class QMqttTopicFilter#

The QMqttTopicFilter class represents a MQTT topic filter. More…

Synopsis#

Methods#

def __init__()
def filter()
def isValid()
def match()
def __ne__()
def setFilter()
def sharedSubscriptionName()
def swap()

Note

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Detailed Description#

QMqttTopicFilter is a thin wrapper around a QString providing an expressive data type for MQTT topic filters. Beside the benefits of having a strong type preventing unintended misuse, QMqttTopicFilter provides convenient functions related to topic filters like isValid() or match() .

For example, the following code would fail to compile and prevent a possible unintended and meaningless matching of two filters, especially if the variable names were less expressive:

QMqttTopicFilter globalFilter{"foo/#"};
QMqttTopicFilter specificFilter{"foo/bar"};
if (globalFilter.match(specificFilter)) {
    //...
}

The usability, however, is not affected since the following snippet compiles and runs as expected:

QMqttTopicFilter globalFilter{"foo/#"};
if (globalFilter.match("foo/bar")) {
    //...
}

See also

QMqttTopicName

class MatchOption#

(inherits enum.Flag) This enum value holds the matching options for the topic filter.

Constant

Description

QMqttTopicFilter.NoMatchOption

No match options are set.

QMqttTopicFilter.WildcardsDontMatchDollarTopicMatchOption

A wildcard at the filter’s beginning does not match a topic name that starts with the dollar sign ($).

Constant	Description
QMqttTopicFilter.NoMatchOption	No match options are set.
QMqttTopicFilter.WildcardsDontMatchDollarTopicMatchOption	A wildcard at the filter’s beginning does not match a topic name that starts with the dollar sign ($).

__init__(filter)#

Parameters:: filter – QLatin1String

Creates a new MQTT topic filter with the specified filter.

__init__(filter)

Parameters:: filter – QMqttTopicFilter

Creates a new MQTT topic filter as a copy of filter.

__init__([filter=""])

Parameters:: filter – str

Creates a new MQTT topic filter with the specified filter.

filter()#

Return type:: str

Returns the topic filter.

See also

setFilter()

isValid()#

Return type:: bool

Returns true if the topic filter is valid according to the MQTT standard section 4.7, or false otherwise.

match(name[, matchOptions=QMqttTopicFilter.MatchOption.NoMatchOption])#

Parameters:

name – QMqttTopicName
matchOptions – Combination of MatchOption

Return type:

bool

Returns true if the topic filter matches the topic name name honoring the given matchOptions, or false otherwise.

__ne__(rhs)#

Parameters:: rhs – QMqttTopicFilter
Return type:: bool

Returns true if the topic filters lhs and rhs are different, otherwise returns false.

setFilter(filter)#

Parameters:: filter – str

Sets the topic filter to filter.

See also

filter()

sharedSubscriptionName()#

Return type:: str

Returns the name of a share if the topic filter has been specified as a shared subscription. The format of shared subscriptions is defined as $share/sharename/topicfilter.

swap(other)#

Parameters:: other – QMqttTopicFilter

Swaps the MQTT topic filter other with this MQTT topic filter. This operation is very fast and never fails.