ClickHouse/src/DataStreams/MongoDBBlockInputStream.cpp

#include <sstream>
#include <string>
#include <vector>

#include <common/logger_useful.h>
#include <Poco/MongoDB/Connection.h>
#include <Poco/MongoDB/Cursor.h>
#include <Poco/MongoDB/Element.h>
#include <Poco/MongoDB/Database.h>
#include <Poco/MongoDB/ObjectId.h>

#include <Columns/ColumnNullable.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnsNumber.h>
#include <IO/ReadHelpers.h>
#include <Common/assert_cast.h>
#include <Common/quoteString.h>
#include <ext/range.h>
#include <DataStreams/MongoDBBlockInputStream.h>
#include <Poco/URI.h>
#include <Poco/Util/AbstractConfiguration.h>
#include <Poco/Version.h>

// only after poco
// naming conflict:
// Poco/MongoDB/BSONWriter.h:54: void writeCString(const std::string & value);
// src/IO/WriteHelpers.h:146 #define writeCString(s, buf)
#include <IO/WriteHelpers.h>
#include <Common/FieldVisitors.h>
#include <ext/enumerate.h>

namespace DB
{

namespace ErrorCodes
{
    extern const int TYPE_MISMATCH;
    extern const int MONGODB_CANNOT_AUTHENTICATE;
    extern const int NOT_FOUND_COLUMN_IN_BLOCK;
    extern const int UNKNOWN_TYPE;
}


#if POCO_VERSION < 0x01070800
/// See https://pocoproject.org/forum/viewtopic.php?f=10&t=6326&p=11426&hilit=mongodb+auth#p11485
void authenticate(Poco::MongoDB::Connection & connection, const std::string & database, const std::string & user, const std::string & password)
{
    Poco::MongoDB::Database db(database);

    /// Challenge-response authentication.
    std::string nonce;

    /// First step: request nonce.
    {
        auto command = db.createCommand();
        command->setNumberToReturn(1);
        command->selector().add<Int32>("getnonce", 1);

        Poco::MongoDB::ResponseMessage response;
        connection.sendRequest(*command, response);

        if (response.documents().empty())
            throw Exception(
                "Cannot authenticate in MongoDB: server returned empty response for 'getnonce' command",
                ErrorCodes::MONGODB_CANNOT_AUTHENTICATE);

        auto doc = response.documents()[0];
        try
        {
            double ok = doc->get<double>("ok", 0);
            if (ok != 1)
                throw Exception(
                    "Cannot authenticate in MongoDB: server returned response for 'getnonce' command that"
                    " has field 'ok' missing or having wrong value",
                    ErrorCodes::MONGODB_CANNOT_AUTHENTICATE);

            nonce = doc->get<std::string>("nonce", "");
            if (nonce.empty())
                throw Exception(
                    "Cannot authenticate in MongoDB: server returned response for 'getnonce' command that"
                    " has field 'nonce' missing or empty",
                    ErrorCodes::MONGODB_CANNOT_AUTHENTICATE);
        }
        catch (Poco::NotFoundException & e)
        {
            throw Exception(
                "Cannot authenticate in MongoDB: server returned response for 'getnonce' command that has missing required field: "
                    + e.displayText(),
                ErrorCodes::MONGODB_CANNOT_AUTHENTICATE);
        }
    }

    /// Second step: use nonce to calculate digest and send it back to the server.
    /// Digest is hex_md5(n.nonce + username + hex_md5(username + ":mongo:" + password))
    {
        std::string first = user + ":mongo:" + password;

        Poco::MD5Engine md5;
        md5.update(first);
        std::string digest_first(Poco::DigestEngine::digestToHex(md5.digest()));
        std::string second = nonce + user + digest_first;
        md5.reset();
        md5.update(second);
        std::string digest_second(Poco::DigestEngine::digestToHex(md5.digest()));

        auto command = db.createCommand();
        command->setNumberToReturn(1);
        command->selector()
            .add<Int32>("authenticate", 1)
            .add<std::string>("user", user)
            .add<std::string>("nonce", nonce)
            .add<std::string>("key", digest_second);

