3 * Copyright 2015 gRPC authors.
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
9 * http://www.apache.org/licenses/LICENSE-2.0
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.
19 #ifndef GRPCPP_IMPL_CODEGEN_SERVER_CONTEXT_H
20 #define GRPCPP_IMPL_CODEGEN_SERVER_CONTEXT_H
26 #include <grpc/impl/codegen/compression_types.h>
28 #include <grpcpp/impl/codegen/call.h>
29 #include <grpcpp/impl/codegen/call_op_set.h>
30 #include <grpcpp/impl/codegen/callback_common.h>
31 #include <grpcpp/impl/codegen/completion_queue_tag.h>
32 #include <grpcpp/impl/codegen/config.h>
33 #include <grpcpp/impl/codegen/create_auth_context.h>
34 #include <grpcpp/impl/codegen/metadata_map.h>
35 #include <grpcpp/impl/codegen/security/auth_context.h>
36 #include <grpcpp/impl/codegen/server_interceptor.h>
37 #include <grpcpp/impl/codegen/string_ref.h>
38 #include <grpcpp/impl/codegen/time.h>
42 struct census_context;
46 class GenericServerContext;
47 class CompletionQueue;
49 class ServerInterface;
50 template <class W, class R>
51 class ServerAsyncReader;
53 class ServerAsyncWriter;
55 class ServerAsyncResponseWriter;
56 template <class W, class R>
57 class ServerAsyncReaderWriter;
64 template <class W, class R>
65 class ServerReaderWriterBody;
66 template <class ServiceType, class RequestType, class ResponseType>
67 class RpcMethodHandler;
68 template <class ServiceType, class RequestType, class ResponseType>
69 class ClientStreamingHandler;
70 template <class ServiceType, class RequestType, class ResponseType>
71 class ServerStreamingHandler;
72 template <class ServiceType, class RequestType, class ResponseType>
73 class BidiStreamingHandler;
74 template <class RequestType, class ResponseType>
75 class CallbackUnaryHandler;
76 template <class RequestType, class ResponseType>
77 class CallbackClientStreamingHandler;
78 template <class RequestType, class ResponseType>
79 class CallbackServerStreamingHandler;
80 template <class RequestType, class ResponseType>
81 class CallbackBidiHandler;
82 template <class Streamer, bool WriteNeeded>
83 class TemplatedBidiStreamingHandler;
84 template <StatusCode code>
85 class ErrorMethodHandler;
88 } // namespace internal
91 class InteropServerContextInspector;
92 class ServerContextTestSpouse;
93 } // namespace testing
95 /// A ServerContext allows the person implementing a service handler to:
97 /// - Add custom initial and trailing metadata key-value pairs that will
98 /// propagated to the client side.
99 /// - Control call settings such as compression and authentication.
100 /// - Access metadata coming from the client.
101 /// - Get performance metrics (ie, census).
103 /// Context settings are only relevant to the call handler they are supplied to,
104 /// that is to say, they aren't sticky across multiple calls. Some of these
105 /// settings, such as the compression options, can be made persistent at server
106 /// construction time by specifying the appropriate \a ChannelArguments
107 /// to a \a grpc::ServerBuilder, via \a ServerBuilder::AddChannelArgument.
109 /// \warning ServerContext instances should \em not be reused across rpcs.
110 class ServerContext {
112 ServerContext(); // for async calls
115 /// Return the deadline for the server call.
116 std::chrono::system_clock::time_point deadline() const {
117 return Timespec2Timepoint(deadline_);
120 /// Return a \a gpr_timespec representation of the server call's deadline.
121 gpr_timespec raw_deadline() const { return deadline_; }
123 /// Add the (\a key, \a value) pair to the initial metadata
124 /// associated with a server call. These are made available at the client side
125 /// by the \a grpc::ClientContext::GetServerInitialMetadata() method.
127 /// \warning This method should only be called before sending initial metadata
128 /// to the client (which can happen explicitly, or implicitly when sending a
129 /// a response message or status to the client).
131 /// \param key The metadata key. If \a value is binary data, it must
133 /// \param value The metadata value. If its value is binary, the key name
134 /// must end in "-bin".
136 /// Metadata must conform to the following format:
137 /// Custom-Metadata -> Binary-Header / ASCII-Header
138 /// Binary-Header -> {Header-Name "-bin" } {binary value}
139 /// ASCII-Header -> Header-Name ASCII-Value
140 /// Header-Name -> 1*( %x30-39 / %x61-7A / "_" / "-" / ".") ; 0-9 a-z _ - .
