doc/html/boost_asio/example/cpp03/http/server4/request_parser.cpp
//
// request_parser.cpp
// ~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2023 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 "request_parser.hpp"
#include <algorithm>
#include <cctype>
#include <boost/lexical_cast.hpp>
#include "request.hpp"
namespace http {
namespace server4 {
// Enable the pseudo-keywords reenter, yield and fork.
#include <boost/asio/yield.hpp>
std::string request_parser::content_length_name_ = "Content-Length";
boost::tribool request_parser::consume(request& req, char c)
{
reenter (this)
{
req.method.clear();
req.uri.clear();
req.http_version_major = 0;
req.http_version_minor = 0;
req.headers.clear();
req.content.clear();
content_length_ = 0;
// Request method.
while (is_char(c) && !is_ctl(c) && !is_tspecial(c) && c != ' ')
{
req.method.push_back(c);
yield return boost::indeterminate;
}
if (req.method.empty())
return false;
// Space.
if (c != ' ') return false;
yield return boost::indeterminate;
// URI.
while (!is_ctl(c) && c != ' ')
{
req.uri.push_back(c);
yield return boost::indeterminate;
}
if (req.uri.empty()) return false;
// Space.
if (c != ' ') return false;
yield return boost::indeterminate;
// HTTP protocol identifier.
if (c != 'H') return false;
yield return boost::indeterminate;
if (c != 'T') return false;
yield return boost::indeterminate;
if (c != 'T') return false;
yield return boost::indeterminate;
if (c != 'P') return false;
yield return boost::indeterminate;
// Slash.
if (c != '/') return false;
yield return boost::indeterminate;
// Major version number.
if (!is_digit(c)) return false;
while (is_digit(c))
{
req.http_version_major = req.http_version_major * 10 + c - '0';
yield return boost::indeterminate;
}
// Dot.
if (c != '.') return false;
yield return boost::indeterminate;
// Minor version number.
if (!is_digit(c)) return false;
while (is_digit(c))
{
req.http_version_minor = req.http_version_minor * 10 + c - '0';
yield return boost::indeterminate;
}
// CRLF.
if (c != '\r') return false;
yield return boost::indeterminate;
if (c != '\n') return false;
yield return boost::indeterminate;
// Headers.
while ((is_char(c) && !is_ctl(c) && !is_tspecial(c) && c != '\r')
|| (c == ' ' || c == '\t'))
{
if (c == ' ' || c == '\t')
{
// Leading whitespace. Must be continuation of previous header's value.
if (req.headers.empty()) return false;
while (c == ' ' || c == '\t')
yield return boost::indeterminate;
}
else
{
// Start the next header.
req.headers.push_back(header());
// Header name.
while (is_char(c) && !is_ctl(c) && !is_tspecial(c) && c != ':')
{
req.headers.back().name.push_back(c);
yield return boost::indeterminate;
}
// Colon and space separates the header name from the header value.
if (c != ':') return false;
yield return boost::indeterminate;
if (c != ' ') return false;
yield return boost::indeterminate;
}
// Header value.
while (is_char(c) && !is_ctl(c) && c != '\r')
{
req.headers.back().value.push_back(c);
yield return boost::indeterminate;
}
// CRLF.
if (c != '\r') return false;
yield return boost::indeterminate;
if (c != '\n') return false;
yield return boost::indeterminate;
}
// CRLF.
if (c != '\r') return false;
yield return boost::indeterminate;
if (c != '\n') return false;
// Check for optional Content-Length header.
for (std::size_t i = 0; i < req.headers.size(); ++i)
{
if (headers_equal(req.headers[i].name, content_length_name_))
{
try
{
content_length_ =
boost::lexical_cast<std::size_t>(req.headers[i].value);
}
catch (boost::bad_lexical_cast&)
{
return false;
}
}
}
// Content.
while (req.content.size() < content_length_)
{
yield return boost::indeterminate;
req.content.push_back(c);
}
}
return true;
}
// Disable the pseudo-keywords reenter, yield and fork.
#include <boost/asio/unyield.hpp>
bool request_parser::is_char(int c)
{
return c >= 0 && c <= 127;
}
bool request_parser::is_ctl(int c)
{
return (c >= 0 && c <= 31) || (c == 127);
}
bool request_parser::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 request_parser::is_digit(int c)
{
return c >= '0' && c <= '9';
}
bool request_parser::tolower_compare(char a, char b)
{
return std::tolower(a) == std::tolower(b);
}
bool request_parser::headers_equal(const std::string& a, const std::string& b)
{
if (a.length() != b.length())
return false;
return std::equal(a.begin(), a.end(), b.begin(),
&request_parser::tolower_compare);
}
} // namespace server4
} // namespace http