        Poco::MongoDB::ResponseMessage response;
        connection.sendRequest(*command, response);

        if (response.empty())
            throw Exception(
                "Cannot authenticate in MongoDB: server returned empty response for 'authenticate' command",
                ErrorCodes::MONGODB_CANNOT_AUTHENTICATE);

        auto doc = response.documents()[0];
        try
        {
            double ok = doc->get<double>("ok", 0);
            if (ok != 1)
                throw Exception(
                    "Cannot authenticate in MongoDB: server returned response for 'authenticate' command that"
                    " has field 'ok' missing or having wrong value",
                    ErrorCodes::MONGODB_CANNOT_AUTHENTICATE);
        }
        catch (Poco::NotFoundException & e)
        {
            throw Exception(
                "Cannot authenticate in MongoDB: server returned response for 'authenticate' command that has missing required field: "
                    + e.displayText(),
                ErrorCodes::MONGODB_CANNOT_AUTHENTICATE);
        }
    }
}
#endif

std::unique_ptr<Poco::MongoDB::Cursor> createCursor(const std::string & database, const std::string & collection, const Block & sample_block_to_select)
{
    auto cursor = std::make_unique<Poco::MongoDB::Cursor>(database, collection);

    /// Looks like selecting _id column is implicit by default.
    if (!sample_block_to_select.has("_id"))
        cursor->query().returnFieldSelector().add("_id", 0);

    for (const auto & column : sample_block_to_select)
        cursor->query().returnFieldSelector().add(column.name, 1);
    return cursor;
}

MongoDBBlockInputStream::MongoDBBlockInputStream(
    std::shared_ptr<Poco::MongoDB::Connection> & connection_,
    std::unique_ptr<Poco::MongoDB::Cursor> cursor_,
    const Block & sample_block,
    UInt64 max_block_size_,
    bool strict_check_names_)
    : connection(connection_)
    , cursor{std::move(cursor_)}
    , max_block_size{max_block_size_}
    , strict_check_names{strict_check_names_}
{
    description.init(sample_block);
}


MongoDBBlockInputStream::~MongoDBBlockInputStream() = default;


namespace
{
    using ValueType = ExternalResultDescription::ValueType;
    using ObjectId = Poco::MongoDB::ObjectId;

    template <typename T>
    void insertNumber(IColumn & column, const Poco::MongoDB::Element & value, const std::string & name)
    {
        switch (value.type())
        {
            case Poco::MongoDB::ElementTraits<Int32>::TypeId:
                assert_cast<ColumnVector<T> &>(column).getData().push_back(
                    static_cast<const Poco::MongoDB::ConcreteElement<Int32> &>(value).value());
                break;
            case Poco::MongoDB::ElementTraits<Poco::Int64>::TypeId:
                assert_cast<ColumnVector<T> &>(column).getData().push_back(
                    static_cast<const Poco::MongoDB::ConcreteElement<Poco::Int64> &>(value).value());
                break;
            case Poco::MongoDB::ElementTraits<Float64>::TypeId:
                assert_cast<ColumnVector<T> &>(column).getData().push_back(
                    static_cast<const Poco::MongoDB::ConcreteElement<Float64> &>(value).value());
                break;
            case Poco::MongoDB::ElementTraits<bool>::TypeId:
                assert_cast<ColumnVector<T> &>(column).getData().push_back(
                    static_cast<const Poco::MongoDB::ConcreteElement<bool> &>(value).value());
                break;
            case Poco::MongoDB::ElementTraits<Poco::MongoDB::NullValue>::TypeId:
                assert_cast<ColumnVector<T> &>(column).getData().emplace_back();
                break;
            case Poco::MongoDB::ElementTraits<String>::TypeId:
                assert_cast<ColumnVector<T> &>(column).getData().push_back(
                    parse<T>(static_cast<const Poco::MongoDB::ConcreteElement<String> &>(value).value()));
                break;
            default:
                throw Exception(
                    "Type mismatch, expected a number, got type id = " + toString(value.type()) + " for column " + name,
                    ErrorCodes::TYPE_MISMATCH);
        }
    }

    void insertValue(IColumn & column, const ValueType type, const Poco::MongoDB::Element & value, const std::string & name)
    {
        switch (type)
        {
            case ValueType::vtUInt8:
                insertNumber<UInt8>(column, value, name);
                break;
            case ValueType::vtUInt16:
                insertNumber<UInt16>(column, value, name);
                break;
            case ValueType::vtUInt32:
                insertNumber<UInt32>(column, value, name);
                break;
            case ValueType::vtUInt64:
                insertNumber<UInt64>(column, value, name);
                break;
            case ValueType::vtInt8:
                insertNumber<Int8>(column, value, name);
                break;
            case ValueType::vtInt16:
                insertNumber<Int16>(column, value, name);
                break;
            case ValueType::vtInt32:
                insertNumber<Int32>(column, value, name);
                break;
            case ValueType::vtInt64:
                insertNumber<Int64>(column, value, name);
                break;
            case ValueType::vtFloat32:
                insertNumber<Float32>(column, value, name);
                break;
            case ValueType::vtFloat64:
                insertNumber<Float64>(column, value, name);
                break;

