http/common/http_msg.cpp

/***
 * Copyright (C) Microsoft. All rights reserved.
 * Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
 *
 * =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
 *
 * HTTP Library: Request and reply message definitions.
 *
 * For the latest on this and related APIs, please see: https://github.com/Microsoft/cpprestsdk
 *
 * =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 ****/
#include "stdafx.h"

#include "../common/internal_http_helpers.h"
#include "cpprest/producerconsumerstream.h"
#include <sstream>

using namespace web;
using namespace utility;
using namespace concurrency;
using namespace utility::conversions;
using namespace http::details;

namespace web
{
namespace http
{
#define CRLF _XPLATSTR("\r\n")

utility::string_t http_headers::content_type() const
{
    utility::string_t result;
    match(http::header_names::content_type, result);
    return result;
}

/// Helper functions to convert a series of bytes from a charset to utf-8 or utf-16.
/// These APIs deal with checking for and handling byte order marker (BOM).
namespace
{
enum endianness
{
    little_endian,
    big_endian,
    unknown
};
endianness check_byte_order_mark(const utf16string& str)
{
    if (str.empty())
    {
        return unknown;
    }
    const unsigned char* src = reinterpret_cast<const unsigned char*>(str.data());

    // little endian
    if (src[0] == 0xFF && src[1] == 0xFE)
    {
        return little_endian;
    }

    // big endian
    else if (src[0] == 0xFE && src[1] == 0xFF)
    {
        return big_endian;
    }

    return unknown;
}

std::string convert_utf16le_to_utf8(utf16string src, bool erase_bom)
{
    if (erase_bom && !src.empty())
    {
        src.erase(0, 1);
    }
    return utf16_to_utf8(std::move(src));
}

utility::string_t convert_utf16le_to_string_t(utf16string src, bool erase_bom)
{
    if (erase_bom && !src.empty())
    {
        src.erase(0, 1);
    }
#ifdef _UTF16_STRINGS
    return src;
#else
    return utf16_to_utf8(std::move(src));
#endif
}

// Helper function to change endian ness from big endian to little endian
utf16string big_endian_to_little_endian(utf16string src, bool erase_bom)
{
    if (erase_bom && !src.empty())
    {
        src.erase(0, 1);
    }
    if (src.empty())
    {
        return src;
    }

    const size_t size = src.size();
    for (size_t i = 0; i < size; ++i)
    {
        utf16char ch = src[i];
        src[i] = static_cast<utf16char>(ch << 8);
        src[i] = static_cast<utf16char>(src[i] | ch >> 8);
    }

    return src;
}

std::string convert_utf16be_to_utf8(utf16string src, bool erase_bom)
{
    return utf16_to_utf8(big_endian_to_little_endian(std::move(src), erase_bom));
}

utf16string convert_utf16be_to_utf16le(utf16string src, bool erase_bom)
{
    return big_endian_to_little_endian(std::move(src), erase_bom);
}

utility::string_t convert_utf16be_to_string_t(utf16string src, bool erase_bom)
{
#ifdef _UTF16_STRINGS
    return convert_utf16be_to_utf16le(std::move(src), erase_bom);
#else
    return convert_utf16be_to_utf8(std::move(src), erase_bom);
#endif
}

std::string convert_utf16_to_utf8(utf16string src)
{
    const endianness endian = check_byte_order_mark(src);
    switch (endian)
    {
        case little_endian: return convert_utf16le_to_utf8(std::move(src), true);
        case big_endian: return convert_utf16be_to_utf8(std::move(src), true);
        case unknown:
            // unknown defaults to big endian.
            return convert_utf16be_to_utf8(std::move(src), false);
    }
    __assume(0);
}

utf16string convert_utf16_to_utf16(utf16string src)
{
    const endianness endian = check_byte_order_mark(src);
    switch (endian)
    {
        case little_endian: src.erase(0, 1); return src;
        case big_endian: return convert_utf16be_to_utf16le(std::move(src), true);
        case unknown:
            // unknown defaults to big endian.
            return convert_utf16be_to_utf16le(std::move(src), false);
    }
    __assume(0);
}
utility::string_t convert_utf16_to_string_t(utf16string src)
{
#ifdef _UTF16_STRINGS
    return convert_utf16_to_utf16(std::move(src));
#else
    return convert_utf16_to_utf8(std::move(src));
#endif
}
} // namespace

