text: // Copyright (c) 2018, uPlexa Team
  //
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  // 
  // Redistribution and use in source and binary forms, with or without modification, are
  // permitted provided that the following conditions are met:
  //
  // 1. Redistributions of source code must retain the above copyright notice, this list of
  //    conditions and the following disclaimer.
  //
  // 2. 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.
  //
  // 3. Neither the name of the copyright holder 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
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  // THE COPYRIGHT HOLDER OR CONTRIBUTORS 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
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  // 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.
  
  #include "gtest/gtest.h"
  #include "net/http_auth.h"
  
  #include <boost/algorithm/string/predicate.hpp>
  #include <boost/algorithm/string/join.hpp>
  #include <boost/fusion/adapted/std_pair.hpp>
  #include <boost/range/algorithm/find_if.hpp>
  #include <boost/range/iterator_range_core.hpp>
  #include <boost/spirit/include/karma_char.hpp>
  #include <boost/spirit/include/karma_list.hpp>
  #include <boost/spirit/include/karma_generate.hpp>
  #include <boost/spirit/include/karma_right_alignment.hpp>
  #include <boost/spirit/include/karma_sequence.hpp>
  #include <boost/spirit/include/karma_string.hpp>
  #include <boost/spirit/include/karma_uint.hpp>
  #include <boost/spirit/include/qi_alternative.hpp>
  #include <boost/spirit/include/qi_char.hpp>
  #include <boost/spirit/include/qi_char_class.hpp>
  #include <boost/spirit/include/qi_difference.hpp>
  #include <boost/spirit/include/qi_eoi.hpp>
  #include <boost/spirit/include/qi_list.hpp>
  #include <boost/spirit/include/qi_parse.hpp>
  #include <boost/spirit/include/qi_plus.hpp>
  #include <boost/spirit/include/qi_sequence.hpp>
  #include <boost/spirit/include/qi_string.hpp>
  #include <cstdint>
  #include <iterator>
  #include <string>
  #include <unordered_map>
  #include <utility>
  #include <vector>
  
  #include "md5_l.h"
  #include "string_tools.h"
  #include "crypto/crypto.h"
  
  namespace {
  namespace http = epee::net_utils::http;
  using fields = std::unordered_map<std::string, std::string>;
  using auth_responses = std::vector<fields>;
  
  void rng(size_t len, uint8_t *ptr)
  {
    crypto::rand(len, ptr);
  }
  
  std::string quoted(std::string str)
  {
    str.insert(str.begin(), '"');
    str.push_back('"');
    return str;
  }
  
  void write_fields(std::string& out, const fields& args)
  {
    namespace karma = boost::spirit::karma;
    karma::generate(
      std::back_inserter(out),
      (karma::string << " = " << karma::string) % " , ", 
      args);
  }
  
  std::string write_fields(const fields& args)
  {
    std::string out{};
    write_fields(out, args);
    return out;
  }
  
  http::http_request_info make_request(const fields& args)
  {
    std::string out{"   DIGEST   "};
    write_fields(out, args);
  
    http::http_request_info request{};
    request.m_http_method_str = "NOP";
    request.m_header_info.m_etc_fields.push_back(
      std::make_pair(u8"authorization", std::move(out))
    );
    return request;
  }
  
  http::http_response_info make_response(const auth_responses& choices)
  {
    http::http_response_info response{};
    for (const auto& choice : choices)
    {
      std::string out{"   DIGEST   "};
      write_fields(out, choice);
  
      response.m_header_info.m_etc_fields.push_back(
        std::make_pair(u8"WWW-authenticate", std::move(out))
      );
    }
    return response;
  }
  
  bool has_same_fields(const auth_responses& in)
  {
    const std::vector<std::string> check{u8"nonce", u8"qop", u8"realm", u8"stale"};
    
    auto current = in.begin();
    const auto end = in.end();
    if (current == end)
      return true;
  
    ++current;
    for ( ; current != end; ++current )
    {
      for (const auto& field : check)
      {
        const std::string& expected = in[0].at(field);
        const std::string& actual = current->at(field);
        EXPECT_EQ(expected, actual);
        if (expected != actual)
          return false;
      }
    }
    return true;
  }
  
  bool is_unauthorized(const http::http_response_info& response)
  {
    EXPECT_EQ(401, response.m_response_code);
    EXPECT_STREQ(u8"Unauthorized", response.m_response_comment.c_str());
    EXPECT_STREQ(u8"text/html", response.m_mime_tipe.c_str());
    return response.m_response_code == 401 &&
      response.m_response_comment == u8"Unauthorized" &&
      response.m_mime_tipe == u8"text/html";
  }
  
  fields parse_fields(const std::string& value)
  {
    namespace qi = boost::spirit::qi;
  
    fields out{};
    const bool rc = qi::parse(
      value.begin(), value.end(),
      qi::lit(u8"Digest ") >> ((
          +qi::ascii::alpha >>
          qi::lit('=') >> (
            (qi::lit('"') >> +(qi::ascii::char_ - '"') >> qi::lit('"')) |
            +(qi::ascii::graph - qi::ascii::char_(u8"()<>@,;:\\\"/[]?={}"))
          )
        ) % ','
      ) >> qi::eoi,
      out
    );
    if (!rc)
      throw std::runtime_error{"Bad field given in HTTP header"};
  
    return out;
  }
  
  auth_responses parse_response(const http::http_response_info& response)
  {
    auth_responses result{};
  
    const auto end = response.m_additional_fields.end();
    for (auto current = response.m_additional_fields.begin();; ++current)
    {
      current = std::find_if(current, end, [] (const std::pair<std::string, std::string>& field) {
          return boost::equals(u8"WWW-authenticate", field.first);
      });
  
      if (current == end)
        return result;
  
      result.push_back(parse_fields(current->second));
    }
    return result;
  }
  
  std::string md5_hex(const std::string& in)
  {
    md5::MD5_CTX ctx{};
    md5::MD5Init(std::addressof(ctx));
    md5::MD5Update(
      std::addressof(ctx),
      reinterpret_cast<const std::uint8_t*>(in.data()),
      in.size()
    );
  
    std::array<std::uint8_t, 16> digest{{}};
    md5::MD5Final(digest.data(), std::addressof(ctx));
    return epee::string_tools::pod_to_hex(digest);
  }
  
  std::string get_a1(const http::login& user, const fields& src)
  {
    const std::string& realm = src.at(u8"realm");
    return boost::join(
      std::vector<std::string>{user.username, realm, std::string(user.password.data(), user.password.size())}, u8":"
    );
  }
  
  std::string get_a1(const http::login& user, const auth_responses& responses)
  {
    return get_a1(user, responses.at(0));
  }
  
  std::string get_a1_sess(const http::login& user, const std::string& cnonce, const auth_responses& responses)
  {
    const std::string& nonce = responses.at(0).at(u8"nonce");
    return boost::join(
      std::vector<std::string>{md5_hex(get_a1(user, responses)), nonce, cnonce}, u8":"
    );
  }
  
  std::string get_a2(const std::string& uri)
  {
    return boost::join(std::vector<std::string>{"NOP", uri}, u8":");
  }
  
  std::string get_nc(std::uint32_t count)
  {
    namespace karma = boost::spirit::karma;
    std::string out;
    karma::generate(
      std::back_inserter(out),
      karma::right_align(8, '0')[karma::uint_generator<std::uint32_t, 16>{}],
      count
    );
  
    return out;
  }
  }
  
  TEST(HTTP_Server_Auth, NotRequired)
  {
    http::http_server_auth auth{}; // no rng here
    EXPECT_FALSE(auth.get_response(http::http_request_info{}));
  }
  
  TEST(HTTP_Server_Auth, MissingAuth)
  {
    http::http_server_auth auth{{"foo", "bar"}, rng};
    EXPECT_TRUE(bool(auth.get_response(http::http_request_info{})));
    {
      http::http_request_info request{};
      request.m_header_info.m_etc_fields.push_back({"\xFF", "\xFF"});
      EXPECT_TRUE(bool(auth.get_response(request)));
    }
  }
  
  TEST(HTTP_Server_Auth, BadSyntax)
  {
    http::http_server_auth auth{{"foo", "bar"}, rng};
    EXPECT_TRUE(bool(auth.get_response(make_request({{u8"algorithm", "fo\xFF"}}))));
    EXPECT_TRUE(bool(auth.get_response(make_request({{u8"cnonce", "\"000\xFF\""}}))));
    EXPECT_TRUE(bool(auth.get_response(make_request({{u8"cnonce \xFF =", "\"000\xFF\""}}))));
    EXPECT_TRUE(bool(auth.get_response(make_request({{u8" \xFF cnonce", "\"000\xFF\""}}))));
  }
  
  TEST(HTTP_Server_Auth, MD5)
  {
    http::login user{"foo", "bar"};
    http::http_server_auth auth{user, rng};
  
    const auto response = auth.get_response(make_request(fields{}));
    ASSERT_TRUE(bool(response));
    EXPECT_TRUE(is_unauthorized(*response));
  
    const auto fields = parse_response(*response);
    ASSERT_LE(2u, fields.size());
    EXPECT_TRUE(has_same_fields(fields));
  
    const std::string& nonce = fields[0].at(u8"nonce");
    EXPECT_EQ(24, nonce.size());
  
    const std::string uri{"/some_foo_thing"};
  
    const std::string a1 = get_a1(user, fields);
    const std::string a2 = get_a2(uri);
  
    const std::string auth_code = md5_hex(
      boost::join(std::vector<std::string>{md5_hex(a1), nonce, md5_hex(a2)}, u8":")
    );
  
    const auto request = make_request({
      {u8"nonce", quoted(nonce)},
      {u8"realm", quoted(fields[0].at(u8"realm"))},
      {u8"response", quoted(auth_code)},
      {u8"uri", quoted(uri)},
      {u8"username", quoted(user.username)}
    });
  
    EXPECT_FALSE(bool(auth.get_response(request)));
  
    const auto response2 = auth.get_response(request);
    ASSERT_TRUE(bool(response2));
    EXPECT_TRUE(is_unauthorized(*response2));
  
    const auto fields2 = parse_response(*response2);
    ASSERT_LE(2u, fields2.size());
    EXPECT_TRUE(has_same_fields(fields2));
  
    EXPECT_NE(nonce, fields2[0].at(u8"nonce"));
    EXPECT_STREQ(u8"true", fields2[0].at(u8"stale").c_str());
  }
  
  TEST(HTTP_Server_Auth, MD5_sess)
  {
    constexpr const char cnonce[] = "not a good cnonce";
  
    http::login user{"foo", "bar"};
    http::http_server_auth auth{user, rng};
  
    const auto response = auth.get_response(make_request(fields{}));
    ASSERT_TRUE(bool(response));
    EXPECT_TRUE(is_unauthorized(*response));
  
    const auto fields = parse_response(*response);
    ASSERT_LE(2u, fields.size());
    EXPECT_TRUE(has_same_fields(fields));
  
    const std::string& nonce = fields[0].at(u8"nonce");
    EXPECT_EQ(24, nonce.size());
  
    const std::string uri{"/some_foo_thing"};
  
    const std::string a1 = get_a1_sess(user, cnonce, fields);
    const std::string a2 = get_a2(uri);
  
    const std::string auth_code = md5_hex(
      boost::join(std::vector<std::string>{md5_hex(a1), nonce, md5_hex(a2)}, u8":")
    );
  
    const auto request = make_request({
      {u8"algorithm", u8"md5-sess"},
      {u8"cnonce", quoted(cnonce)},
      {u8"nonce", quoted(nonce)},
      {u8"realm", quoted(fields[0].at(u8"realm"))},
      {u8"response", quoted(auth_code)},
      {u8"uri", quoted(uri)},
      {u8"username", quoted(user.username)}
    });
  
    EXPECT_FALSE(bool(auth.get_response(request)));
  
    const auto response2 = auth.get_response(request);
    ASSERT_TRUE(bool(response2));
    EXPECT_TRUE(is_unauthorized(*response2));
  
    const auto fields2 = parse_response(*response2);
    ASSERT_LE(2u, fields2.size());
    EXPECT_TRUE(has_same_fields(fields2));
  