141 /// ASCII-Value -> 1*( %x20-%x7E ) ; space and printable ASCII
142 void AddInitialMetadata(const grpc::string& key, const grpc::string& value);
144 /// Add the (\a key, \a value) pair to the initial metadata
145 /// associated with a server call. These are made available at the client
146 /// side by the \a grpc::ClientContext::GetServerTrailingMetadata() method.
148 /// \warning This method should only be called before sending trailing
149 /// metadata to the client (which happens when the call is finished and a
150 /// status is sent to the client).
152 /// \param key The metadata key. If \a value is binary data,
153 /// it must end in "-bin".
154 /// \param value The metadata value. If its value is binary, the key name
155 /// must end in "-bin".
157 /// Metadata must conform to the following format:
158 /// Custom-Metadata -> Binary-Header / ASCII-Header
159 /// Binary-Header -> {Header-Name "-bin" } {binary value}
160 /// ASCII-Header -> Header-Name ASCII-Value
161 /// Header-Name -> 1*( %x30-39 / %x61-7A / "_" / "-" / ".") ; 0-9 a-z _ - .
162 /// ASCII-Value -> 1*( %x20-%x7E ) ; space and printable ASCII
163 void AddTrailingMetadata(const grpc::string& key, const grpc::string& value);
165 /// IsCancelled is always safe to call when using sync or callback API.
166 /// When using async API, it is only safe to call IsCancelled after
167 /// the AsyncNotifyWhenDone tag has been delivered.
168 bool IsCancelled() const;
170 /// Cancel the Call from the server. This is a best-effort API and
171 /// depending on when it is called, the RPC may still appear successful to
173 /// For example, if TryCancel() is called on a separate thread, it might race
174 /// with the server handler which might return success to the client before
175 /// TryCancel() was even started by the thread.
177 /// It is the caller's responsibility to prevent such races and ensure that if
178 /// TryCancel() is called, the serverhandler must return Status::CANCELLED.
179 /// The only exception is that if the serverhandler is already returning an
180 /// error status code, it is ok to not return Status::CANCELLED even if
181 /// TryCancel() was called.
183 /// Note that TryCancel() does not change any of the tags that are pending
184 /// on the completion queue. All pending tags will still be delivered
185 /// (though their ok result may reflect the effect of cancellation).
186 void TryCancel() const;
188 /// Return a collection of initial metadata key-value pairs sent from the
189 /// client. Note that keys may happen more than
190 /// once (ie, a \a std::multimap is returned).
192 /// It is safe to use this method after initial metadata has been received,
193 /// Calls always begin with the client sending initial metadata, so this is
194 /// safe to access as soon as the call has begun on the server side.
196 /// \return A multimap of initial metadata key-value pairs from the server.
197 const std::multimap<grpc::string_ref, grpc::string_ref>& client_metadata()
199 return *client_metadata_.map();
202 /// Return the compression algorithm to be used by the server call.
203 grpc_compression_level compression_level() const {
204 return compression_level_;
207 /// Set \a level to be the compression level used for the server call.
209 /// \param level The compression level used for the server call.
210 void set_compression_level(grpc_compression_level level) {
211 compression_level_set_ = true;
212 compression_level_ = level;
215 /// Return a bool indicating whether the compression level for this call
216 /// has been set (either implicitly or through a previous call to
217 /// \a set_compression_level.
218 bool compression_level_set() const { return compression_level_set_; }
220 /// Return the compression algorithm the server call will request be used.
221 /// Note that the gRPC runtime may decide to ignore this request, for example,
222 /// due to resource constraints, or if the server is aware the client doesn't
223 /// support the requested algorithm.
224 grpc_compression_algorithm compression_algorithm() const {
225 return compression_algorithm_;
227 /// Set \a algorithm to be the compression algorithm used for the server call.
229 /// \param algorithm The compression algorithm used for the server call.
230 void set_compression_algorithm(grpc_compression_algorithm algorithm);
232 /// Set the serialized load reporting costs in \a cost_data for the call.
233 void SetLoadReportingCosts(const std::vector<grpc::string>& cost_data);
235 /// Return the authentication context for this server call.
237 /// \see grpc::AuthContext.
238 std::shared_ptr<const AuthContext> auth_context() const {
239 if (auth_context_.get() == nullptr) {
240 auth_context_ = CreateAuthContext(call_);
242 return auth_context_;
245 /// Return the peer uri in a string.
246 /// WARNING: this value is never authenticated or subject to any security
247 /// related code. It must not be used for any authentication related
248 /// functionality. Instead, use auth_context.
249 grpc::string peer() const;
251 /// Get the census context associated with this server call.
