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Wt::WFileUpload Class Reference

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

#include <Wt/WFileUpload>

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

 WFileUpload (WContainerWidget *parent=0)
 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.
 
bool emptyFileName () const
 Checks if no filename was given and thus no file uploaded. (Deprecated) More...
 
const std::vector
< Http::UploadedFile > & 
uploadedFiles () const
 Returns the uploaded files.
 
bool canUpload () const
 Returns whether upload() will start a new file upload. More...
 
bool isUploaded () const
 Returns whether the upload() slot will not start a new upload. (Deprecated) More...
 
EventSignaluploaded ()
 Signal emitted when a new file was uploaded. More...
 
Signal< ::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...
 
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 ()
 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 (WContainerWidget *parent=0)
 Construct a WebWidget with a given parent. More...
 
virtual void setPositionScheme (PositionScheme scheme)
 Sets the CSS position scheme. More...
 
virtual PositionScheme positionScheme () const
 Returns the CSS position scheme. More...
 
virtual void setOffsets (const WLength &offset, WFlags< Side > sides=All)
 Sets CSS offsets for a non-statically positioned widget. More...
 
virtual WLength offset (Side s) const
 Returns a CSS offset. More...
 
virtual void resize (const WLength &width, const WLength &height)
 Resizes the widget. More...
 
virtual WLength width () const
 Returns the width. More...
 
virtual WLength height () const
 Returns the height. More...
 
virtual void setMinimumSize (const WLength &width, const WLength &height)
 Sets a minimum size. More...
 
virtual WLength minimumWidth () const
 Returns the minimum width. More...
 
virtual WLength minimumHeight () const
 Returns the minimum height. More...
 
virtual void setMaximumSize (const WLength &width, const WLength &height)
 Sets a maximum size. More...
 
virtual WLength maximumWidth () const
 Returns the maximum width. More...
 
virtual WLength maximumHeight () const
 Returns the maximum height. More...
 
virtual void setLineHeight (const WLength &height)
 Sets the CSS line height for contained text.
 
virtual WLength lineHeight () const
 Returns the CSS line height for contained text. More...
 
virtual void setFloatSide (Side s)
 Specifies a CSS float side. More...
 
virtual Side floatSide () const
 Returns the CSS float side. More...
 
virtual void setClearSides (WFlags< Side > sides)
 Sets the sides that should be cleared of floats. More...
 
virtual WFlags< SideclearSides () const
 Returns the sides that should remain empty. More...
 
virtual void setMargin (const WLength &margin, WFlags< Side > sides=All)
 Sets CSS margins around the widget. More...
 
virtual WLength margin (Side side) const
 Returns a CSS margin set. More...
 
virtual void setHiddenKeepsGeometry (bool enabled)
 Sets whether the widget keeps its geometry when hidden. More...
 
virtual bool hiddenKeepsGeometry () const
 Returns whether the widget keeps its geometry when hidden. More...
 
virtual void setHidden (bool hidden, const WAnimation &animation=WAnimation())
 Hides or shows the widget. More...
 
virtual bool isHidden () const
 Returns whether the widget is set hidden. More...
 
virtual bool isVisible () const
 Returns whether the widget is visible. More...
 
virtual void setDisabled (bool disabled)
 Sets whether the widget is disabled. More...
 
virtual bool isDisabled () const
 Returns whether the widget is set disabled. More...
 
virtual bool isEnabled () const
 Returns whether the widget is enabled. More...
 
virtual void setPopup (bool popup)
 Lets the widget overlay over other sibling widgets. More...
 
virtual bool isPopup () const
 Returns whether the widget is overlayed. More...
 
virtual void setInline (bool isInline)
 Sets whether the widget is displayed inline or as a block. More...
 
virtual bool isInline () const
 Returns whether the widget is displayed inline or as block. More...
 
virtual void setDecorationStyle (const WCssDecorationStyle &style)
 Sets a CSS decoration style. More...
 
virtual WCssDecorationStyledecorationStyle ()
 Returns the decoration style of this widget. More...
 
virtual void setStyleClass (const WString &styleClass)
 Sets (one or more) CSS style classes. More...
 
virtual WString styleClass () const
 Returns the CSS style class. More...
 
virtual void addStyleClass (const WString &styleClass, bool force=false)
 Adds a CSS style class. More...
 
virtual void removeStyleClass (const WString &styleClass, bool force=false)
 Removes a CSS style class. More...
 
virtual bool hasStyleClass (const WString &styleClass) const
 Returns whether the widget has a style class.
 
virtual void setVerticalAlignment (AlignmentFlag alignment, const WLength &length=WLength())
 Sets the vertical alignment. More...
 
virtual AlignmentFlag verticalAlignment () const
 Returns the vertical alignment. More...
 
virtual WLength verticalAlignmentLength () const
 Returns the fixed vertical alignment that was set. More...
 
