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

#include <Wt/WFileUpload.h>

Inheritance diagram for Wt::WFileUpload:

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...

void	setDisplayWidget (WInteractWidget *widget)
	Use the click signal of another widget to open the file picker. More...

EventSignal &	uploaded ()
	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...

EventSignal &	changed ()
	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...

WProgressBar *	progressBar () 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...

Signal &	childrenChanged ()
	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< Side >	clearSides () 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 WCssDecorationStyle &	decorationStyle () 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 WWidget *	find (const std::string &name) override
	Finds a descendent widget by name. More...

virtual WWidget *	findById (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...

EventSignal &	blurred ()
	Signal emitted when the widget lost focus. More...

EventSignal &	focussed ()
	Signal emitted when the widget recieved focus. More...

virtual bool	scrollVisibilityEnabled () const final override
	Returns whether scroll visibility detection is enabled for this widget. More...

virtual void	setScrollVisibilityEnabled (bool enabled) final override
	Sets whether scroll visibility detection is enabled for this widget. More...

virtual int	scrollVisibilityMargin () const final override
	Returns the margin around the viewport within which the widget is considered visible. More...

virtual void	setScrollVisibilityMargin (int margin) final override
	Sets the margin around the viewport within which the widget is considered visible. More...

virtual Signal< bool > &	scrollVisibilityChanged () final override
	Signal triggered when the scroll visibility of this widget changes. More...

virtual bool	isScrollVisible () const final override
	Returns whether this widget is currently considered scroll visible. More...

virtual void	setThemeStyleEnabled (bool enabled) final override
	Sets whether theme styling for a widget is enabled or disabled. More...

virtual bool	isThemeStyleEnabled () const final override
	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...

void	setFocus ()
	Sets focus. More...

virtual void	setFocus (bool focus)=0
	Sets focus. More...

Public Member Functions inherited from Wt::WWidget
virtual	~WWidget ()
	Destructor. More...

WWidget *	parent () const
	Returns the parent widget.

virtual std::unique_ptr< WWidget >	removeWidget (WWidget *widget)
	Removes a child widget.

template<typename Widget >
std::unique_ptr< Widget >	removeWidget (Widget *widget)
	Removes a child widget. More...

std::unique_ptr< WWidget >	removeFromParent ()
	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< WObject >	removeChild (WObject *child)
	Remove a child WObject, so its lifetime is no longer determined by this WObject.

template<typename Child >
std::unique_ptr< Child >	removeChild (Child *child)
	Remove a child WObject, so its lifetime is no longer determined by this WObject. More...

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 () noexcept
	Default constructor.

virtual	~observable ()
	Destructor. More...

template<typename... Args, typename C >
auto	bindSafe (void(C::*method)(Args...)) noexcept
	Protects a method call against object destruction. More...

template<typename... Args, typename C >
auto	bindSafe (void(C::*method)(Args...) const) const noexcept
	Protects a const method call against object destruction. More...

template<typename Function >
auto	bindSafe (const Function &function) noexcept
	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:

Be prepared to handle the uploaded() or fileTooLarge() signals also when upload() was not called.
Check using canUpload() if upload() will schedule a new upload. if (!canUpload()) then upload() will not have any effect. if (canUpload()), upload() will start a new file upload, which completes succesfully using an uploaded() signal or a fileTooLarge() signals gets emitted.

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

◆ canUpload()

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.

◆ changed()

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.

◆ clientFileName()

WString Wt::WFileUpload::clientFileName ( ) const

Returns the client filename.

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

Note: Depending on the browser this is an absolute path or only the file name.

◆ contentDescription()

WString Wt::WFileUpload::contentDescription ( ) const

Returns the client content description.

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

◆ dataReceived()

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.

The first argument is the number of bytes received so far, and the second argument is the total number of bytes.

◆ enableAjax()

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.

◆ fileTooLarge()

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 (in bytes) 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()

◆ multiple()

bool Wt::WFileUpload::multiple ( ) const

Returns whether multiple files can be uploaded.

See also: setMultiple()

◆ progressBar()

WProgressBar* Wt::WFileUpload::progressBar ( ) const

Returns the progress bar.

See also: setProgressBar()

◆ propagateSetEnabled()

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.

◆ setDisplayWidget()

void Wt::WFileUpload::setDisplayWidget ( WInteractWidget * widget )

Use the click signal of another widget to open the file picker.

This hides the default WFileUpload widget and uses the click-signal of the argument to open the file picker. The upload logic is still handled by WFileUpload behind the scenes. This action cannot be undone.

WFileUpload does not take ownership of the widget, nor does it display it. You must still place it in the widget tree yourself.

◆ setFilters()

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/*");
*  

◆ setMultiple()

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.

◆ setProgressBar() [1/2]

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()

◆ setProgressBar() [2/2]

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()

◆ spoolFileName()

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

◆ stealSpooledFile()

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.

◆ upload()

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()

◆ uploaded()

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()

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

CSS

Member Function Documentation

◆ canUpload()

◆ changed()

◆ clientFileName()

◆ contentDescription()

◆ dataReceived()

◆ enableAjax()

◆ fileTooLarge()

◆ multiple()

◆ progressBar()

◆ propagateSetEnabled()

◆ setDisplayWidget()

◆ setFilters()

◆ setMultiple()

◆ setProgressBar() [1/2]

◆ setProgressBar() [2/2]

◆ spoolFileName()

◆ stealSpooledFile()

◆ upload()

◆ uploaded()