Qt Documentation

Qt 5.12
Qt WebEngine
QML Types
WebEngineDownloadItem QML Type

WebEngineDownloadItem QML Type

Provides information about a download. More...

Import Statement:	import QtWebEngine 1.8
Since:	QtWebEngine 1.1

Properties

id : int
interruptReason : enumeration
interruptReasonString : string
isFinished : bool
isPaused : bool
isSavePageDownload : bool
mimeType : string
path : string
receivedBytes : int
savePageFormat : enumeration
state : enumeration
totalBytes : int
view : WebEngineView

Methods

void accept()
void cancel()
void pause()
void resume()

Detailed Description

WebEngineDownloadItem models a download throughout its life cycle, starting with a pending download request and finishing with a completed download. It can be used, for example, to get information about new downloads, to monitor progress, and to pause, resume, and cancel downloads.

Downloads are usually triggered by user interaction on a web page. It is the WebEngineProfile's responsibility to notify the application of new download requests, which it does by emitting the downloadRequested signal together with a newly created WebEngineDownloadItem. The application can then examine this item and decide whether to accept it or not. A signal handler must explicitly call accept() on the item for Qt WebEngine to actually start downloading and writing data to disk. If no signal handler calls accept(), then the download request will be automatically rejected and nothing will be written to disk.

Note: Some properties, like the path under which the file will be saved, can only be changed before calling accept().

Object Life Cycle

All items are guaranteed to be valid during the emission of the downloadRequested signal. If accept() is not called by any signal handler, then the item will be deleted immediately after signal emission. This means that the application must not keep references to rejected download items.

Web Page Downloads

In addition to normal file downloads, which consist simply of retrieving some raw bytes from the network and writing them to disk, Qt WebEngine also supports saving complete web pages, which involves parsing the page's HTML, downloading any dependent resources, and potentially packaging everything into a special file format (savePageFormat). To check if a download is for a file or a web page, use isSavePageDownload.

Property Documentation

id : int

Holds the download item's ID.

[read-only] interruptReason : enumeration

Returns the reason why the download was interrupted:

Constant	Description
`WebEngineDownloadItem.NoReason`	Unknown reason or not interrupted.
`WebEngineDownloadItem.FileFailed`	General file operation failure.
`WebEngineDownloadItem.FileAccessDenied`	The file cannot be written locally, due to access restrictions.
`WebEngineDownloadItem.FileNoSpace`	Insufficient space on the target drive.
`WebEngineDownloadItem.FileNameTooLong`	The directory or file name is too long.
`WebEngineDownloadItem.FileTooLarge`	The file size exceeds the file system limitation.
`WebEngineDownloadItem.FileVirusInfected`	The file is infected with a virus.
`WebEngineDownloadItem.FileTransientError`	Temporary problem (for example the file is in use, out of memory, or too many files are opened at once).
`WebEngineDownloadItem.FileBlocked`	The file was blocked due to local policy.
`WebEngineDownloadItem.FileSecurityCheckFailed`	An attempt to check the safety of the download failed due to unexpected reasons.
`WebEngineDownloadItem.FileTooShort`	An attempt was made to seek past the end of a file when opening a file (as part of resuming a previously interrupted download).
`WebEngineDownloadItem.FileHashMismatch`	The partial file did not match the expected hash.
`WebEngineDownloadItem.NetworkFailed`	General network failure.
`WebEngineDownloadItem.NetworkTimeout`	The network operation has timed out.
`WebEngineDownloadItem.NetworkDisconnected`	The network connection has been terminated.
`WebEngineDownloadItem.NetworkServerDown`	The server has gone down.
`WebEngineDownloadItem.NetworkInvalidRequest`	The network request was invalid (for example, the original or redirected URL is invalid, has an unsupported scheme, or is disallowed by policy).
`WebEngineDownloadItem.ServerFailed`	General server failure.
`WebEngineDownloadItem.ServerBadContent`	The server does not have the requested data.
`WebEngineDownloadItem.ServerUnauthorized`	The server did not authorize access to the resource.
`WebEngineDownloadItem.ServerCertProblem`	A problem with the server certificate occurred.
`WebEngineDownloadItem.ServerForbidden`	Access forbidden by the server.
`WebEngineDownloadItem.ServerUnreachable`	Unexpected server response (might indicate that the responding server may not be the intended server).
`WebEngineDownloadItem.UserCanceled`	The user canceled the download.

