceived()
std::string Wt::WFileUpload::spoolFileName ( ) const

Returns the spooled location of the uploaded file.

Returns the temporary filename in which the uploaded file was spooled. The file is guaranteed to exist as long as the WFileUpload widget is not deleted, or a new file is not uploaded.

When multiple files were uploaded, this returns the information from the first file.

See also
stealSpooledFile()
uploaded
void Wt::WFileUpload::stealSpooledFile ( )

Steals the spooled file.

By stealing the file, the spooled file will no longer be deleted together with this widget, which means you need to take care of managing that.

When multiple files were uploaded, this returns the information from the first file.

void Wt::WFileUpload::upload ( )

Starts the file upload.

The uploaded() signal is emitted when a file is uploaded, or the fileTooLarge() signal is emitted when the file size exceeded the maximum request size.

See also
uploaded()
canUpload()
EventSignal & Wt::WFileUpload::uploaded ( )

Signal emitted when a new file was uploaded.

This signal is emitted when file upload has been completed. It is good practice to hide or delete the WFileUpload widget when a file has been uploaded succesfully.

See also
upload()
fileTooLarge()

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