grpc-swift/Sources/GRPCCore/Call/Server/ServerContext.swift

/*
 * Copyright 2024, gRPC Authors All rights reserved.
 *
 * Licensed 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.
 */

/// Additional information about an RPC handled by a server.
public struct ServerContext: Sendable {

  /// Protocol used to help identify transport specific context fields
  public protocol TransportSpecific: Sendable {}

  /// A description of the method being called.
  public var descriptor: MethodDescriptor

  /// A description of the remote peer.
  ///
  /// The format of the description should follow the pattern "<transport>:<address>" where
  /// "<transport>" indicates the underlying network transport (such as "ipv4", "unix", or
  /// "in-process"). This is a guideline for how descriptions should be formatted; different
  /// implementations may not follow this format so you shouldn't make assumptions based on it.
  ///
  /// Some examples include:
  /// - "ipv4:127.0.0.1:31415",
  /// - "ipv6:[::1]:443",
  /// - "in-process:27182".
  public var remotePeer: String

  /// A description of the local peer.
  ///
  /// The format of the description should follow the pattern "<transport>:<address>" where
  /// "<transport>" indicates the underlying network transport (such as "ipv4", "unix", or
  /// "in-process"). This is a guideline for how descriptions should be formatted; different
  /// implementations may not follow this format so you shouldn't make assumptions based on it.
  ///
  /// Some examples include:
  /// - "ipv4:127.0.0.1:31415",
  /// - "ipv6:[::1]:443",
  /// - "in-process:27182".
  public var localPeer: String

  /// An optional field for transports to store specific data
  ///
  /// Refer to the transport documentation to understand what type of
  /// value this field will contain, if any.
  ///
  /// An example of what this field can be used for, would be to store
  /// things like a peer certificate from a mTLS connection
  public var transportSpecific: (any TransportSpecific)?

  /// A handle for checking the cancellation status of an RPC.
  public var cancellation: RPCCancellationHandle

  /// Create a new server context.
  ///
  /// - Parameters:
  ///   - descriptor: A description of the method being called.
  ///   - remotePeer: A description of the remote peer.
  ///   - localPeer: A description of the local peer.
  ///   - cancellation: A cancellation handle. You can create a cancellation handle
  ///     using ``withServerContextRPCCancellationHandle(_:)``.
  public init(
    descriptor: MethodDescriptor,
    remotePeer: String,
    localPeer: String,
    cancellation: RPCCancellationHandle
  ) {
    self.descriptor = descriptor
    self.remotePeer = remotePeer
    self.localPeer = localPeer
    self.cancellation = cancellation
  }
}