    EXPECT_NE(nonce, fields2[0].at(u8"nonce"));
    EXPECT_STREQ(u8"true", fields2[0].at(u8"stale").c_str());
  }
  
  TEST(HTTP_Server_Auth, MD5_auth)
  {
    constexpr const char cnonce[] = "not a nonce";
    constexpr const char qop[] = "auth";
  
    http::login user{"foo", "bar"};
    http::http_server_auth auth{user, rng};
  
    const auto response = auth.get_response(make_request(fields{}));
    ASSERT_TRUE(bool(response));
    EXPECT_TRUE(is_unauthorized(*response));
  
    const auto parsed = parse_response(*response);
    ASSERT_LE(2u, parsed.size());
    EXPECT_TRUE(has_same_fields(parsed));
  
    const std::string& nonce = parsed[0].at(u8"nonce");
    EXPECT_EQ(24, nonce.size());
  
    const std::string uri{"/some_foo_thing"};
  
    const std::string a1 = get_a1(user, parsed);
    const std::string a2 = get_a2(uri);
    std::string nc = get_nc(1);
  
    const auto generate_auth = [&] {
      return md5_hex(
        boost::join(
          std::vector<std::string>{md5_hex(a1), nonce, nc, cnonce, qop, md5_hex(a2)}, u8":"
        )
      );
    };
  
    fields args{
      {u8"algorithm", quoted(u8"md5")},
      {u8"cnonce", quoted(cnonce)},
      {u8"nc", nc},
      {u8"nonce", quoted(nonce)},
      {u8"qop", quoted(qop)},
      {u8"realm", quoted(parsed[0].at(u8"realm"))},
      {u8"response", quoted(generate_auth())},
      {u8"uri", quoted(uri)},
      {u8"username", quoted(user.username)}
    };
  
    const auto request = make_request(args);
    EXPECT_FALSE(bool(auth.get_response(request)));
  
    for (unsigned i = 2; i < 20; ++i)
    {
      nc = get_nc(i);
      args.at(u8"nc") = nc;
      args.at(u8"response") = quoted(generate_auth());
      EXPECT_FALSE(auth.get_response(make_request(args)));
    }
  
    const auto replay = auth.get_response(request);
    ASSERT_TRUE(bool(replay));
    EXPECT_TRUE(is_unauthorized(*replay));
  
    const auto parsed_replay = parse_response(*replay);
    ASSERT_LE(2u, parsed_replay.size());
    EXPECT_TRUE(has_same_fields(parsed_replay));
  
    EXPECT_NE(nonce, parsed_replay[0].at(u8"nonce"));
    EXPECT_STREQ(u8"true", parsed_replay[0].at(u8"stale").c_str());
  }
  
  TEST(HTTP_Server_Auth, MD5_sess_auth)
  {
    constexpr const char cnonce[] = "not a nonce";
    constexpr const char qop[] = "auth";
  
    http::login user{"foo", "bar"};
    http::http_server_auth auth{user, rng};
  
    const auto response = auth.get_response(make_request(fields{}));
    ASSERT_TRUE(bool(response));
    EXPECT_TRUE(is_unauthorized(*response));
  
    const auto parsed = parse_response(*response);
    ASSERT_LE(2u, parsed.size());
    EXPECT_TRUE(has_same_fields(parsed));
  
    const std::string& nonce = parsed[0].at(u8"nonce");
    EXPECT_EQ(24, nonce.size());
  
    const std::string uri{"/some_foo_thing"};
  
    const std::string a1 = get_a1_sess(user, cnonce, parsed);
    const std::string a2 = get_a2(uri);
    std::string nc = get_nc(1);
  
    const auto generate_auth = [&] {
      return md5_hex(
        boost::join(
          std::vector<std::string>{md5_hex(a1), nonce, nc, cnonce, qop, md5_hex(a2)}, u8":"
        )
      );
    };
  
    fields args{
      {u8"algorithm", u8"md5-sess"},
      {u8"cnonce", quoted(cnonce)},
      {u8"nc", nc},
      {u8"nonce", quoted(nonce)},
      {u8"qop", qop},
      {u8"realm", quoted(parsed[0].at(u8"realm"))},
      {u8"response", quoted(generate_auth())},
      {u8"uri", quoted(uri)},
      {u8"username", quoted(user.username)}
    };
  
    const auto request = make_request(args);
    EXPECT_FALSE(bool(auth.get_response(request)));
  
    for (unsigned i = 2; i < 20; ++i)
    {
      nc = get_nc(i);
      args.at(u8"nc") = nc;
      args.at(u8"response") = quoted(generate_auth());
      EXPECT_FALSE(auth.get_response(make_request(args)));
    }
  
    const auto replay = auth.get_response(request);
    ASSERT_TRUE(bool(replay));
    EXPECT_TRUE(is_unauthorized(*replay));
  
    const auto parsed_replay = parse_response(*replay);
    ASSERT_LE(2u, parsed_replay.size());
    EXPECT_TRUE(has_same_fields(parsed_replay));
  
    EXPECT_NE(nonce, parsed_replay[0].at(u8"nonce"));
    EXPECT_STREQ(u8"true", parsed_replay[0].at(u8"stale").c_str());
  }
  
  
  TEST(HTTP_Auth, DogFood)
  {
    const auto add_auth_field = [] (http::http_request_info& request, http::http_client_auth& client)
    {
      auto field = client.get_auth_field(request.m_http_method_str, request.m_URI);
      EXPECT_TRUE(bool(field));
      if (!field)
        return false;
      request.m_header_info.m_etc_fields.push_back(std::move(*field));
      return true;
    };
  
    const http::login user{"some_user", "ultimate password"};
  
    http::http_server_auth server{user, rng};
    http::http_client_auth client{user};
  
    http::http_request_info request{};
    request.m_http_method_str = "GET";
    request.m_URI = "/FOO";
  
    auto response = server.get_response(request);
    ASSERT_TRUE(bool(response));
    EXPECT_TRUE(is_unauthorized(*response));
    EXPECT_TRUE(response->m_header_info.m_etc_fields.empty());
    response->m_header_info.m_etc_fields = response->m_additional_fields;
  
    EXPECT_EQ(http::http_client_auth::kSuccess, client.handle_401(*response));
    EXPECT_TRUE(add_auth_field(request, client));
    EXPECT_FALSE(bool(server.get_response(request)));
  
    for (unsigned i = 0; i < 1000; ++i)
    {
      request.m_http_method_str += std::to_string(i);
      request.m_header_info.m_etc_fields.clear();
      EXPECT_TRUE(add_auth_field(request, client));
      EXPECT_FALSE(bool(server.get_response(request)));
    }
  
    // resetting counter should be rejected by server
    request.m_header_info.m_etc_fields.clear();
    client = http::http_client_auth{user};
    EXPECT_EQ(http::http_client_auth::kSuccess, client.handle_401(*response));
    EXPECT_TRUE(add_auth_field(request, client));
  
    auto response2 = server.get_response(request);
    ASSERT_TRUE(bool(response2));
    EXPECT_TRUE(is_unauthorized(*response2));
    EXPECT_TRUE(response2->m_header_info.m_etc_fields.empty());
    response2->m_header_info.m_etc_fields = response2->m_additional_fields;
  
    const auth_responses parsed1 = parse_response(*response);
    const auth_responses parsed2 = parse_response(*response2);
    ASSERT_LE(1u, parsed1.size());
    ASSERT_LE(1u, parsed2.size());
    EXPECT_NE(parsed1[0].at(u8"nonce"), parsed2[0].at(u8"nonce"));
  
    // with stale=true client should reset
    request.m_header_info.m_etc_fields.clear();
    EXPECT_EQ(http::http_client_auth::kSuccess, client.handle_401(*response2));
    EXPECT_TRUE(add_auth_field(request, client));
    EXPECT_FALSE(bool(server.get_response(request)));
  