void http_headers::set_content_type(utility::string_t type)
{
    m_headers[http::header_names::content_type] = std::move(type);
}

utility::string_t http_headers::cache_control() const
{
    utility::string_t result;
    match(http::header_names::cache_control, result);
    return result;
}

void http_headers::set_cache_control(utility::string_t control)
{
    add(http::header_names::cache_control, std::move(control));
}

utility::string_t http_headers::date() const
{
    utility::string_t result;
    match(http::header_names::date, result);
    return result;
}

void http_headers::set_date(const utility::datetime& date)
{
    m_headers[http::header_names::date] = date.to_string(utility::datetime::RFC_1123);
}

utility::size64_t http_headers::content_length() const
{
    utility::size64_t length = 0;
    match(http::header_names::content_length, length);
    return length;
}

void http_headers::set_content_length(utility::size64_t length)
{
    m_headers[http::header_names::content_length] = utility::conversions::details::to_string_t(length);
}

namespace details
{
utility::string_t flatten_http_headers(const http_headers& headers)
{
    utility::string_t flattened_headers;
    for (auto iter = headers.begin(); iter != headers.end(); ++iter)
    {
        flattened_headers.append(iter->first);
        flattened_headers.push_back(':');
        flattened_headers.append(iter->second);
        flattened_headers.append(CRLF);
    }
    return flattened_headers;
}

void parse_headers_string(_Inout_z_ utility::char_t* headersStr, web::http::http_headers& headers)
{
    utility::string_t str(headersStr);
    std::size_t pos = str.find_first_of(_XPLATSTR("\r\n"));
    std::size_t startpos = 0;
    while (pos!=std::string::npos)
    {
        const utility::string_t header_line(str, startpos, pos - startpos);
        const size_t colonIndex = header_line.find_first_of(_XPLATSTR(":"));
        if (colonIndex != utility::string_t::npos)
        {
            utility::string_t key = header_line.substr(0, colonIndex);
            utility::string_t value = header_line.substr(colonIndex + 1, header_line.length() - colonIndex - 1);
            web::http::details::trim_whitespace(key);
            web::http::details::trim_whitespace(value);
            headers.add(key, value);
        }
        startpos = pos + 1;
        pos = str.find_first_of(_XPLATSTR("\r\n"), pos + 1);
    }
}

} // namespace details

http_version __cdecl http_version::from_string(const std::string& http_version_string)
{
    std::istringstream str(http_version_string);
    str.imbue(std::locale::classic());

    std::string http;
    std::getline(str, http, '/');
    unsigned int major = 0;
    str >> major;
    char dot = '\0';
    str >> dot;
    unsigned int minor = 0;
    str >> minor;

    // check no failure, fully consumed, and correct fixed text
    if (!str.fail() && str.eof() && "HTTP" == http && '.' == dot)
    {
        return {(uint8_t)major, (uint8_t)minor};
    }
    return {0, 0};
}

std::string http_version::to_utf8string() const
{
    std::string ret;
    ret.reserve(8);
    ret.append("HTTP/");
    ret.append(std::to_string(static_cast<unsigned int>(major)));
    ret.append(".");
    ret.append(std::to_string(static_cast<unsigned int>(minor)));
    return ret;
}

static const utility::char_t* stream_was_set_explicitly =
    _XPLATSTR("A stream was set on the message and extraction is not possible");
static const utility::char_t* unsupported_charset =
    _XPLATSTR("Charset must be iso-8859-1, utf-8, utf-16, utf-16le, or utf-16be to be extracted.");

http_msg_base::http_msg_base() : m_http_version(http::http_version {0, 0}), m_headers(), m_default_outstream(false) {}

void http_msg_base::_prepare_to_receive_data()
{
    // See if the user specified an outstream
    if (!outstream())
    {
        // The user did not specify an outstream.
        // We will create one...
        concurrency::streams::producer_consumer_buffer<uint8_t> buf;
        set_outstream(buf.create_ostream(), true);

        // Since we are creating the streambuffer, set the input stream
        // so that the user can retrieve the data.
        set_instream(buf.create_istream());
    }

    // If the user did specify an outstream we leave the instream
    // as invalid. It is assumed that user either has a read head
    // to the out streambuffer or the data is streamed into a container
    // or media (like file) that the user can read from...
}

size_t http_msg_base::_get_stream_length()
{
    auto& stream = instream();

    if (stream.can_seek())
    {
        auto offset = stream.tell();
        auto end = stream.seek(0, std::ios_base::end);
        stream.seek(offset);
        return static_cast<size_t>(end - offset);
    }

    return (std::numeric_limits<size_t>::max)();
}

size_t http_msg_base::_get_content_length(bool honor_compression)
{
    // An invalid response_stream indicates that there is no body
    if ((bool)instream())
    {
        size_t content_length;
        utility::string_t transfer_encoding;

        if (headers().match(header_names::transfer_encoding, transfer_encoding))
        {
            // Transfer encoding is set; it trumps any content length that may or may not be present
            if (honor_compression && m_compressor)
            {
                http::http_headers tmp;

                // Build a header for comparison with the existing one
                tmp.add(header_names::transfer_encoding, m_compressor->algorithm());
                tmp.add(header_names::transfer_encoding, _XPLATSTR("chunked"));

                if (!utility::details::str_iequal(transfer_encoding, tmp[header_names::transfer_encoding]))
                {
                    // Some external entity added this header, and it doesn't match our
                    // expectations; bail out, since the caller's intentions are not clear
                    throw http_exception("Transfer-Encoding header is internally managed when compressing");
                }
            }

            return (std::numeric_limits<size_t>::max)();
        }

        if (honor_compression && m_compressor)
        {
            // A compressor is set; this implies transfer encoding, since we don't know the compressed length
            // up front for content encoding.  We return the uncompressed length if we can figure it out.
            headers().add(header_names::transfer_encoding, m_compressor->algorithm());
            headers().add(header_names::transfer_encoding, _XPLATSTR("chunked"));
            return (std::numeric_limits<size_t>::max)();
        }

        if (headers().match(header_names::content_length, content_length))
        {
            // An explicit content length is set; trust it, since we
            // may not be required to send the stream's entire contents
            return content_length;
        }

        content_length = _get_stream_length();
        if (content_length != (std::numeric_limits<size_t>::max)())
        {
            // The content length wasn't explicitly set, but we figured it out;
            // use it, since sending this way is more efficient than chunking
            headers().add(header_names::content_length, content_length);
            return content_length;
        }

        // We don't know the content length; we'll chunk the stream
        headers().add(header_names::transfer_encoding, _XPLATSTR("chunked"));
        return (std::numeric_limits<size_t>::max)();
    }

    // There is no content
    return 0;
}

size_t http_msg_base::_get_content_length_and_set_compression() { return _get_content_length(true); }

size_t http_msg_base::_get_content_length() { return _get_content_length(false); }

// Helper function to inline continuation if possible.
struct inline_continuation
{
    inline_continuation(pplx::task<void>& prev, const std::function<void(pplx::task<void>)>& next)
        : m_prev(prev), m_next(next)
    {
    }
    ~inline_continuation()
    {
        if (m_prev.is_done())
        {
            m_next(m_prev);
        }
        else
        {
            m_prev.then(m_next);
        }
    }
    pplx::task<void>& m_prev;
    std::function<void(pplx::task<void>)> m_next;

private:
    inline_continuation(const inline_continuation&);
    inline_continuation& operator=(const inline_continuation&);
};

void http_msg_base::_complete(utility::size64_t body_size, const std::exception_ptr& exceptionPtr)
{
    const auto& completionEvent = _get_data_available();
    auto closeTask = pplx::task_from_result();
    if (m_default_outstream)
    {
        // if the outstream is one we created by default on the customer's behalf, try to close it
        auto& out = outstream();
        if (out.is_valid())
        {
            if (exceptionPtr == std::exception_ptr())
            {
                closeTask = out.close();
            }
            else
            {
                closeTask = out.close(exceptionPtr);
            }
        }
    }

    if (exceptionPtr == std::exception_ptr())
    {
        inline_continuation(closeTask, [completionEvent, body_size](pplx::task<void> t) {
            try
            {
                t.get();
                completionEvent.set(body_size);
            }
            catch (...)
            {
                // If close throws an exception report back to user.
                completionEvent.set_exception(std::current_exception());
                pplx::create_task(completionEvent).then([](pplx::task<utility::size64_t> t) {
                    try
                    {
                        t.get();
                    }
                    catch (...)
                    {
                    }
                });
            }
        });
    }
    else
    {
        inline_continuation(closeTask, [completionEvent, exceptionPtr](pplx::task<void> t) {
            // If closing stream throws an exception ignore since we already have an error.
            try
            {
                t.get();
            }
            catch (...)
            {
            }
            completionEvent.set_exception(exceptionPtr);
            pplx::create_task(completionEvent).then([](pplx::task<utility::size64_t> t) {
                try
                {
                    t.get();
                }
                catch (...)
                {
                }
            });
        });
    }
}

static bool is_content_type_one_of(const utility::string_t* first,
                                   const utility::string_t* last,
                                   const utility::string_t& value)
{
    while (first != last)
    {
        if (utility::details::str_iequal(*first, value))
        {
            return true;
        }
        ++first;
    }
    return false;
}

// Remove once VS 2013 is no longer supported.
#if defined(_WIN32) && _MSC_VER < 1900
// Not referring to mime_types to avoid static initialization order fiasco.
static const utility::string_t textual_types[] = {U("message/http"),
                                                  U("application/json"),
                                                  U("application/xml"),
                                                  U("application/atom+xml"),
                                                  U("application/http"),
                                                  U("application/x-www-form-urlencoded")};
#endif

/// <summary>
/// Determines whether or not the given content type is 'textual' according the feature specifications.
/// </summary>
static bool is_content_type_textual(const utility::string_t& content_type)
{
#if !defined(_WIN32) || _MSC_VER >= 1900
    static const utility::string_t textual_types[] = {mime_types::message_http,
                                                      mime_types::application_json,
                                                      mime_types::application_xml,
                                                      mime_types::application_atom_xml,
                                                      mime_types::application_http,
                                                      mime_types::application_x_www_form_urlencoded};
#endif

    if (content_type.size() >= 4 && utility::details::str_iequal(content_type.substr(0, 4), _XPLATSTR("text")))
    {
        return true;
    }
    return (is_content_type_one_of(std::begin(textual_types), std::end(textual_types), content_type));
}

// Remove once VS 2013 is no longer supported.
#if defined(_WIN32) && _MSC_VER < 1900
// Not referring to mime_types to avoid static initialization order fiasco.
static const utility::string_t json_types[] = {U("application/json"),
                                               U("application/x-json"),
                                               U("text/json"),
                                               U("text/x-json"),
                                               U("text/javascript"),
                                               U("text/x-javascript"),
                                               U("application/javascript"),
                                               U("application/x-javascript")};
#endif

/// <summary>
/// Determines whether or not the given content type is JSON according the feature specifications.
/// </summary>
static bool is_content_type_json(const utility::string_t& content_type)
{
#if !defined(_WIN32) || _MSC_VER >= 1900
    static const utility::string_t json_types[] = {mime_types::application_json,
                                                   mime_types::application_xjson,
                                                   mime_types::text_json,
                                                   mime_types::text_xjson,
                                                   mime_types::text_javascript,
                                                   mime_types::text_xjavascript,
                                                   mime_types::application_javascript,
                                                   mime_types::application_xjavascript};
#endif

    return (is_content_type_one_of(std::begin(json_types), std::end(json_types), content_type));
}

/// <summary>
/// Gets the default charset for given content type. If the MIME type is not textual or recognized Latin1 will be
/// returned.
/// </summary>
static utility::string_t get_default_charset(const utility::string_t& content_type)
{
    // We are defaulting everything to Latin1 except JSON which is utf-8.
    if (is_content_type_json(content_type))
    {
        return charset_types::utf8;
    }
    else
    {
        return charset_types::latin1;
    }
}

/// <summary>
/// Parses the given Content-Type header value to get out actual content type and charset.
/// If the charset isn't specified the default charset for the content type will be set.
/// </summary>
static void parse_content_type_and_charset(const utility::string_t& content_type,
                                           utility::string_t& content,
                                           utility::string_t& charset)
{
    const size_t semi_colon_index = content_type.find_first_of(_XPLATSTR(";"));

    // No charset specified.
    if (semi_colon_index == utility::string_t::npos)
    {
        content = content_type;
        trim_whitespace(content);
        charset = get_default_charset(content);
        return;
    }

    // Split into content type and second part which could be charset.
    content = content_type.substr(0, semi_colon_index);
    trim_whitespace(content);
    utility::string_t possible_charset = content_type.substr(semi_colon_index + 1);
    trim_whitespace(possible_charset);
    const size_t equals_index = possible_charset.find_first_of(_XPLATSTR("="));

    // No charset specified.
    if (equals_index == utility::string_t::npos)
    {
        charset = get_default_charset(content);
        return;
    }

    // Split and make sure 'charset'
    utility::string_t charset_key = possible_charset.substr(0, equals_index);
    trim_whitespace(charset_key);
    if (!utility::details::str_iequal(charset_key, _XPLATSTR("charset")))
    {
        charset = get_default_charset(content);
        return;
    }
    charset = possible_charset.substr(equals_index + 1);
    // Remove the redundant ';' at the end of charset.
    while (charset.back() == ';')
    {
        charset.pop_back();
    }
    trim_whitespace(charset);
    if (charset.front() == _XPLATSTR('"') && charset.back() == _XPLATSTR('"'))
    {
        charset = charset.substr(1, charset.size() - 2);
        trim_whitespace(charset);
    }
}

utility::string_t details::http_msg_base::parse_and_check_content_type(
    bool ignore_content_type, const std::function<bool(const utility::string_t&)>& check_content_type)
{
    if (!instream())
    {
        throw http_exception(stream_was_set_explicitly);
    }

    utility::string_t content, charset = charset_types::utf8;
    if (!ignore_content_type)
    {
        parse_content_type_and_charset(headers().content_type(), content, charset);

        // If no Content-Type or empty body then just return an empty string.
        if (content.empty() || instream().streambuf().in_avail() == 0)
        {
            return utility::string_t();
        }

        if (!check_content_type(content))
        {
            throw http_exception(
                _XPLATSTR("Incorrect Content-Type: must be textual to extract_string, JSON to extract_json."));
        }
    }
    return charset;
}

utf8string details::http_msg_base::extract_utf8string(bool ignore_content_type)
{
    const auto& charset = parse_and_check_content_type(ignore_content_type, is_content_type_textual);
    if (charset.empty())
    {
        return utf8string();
    }
    auto buf_r = instream().streambuf();

    // Perform the correct character set conversion if one is necessary.
    if (utility::details::str_iequal(charset, charset_types::utf8) ||
        utility::details::str_iequal(charset, charset_types::usascii) ||
        utility::details::str_iequal(charset, charset_types::ascii))
    {
        std::string body;
        body.resize((std::string::size_type)buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        return body;
    }

    // Latin1
    else if (utility::details::str_iequal(charset, charset_types::latin1))
    {
        std::string body;
        body.resize((std::string::size_type)buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        return latin1_to_utf8(std::move(body));
    }

    // utf-16
    else if (utility::details::str_iequal(charset, charset_types::utf16))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return convert_utf16_to_utf8(std::move(body));
    }

    // utf-16le
    else if (utility::details::str_iequal(charset, charset_types::utf16le))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return utility::conversions::utf16_to_utf8(std::move(body));
    }

    // utf-16be
    else if (utility::details::str_iequal(charset, charset_types::utf16be))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return convert_utf16be_to_utf8(std::move(body), false);
    }

    else
    {
        throw http_exception(unsupported_charset);
    }
}

utf16string details::http_msg_base::extract_utf16string(bool ignore_content_type)
{
    const auto& charset = parse_and_check_content_type(ignore_content_type, is_content_type_textual);
    if (charset.empty())
    {
        return utf16string();
    }
    auto buf_r = instream().streambuf();

    // Perform the correct character set conversion if one is necessary.
    if (utility::details::str_iequal(charset, charset_types::utf16le))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return body;
    }

    // utf-8, ascii
    else if (utility::details::str_iequal(charset, charset_types::utf8) ||
             utility::details::str_iequal(charset, charset_types::usascii) ||
             utility::details::str_iequal(charset, charset_types::ascii))
    {
        std::string body;
        body.resize((std::string::size_type)buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        return utility::conversions::utf8_to_utf16(std::move(body));
    }

    // Latin1
    else if (utility::details::str_iequal(charset, charset_types::latin1))
    {
        std::string body;
        body.resize((std::string::size_type)buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        return latin1_to_utf16(std::move(body));
    }

    // utf-16
    else if (utility::details::str_iequal(charset, charset_types::utf16))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return convert_utf16_to_utf16(std::move(body));
    }

    // utf-16be
    else if (utility::details::str_iequal(charset, charset_types::utf16be))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return convert_utf16be_to_utf16le(std::move(body), false);
    }

    else
    {
        throw http_exception(unsupported_charset);
    }
}

utility::string_t details::http_msg_base::extract_string(bool ignore_content_type)
{
    const auto& charset = parse_and_check_content_type(ignore_content_type, is_content_type_textual);
    if (charset.empty())
    {
        return utility::string_t();
    }
    auto buf_r = instream().streambuf();

    // Perform the correct character set conversion if one is necessary.
    if (utility::details::str_iequal(charset, charset_types::usascii) ||
        utility::details::str_iequal(charset, charset_types::ascii))
    {
        std::string body;
        body.resize((std::string::size_type)buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        return to_string_t(std::move(body));
    }

    // Latin1
    if (utility::details::str_iequal(charset, charset_types::latin1))
    {
        std::string body;
        body.resize((std::string::size_type)buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        // Could optimize for linux in the future if a latin1_to_utf8 function was written.
        return to_string_t(latin1_to_utf16(std::move(body)));
    }

    // utf-8.
    else if (utility::details::str_iequal(charset, charset_types::utf8))
    {
        std::string body;
        body.resize((std::string::size_type)buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        return to_string_t(std::move(body));
    }

    // utf-16.
    else if (utility::details::str_iequal(charset, charset_types::utf16))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return convert_utf16_to_string_t(std::move(body));
    }

    // utf-16le
    else if (utility::details::str_iequal(charset, charset_types::utf16le))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return convert_utf16le_to_string_t(std::move(body), false);
    }

    // utf-16be
    else if (utility::details::str_iequal(charset, charset_types::utf16be))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return convert_utf16be_to_string_t(std::move(body), false);
    }

    else
    {
        throw http_exception(unsupported_charset);
    }
}

json::value details::http_msg_base::_extract_json(bool ignore_content_type)
{
    const auto& charset = parse_and_check_content_type(ignore_content_type, is_content_type_json);
    if (charset.empty())
    {
        return json::value();
    }
    auto buf_r = instream().streambuf();

    // Latin1
    if (utility::details::str_iequal(charset, charset_types::latin1))
    {
        std::string body;
        body.resize(buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        // On Linux could optimize in the future if a latin1_to_utf8 function is written.
        return json::value::parse(to_string_t(latin1_to_utf16(std::move(body))));
    }

    // utf-8, usascii and ascii
    else if (utility::details::str_iequal(charset, charset_types::utf8) ||
             utility::details::str_iequal(charset, charset_types::usascii) ||
             utility::details::str_iequal(charset, charset_types::ascii))
    {
        std::string body;
        body.resize(buf_r.in_avail());
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), body.size())
            .get(); // There is no risk of blocking.
        return json::value::parse(to_string_t(std::move(body)));
    }