            case ValueType::vtString:
            {
                if (value.type() == Poco::MongoDB::ElementTraits<ObjectId::Ptr>::TypeId)
                {
                    std::string string_id = value.toString();
                    assert_cast<ColumnString &>(column).insertDataWithTerminatingZero(string_id.data(), string_id.size() + 1);
                    break;
                }
                else if (value.type() == Poco::MongoDB::ElementTraits<String>::TypeId)
                {
                    String string = static_cast<const Poco::MongoDB::ConcreteElement<String> &>(value).value();
                    assert_cast<ColumnString &>(column).insertDataWithTerminatingZero(string.data(), string.size() + 1);
                    break;
                }

                throw Exception{"Type mismatch, expected String, got type id = " + toString(value.type()) + " for column " + name,
                                ErrorCodes::TYPE_MISMATCH};
            }

            case ValueType::vtDate:
            {
                if (value.type() != Poco::MongoDB::ElementTraits<Poco::Timestamp>::TypeId)
                    throw Exception{"Type mismatch, expected Timestamp, got type id = " + toString(value.type()) + " for column " + name,
                                    ErrorCodes::TYPE_MISMATCH};

                assert_cast<ColumnUInt16 &>(column).getData().push_back(UInt16{DateLUT::instance().toDayNum(
                    static_cast<const Poco::MongoDB::ConcreteElement<Poco::Timestamp> &>(value).value().epochTime())});
                break;
            }

            case ValueType::vtDateTime:
            {
                if (value.type() != Poco::MongoDB::ElementTraits<Poco::Timestamp>::TypeId)
                    throw Exception{"Type mismatch, expected Timestamp, got type id = " + toString(value.type()) + " for column " + name,
                                    ErrorCodes::TYPE_MISMATCH};

                assert_cast<ColumnUInt32 &>(column).getData().push_back(
                    static_cast<const Poco::MongoDB::ConcreteElement<Poco::Timestamp> &>(value).value().epochTime());
                break;
            }
            case ValueType::vtUUID:
            {
                if (value.type() == Poco::MongoDB::ElementTraits<String>::TypeId)
                {
                    String string = static_cast<const Poco::MongoDB::ConcreteElement<String> &>(value).value();
                    assert_cast<ColumnUInt128 &>(column).getData().push_back(parse<UUID>(string));
                }
                else
                    throw Exception{"Type mismatch, expected String (UUID), got type id = " + toString(value.type()) + " for column "
                                        + name,
                                    ErrorCodes::TYPE_MISMATCH};
                break;
            }
            default:
                throw Exception("Value of unsupported type:" + column.getName(), ErrorCodes::UNKNOWN_TYPE);
        }
    }

    void insertDefaultValue(IColumn & column, const IColumn & sample_column) { column.insertFrom(sample_column, 0); }
}


Block MongoDBBlockInputStream::readImpl()
{
    if (all_read)
        return {};

    MutableColumns columns(description.sample_block.columns());
    const size_t size = columns.size();

    for (const auto i : ext::range(0, size))
        columns[i] = description.sample_block.getByPosition(i).column->cloneEmpty();

    size_t num_rows = 0;
    while (num_rows < max_block_size)
    {
        Poco::MongoDB::ResponseMessage & response = cursor->next(*connection);

        for (auto & document : response.documents())
        {
            ++num_rows;

            for (const auto idx : ext::range(0, size))
            {
                const auto & name = description.sample_block.getByPosition(idx).name;

                if (strict_check_names && !document->exists(name))
                    throw Exception(fmt::format("Column {} is absent in MongoDB collection", backQuote(name)), ErrorCodes::NOT_FOUND_COLUMN_IN_BLOCK);

                const Poco::MongoDB::Element::Ptr value = document->get(name);

                if (value.isNull() || value->type() == Poco::MongoDB::ElementTraits<Poco::MongoDB::NullValue>::TypeId)
                    insertDefaultValue(*columns[idx], *description.sample_block.getByPosition(idx).column);
                else
                {
                    if (description.types[idx].second)
                    {
                        ColumnNullable & column_nullable = assert_cast<ColumnNullable &>(*columns[idx]);
                        insertValue(column_nullable.getNestedColumn(), description.types[idx].first, *value, name);
                        column_nullable.getNullMapData().emplace_back(0);
                    }
                    else
                        insertValue(*columns[idx], description.types[idx].first, *value, name);
                }
            }
        }

        if (response.cursorID() == 0)
        {
            all_read = true;
            break;
        }
    }

    if (num_rows == 0)
        return {};

    return description.sample_block.cloneWithColumns(std::move(columns));
}

}