/Qt 5.15

QWebEngineUrlScheme Class

The QWebEngineUrlScheme class configures a custom URL scheme. More...

Header: #include <QWebEngineUrlScheme>
Since: Qt 5.12

This class was introduced in Qt 5.12.

Public Types

enum Flag { SecureScheme, LocalScheme, LocalAccessAllowed, NoAccessAllowed, ServiceWorkersAllowed, …, CorsEnabled }
flags Flags
enum SpecialPort { PortUnspecified }
enum class Syntax { HostPortAndUserInformation, HostAndPort, Host, Path }

Public Functions

QWebEngineUrlScheme(QWebEngineUrlScheme &&that)
QWebEngineUrlScheme(const QWebEngineUrlScheme &that)
QWebEngineUrlScheme(const QByteArray &name)
QWebEngineUrlScheme & operator=(QWebEngineUrlScheme &&that)
QWebEngineUrlScheme & operator=(const QWebEngineUrlScheme &that)
int defaultPort() const
QWebEngineUrlScheme::Flags flags() const
QByteArray name() const
void setDefaultPort(int newValue)
void setFlags(QWebEngineUrlScheme::Flags newValue)
void setName(const QByteArray &newValue)
void setSyntax(QWebEngineUrlScheme::Syntax newValue)
QWebEngineUrlScheme::Syntax syntax() const
bool operator!=(const QWebEngineUrlScheme &that) const
bool operator==(const QWebEngineUrlScheme &that) const

Static Public Members

void registerScheme(const QWebEngineUrlScheme &scheme)
QWebEngineUrlScheme schemeByName(const QByteArray &name)

Detailed Description

A web engine URL scheme describes a URL scheme from the web engine's perspective, specifying how URLs of this scheme should be parsed, and which security restrictions should be placed on resources originating from such URLs.

Custom URL schemes must be configured early at application startup, before creating any Qt WebEngine classes. In general this means the schemes need to be configured before a QGuiApplication or QApplication instance is created.

Every registered scheme configuration applies globally to all profiles.

int main(int argc, char **argv)
    QWebEngineUrlScheme scheme("myscheme");

To actually make use of the custom URL scheme, a QWebEngineUrlSchemeHandler must be created and registered in a profile.

See also QWebEngineUrlSchemeHandler.

Member Type Documentation

enum QWebEngineUrlScheme::Flagflags QWebEngineUrlScheme::Flags

This enum type specifies security options that should apply to a URL scheme.

Constant Value Description
QWebEngineUrlScheme::SecureScheme 0x1 Indicates that the URL scheme is potentially trustworthy. This flag should only be applied to URL schemes which ensure data authenticity, confidentiality, and integrity, either through encryption or other means. Examples of secure builtin schemes include https (authenticated and encrypted) and qrc (local resources only), whereas http is an example of an insecure scheme.
QWebEngineUrlScheme::LocalScheme 0x2 Indicates that the URL scheme provides access to local resources. The purpose of this flag is to prevent network content from accessing local resources. Only schemes with the LocalAccessAllowed flag may load resources from a scheme with the Local flag. The only builtin schemes with this flag are file and qrc.
QWebEngineUrlScheme::LocalAccessAllowed 0x4 Indicates that content from this scheme should be allowed to load resources from schemes with the Local flag.
QWebEngineUrlScheme::NoAccessAllowed 0x8 Indicates that all content from this scheme should be forced to have unique opaque origins: no two resources will have the same origin.
QWebEngineUrlScheme::ServiceWorkersAllowed 0x10 Indicates that the Service Workers API should be enabled.
QWebEngineUrlScheme::ViewSourceAllowed 0x20 Indicates that the View Source feature should be enabled.
QWebEngineUrlScheme::ContentSecurityPolicyIgnored 0x40 Indicates that accesses to this scheme should bypass all Content-Security-Policy checks.
QWebEngineUrlScheme::CorsEnabled 0x80 Enables cross-origin resource sharing (CORS) for this scheme. This flag is required in order to, for example, use the scheme with the Fetch API, or to deliver CSS fonts to a different origin. The appropriate CORS headers are generated automatically by the QWebEngineUrlRequestJob class. (Added in Qt 5.14)

The Flags type is a typedef for QFlags<Flag>. It stores an OR combination of Flag values.

enum QWebEngineUrlScheme::SpecialPort

This enum type defines special values for defaultPort.