This property was introduced in QtWebEngine 1.5.

See also interruptReasonString.

interruptReasonString : string

Returns a human-readable description of the reason for interrupting the download.

This property was introduced in QtWebEngine 1.5.

See also interruptReason.

[read-only] isFinished : bool

Whether this download is finished (completed, cancelled, or non-resumable interrupted state).

This property was introduced in QtWebEngine 1.6.

[read-only] isPaused : bool

Whether this download is paused.

This property was introduced in QtWebEngine 1.6.

See also pause and resume.

[read-only] isSavePageDownload : bool

Whether this is a download request for saving a web page or a file.

This property was introduced in QtWebEngine 1.7.

See also savePageFormat.

mimeType : string

Holds the MIME type of the download.

This property was introduced in QtWebEngine 1.2.

path : string

Holds the full target path where data is being downloaded to.

The path includes the file name. The default suggested path is the standard download location and file name is deduced not to overwrite already existing files.

The download path can only be set in the downloadRequested handler before the download is accepted.

receivedBytes : int

Holds the amount of data in bytes that has been downloaded so far.

savePageFormat : enumeration

Describes the format that is used to save a web page.

Constant	Description
`WebEngineDownloadItem.UnknownSaveFormat`	This is not a request for downloading a complete web page.
`WebEngineDownloadItem.SingleHtmlSaveFormat`	The page is saved as a single HTML page. Resources such as images are not saved.
`WebEngineDownloadItem.CompleteHtmlSaveFormat`	The page is saved as a complete HTML page, for example a directory containing the single HTML page and the resources.
`WebEngineDownloadItem.MimeHtmlSaveFormat`	The page is saved as a complete web page in the MIME HTML format.

This property was introduced in QtWebEngine 1.3.

state : enumeration

Describes the state of the download:

Constant	Description
`WebEngineDownloadItem.DownloadRequested`	Download has been requested, but it has not been accepted yet.
`WebEngineDownloadItem.DownloadInProgress`	Download is in progress.
`WebEngineDownloadItem.DownloadCompleted`	Download completed successfully.
`WebEngineDownloadItem.DownloadCancelled`	Download was cancelled by the user.
`WebEngineDownloadItem.DownloadInterrupted`	Download has been interrupted (by the server or because of lost connectivity).

totalBytes : int

Holds the total amount of data to download in bytes.

-1 means the total size is unknown.

[read-only] view : WebEngineView

Returns the view the download was requested on. If the download was not triggered by content in a view, nullptr is returned.

This property was introduced in QtWebEngine 1.8.

See also WebEngineView.

Method Documentation

void accept()

Accepts the download request, which will start the download.

If the item is in the DownloadRequested state, then it will transition into the DownloadInProgress state and the downloading will begin. If the item is in any other state, then nothing will happen.

See also state.

void cancel()

Cancels the download.

If the item is in the DownloadInProgress state, then it will transition into the DownloadCancelled state, the downloading will stop, and partially downloaded files will be deleted from disk.

If the item is in the DownloadCompleted state, then nothing will happen. If the item is in any other state, then it will transition into the DownloadCancelled state without further effect.

See also state.

void pause()

Pauses the download.

Has no effect if the state is not DownloadInProgress. Does not change the state.

This method was introduced in QtWebEngine 1.6.

See also resume and isPaused.

void resume()

Resumes the download if it was paused or interrupted.

Has no effect if the state is not DownloadInProgress or DownloadInterrupted. Does not change the state.