1 /* 2 * 3 * Copyright 2015 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 #ifndef GRPCPP_IMPL_CODEGEN_SERVER_CONTEXT_H 20 #define GRPCPP_IMPL_CODEGEN_SERVER_CONTEXT_H 21 22 #include <map> 23 #include <memory> 24 #include <vector> 25 26 #include <grpc/impl/codegen/compression_types.h> 27 28 #include <grpcpp/impl/codegen/call.h> 29 #include <grpcpp/impl/codegen/completion_queue_tag.h> 30 #include <grpcpp/impl/codegen/config.h> 31 #include <grpcpp/impl/codegen/create_auth_context.h> 32 #include <grpcpp/impl/codegen/metadata_map.h> 33 #include <grpcpp/impl/codegen/security/auth_context.h> 34 #include <grpcpp/impl/codegen/string_ref.h> 35 #include <grpcpp/impl/codegen/time.h> 36 37 struct grpc_metadata; 38 struct grpc_call; 39 struct census_context; 40 41 namespace grpc { 42 class ClientContext; 43 template <class W, class R> 44 class ServerAsyncReader; 45 template <class W> 46 class ServerAsyncWriter; 47 template <class W> 48 class ServerAsyncResponseWriter; 49 template <class W, class R> 50 class ServerAsyncReaderWriter; 51 template <class R> 52 class ServerReader; 53 template <class W> 54 class ServerWriter; 55 namespace internal { 56 template <class W, class R> 57 class ServerReaderWriterBody; 58 template <class ServiceType, class RequestType, class ResponseType> 59 class RpcMethodHandler; 60 template <class ServiceType, class RequestType, class ResponseType> 61 class ClientStreamingHandler; 62 template <class ServiceType, class RequestType, class ResponseType> 63 class ServerStreamingHandler; 64 template <class ServiceType, class RequestType, class ResponseType> 65 class BidiStreamingHandler; 66 template <class Streamer, bool WriteNeeded> 67 class TemplatedBidiStreamingHandler; 68 template <StatusCode code> 69 class ErrorMethodHandler; 70 class Call; 71 } // namespace internal 72 73 class CompletionQueue; 74 class Server; 75 class ServerInterface; 76 77 namespace testing { 78 class InteropServerContextInspector; 79 class ServerContextTestSpouse; 80 } // namespace testing 81 82 /// A ServerContext allows the person implementing a service handler to: 83 /// 84 /// - Add custom initial and trailing metadata key-value pairs that will 85 /// propagated to the client side. 86 /// - Control call settings such as compression and authentication. 87 /// - Access metadata coming from the client. 88 /// - Get performance metrics (ie, census). 89 /// 90 /// Context settings are only relevant to the call handler they are supplied to, 91 /// that is to say, they aren't sticky across multiple calls. Some of these 92 /// settings, such as the compression options, can be made persistent at server 93 /// construction time by specifying the appropriate \a ChannelArguments 94 /// to a \a grpc::ServerBuilder, via \a ServerBuilder::AddChannelArgument. 95 /// 96 /// \warning ServerContext instances should \em not be reused across rpcs. 97 class ServerContext { 98 public: 99 ServerContext(); // for async calls 100 ~ServerContext(); 101 102 /// Return the deadline for the server call. deadline()103 std::chrono::system_clock::time_point deadline() const { 104 return Timespec2Timepoint(deadline_); 105 } 106 107 /// Return a \a gpr_timespec representation of the server call's deadline. raw_deadline()108 gpr_timespec raw_deadline() const { return deadline_; } 109 110 /// Add the (\a meta_key, \a meta_value) pair to the initial metadata 111 /// associated with a server call. These are made available at the client side 112 /// by the \a grpc::ClientContext::GetServerInitialMetadata() method. 113 /// 114 /// \warning This method should only be called before sending initial metadata 115 /// to the client (which can happen explicitly, or implicitly when sending a 116 /// a response message or status to the client). 117 /// 118 /// \param meta_key The metadata key. If \a meta_value is binary data, it must 119 /// end in "-bin". 120 /// \param meta_value The metadata value. If its value is binary, the key name 121 /// must end in "-bin". 122 void AddInitialMetadata(const grpc::string& key, const grpc::string& value); 123 124 /// Add the (\a meta_key, \a meta_value) pair to the initial metadata 125 /// associated with a server call. These are made available at the client 126 /// side by the \a grpc::ClientContext::GetServerTrailingMetadata() method. 