Question

我已经使用Boost.Spirit实现了HTTP头解析器：

#define BOOST_SPIRIT_DEBUG
#include <boost/spirit/include/classic.hpp>
#include <boost/config/warning_disable.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/fusion/include/std_pair.hpp>
#include <boost/fusion/include/map.hpp>
#include <boost/fusion/adapted/struct.hpp>
#include <iostream>
#include <string>

using namespace boost;

typedef std::map<std::string, std::string> header_fields_t;
struct HttpRequestHeader
{
    std::string _method;
    std::string _uri;
    std::string _http_version;
    header_fields_t _header_fields;
};

BOOST_FUSION_ADAPT_STRUCT
(
    HttpRequestHeader,
    (std::string, _method)
    (std::string, _uri)
    (std::string, _http_version)
    (header_fields_t, _header_fields)
)

template <typename Iterator>
struct HttpHeaderGrammar: spirit::qi::grammar < Iterator,      
HttpRequestHeader(), spirit::ascii::space_type >
{
    HttpHeaderGrammar() : HttpHeaderGrammar::base_type(http_header,     "HttpHeaderGrammar Grammar")
    {
        auto eol_rule = spirit::qi::no_skip[spirit::qi::lit('\r')] >> spirit::qi::no_skip[spirit::qi::lit('\n')];
        method = spirit::qi::lexeme[+spirit::qi::alpha];
        uri = spirit::qi::lexeme[+(spirit::qi::char_ - spirit::qi::space)];
        http_ver = spirit::lexeme[spirit::qi::lit("HTTP/") >> +(spirit::qi::char_("0-9."))];

        auto field_key = spirit::lexeme[+(spirit::qi::char_("a-zA-Z-") | spirit::qi::digit)];
        auto field_value = spirit::lexeme[+(spirit::qi::char_ - '\r' - '\n')];
        fields = *(field_key >> ':' >> field_value >> eol_rule);
        http_header =
            method >> uri >> http_ver >> eol_rule
            >> fields
            ;
        BOOST_SPIRIT_DEBUG_NODES((method)(uri)(http_ver)(fields))
    }

    spirit::qi::rule<Iterator, std::string(), spirit::ascii::space_type> method;
    spirit::qi::rule<Iterator, std::string(), spirit::ascii::space_type> uri;
    spirit::qi::rule<Iterator, std::string(), spirit::ascii::space_type> http_ver;
    spirit::qi::rule<Iterator, std::map<std::string, std::string>(), spirit::ascii::space_type> fields;
    spirit::qi::rule<Iterator, HttpRequestHeader(),     spirit::ascii::space_type> http_header;
};

int main(int argc, char* argv[])
{
    std::cout << "/////////////////////////////////////////////////////////\n\n";
    std::cout << "Expression parser...\n\n";
    std::cout <<     "/////////////////////////////////////////////////////////\n\n";

    typedef std::string::const_iterator iterator_type;
    HttpHeaderGrammar<iterator_type> httpGrammar;
    BOOST_SPIRIT_DEBUG_NODE(httpGrammar);

    HttpRequestHeader httpHeader;

    std::string str(
        "CONNECT www.tutorialspoint.com HTTP/1.1\r\n"
        "User-Agent: Mozilla/4.0 (compatible; MSIE5.01; Windows NT)\r\n");

    {
        std::string::const_iterator iter = str.begin();
        std::string::const_iterator end = str.end();
        bool r = spirit::qi::phrase_parse(iter, end, httpGrammar,     spirit::ascii::space, httpHeader);

        if (r && iter == end)
        {
            std::cout << "-------------------------\n";
            std::cout << "Parsing succeeded\n";
            std::cout << "-------------------------\n";
        }
        else
        {
            std::string rest(iter, end);
            std::cout << "-------------------------\n";
            std::cout << "Parsing failed\n";
            std::cout << "stopped at: \": " << rest << "\"\n";
            std::cout << "-------------------------\n";
        }
    }

    std::cout << "Bye... :-) \n\n";
    return 0;
}

最后，我遇到了两个问题：

1）在Windows上运行时，它可以正常工作并解析。在linux上运行时，解析失败。在调试时，我注意到http请求文本保持“... \\ r \\ n ...”并且看起来像Boost.Spirit错误地继续这些符号。我几乎不明白怎么修错了。

2）我没有看到任何跟踪输出。我做错了什么来制作Boost.Spirit打印跟踪输出？

-Thanks

Answer 1

确实发生了一些事情：

无法将表达式分配给自动（请参阅https://stackoverflow.com/a/31294109/2417774）
无法匹配eol（使用case 0）
不需要添加lexemes，只需删除队长; Boost spirit skipper issues
图表已经是除空格
考虑使语法更具体（动词blank正在征求问题）
停止包含10年过时的“经典”标题。

在这里： Live On Coliru

+alpha

输出：

#define BOOST_SPIRIT_DEBUG
#include <boost/spirit/include/qi.hpp>
#include <boost/fusion/include/std_pair.hpp>
#include <map>
#include <iostream>

typedef std::map<std::string, std::string> header_fields_t;

struct HttpRequestHeader
{
    std::string _method;
    std::string _uri;
    std::string _http_version;
    header_fields_t _header_fields;
};

BOOST_FUSION_ADAPT_STRUCT(HttpRequestHeader, _method, _uri, _http_version, _header_fields)

namespace qi = boost::spirit::qi;

template <typename Iterator, typename Skipper = qi::ascii::blank_type>
struct HttpHeaderGrammar: qi::grammar <Iterator, HttpRequestHeader(), Skipper> {
    HttpHeaderGrammar() : HttpHeaderGrammar::base_type(http_header, "HttpHeaderGrammar Grammar") {
        method        = +qi::alpha;
        uri           = +qi::graph;
        http_ver      = "HTTP/" >> +qi::char_("0-9.");

        field_key     = +qi::char_("0-9a-zA-Z-");
        field_value   = +~qi::char_("\r\n");

        fields = *(field_key >> ':' >> field_value >> qi::lexeme["\r\n"]);

        http_header = method >> uri >> http_ver >> qi::lexeme["\r\n"] >> fields;

        BOOST_SPIRIT_DEBUG_NODES((method)(uri)(http_ver)(fields)(http_header))
    }

  private:
    qi::rule<Iterator, std::map<std::string, std::string>(), Skipper> fields;
    qi::rule<Iterator, HttpRequestHeader(), Skipper> http_header;
    // lexemes
    qi::rule<Iterator, std::string()> method, uri, http_ver;
    qi::rule<Iterator, std::string()> field_key, field_value;
};

int main()
{
    typedef std::string::const_iterator It;
    HttpHeaderGrammar<It> httpGrammar;

    HttpRequestHeader httpHeader;

    std::string str(
        "CONNECT www.tutorialspoint.com HTTP/1.1\r\n"
        "User-Agent: Mozilla/4.0 (compatible; MSIE5.01; Windows NT)\r\n");

    It iter = str.begin(), end = str.end();
    bool r = phrase_parse(iter, end, httpGrammar, qi::ascii::blank, httpHeader);

    if (r && iter == end) {
        std::cout << "Parsing succeeded\n";
    } else {
        std::cout << "Parsing failed\n";
        std::cout << "stopped at: \"" << std::string(iter, end) << "\"\n";
    }

    std::cout << "Bye... :-) \n\n";
}

调试信息：

Parsing succeeded
Bye... :-)

Boost.Spirit HTTP头解析器，跟踪

1 个答案: