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AzSuicideDataVisualization/.venv/Lib/site-packages/pyarrow/include/arrow/flight/server_middleware.h
2022-05-23 00:16:32 +04:00

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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
// Interfaces for defining middleware for Flight servers. Currently
// experimental.
#pragma once
#include <memory>
#include <string>
#include "arrow/flight/middleware.h"
#include "arrow/flight/visibility.h" // IWYU pragma: keep
#include "arrow/status.h"
namespace arrow {
namespace flight {
/// \brief Server-side middleware for a call, instantiated per RPC.
///
/// Middleware should be fast and must be infallible: there is no way
/// to reject the call or report errors from the middleware instance.
class ARROW_FLIGHT_EXPORT ServerMiddleware {
public:
virtual ~ServerMiddleware() = default;
/// \brief Unique name of middleware, used as alternative to RTTI
/// \return the string name of the middleware
virtual std::string name() const = 0;
/// \brief A callback before headers are sent. Extra headers can be
/// added, but existing ones cannot be read.
virtual void SendingHeaders(AddCallHeaders* outgoing_headers) = 0;
/// \brief A callback after the call has completed.
virtual void CallCompleted(const Status& status) = 0;
};
/// \brief A factory for new middleware instances.
///
/// If added to a server, this will be called for each RPC (including
/// Handshake) to give the opportunity to intercept the call.
///
/// It is guaranteed that all server middleware methods are called
/// from the same thread that calls the RPC method implementation.
class ARROW_FLIGHT_EXPORT ServerMiddlewareFactory {
public:
virtual ~ServerMiddlewareFactory() = default;
/// \brief A callback for the start of a new call.
///
/// Return a non-OK status to reject the call with the given status.
///
/// \param info Information about the call.
/// \param incoming_headers Headers sent by the client for this call.
/// Do not retain a reference to this object.
/// \param[out] middleware The middleware instance for this call. If
/// null, no middleware will be added to this call instance from
/// this factory.
/// \return Status A non-OK status will reject the call with the
/// given status. Middleware previously in the chain will have
/// their CallCompleted callback called. Other middleware
/// factories will not be called.
virtual Status StartCall(const CallInfo& info, const CallHeaders& incoming_headers,
std::shared_ptr<ServerMiddleware>* middleware) = 0;
};
} // namespace flight
} // namespace arrow