    // utf-16.
    else if (utility::details::str_iequal(charset, charset_types::utf16))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return json::value::parse(convert_utf16_to_string_t(std::move(body)));
    }

    // utf-16le
    else if (utility::details::str_iequal(charset, charset_types::utf16le))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return json::value::parse(convert_utf16le_to_string_t(std::move(body), false));
    }

    // utf-16be
    else if (utility::details::str_iequal(charset, charset_types::utf16be))
    {
        utf16string body;
        body.resize(buf_r.in_avail() / sizeof(utf16string::value_type));
        buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())),
                   body.size() * sizeof(utf16string::value_type)); // There is no risk of blocking.
        return json::value::parse(convert_utf16be_to_string_t(std::move(body), false));
    }

    else
    {
        throw http_exception(unsupported_charset);
    }
}

std::vector<uint8_t> details::http_msg_base::_extract_vector()
{
    if (!instream())
    {
        throw http_exception(stream_was_set_explicitly);
    }

    std::vector<uint8_t> body;
    auto buf_r = instream().streambuf();
    const size_t size = buf_r.in_avail();
    body.resize(size);
    buf_r.getn(const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(body.data())), size)
        .get(); // There is no risk of blocking.

    return body;
}

// Helper function to convert message body without extracting.
static utility::string_t convert_body_to_string_t(const utility::string_t& content_type,
                                                  concurrency::streams::istream instream)
{
    if (!instream)
    {
        // The instream is not yet set
        return utility::string_t();
    }

    concurrency::streams::streambuf<uint8_t> streambuf = instream.streambuf();

    _ASSERTE((bool)streambuf);
    _ASSERTE(streambuf.is_open());
    _ASSERTE(streambuf.can_read());

    utility::string_t content, charset;
    parse_content_type_and_charset(content_type, content, charset);

    // Content-Type must have textual type.
    if (!is_content_type_textual(content) || streambuf.in_avail() == 0)
    {
        return utility::string_t();
    }

    // Latin1
    if (utility::details::str_iequal(charset, charset_types::latin1))
    {
        std::string body;
        body.resize(streambuf.in_avail());
        if (streambuf.scopy((unsigned char*)&body[0], body.size()) == 0) return string_t();
        return to_string_t(latin1_to_utf16(std::move(body)));
    }

    // utf-8.
    else if (utility::details::str_iequal(charset, charset_types::utf8))
    {
        std::string body;
        body.resize(streambuf.in_avail());
        if (streambuf.scopy((unsigned char*)&body[0], body.size()) == 0) return string_t();
        return to_string_t(std::move(body));
    }

    // utf-16.
    else if (utility::details::str_iequal(charset, charset_types::utf16))
    {
        utf16string body;
        body.resize(streambuf.in_avail() / sizeof(utf16string::value_type));
        if (streambuf.scopy((unsigned char*)&body[0], body.size() * sizeof(utf16string::value_type)) == 0)
            return string_t();
        return convert_utf16_to_string_t(std::move(body));
    }

    // utf-16le
    else if (utility::details::str_iequal(charset, charset_types::utf16le))
    {
        utf16string body;
        body.resize(streambuf.in_avail() / sizeof(utf16string::value_type));
        if (streambuf.scopy((unsigned char*)&body[0], body.size() * sizeof(utf16string::value_type)) == 0)
            return string_t();
        return convert_utf16le_to_string_t(std::move(body), false);
    }