    // client should give up if stale=false
    EXPECT_EQ(http::http_client_auth::kBadPassword, client.handle_401(*response));
  }
  
  TEST(HTTP_Client_Auth, Unavailable)
  {
    http::http_client_auth auth{};
    EXPECT_EQ(http::http_client_auth::kBadPassword, auth.handle_401(http::http_response_info{}));
    EXPECT_FALSE(bool(auth.get_auth_field("GET", "/file")));
  }
  
  TEST(HTTP_Client_Auth, MissingAuthenticate)
  {
    http::http_client_auth auth{{"foo", "bar"}};
    EXPECT_EQ(http::http_client_auth::kParseFailure, auth.handle_401(http::http_response_info{}));
    EXPECT_FALSE(bool(auth.get_auth_field("POST", "/\xFFname")));
    {
      http::http_response_info response{};
      response.m_additional_fields.push_back({"\xFF", "\xFF"});
      EXPECT_EQ(http::http_client_auth::kParseFailure, auth.handle_401(response));
    }
    EXPECT_FALSE(bool(auth.get_auth_field("DELETE", "/file/does/not/exist")));
  }
  
  TEST(HTTP_Client_Auth, BadSyntax)
  {
    http::http_client_auth auth{{"foo", "bar"}};
    EXPECT_EQ(http::http_client_auth::kParseFailure, auth.handle_401(make_response({{{u8"realm", "fo\xFF"}}})));
    EXPECT_EQ(http::http_client_auth::kParseFailure, auth.handle_401(make_response({{{u8"domain", "fo\xFF"}}})));
    EXPECT_EQ(http::http_client_auth::kParseFailure, auth.handle_401(make_response({{{u8"nonce", "fo\xFF"}}})));
    EXPECT_EQ(http::http_client_auth::kParseFailure, auth.handle_401(make_response({{{u8"nonce \xFF =", "fo\xFF"}}})));
    EXPECT_EQ(http::http_client_auth::kParseFailure, auth.handle_401(make_response({{{u8" \xFF nonce", "fo\xFF"}}})));
  }
  
  TEST(HTTP_Client_Auth, MD5)
  {
    constexpr char method[] = "NOP";
    constexpr char nonce[] = "some crazy nonce";
    constexpr char realm[] = "the only realm";
    constexpr char uri[] = "/some_file";
  
    const http::login user{"foo", "bar"};
    http::http_client_auth auth{user};
  
    auto response = make_response({
      {
        {u8"domain", quoted("ignored")},
        {u8"nonce", quoted(nonce)},
        {u8"REALM", quoted(realm)}
      },
      {
        {u8"algorithm", "null"},
        {u8"domain", quoted("ignored")},
        {u8"nonce", quoted(std::string{"e"} + nonce)},
        {u8"realm", quoted(std::string{"e"} + realm)}
      },
    });
  
    EXPECT_EQ(http::http_client_auth::kSuccess, auth.handle_401(response));
    const auto auth_field = auth.get_auth_field(method, uri);
    ASSERT_TRUE(bool(auth_field));
  
    const auto parsed = parse_fields(auth_field->second);
    EXPECT_STREQ(u8"Authorization", auth_field->first.c_str());
    EXPECT_EQ(parsed.end(), parsed.find(u8"opaque"));
    EXPECT_EQ(parsed.end(), parsed.find(u8"qop"));
    EXPECT_EQ(parsed.end(), parsed.find(u8"nc"));
    EXPECT_STREQ(u8"MD5", parsed.at(u8"algorithm").c_str());
    EXPECT_STREQ(nonce, parsed.at(u8"nonce").c_str());
    EXPECT_STREQ(uri, parsed.at(u8"uri").c_str());
    EXPECT_EQ(user.username, parsed.at(u8"username"));
    EXPECT_STREQ(realm, parsed.at(u8"realm").c_str());
  
    const std::string a1 = get_a1(user, parsed);
    const std::string a2 = get_a2(uri);
    const std::string auth_code = md5_hex(
      boost::join(std::vector<std::string>{md5_hex(a1), nonce, md5_hex(a2)}, u8":")
    );
    EXPECT_TRUE(boost::iequals(auth_code, parsed.at(u8"response")));
    {
      const auto auth_field_dup = auth.get_auth_field(method, uri);
      ASSERT_TRUE(bool(auth_field_dup));
      EXPECT_EQ(*auth_field, *auth_field_dup);
    }
  