127 /// 128 /// \warning This method should only be called before sending trailing 129 /// metadata to the client (which happens when the call is finished and a 130 /// status is sent to the client). 131 /// 132 /// \param meta_key The metadata key. If \a meta_value is binary data, 133 /// it must end in "-bin". 134 /// \param meta_value The metadata value. If its value is binary, the key name 135 /// must end in "-bin". 136 void AddTrailingMetadata(const grpc::string& key, const grpc::string& value); 137 138 /// IsCancelled is always safe to call when using sync API. 139 /// When using async API, it is only safe to call IsCancelled after 140 /// the AsyncNotifyWhenDone tag has been delivered. 141 bool IsCancelled() const; 142 143 /// Cancel the Call from the server. This is a best-effort API and 144 /// depending on when it is called, the RPC may still appear successful to 145 /// the client. 146 /// For example, if TryCancel() is called on a separate thread, it might race 147 /// with the server handler which might return success to the client before 148 /// TryCancel() was even started by the thread. 149 /// 150 /// It is the caller's responsibility to prevent such races and ensure that if 151 /// TryCancel() is called, the serverhandler must return Status::CANCELLED. 152 /// The only exception is that if the serverhandler is already returning an 153 /// error status code, it is ok to not return Status::CANCELLED even if 154 /// TryCancel() was called. 155 /// 156 /// Note that TryCancel() does not change any of the tags that are pending 157 /// on the completion queue. All pending tags will still be delivered 158 /// (though their ok result may reflect the effect of cancellation). 159 void TryCancel() const; 160 161 /// Return a collection of initial metadata key-value pairs sent from the 162 /// client. Note that keys may happen more than 163 /// once (ie, a \a std::multimap is returned). 164 /// 165 /// It is safe to use this method after initial metadata has been received, 166 /// Calls always begin with the client sending initial metadata, so this is 167 /// safe to access as soon as the call has begun on the server side. 168 /// 169 /// \return A multimap of initial metadata key-value pairs from the server. client_metadata()170 const std::multimap<grpc::string_ref, grpc::string_ref>& client_metadata() 171 const { 172 return *client_metadata_.map(); 173 } 174 175 /// Return the compression algorithm to be used by the server call. compression_level()176 grpc_compression_level compression_level() const { 177 return compression_level_; 178 } 179 180 /// Set \a algorithm to be the compression algorithm used for the server call. 181 /// 182 /// \param algorithm The compression algorithm used for the server call. set_compression_level(grpc_compression_level level)183 void set_compression_level(grpc_compression_level level) { 184 compression_level_set_ = true; 185 compression_level_ = level; 186 } 187 188 /// Return a bool indicating whether the compression level for this call 189 /// has been set (either implicitly or through a previous call to 190 /// \a set_compression_level. compression_level_set()191 bool compression_level_set() const { return compression_level_set_; } 192 193 /// Return the compression algorithm the server call will request be used. 194 /// Note that the gRPC runtime may decide to ignore this request, for example, 195 /// due to resource constraints, or if the server is aware the client doesn't 196 /// support the requested algorithm. compression_algorithm()197 grpc_compression_algorithm compression_algorithm() const { 198 return compression_algorithm_; 199 } 200 /// Set \a algorithm to be the compression algorithm used for the server call. 201 /// 202 /// \param algorithm The compression algorithm used for the server call. 203 void set_compression_algorithm(grpc_compression_algorithm algorithm); 204 205 /// Set the serialized load reporting costs in \a cost_data for the call. 206 void SetLoadReportingCosts(const std::vector<grpc::string>& cost_data); 207 208 /// Return the authentication context for this server call. 209 /// 210 /// \see grpc::AuthContext. auth_context()211 std::shared_ptr<const AuthContext> auth_context() const { 212 if (auth_context_.get() == nullptr) { 213 auth_context_ = CreateAuthContext(call_); 214 } 215 return auth_context_; 216 } 217 218 /// Return the peer uri in a string. 