Constant Value Description
QWebEngineUrlScheme::PortUnspecified -1 Indicates that the URL scheme does not have a port element.

enum class QWebEngineUrlScheme::Syntax

This enum type lists types of URL syntax.

To apply the same-origin policy to a custom URL scheme, WebEngine must be able to compute the origin (host and port combination) of a URL. The Host... options indicate that the URL scheme conforms to the standard URL syntax (like http) and automatically enable the same-origin policy. The Path option indicates that the URL scheme uses a non-standard syntax and that the same-origin policy cannot be applied.

Constant Value Description
QWebEngineUrlScheme::Syntax::HostPortAndUserInformation 0 The authority component of a URL of this type has all of the standard elements: host, port, user name, and password. A URL without a port will use the defaultPort (which must not be PortUnspecified).
QWebEngineUrlScheme::Syntax::HostAndPort 1 The authority component of a URL of this type has only the host and port elements. A URL without a port will use the defaultPort (which must not be PortUnspecified).
QWebEngineUrlScheme::Syntax::Host 2 The authority component of a URL of this type has only the host part and no port. The defaultPort must be set to PortUnspecified.
QWebEngineUrlScheme::Syntax::Path 3 A URL of this type has no authority component at all. Everything after scheme name and separator character (:) will be preserved as is without validation or canonicalization. All URLs of such a scheme will be considered as having the same origin (unless the NoAccessAllowed flag is used).

Member Function Documentation

QWebEngineUrlScheme::QWebEngineUrlScheme(QWebEngineUrlScheme &&that)

Moves that.

QWebEngineUrlScheme::QWebEngineUrlScheme(const QWebEngineUrlScheme &that)

Copies that.

QWebEngineUrlScheme::QWebEngineUrlScheme(const QByteArray &name)

Constructs a web engine URL scheme with given name.


Constructs a web engine URL scheme with default values.

QWebEngineUrlScheme &QWebEngineUrlScheme::operator=(QWebEngineUrlScheme &&that)

Moves that.

QWebEngineUrlScheme &QWebEngineUrlScheme::operator=(const QWebEngineUrlScheme &that)

Copies that.


Destructs this object.

int QWebEngineUrlScheme::defaultPort() const

Returns the default port of this URL scheme.

The default value is PortUnspecified.

See also setDefaultPort().

QWebEngineUrlScheme::Flags QWebEngineUrlScheme::flags() const

Returns the flags for this URL scheme.

The default value is an empty set of flags.

See also Flags and setFlags().

QByteArray QWebEngineUrlScheme::name() const

Returns the name of this URL scheme.

The default value is an empty string.

See also setName().

[static] void QWebEngineUrlScheme::registerScheme(const QWebEngineUrlScheme &scheme)

Registers scheme with the web engine's URL parser and security model.

It is recommended that all custom URL schemes are first registered with this function at application startup, even if the default options are to be used.

Warning: This function must be called early at application startup, before creating any WebEngine classes. Late calls will be ignored.

See also schemeByName().

[static] QWebEngineUrlScheme QWebEngineUrlScheme::schemeByName(const QByteArray &name)

Returns the web engine URL scheme with the given name or the default-constructed scheme.

See also registerScheme().

void QWebEngineUrlScheme::setDefaultPort(int newValue)

Sets the default port of this URL scheme to newValue.

See also defaultPort().

void QWebEngineUrlScheme::setFlags(QWebEngineUrlScheme::Flags newValue)

Sets the flags for this URL scheme to newValue.

See also Flags and flags().

void QWebEngineUrlScheme::setName(const QByteArray &newValue)

Sets the name of this URL scheme to newValue.

Note: The name is automatically converted to lower case.

See also name().

void QWebEngineUrlScheme::setSyntax(QWebEngineUrlScheme::Syntax newValue)

Sets the syntax type of this URL scheme to newValue.

See also Syntax and syntax().

QWebEngineUrlScheme::Syntax QWebEngineUrlScheme::syntax() const

Returns the syntax type of this URL scheme.

The default value is Path.

See also Syntax and setSyntax().

bool QWebEngineUrlScheme::operator!=(const QWebEngineUrlScheme &that) const

Returns true if this and that object are not equal.

bool QWebEngineUrlScheme::operator==(const QWebEngineUrlScheme &that) const

Returns true if this and that object are equal.

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