QHttp2Configuration Class

The QHttp2Configuration class controls HTTP/2 parameters and settings. More...

Header: #include <QHttp2Configuration>
qmake: QT += network
Since: Qt 5.14

This class was introduced in Qt 5.14.

Note: All functions in this class are reentrant.

Public Functions

QHttp2Configuration(QHttp2Configuration &&other)
QHttp2Configuration(const QHttp2Configuration &other)
QHttp2Configuration &operator=(QHttp2Configuration &&other)
QHttp2Configuration &operator=(const QHttp2Configuration &other)
bool huffmanCompressionEnabled() const
unsigned int maxFrameSize() const
bool serverPushEnabled() const
unsigned int sessionReceiveWindowSize() const
void setHuffmanCompressionEnabled(bool enable)
bool setMaxFrameSize(unsigned int size)
void setServerPushEnabled(bool enable)
bool setSessionReceiveWindowSize(unsigned int size)
bool setStreamReceiveWindowSize(unsigned int size)
unsigned int streamReceiveWindowSize() const
void swap(QHttp2Configuration &other)

Detailed Description

QHttp2Configuration controls HTTP/2 parameters and settings that QNetworkAccessManager will use to send requests and process responses when the HTTP/2 protocol is enabled.

The HTTP/2 parameters that QHttp2Configuration currently supports include:

  • The session window size for connection-level flow control. Will be sent to a remote peer when needed as 'WINDOW_UPDATE' frames on the stream with an identifier 0.
  • The stream receiving window size for stream-level flow control. Sent as 'SETTINGS_INITIAL_WINDOW_SIZE' parameter in the initial SETTINGS frame and, when needed, 'WINDOW_UPDATE' frames will be sent on streams that QNetworkAccessManager opens.
  • The maximum frame size. This parameter limits the maximum payload a frame coming from the remote peer can have. Sent by QNetworkAccessManager as 'SETTINGS_MAX_FRAME_SIZE' parameter in the initial 'SETTINGS' frame.
  • The server push. Allows to enable or disable server push. Sent as 'SETTINGS_ENABLE_PUSH' parameter in the initial 'SETTINGS' frame.

The QHttp2Configuration class also controls if the header compression algorithm (HPACK) is additionally using Huffman coding for string compression.

Note: The configuration must be set before the first request was sent to a given host (and thus an HTTP/2 session established).

Note: Details about flow control, server push and 'SETTINGS' can be found in RFC 7540. Different modes and parameters of the HPACK compression algorithm are described in RFC 7541.

See also QNetworkRequest::setHttp2Configuration(), QNetworkRequest::http2Configuration(), and QNetworkAccessManager.

Member Function Documentation

QHttp2Configuration::QHttp2Configuration(QHttp2Configuration &&other)

Move-constructs this QHttp2Configuration from other

QHttp2Configuration::QHttp2Configuration(const QHttp2Configuration &other)

Copy-constructs this QHttp2Configuration.


Default constructs a QHttp2Configuration object.

Such a configuration has the following values:

  • Server push is disabled
  • Huffman string compression is enabled
  • Window size for connection-level flow control is 65535 octets
  • Window size for stream-level flow control is 65535 octets
  • Frame size is 16384 octets

QHttp2Configuration &QHttp2Configuration::operator=(QHttp2Configuration &&other)

Move-assigns to this QHttp2Configuration.

QHttp2Configuration &QHttp2Configuration::operator=(const QHttp2Configuration &other)

Copy-assigns to this QHttp2Configuration.



bool QHttp2Configuration::huffmanCompressionEnabled() const

Returns true if the Huffman coding in HPACK is enabled.

See also setHuffmanCompressionEnabled.

unsigned int QHttp2Configuration::maxFrameSize() const

The maximum payload size that HTTP/2 frames can have. The default (initial) value is 16384 octets.

See also setMaxFrameSize().

bool QHttp2Configuration::serverPushEnabled() const

Returns true if server push was enabled.

Note: By default, QNetworkAccessManager disables server push via the 'SETTINGS' frame.

See also setServerPushEnabled.

unsigned int QHttp2Configuration::sessionReceiveWindowSize() const

Returns the window size for connection-level flow control. The default value QNetworkAccessManager will be using is 2147483647 octets.

See also setSessionReceiveWindowSize().

void QHttp2Configuration::setHuffmanCompressionEnabled(bool enable)

If enable is true, HPACK compression will additionally compress string using the Huffman coding. Enabled by default.

Note: This parameter only affects 'HEADERS' frames that QNetworkAccessManager is sending.

See also huffmanCompressionEnabled.

bool QHttp2Configuration::setMaxFrameSize(unsigned int size)

Sets the maximum frame size that QNetworkAccessManager will advertise to the server when sending its initial SETTINGS frame.

Note: While this size is required to be within a range between 16384 and 16777215 inclusive, the actual payload size in frames that carry payload maybe be less than 16384.

See also maxFrameSize().

void QHttp2Configuration::setServerPushEnabled(bool enable)

If enable is true, a remote server can potentially use server push to send reponses in advance.

See also serverPushEnabled.

bool QHttp2Configuration::setSessionReceiveWindowSize(unsigned int size)

Sets the window size for connection-level flow control. size cannot be 0 and must not exceed 2147483647 octets.

See also sessionReceiveWindowSize.

bool QHttp2Configuration::setStreamReceiveWindowSize(unsigned int size)

Sets the window size for stream-level flow control. size cannot be 0 and must not exceed 2147483647 octets.

See also streamReceiveWindowSize.

unsigned int QHttp2Configuration::streamReceiveWindowSize() const

Returns the window size for stream-level flow control. The default value QNetworkAccessManager will be using is 21474836 octets.

See also setStreamReceiveWindowSize().

void QHttp2Configuration::swap(QHttp2Configuration &other)

Swaps this configuration with the other configuration.

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