  
    EXPECT_EQ(http::http_client_auth::kBadPassword, auth.handle_401(response));
    response.m_header_info.m_etc_fields.front().second.append(u8"," + write_fields({{u8"stale", u8"TRUE"}}));
    EXPECT_EQ(http::http_client_auth::kSuccess, auth.handle_401(response));
  }
  
  TEST(HTTP_Client_Auth, MD5_auth)
  {
    constexpr char cnonce[] = "";
    constexpr char method[] = "NOP";
    constexpr char nonce[] = "some crazy nonce";
    constexpr char opaque[] = "this is the opaque";
    constexpr char qop[] = u8"ignore,auth,ignore";
    constexpr char realm[] = "the only realm";
    constexpr char uri[] = "/some_file";
  
    const http::login user{"foo", "bar"};
    http::http_client_auth auth{user};
  
    auto response = make_response({
      {
        {u8"algorithm", u8"MD5"},
        {u8"domain", quoted("ignored")},
        {u8"nonce", quoted(std::string{"e"} + nonce)},
        {u8"realm", quoted(std::string{"e"} + realm)},
        {u8"qop", quoted("some,thing,to,ignore")}
      },
      {
        {u8"algorIthm", quoted(u8"md5")},
        {u8"domain", quoted("ignored")},
        {u8"noNce", quoted(nonce)},
        {u8"opaque", quoted(opaque)},
        {u8"realm", quoted(realm)},
        {u8"QoP", quoted(qop)}
      }
    });
  
    EXPECT_EQ(http::http_client_auth::kSuccess, auth.handle_401(response));
  
    for (unsigned i = 1; i < 1000; ++i)
    {
      const std::string nc = get_nc(i);
  
      const auto auth_field = auth.get_auth_field(method, uri);
      ASSERT_TRUE(bool(auth_field));
  
      const auto parsed = parse_fields(auth_field->second);
      EXPECT_STREQ(u8"Authorization", auth_field->first.c_str());
      EXPECT_STREQ(u8"MD5", parsed.at(u8"algorithm").c_str());
      EXPECT_STREQ(nonce, parsed.at(u8"nonce").c_str());
      EXPECT_STREQ(opaque, parsed.at(u8"opaque").c_str());
      EXPECT_STREQ(u8"auth", parsed.at(u8"qop").c_str());
      EXPECT_STREQ(uri, parsed.at(u8"uri").c_str());
      EXPECT_EQ(user.username, parsed.at(u8"username"));
      EXPECT_STREQ(realm, parsed.at(u8"realm").c_str());
      EXPECT_EQ(nc, parsed.at(u8"nc"));
  
      const std::string a1 = get_a1(user, parsed);
      const std::string a2 = get_a2(uri);
      const std::string auth_code = md5_hex(
        boost::join(std::vector<std::string>{md5_hex(a1), nonce, nc, cnonce, u8"auth", md5_hex(a2)}, u8":")
      );
      EXPECT_TRUE(boost::iequals(auth_code, parsed.at(u8"response")));
    }
  
    EXPECT_EQ(http::http_client_auth::kBadPassword, auth.handle_401(response));
    response.m_header_info.m_etc_fields.back().second.append(u8"," + write_fields({{u8"stale", u8"trUe"}}));
    EXPECT_EQ(http::http_client_auth::kSuccess, auth.handle_401(response));
  }
  
  
  TEST(HTTP, Add_Field)
  {
    std::string str{"leading text"};
    epee::net_utils::http::add_field(str, "foo", "bar");
    epee::net_utils::http::add_field(str, std::string("bar"), std::string("foo"));
    epee::net_utils::http::add_field(str, {"moarbars", "moarfoo"});
  
    EXPECT_STREQ("leading textfoo: bar\r\nbar: foo\r\nmoarbars: moarfoo\r\n", str.c_str());
  }
  