http/impl/parser.hpp

/*
 * Copyright (c) 2014, Peter Thorson. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the WebSocket++ Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef HTTP_PARSER_IMPL_HPP
#define HTTP_PARSER_IMPL_HPP

#include <algorithm>
#include <cstdlib>
#include <istream>
#include <sstream>
#include <string>

namespace websocketpp {
namespace http {
namespace parser {

inline void parser::set_version(std::string const & version) {
    m_version = version;
}

inline std::string const & parser::get_header(std::string const & key) const {
    header_list::const_iterator h = m_headers.find(key);

    if (h == m_headers.end()) {
        return empty_header;
    } else {
        return h->second;
    }
}

inline bool parser::get_header_as_plist(std::string const & key,
    parameter_list & out) const
{
    header_list::const_iterator it = m_headers.find(key);

    if (it == m_headers.end() || it->second.size() == 0) {
        return false;
    }

    return this->parse_parameter_list(it->second,out);
}

inline void parser::append_header(std::string const & key, std::string const &
    val)
{
    if (std::find_if(key.begin(),key.end(),is_not_token_char) != key.end()) {
        throw exception("Invalid header name",status_code::bad_request);
    }

    if (this->get_header(key) == "") {
        m_headers[key] = val;
    } else {
        m_headers[key] += ", " + val;
    }
}

inline void parser::replace_header(std::string const & key, std::string const &
    val)
{
    m_headers[key] = val;
}

inline void parser::remove_header(std::string const & key) {
    m_headers.erase(key);
}

inline void parser::set_body(std::string const & value) {
    if (value.size() == 0) {
        remove_header("Content-Length");
        m_body = "";
        return;
    }

    // TODO: should this method respect the max size? If so how should errors
    // be indicated?

    std::stringstream len;
    len << value.size();
    replace_header("Content-Length", len.str());
    m_body = value;
}

inline bool parser::parse_parameter_list(std::string const & in,
    parameter_list & out) const
{
    if (in.size() == 0) {
        return false;
    }

    std::string::const_iterator it;
    it = extract_parameters(in.begin(),in.end(),out);
    return (it == in.begin());
}

inline bool parser::prepare_body() {
    if (get_header("Content-Length") != "") {
        std::string const & cl_header = get_header("Content-Length");
        char * end;

        // TODO: not 100% sure what the compatibility of this method is. Also,
        // I believe this will only work up to 32bit sizes. Is there a need for
        // > 4GiB HTTP payloads?
        m_body_bytes_needed = std::strtoul(cl_header.c_str(),&end,10);

        if (m_body_bytes_needed > m_body_bytes_max) {
            throw exception("HTTP message body too large",
                status_code::request_entity_too_large);
        }

        m_body_encoding = body_encoding::plain;
        return true;
    } else {
        return false;
    }
}

inline size_t parser::process_body(char const * buf, size_t len) {
    if (m_body_encoding == body_encoding::plain) {
        size_t processed = (std::min)(m_body_bytes_needed,len);
        m_body.append(buf,processed);
        m_body_bytes_needed -= processed;
        return processed;
    } else if (m_body_encoding == body_encoding::chunked) {
        // TODO:
        throw exception("Unexpected body encoding",
            status_code::internal_server_error);
    } else {
        throw exception("Unexpected body encoding",
            status_code::internal_server_error);
    }
}

inline void parser::process_header(std::string::iterator begin,
    std::string::iterator end)
{
    std::string::iterator cursor = std::search(
        begin,
        end,
        header_separator,
        header_separator + sizeof(header_separator) - 1
    );

    if (cursor == end) {
        throw exception("Invalid header line",status_code::bad_request);
    }

    append_header(strip_lws(std::string(begin,cursor)),
                  strip_lws(std::string(cursor+sizeof(header_separator)-1,end)));
}

inline std::string parser::raw_headers() const {
    std::stringstream raw;

    header_list::const_iterator it;
    for (it = m_headers.begin(); it != m_headers.end(); it++) {
        raw << it->first << ": " << it->second << "\r\n";
    }

    return raw.str();
}


} // namespace parser
} // namespace http
} // namespace websocketpp

#endif // HTTP_PARSER_IMPL_HPP