http_request_parser.cpp

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//
// http_request_parser.cpp
// ~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2011 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#include "async_web_server_cpp/http_request_parser.hpp"

namespace async_web_server_cpp
{
HttpRequestParser::HttpRequestParser() : state_(method_start) {}

void HttpRequestParser::reset()
{
    state_ = method_start;
}

boost::tribool HttpRequestParser::consume(HttpRequest& req, char input)
{
    switch (state_)
    {
        case method_start:
            if (!is_char(input) || is_ctl(input) || is_tspecial(input))
            {
                return false;
            }
            else
            {
                state_ = method;
                req.method.push_back(input);
                return boost::indeterminate;
            }
        case method:
            if (input == ' ')
            {
                state_ = uri;
                return boost::indeterminate;
            }
            else if (!is_char(input) || is_ctl(input) || is_tspecial(input))
            {
                return false;
            }
            else
            {
                req.method.push_back(input);
                return boost::indeterminate;
            }
        case uri:
            if (input == ' ')
            {
                state_ = http_version_h;
                return boost::indeterminate;
            }
            else if (is_ctl(input))
            {
                return false;
            }
            else
            {
                req.uri.push_back(input);
                return boost::indeterminate;
            }
        case http_version_h:
            if (input == 'H')
            {
                state_ = http_version_t_1;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case http_version_t_1:
            if (input == 'T')
            {
                state_ = http_version_t_2;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case http_version_t_2:
            if (input == 'T')
            {
                state_ = http_version_p;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case http_version_p:
            if (input == 'P')
            {
                state_ = http_version_slash;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case http_version_slash:
            if (input == '/')
            {
                req.http_version_major = 0;
                req.http_version_minor = 0;
                state_ = http_version_major_start;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case http_version_major_start:
            if (is_digit(input))
            {
                req.http_version_major =
                    req.http_version_major * 10 + input - '0';
                state_ = http_version_major;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case http_version_major:
            if (input == '.')
            {
                state_ = http_version_minor_start;
                return boost::indeterminate;
            }
            else if (is_digit(input))
            {
                req.http_version_major =
                    req.http_version_major * 10 + input - '0';
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case http_version_minor_start:
            if (is_digit(input))
            {
                req.http_version_minor =
                    req.http_version_minor * 10 + input - '0';
                state_ = http_version_minor;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case http_version_minor:
            if (input == '\r')
            {
                state_ = expecting_newline_1;
                return boost::indeterminate;
            }
            else if (is_digit(input))
            {
                req.http_version_minor =
                    req.http_version_minor * 10 + input - '0';
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case expecting_newline_1:
            if (input == '\n')
            {
                state_ = header_line_start;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case header_line_start:
            if (input == '\r')
            {
                state_ = expecting_newline_3;
                return boost::indeterminate;
            }
            else if (!req.headers.empty() && (input == ' ' || input == '\t'))
            {
                state_ = header_lws;
                return boost::indeterminate;
            }
            else if (!is_char(input) || is_ctl(input) || is_tspecial(input))
            {
                return false;
            }
            else
            {
                req.headers.push_back(HttpHeader());
                req.headers.back().name.push_back(input);
                state_ = header_name;
                return boost::indeterminate;
            }
        case header_lws:
            if (input == '\r')
            {
                state_ = expecting_newline_2;
                return boost::indeterminate;
            }
            else if (input == ' ' || input == '\t')
            {
                return boost::indeterminate;
            }
            else if (is_ctl(input))
            {
                return false;
            }
            else
            {
                state_ = header_value;
                req.headers.back().value.push_back(input);
                return boost::indeterminate;
            }
        case header_name:
            if (input == ':')
            {
                state_ = space_before_header_value;
                return boost::indeterminate;
            }
            else if (!is_char(input) || is_ctl(input) || is_tspecial(input))
            {
                return false;
            }
            else
            {
                req.headers.back().name.push_back(input);
                return boost::indeterminate;
            }
        case space_before_header_value:
            if (input == ' ')
            {
                state_ = header_value;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case header_value:
            if (input == '\r')
            {
                state_ = expecting_newline_2;
                return boost::indeterminate;
            }
            else if (is_ctl(input))
            {
                return false;
            }
            else
            {
                req.headers.back().value.push_back(input);
                return boost::indeterminate;
            }
        case expecting_newline_2:
            if (input == '\n')
            {
                state_ = header_line_start;
                return boost::indeterminate;
            }
            else
            {
                return false;
            }
        case expecting_newline_3:
            return (input == '\n');
        default:
            return false;
    }
}

bool HttpRequestParser::is_char(int c)
{
    return c >= 0 && c <= 127;
}

bool HttpRequestParser::is_ctl(int c)
{
    return (c >= 0 && c <= 31) || (c == 127);
}

bool HttpRequestParser::is_tspecial(int c)
{
    switch (c)
    {
        case '(':
        case ')':
        case '<':
        case '>':
        case '@':
        case ',':
        case ';':
        case ':':
        case '\\':
        case '"':
        case '/':
        case '[':
        case ']':
        case '?':
        case '=':
        case '{':
        case '}':
        case ' ':
        case '\t':
            return true;
        default:
            return false;
    }
}

bool HttpRequestParser::is_digit(int c)
{
    return c >= '0' && c <= '9';
}

}  // namespace async_web_server_cpp