forked from boostorg/beast
43 lines
1.8 KiB
Plaintext
43 lines
1.8 KiB
Plaintext
[/
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Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
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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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Official repository: https://github.com/boostorg/beast
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]
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[section Custom Parsers]
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While the parsers included in the library will handle a broad number of
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use-cases, the __basic_parser__ interface can be subclassed to implement
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custom strategies for storing parsed results: the basic parser processes
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the incoming octets into elements according to the HTTP/1 protocol
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specification, while the derived class decides what to do with those
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elements. In particular, users who create exotic containers for [*Fields]
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may need to also create their own parser. Custom parsers will work with
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all of the stream read operations that work on parsers, as those algorithms
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use only the basic parser interface. Some use cases for implementing custom
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parsers are:
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* Inspect incoming header fields and keep or discard them.
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* Use a container provided by an external interface.
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* Store header data in a user-defined __Fields__ type.
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The basic parser uses the
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[@https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern Curiously Recurring Template Pattern].
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To declare your user defined parser, derive it from __basic_parser__.
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The interface to the parser is event-driven. Member functions of the derived
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class (termed "callbacks" in this context) are invoked with parsed elements
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as they become available, requiring either the `friend` declaration as shown
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above or that the member functions are declared public (not recommended).
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Buffers provided by the parser are non-owning references; it is the
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responsibility of the derived class to copy any information it needs before
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returning from the callback.
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[example_http_custom_parser]
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[endsect]
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