ClickHouse

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#include "SchemaAllowedHandler.h"
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#if USE_ODBC
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#include <Server/HTTP/HTMLForm.h>
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#include <Server/HTTP/WriteBufferFromHTTPServerResponse.h>
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#include <IO/ReadHelpers.h>
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#include <IO/WriteHelpers.h>
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#include <Poco/Net/HTTPServerRequest.h>
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#include <Poco/Net/HTTPServerResponse.h>
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#include <Common/BridgeProtocolVersion.h>
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#include <Common/logger_useful.h>
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#include "validateODBCConnectionString.h"
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#include "ODBCPooledConnectionFactory.h"
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#include <sql.h>
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#include <sqlext.h>
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namespace DB
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{
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namespace
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{
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    bool isSchemaAllowed(nanodbc::ConnectionHolderPtr connection_holder)
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    {
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        uint32_t result = execute<uint32_t>(connection_holder,
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                    [&](nanodbc::connection & connection) { return connection.get_info<uint32_t>(SQL_SCHEMA_USAGE); });
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        return result != 0;
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    }
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}
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void SchemaAllowedHandler::handleRequest(HTTPServerRequest & request, HTTPServerResponse & response, const ProfileEvents::Event & /*write_event*/)
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{
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    HTMLForm params(getContext()->getSettingsRef(), request, request.getStream());
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    LOG_TRACE(log, "Request URI: {}", request.getURI());
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    auto process_error = [&response, this](const std::string & message)
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    {
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        response.setStatusAndReason(Poco::Net::HTTPResponse::HTTP_INTERNAL_SERVER_ERROR);
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        if (!response.sent())
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            *response.send() << message << '\n';
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        LOG_WARNING(log, fmt::runtime(message));
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    };
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    size_t version;
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    if (!params.has("version"))
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        version = 0; /// assumed version for too old servers which do not send a version
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    else
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    {
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        String version_str = params.get("version");
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        if (!tryParse(version, version_str))
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        {
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            process_error("Unable to parse 'version' string in request URL: '" + version_str + "' Check if the server and library-bridge have the same version.");
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            return;
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        }
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    }
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    if (version != XDBC_BRIDGE_PROTOCOL_VERSION)
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    {
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        /// backwards compatibility is considered unnecessary for now, just let the user know that the server and the bridge must be upgraded together
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        process_error("Server and library-bridge have different versions: '" + std::to_string(version) + "' vs. '" + std::to_string(LIBRARY_BRIDGE_PROTOCOL_VERSION) + "'");
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        return;
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    }
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    if (!params.has("connection_string"))
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    {
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        process_error("No 'connection_string' in request URL");
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        return;
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    }
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     bool use_connection_pooling = params.getParsed<bool>("use_connection_pooling", true);
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    try
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    {
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        std::string connection_string = params.get("connection_string");
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        nanodbc::ConnectionHolderPtr connection;
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        if (use_connection_pooling)
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            connection = ODBCPooledConnectionFactory::instance().get(
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                validateODBCConnectionString(connection_string), getContext()->getSettingsRef().odbc_bridge_connection_pool_size);
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        else
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            connection = std::make_shared<nanodbc::ConnectionHolder>(validateODBCConnectionString(connection_string));
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        bool result = isSchemaAllowed(std::move(connection));
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        WriteBufferFromHTTPServerResponse out(response, request.getMethod() == Poco::Net::HTTPRequest::HTTP_HEAD, keep_alive_timeout);
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        try
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        {
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            writeBoolText(result, out);
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            out.finalize();
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        }
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        catch (...)
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        {
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            out.finalize();
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        }
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    }
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    catch (...)
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    {
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        process_error("Error getting schema usage from ODBC '" + getCurrentExceptionMessage(false) + "'");
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        tryLogCurrentException(log);
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    }
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}
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}
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#endif
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