    // utf-16be
    else if (utility::details::str_iequal(charset, charset_types::utf16be))
    {
        utf16string body;
        body.resize(streambuf.in_avail() / sizeof(utf16string::value_type));
        if (streambuf.scopy((unsigned char*)&body[0], body.size() * sizeof(utf16string::value_type)) == 0)
            return string_t();
        return convert_utf16be_to_string_t(std::move(body), false);
    }

    else
    {
        return utility::string_t();
    }
}

//
// Helper function to generate a wstring from given http_headers and message body.
//
static utility::string_t http_headers_body_to_string(const http_headers& headers,
                                                     concurrency::streams::istream instream)
{
    utility::string_t result;
    for (const auto& header : headers)
    {
        result += header.first;
        result += _XPLATSTR(": ");
        result += header.second;
        result += CRLF;
    }

    result += CRLF;

    utility::string_t content_type;
    if (headers.match(http::header_names::content_type, content_type))
    {
        result += convert_body_to_string_t(content_type, instream);
    }

    return result;
}

utility::string_t details::http_msg_base::to_string() const
{
    return http_headers_body_to_string(m_headers, instream());
}

static void set_content_type_if_not_present(http::http_headers& headers, const utility::string_t& content_type)
{
    utility::string_t temp;
    if (!headers.match(http::header_names::content_type, temp))
    {
        headers.add(http::header_names::content_type, content_type);
    }
}

void details::http_msg_base::set_body(const streams::istream& instream, const utf8string& contentType)
{
    set_content_type_if_not_present(headers(),
#ifdef _UTF16_STRINGS
                                    utility::conversions::utf8_to_utf16(contentType));
#else
                                    contentType);
#endif
    set_instream(instream);
}

void details::http_msg_base::set_body(const streams::istream& instream, const utf16string& contentType)
{
    set_content_type_if_not_present(headers(),
#ifdef _UTF16_STRINGS
                                    contentType);
#else
                                    utility::conversions::utf16_to_utf8(contentType));
#endif
    set_instream(instream);
}

void details::http_msg_base::set_body(const streams::istream& instream,
                                      utility::size64_t contentLength,
                                      const utf8string& contentType)
{
    headers().set_content_length(contentLength);
    set_body(instream, contentType);
    m_data_available.set(contentLength);
}

void details::http_msg_base::set_body(const concurrency::streams::istream& instream,
                                      utility::size64_t contentLength,
                                      const utf16string& contentType)
{
    headers().set_content_length(contentLength);
    set_body(instream, contentType);
    m_data_available.set(contentLength);
}

details::_http_request::_http_request(http::method mtd)
    : m_method(std::move(mtd))
    , m_initiated_response(0)
    , m_server_context()
    , m_cancellationToken(pplx::cancellation_token::none())
{
    if (m_method.empty())
    {
        throw std::invalid_argument("Invalid HTTP method specified. Method can't be an empty string.");
    }
}

details::_http_request::_http_request(std::unique_ptr<http::details::_http_server_context> server_context)
    : m_initiated_response(0)
    , m_server_context(std::move(server_context))
    , m_cancellationToken(pplx::cancellation_token::none())
{
}

void http_request::set_decompress_factories()
{
    return _m_impl->set_decompress_factories(compression::details::builtin::get_decompress_factories());
}

const http_version http_versions::HTTP_0_9 = {0, 9};
const http_version http_versions::HTTP_1_0 = {1, 0};
const http_version http_versions::HTTP_1_1 = {1, 1};

#define _METHODS
#define DAT(a, b) const method methods::a = b;
#include "cpprest/details/http_constants.dat"
#undef _METHODS
#undef DAT

#define _HEADER_NAMES
#define DAT(a, b) const utility::string_t header_names::a = _XPLATSTR(b);
#include "cpprest/details/http_constants.dat"
#undef _HEADER_NAMES
#undef DAT

#define _MIME_TYPES
#define DAT(a, b) const utility::string_t mime_types::a = _XPLATSTR(b);
#include "cpprest/details/http_constants.dat"
#undef _MIME_TYPES
#undef DAT

#define _CHARSET_TYPES
#define DAT(a, b) const utility::string_t charset_types::a = _XPLATSTR(b);
#include "cpprest/details/http_constants.dat"
#undef _CHARSET_TYPES
#undef DAT

// This is necessary for Linux because of a bug in GCC 4.7
#ifndef _WIN32
#define _PHRASES
#define DAT(a, b, c) const status_code status_codes::a;
#include "cpprest/details/http_constants.dat"
#undef _PHRASES
#undef DAT
#endif
} // namespace http
} // namespace web