forked from boostorg/mqtt5
Korina Šimičević
5034734fc4
Summary: resolves T13155 Reviewers: ivica Reviewed By: ivica Subscribers: miljen, iljazovic Maniphest Tasks: T13155 Differential Revision: https://repo.mireo.local/D26681
48 lines
1.9 KiB
Plaintext
48 lines
1.9 KiB
Plaintext
[/
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Copyright (c) 2023 Mireo
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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[section:pubcomp_props PUBCOMP properties]
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The last field in the Variable header of __PUBCOMP__ packet is a set of Properties.
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A set contains a Property Length followed by the Properties.
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A Property consists of an Identifier and a value.
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This section lists all possible __PUBCOMP__ Properties and describes their usage:
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[table:pubcomp_props PUBCOMP properties
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[[Identifier] [Value type] [Description]]
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[[reason_string] [`std::string`] [A UTF-8 Encoded String representing the reason associated with this response.]]
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[[user_property] [`std::vector<std::string>`] [A list of name, value pairs (__UTF8_STRING_PAIR__) defining User Properties.
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This property may be used to provide additional diagnostic or other information. ]]
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]
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[h4 Usage]
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After obtaining an instance of `async_mqtt5::pubcomp_props`, the subscript operator can be used to access a Property.
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The Identifiers listed in the table above are available within the `async_mqtt5::prop` namespace for Property access.
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[h4 Example]
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The following example shows how to set a Property value:
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[!c++]
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async_mqtt5::pubcomp_props props;
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props[async_mqtt5::prop::reason_string] = "Some reason...";
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The following example shows how to retrieve a Property value:
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[note When retrieving a property value, the subscript operator will consistently return a `std::optional` of the value type for all properties,
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except for `async_mqtt5::prop::user_property`, where it will return an instance of its value type, `std::vector<std::string>`.]
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[!c++]
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std::optional<std::string> reason_string = props[async_mqtt5::prop::reason_string];
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if (reason_string.has_value())
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// reason string property was previously set
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else
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// reason string property was not set
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[endsect]
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