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Public Member Functions
Wt::WFileResource Class Reference

A resource which streams the data from a local file. More...

#include <Wt/WFileResource>

Inheritance diagram for Wt::WFileResource:
Inheritance graph
[legend]

List of all members.

Public Member Functions

 WFileResource (WObject *parent=0)
 Default constructor.
 WFileResource (const std::string &fileName, WObject *parent=0)
 Creates a new resource for a file.
 WFileResource (const std::string &mimeType, const std::string &fileName, WObject *parent=0)
 Creates a new resource with given mime-type for a file.
 ~WFileResource ()
 Destructor.
void setFileName (const std::string &fileName)
 Sets a (different) filename.
const std::string & fileName () const
 Returns the filename.
virtual void handleRequest (const Http::Request &request, Http::Response &response)
 Handles a request.
- Public Member Functions inherited from Wt::WStreamResource
 WStreamResource (WObject *parent=0)
 Default constructor.
 WStreamResource (const std::string &mimeType, WObject *parent=0)
 Creates a new resource with given mime-type.
 ~WStreamResource ()
 Destructor.
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.
int bufferSize () const
 Returns the buffer size.
- Public Member Functions inherited from Wt::WResource
 WResource (WObject *parent=0)
 Creates a new resource.
 ~WResource ()
 Destroys the resource.
void suggestFileName (const Wt::WString &name, DispositionType dispositionType=Attachment)
 Suggests a filename to the user for the data streamed by this resource.
const Wt::WStringsuggestedFileName () const
 Returns the suggested file name.
void setDispositionType (DispositionType cd)
 Configures the Content-Disposition header.
DispositionType dispositionType () const
 Returns the currently configured content disposition.
void setChanged ()
 Generates a new URL for this resource and emits the changed signal.
void setInternalPath (const std::string &path)
 Sets an internal path for this resource.
std::string internalPath () const
 Returns the internal path.
const std::string & generateUrl ()
 Generates an URL for this resource.
const std::string & url () const
 Returns the current URL for this resource.
SignaldataChanged ()
 Signal emitted when the data presented in this resource has changed.
void setUploadProgress (bool enabled)
 Indicate interest in upload progress.
Signal< ::uint64_t,::uint64_t > & dataReceived ()
 Signal emitted when data has been received for this resource.
void write (std::ostream &out, const Http::ParameterMap &parameters=Http::ParameterMap(), const Http::UploadedFileMap &files=Http::UploadedFileMap())
 Stream the resource to a stream.
void haveMoreData ()
 Indicate that more data is available.
- Public Member Functions inherited from Wt::WObject
 WObject (WObject *parent=0)
 Create a WObject with a given parent object.
virtual ~WObject ()
 Destructor.
virtual const std::string id () const
 Returns the (unique) identifier for this object.
void setObjectName (const std::string &name)
 Sets an object name.
virtual std::string objectName () const
 Returns the object name.
void resetLearnedSlots ()
 Resets learned stateless slot implementations.
template<class T >
void resetLearnedSlot (void(T::*method)())
 Resets a learned stateless slot implementation.
template<class T >
WStatelessSlot * implementStateless (void(T::*method)())
 Declares a slot to be stateless and learn client-side behaviour on first invocation.
template<class T >
WStatelessSlot * implementStateless (void(T::*method)(), void(T::*undoMethod)())
 Declares a slot to be stateless and learn client-side behaviour in advance.
template<class T >
WStatelessSlot * implementJavaScript (void(T::*method)(), const std::string &jsCode)
 Provides a JavaScript implementation for a method.
void addChild (WObject *child)
 Adds a child object.
virtual void removeChild (WObject *child)
 Removes a child object.
const std::vector< WObject * > & children () const
 Returns the children.
WObjectparent () const
 Returns the parent object.

Additional Inherited Members

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

Detailed Description

A resource which streams the data from a local file.

To update the resource, either use setFileName() to point it to a new file, or emit the WResource::dataChanged() signal when only the file contents has changed, but not the filename.

The resource makes use of continuations to transmit data piecewise, without blocking a thread or requiring the entire file to be read in memory. The size of the buffer can be changed using setBufferSize().

Usage examples:

Wt::WFileResource *csvFile = new Wt::WFileResource("text/csv", "/opt/files/afile.csv");
csvFile->suggestFileName("data.csv");
Wt::WAnchor *anchor = new Wt::WAnchor(csvFile, "CSV data");
Wt::WFileResource *imageFile = new Wt::WFileResource("image/png", "/opt/files/image.png");
imageFile->suggestFileName("data.png");
Wt::WImage *image = new Wt::WImage(imageFile, "PNG version");
See also:
WStreamResource, WMemoryResource

Constructor & Destructor Documentation

Wt::WFileResource::WFileResource ( WObject parent = 0)

Default constructor.

You need to set a file name (and mime type) for the resource using setFileName() and setMimeType().

Wt::WFileResource::WFileResource ( const std::string &  fileName,
WObject parent = 0 
)

Creates a new resource for a file.

The mime type defaults to "text/plain".

Wt::WFileResource::~WFileResource ( )

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

void Wt::WFileResource::handleRequest ( const Http::Request request,
Http::Response response 
)
virtual

Handles a request.

Reimplement this method so that a proper response is generated for the given request. From the request object you can access request parameters and whether the request is a continuation request. In the response object, you should set the mime type and stream the output data.

A request may also concern a continuation, indicated in Http::Request::continuation(), in which case the next part for a previously created continuation should be served.

While handling a request, which may happen at any time together with event handling, the library makes sure that the resource is not being concurrently deleted, but multiple requests may happend simultaneously for a single resource.

Implements Wt::WResource.

void Wt::WFileResource::setFileName ( const std::string &  fileName)

Sets a (different) filename.

Set the location of the file on the local filesystem which must be streamed for this resource.


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