219 /// WARNING: this value is never authenticated or subject to any security 220 /// related code. It must not be used for any authentication related 221 /// functionality. Instead, use auth_context. 222 grpc::string peer() const; 223 224 /// Get the census context associated with this server call. 225 const struct census_context* census_context() const; 226 227 /// Async only. Has to be called before the rpc starts. 228 /// Returns the tag in completion queue when the rpc finishes. 229 /// IsCancelled() can then be called to check whether the rpc was cancelled. 230 /// TODO(vjpai): Fix this so that the tag is returned even if the call never 231 /// starts (https://github.com/grpc/grpc/issues/10136). AsyncNotifyWhenDone(void * tag)232 void AsyncNotifyWhenDone(void* tag) { 233 has_notify_when_done_tag_ = true; 234 async_notify_when_done_tag_ = tag; 235 } 236 237 /// Should be used for framework-level extensions only. 238 /// Applications never need to call this method. c_call()239 grpc_call* c_call() { return call_; } 240 241 private: 242 friend class ::grpc::testing::InteropServerContextInspector; 243 friend class ::grpc::testing::ServerContextTestSpouse; 244 friend class ::grpc::ServerInterface; 245 friend class ::grpc::Server; 246 template <class W, class R> 247 friend class ::grpc::ServerAsyncReader; 248 template <class W> 249 friend class ::grpc::ServerAsyncWriter; 250 template <class W> 251 friend class ::grpc::ServerAsyncResponseWriter; 252 template <class W, class R> 253 friend class ::grpc::ServerAsyncReaderWriter; 254 template <class R> 255 friend class ::grpc::ServerReader; 256 template <class W> 257 friend class ::grpc::ServerWriter; 258 template <class W, class R> 259 friend class ::grpc::internal::ServerReaderWriterBody; 260 template <class ServiceType, class RequestType, class ResponseType> 261 friend class ::grpc::internal::RpcMethodHandler; 262 template <class ServiceType, class RequestType, class ResponseType> 263 friend class ::grpc::internal::ClientStreamingHandler; 264 template <class ServiceType, class RequestType, class ResponseType> 265 friend class ::grpc::internal::ServerStreamingHandler; 266 template <class Streamer, bool WriteNeeded> 267 friend class ::grpc::internal::TemplatedBidiStreamingHandler; 268 template <StatusCode code> 269 friend class internal::ErrorMethodHandler; 270 friend class ::grpc::ClientContext; 271 272 /// Prevent copying. 273 ServerContext(const ServerContext&); 274 ServerContext& operator=(const ServerContext&); 275 276 class CompletionOp; 277 278 void BeginCompletionOp(internal::Call* call); 279 /// Return the tag queued by BeginCompletionOp() 280 internal::CompletionQueueTag* GetCompletionOpTag(); 281 282 ServerContext(gpr_timespec deadline, grpc_metadata_array* arr); 283 set_call(grpc_call * call)284 void set_call(grpc_call* call) { call_ = call; } 285 initial_metadata_flags()286 uint32_t initial_metadata_flags() const { return 0; } 287 288 CompletionOp* completion_op_; 289 bool has_notify_when_done_tag_; 290 void* async_notify_when_done_tag_; 291 292 gpr_timespec deadline_; 293 grpc_call* call_; 294 CompletionQueue* cq_; 295 bool sent_initial_metadata_; 296 mutable std::shared_ptr<const AuthContext> auth_context_; 297 mutable internal::MetadataMap client_metadata_; 298 std::multimap<grpc::string, grpc::string> initial_metadata_; 299 std::multimap<grpc::string, grpc::string> trailing_metadata_; 300 301 bool compression_level_set_; 302 grpc_compression_level compression_level_; 303 grpc_compression_algorithm compression_algorithm_; 304 305 internal::CallOpSet<internal::CallOpSendInitialMetadata, 306 internal::CallOpSendMessage> 307 pending_ops_; 308 bool has_pending_ops_; 309 }; 310 311 } // namespace grpc 312 313 #endif // GRPCPP_IMPL_CODEGEN_SERVER_CONTEXT_H 314