virtual void setToolTip (const WString &text, TextFormat textFormat=PlainText)
 Sets a tooltip. More...
 
virtual void setDeferredToolTip (bool enable, TextFormat textFormat=PlainText)
 Enable deferred tooltip. More...
 
virtual WString toolTip () const
 Returns the tooltip.
 
virtual void refresh ()
 Refresh the widget. More...
 
virtual void setAttributeValue (const std::string &name, const WString &value)
 Sets an attribute value. More...
 
virtual WString attributeValue (const std::string &name) const
 Returns an attribute value. More...
 
virtual void setJavaScriptMember (const std::string &name, const std::string &value)
 Sets a JavaScript member. More...
 
virtual std::string javaScriptMember (const std::string &name) const
 Returns the value of a JavaScript member. More...
 
virtual void callJavaScriptMember (const std::string &name, const std::string &args)
 Calls a JavaScript member. More...
 
virtual void load ()
 Loads content just before the widget is used. More...
 
virtual bool loaded () const
 Returns whether this widget has been loaded. More...
 
virtual void setTabIndex (int index)
 Sets the tab index. More...
 
virtual int tabIndex () const
 Returns the tab index. More...
 
virtual void setId (const std::string &id)
 Sets the CSS Id. More...
 
virtual WWidgetfind (const std::string &name)
 Finds a descendent widget by name. More...
 
virtual void setSelectable (bool selectable)
 Sets as selectable. More...
 
virtual void doJavaScript (const std::string &javascript)
 Executes the given JavaScript statements when the widget is rendered or updated. More...
 
virtual const std::string id () const
 Returns the (unique) identifier for this object. More...
 
void setLoadLaterWhenInvisible (bool)
 Change the way the widget is loaded when invisible. More...
 
const std::vector< WWidget * > & children () const
 Returns contained widgets. More...
 
SignalchildrenChanged ()
 Signal emitted when children have been added or removed. More...
 
virtual bool setFirstFocus ()
 Set focus on the widget's first descendant. More...
 
- Public Member Functions inherited from Wt::WWidget
virtual ~WWidget ()
 Destructor. More...
 
WWidgetparent () const
 Returns the parent widget. More...
 
virtual void removeChild (WObject *child)
 Removes a child object. 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=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...
 
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
 WObject (WObject *parent=0)
 Create a WObject with a given parent object. More...
 
virtual ~WObject ()
 Destructor. More...
 
virtual void setObjectName (const std::string &name)
 Sets an object name. 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...
 
template<class T >
WStatelessSlot * implementJavaScript (void(T::*method)(), const std::string &jsCode)
 Provides a JavaScript implementation for a method. More...
 
void addChild (WObject *child)
 Adds a child object. More...
 
const std::vector< WObject * > & children () const
 Returns the children.
 
WObjectparent () const
 Returns the parent object.
 

Protected Member Functions

virtual void propagateSetEnabled (bool enabled)
 Propagates that a widget was enabled or disabled through children. More...
 
- Protected Member Functions inherited from Wt::WWebWidget
virtual void render (WFlags< RenderFlag > flags)
 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 (WContainerWidget *parent=0)
 Creates a widget. More...
 
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=0)
 Schedules rerendering of the widget. More...
 
virtual WStatelessSlot * getStateless (Method method)
 On-demand stateless slot implementation. 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 WString escapeText (const WString &text, bool newlinesToo=false)
 Escape HTML control characters in the text, to display literally (deprecated). More...
 
static std::string & escapeText (std::string &text, bool newlinestoo=false)
 Escape HTML control characters in the text, to display literally (deprecated). More...
 
static bool removeScript (WString &text)
 Remove tags/attributes from text that are not passive (deprecated). More...
 
static std::string jsStringLiteral (const std::string &v, char delimiter= '\'')
 Turn a UTF8 encoded string into a JavaScript string literal. More...
 
- Static Protected Member Functions inherited from Wt::WObject
static WObjectsender ()
 Returns the sender of the current slot call. 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:

upload->setFileTextSize(40);
// Provide a button
Wt::WPushButton *uploadButton = new Wt::WPushButton("Send", this);
// 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.

Note
This method was renamed, and its result inverted, from the now deprecated method isUploaded()
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.

bool Wt::WFileUpload::emptyFileName ( ) const

Checks if no filename was given and thus no file uploaded. (Deprecated)

Return whether a non-empty filename was given.

Deprecated:
This method was renamed to empty()
void Wt::WFileUpload::enableAjax ( )
virtual

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.

Signal< ::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::isUploaded ( ) const

Returns whether the upload() slot will not start a new upload. (Deprecated)

Deprecated:
use canUpload() instead – canUpload() == !isUploaded(). the name was confusing.
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)
protectedvirtual

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.

If the provided progress bar already has a parent, then the file upload itself is hidden as soon as the upload starts. If the provided progress bar does not yet have a parent, then 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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