dvmhost/network/rest/http/HTTPRequestLexer.h

/**
* Digital Voice Modem - Host Software
* GPLv2 Open Source. Use is subject to license terms.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* @package DVM / Host Software
*
*/
//
// Based on code from the CRUD project. (https://github.com/venediktov/CRUD)
// Licensed under the BPL-1.0 License (https://opensource.org/license/bsl1-0-html)
//
/*
*   Copyright (c) 2003-2013 Christopher M. Kohlhoff
*   Copyright (C) 2023 by Bryan Biedenkapp N2PLL
*
*   Permission is hereby granted, free of charge, to any person or organization 
*   obtaining a copy of the software and accompanying documentation covered by 
*   this license (the “Software”) to use, reproduce, display, distribute, execute, 
*   and transmit the Software, and to prepare derivative works of the Software, and
*   to permit third-parties to whom the Software is furnished to do so, all subject
*   to the following:
*
*   The copyright notices in the Software and this entire statement, including the
*   above license grant, this restriction and the following disclaimer, must be included
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*   Software, unless such copies or derivative works are solely in the form of
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#if !defined(__REST_HTTP__HTTP_REQUEST_PARSER_H__)
#define __REST_HTTP__HTTP_REQUEST_PARSER_H__

#include <tuple>
#include <vector>

namespace network 
{
    namespace rest 
    {
        namespace http 
        {

            // ---------------------------------------------------------------------------
            //  Class Prototypes
            // ---------------------------------------------------------------------------

            struct HTTPRequest;
        
            // ---------------------------------------------------------------------------
            //  Class Declaration
            //      This class implements the lexer for incoming requests.
            // ---------------------------------------------------------------------------

            class HTTPRequestLexer
            {
            public:
                enum ResultType { GOOD, BAD, INDETERMINATE };

                /// <summary>Initializes a new instance of the HTTPRequestLexer class.</summary>
                HTTPRequestLexer();

                /// <summary>Reset to initial parser state.</summary>
                void reset();

                /// <summary>Parse some data. The enum return value is good when a complete request has
                /// been parsed, bad if the data is invalid, indeterminate when more data is
                /// required. The InputIterator return value indicates how much of the input
                /// has been consumed.</summary>
                template <typename InputIterator>
                std::tuple<ResultType, InputIterator> parse(HTTPRequest& req, InputIterator begin, InputIterator end)
                {
                    while (begin != end) {
                        ResultType result = consume(req, *begin++);
                        if (result == GOOD || result == BAD)
                            return std::make_tuple(result, begin);
                    }
                    return std::make_tuple(INDETERMINATE, begin);
                }

            private:
                /// <summary>Handle the next character of input.</summary>
                ResultType consume(HTTPRequest& req, char input);

                /// <summary>Check if a byte is an HTTP character.</summary>
                static bool isChar(int c);
                /// <summary>Check if a byte is an HTTP control character.</summary>
                static bool isControl(int c);
                /// <summary>Check if a byte is an HTTP special character.</summary>
                static bool isSpecial(int c);
                /// <summary>Check if a byte is an digit.</summary>
                static bool isDigit(int c);

                struct LexedHeader
                {
                    std::string name;
                    std::string value;

                    LexedHeader() { /* stub */ }
                    LexedHeader(const std::string& name, const std::string& value) : name(name), value(value) {}
                };

                std::vector<LexedHeader> m_headers;

                enum state
                {
                    METHOD_START,
                    METHOD,
                    URI,
                    HTTP_VERSION_H,
                    HTTP_VERSION_T_1,
                    HTTP_VERSION_T_2,
                    HTTP_VERSION_P,
                    HTTP_VERSION_SLASH,
                    HTTP_VERSION_MAJOR_START,
                    HTTP_VERSION_MAJOR,
                    HTTP_VERSION_MINOR_START,
                    HTTP_VERSION_MINOR,
                    EXPECTING_NEWLINE_1,
                    HEADER_LINE_START,
                    HEADER_LWS,
                    HEADER_NAME,
                    SPACE_BEFORE_HEADER_VALUE,
                    HEADER_VALUE,
                    EXPECTING_NEWLINE_2,
                    EXPECTING_NEWLINE_3
                } m_state;
            };
        } // namespace http
    } // namespace rest
} // namespace network

#endif // __REST_HTTP__HTTP_REQUEST_PARSER_H__