Wt::WStreamResource Class Reference

An object which streams the data from a std::istream. More...

#include <Wt/WStreamResource>

Inheritance diagram for Wt::WStreamResource:

Public Member Functions
	WStreamResource (WObject *parent=0)
	Default constructor. More...
	WStreamResource (const std::string &mimeType, WObject *parent=0)
	Creates a new resource with given mime-type.
	~WStreamResource ()
	Destructor. More...
void	setMimeType (const std::string &mimeType)
	Sets the mime-type.
const std::string &	mimeType () const
	Returns the mime-type.
void	setBufferSize (int size)
	Configures the buffer size. More...
int	bufferSize () const
	Returns the buffer size. More...
Public Member Functions inherited from Wt::WResource
	WResource (WObject *parent=0)
	Creates a new resource.
	~WResource ()
	Destroys the resource. More...
void	suggestFileName (const Wt::WString &name, DispositionType dispositionType=Attachment)
	Suggests a filename to the user for the data streamed by this resource. More...
const Wt::WString &	suggestedFileName () const
	Returns the suggested file name. More...
void	setDispositionType (DispositionType cd)
	Configures the Content-Disposition header. More...
DispositionType	dispositionType () const
	Returns the currently configured content disposition. More...
void	setChanged ()
	Generates a new URL for this resource and emits the changed signal. More...
void	setInternalPath (const std::string &path)
	Sets an internal path for this resource. More...
std::string	internalPath () const
	Returns the internal path. More...
const std::string &	generateUrl ()
	Generates an URL for this resource. More...
const std::string &	url () const
	Returns the current URL for this resource. More...
Signal &	dataChanged ()
	Signal emitted when the data presented in this resource has changed. More...
void	setUploadProgress (bool enabled)
	Indicate interest in upload progress. More...
Signal< ::uint64_t, ::uint64_t > &	dataReceived ()
	Signal emitted when data has been received for this resource. More...
void	write (std::ostream &out, const Http::ParameterMap &parameters=Http::ParameterMap(), const Http::UploadedFileMap &files=Http::UploadedFileMap())
	Stream the resource to a stream. More...
virtual void	handleRequest (const Http::Request &request, Http::Response &response)=0
	Handles a request. More...
virtual void	handleAbort (const Http::Request &request)
	Handles a continued request being aborted. More...
void	haveMoreData ()
	Indicate that more data is available. More...
void	setTakesUpdateLock (bool enabled)
	Set whether this resource takes the WApplication's update lock. More...
bool	takesUpdateLock () const
	Returns whether this resources takes the WApplication's update lock. 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 const std::string	id () const
	Returns the (unique) identifier for this object. 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...
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...
void	addChild (WObject *child)
	Adds a child object. More...
virtual void	removeChild (WObject *child)
	Removes a child object. More...
const std::vector< WObject * > &	children () const
	Returns the children.
WObject *	parent () const
	Returns the parent object.

Protected Member Functions
void	handleRequestPiecewise (const Http::Request &request, Http::Response &response, std::istream &input)
	Handles a request and streams the data from a std::istream. More...
Protected Member Functions inherited from Wt::WResource
void	beingDeleted ()
	Prepares the resource for deletion. More...
Protected Member Functions inherited from Wt::WObject
virtual WStatelessSlot *	getStateless (Method method)
	On-demand stateless slot implementation. More...

Additional Inherited Members
Public Types inherited from Wt::WResource
enum	DispositionType { NoDisposition, Attachment, Inline }
	Values for the disposition type in the Content-Disposition header. More...
Public Types inherited from Wt::WObject
typedef void(WObject::*	Method) ()
	Typedef for a WObject method without arguments.
Static Protected Member Functions inherited from Wt::WObject
static WObject *	sender ()
	Returns the sender of the current slot call. More...

Detailed Description

An object which streams the data from a std::istream.

This class can be useful base for implementing resources which streams the data from std::istream derivatives.

The utility method handleRequestPiecewise() makes use of continuations to transmit data piecewise, without blocking a thread or requiring the whole data to be read in memory. The size of the buffer can be changed by using setBufferSize().

Example for a custom stream resource implementation:

class MyStreamResource : public Wt::WStreamResource
{
public:
  MyStreamResource(const std::string& fileName, Wt::WObject *parent = 0)
    : Wt::WStreamResource(parent),
      fileName_(fileName)
  {
    suggestFileName("data.txt");
  }

  ~MyStreamResource() {
    beingDeleted();
  }

  void handleRequest(const Wt::Http::Request& request,
                     Wt::Http::Response& response) {
    std::ifstream r(fileName_.c_str(), std::ios::in | std::ios::binary);
    handleRequestPiecewise(request, response, r);
  }

private:
  std::string fileName_;
};

See also

WFileResource

Constructor & Destructor Documentation

WStreamResource()

Wt::WStreamResource::WStreamResource

(

WObject *

parent = 0

)

Default constructor.

The mime type defaults to "text/plain".

~WStreamResource()

Wt::WStreamResource::~WStreamResource

(

)

Destructor.

It is up to the user to make sure that the resource is no longer in use (by e.g. a WImage).

Member Function Documentation

bufferSize()

int Wt::WStreamResource::bufferSize

(

)

const

Returns the buffer size.

See also

setBufferSize()

handleRequestPiecewise()

void Wt::WStreamResource::handleRequestPiecewise ( const Http::Request &  request, Http::Response &  response, std::istream &  input  )

protected

Handles a request and streams the data from a std::istream.

You can call this method from a custom handleRequest() implementations.

setBufferSize()

void Wt::WStreamResource::setBufferSize

(

int

size

)

Configures the buffer size.

This configures the size of the buffer used to transmit the data piece by piece.