Davide Pesavento
296c3a185d
Also, explicitly declare the nullptr_t overloads as deleted, so that users get a clear compilation error instead of a potentially confusing "ambiguous overload" if they try to pass nullptr to these functions. Change-Id: I399efcbd698a0d3f7e29219d21eb1a53a1d71070
68 lines
2.8 KiB
ReStructuredText
68 lines
2.8 KiB
ReStructuredText
Trivial applications
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====================
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.. note::
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To successfully run the following examples, please make sure that NFD is properly
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configured and running. For more information about NFD, refer to `NFD's official
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homepage <https://docs.named-data.net/NFD/>`__.
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Trivial consumer
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----------------
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In the following trivial example, a consumer creates a :ndn-cxx:`Face` with default
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transport (:ndn-cxx:`UnixTransport`) and sends an Interest for
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``/localhost/testApp/randomData``. While expressing Interest, the app specifies three
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callbacks to be called when Data/Nack is retrieved or Interest times out.
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.. literalinclude:: ../examples/consumer.cpp
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:language: c++
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:linenos:
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:emphasize-lines: 43-48,51-54,62,76,82
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Trivial producer
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----------------
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The following example demonstrates how to write a simple producer application.
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First, the application sets an Interest filter for ``/localhost/testApp`` to receive all
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Interests that have this prefix. The :ndn-cxx:`Face::setInterestFilter` call accepts two
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callbacks; the first will be called when an Interest is received and the second if prefix
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registration fails.
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After an Interest is received, the producer creates a Data packet with the same name as
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the received Interest, adds content, and signs it with the system-default identity. It is
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also possible to specify a particular key to be used during the signing. For more
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information, refer to :ndn-cxx:`KeyChain API documentation <KeyChain>`.
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Finally, after Data packet has been created and signed, it is returned to the requester
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using :ndn-cxx:`Face::put` method.
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.. literalinclude:: ../examples/producer.cpp
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:language: c++
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:linenos:
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:emphasize-lines: 39-42,55,60-63,78,86,90
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Consumer that uses Scheduler
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----------------------------
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The following example demonstrates how to use :ndn-cxx:`Scheduler` to schedule arbitrary
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events for execution at specific points of time.
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The library internally uses `boost::asio::io_service
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<https://www.boost.org/doc/libs/1_65_1/doc/html/boost_asio/reference/io_service.html>`_ to
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implement fully asynchronous NDN operations (i.e., sending and receiving Interests and
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Data). In addition to network-related operations, ``boost::asio::io_service`` can be used
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to execute any arbitrary callback within the processing thread (run either explicitly via
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``io_service::run()`` or implicitly via :ndn-cxx:`Face::processEvents` as in previous
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examples). :ndn-cxx:`Scheduler` is just a wrapper on top of ``io_service``, providing a
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simple interface to schedule tasks at specific times.
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The highlighted lines in the example demonstrate all that is needed to express a second
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Interest approximately 3 seconds after the first one.
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.. literalinclude:: ../examples/consumer-with-timer.cpp
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:language: c++
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:linenos:
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:emphasize-lines: 47-50,53,84,96-99,104-106
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