252 const struct census_context* census_context() const;
254 /// Async only. Has to be called before the rpc starts.
255 /// Returns the tag in completion queue when the rpc finishes.
256 /// IsCancelled() can then be called to check whether the rpc was cancelled.
257 /// TODO(vjpai): Fix this so that the tag is returned even if the call never
258 /// starts (https://github.com/grpc/grpc/issues/10136).
259 void AsyncNotifyWhenDone(void* tag) {
260 has_notify_when_done_tag_ = true;
261 async_notify_when_done_tag_ = tag;
264 /// Should be used for framework-level extensions only.
265 /// Applications never need to call this method.
266 grpc_call* c_call() { return call_; }
269 friend class ::grpc::testing::InteropServerContextInspector;
270 friend class ::grpc::testing::ServerContextTestSpouse;
271 friend class ::grpc::ServerInterface;
272 friend class ::grpc::Server;
273 template <class W, class R>
274 friend class ::grpc::ServerAsyncReader;
276 friend class ::grpc::ServerAsyncWriter;
278 friend class ::grpc::ServerAsyncResponseWriter;
279 template <class W, class R>
280 friend class ::grpc::ServerAsyncReaderWriter;
282 friend class ::grpc::ServerReader;
284 friend class ::grpc::ServerWriter;
285 template <class W, class R>
286 friend class ::grpc::internal::ServerReaderWriterBody;
287 template <class ServiceType, class RequestType, class ResponseType>
288 friend class ::grpc::internal::RpcMethodHandler;
289 template <class ServiceType, class RequestType, class ResponseType>
290 friend class ::grpc::internal::ClientStreamingHandler;
291 template <class ServiceType, class RequestType, class ResponseType>
292 friend class ::grpc::internal::ServerStreamingHandler;
293 template <class Streamer, bool WriteNeeded>
294 friend class ::grpc::internal::TemplatedBidiStreamingHandler;
295 template <class RequestType, class ResponseType>
296 friend class ::grpc::internal::CallbackUnaryHandler;
297 template <class RequestType, class ResponseType>
298 friend class ::grpc::internal::CallbackClientStreamingHandler;
299 template <class RequestType, class ResponseType>
300 friend class ::grpc::internal::CallbackServerStreamingHandler;
301 template <class RequestType, class ResponseType>
302 friend class ::grpc::internal::CallbackBidiHandler;
303 template <StatusCode code>
304 friend class internal::ErrorMethodHandler;
305 friend class ::grpc::ClientContext;
306 friend class ::grpc::GenericServerContext;
309 ServerContext(const ServerContext&);
310 ServerContext& operator=(const ServerContext&);
314 void BeginCompletionOp(internal::Call* call,
315 std::function<void(bool)> callback,
316 internal::ServerReactor* reactor);
317 /// Return the tag queued by BeginCompletionOp()
318 internal::CompletionQueueTag* GetCompletionOpTag();
320 ServerContext(gpr_timespec deadline, grpc_metadata_array* arr);
322 void set_call(grpc_call* call) { call_ = call; }
324 void BindDeadlineAndMetadata(gpr_timespec deadline, grpc_metadata_array* arr);
328 void Setup(gpr_timespec deadline);
330 uint32_t initial_metadata_flags() const { return 0; }
332 void SetCancelCallback(std::function<void()> callback);
333 void ClearCancelCallback();
335 experimental::ServerRpcInfo* set_server_rpc_info(
336 const char* method, internal::RpcMethod::RpcType type,
338 std::unique_ptr<experimental::ServerInterceptorFactoryInterface>>&
340 if (creators.size() != 0) {
341 rpc_info_ = new experimental::ServerRpcInfo(this, method, type);
342 rpc_info_->RegisterInterceptors(creators);
347 CompletionOp* completion_op_;
348 bool has_notify_when_done_tag_;
349 void* async_notify_when_done_tag_;
350 internal::CallbackWithSuccessTag completion_tag_;
352 gpr_timespec deadline_;
354 CompletionQueue* cq_;
355 bool sent_initial_metadata_;
356 mutable std::shared_ptr<const AuthContext> auth_context_;
357 mutable internal::MetadataMap client_metadata_;
358 std::multimap<grpc::string, grpc::string> initial_metadata_;
359 std::multimap<grpc::string, grpc::string> trailing_metadata_;
361 bool compression_level_set_;
362 grpc_compression_level compression_level_;
363 grpc_compression_algorithm compression_algorithm_;
365 internal::CallOpSet<internal::CallOpSendInitialMetadata,
366 internal::CallOpSendMessage>
368 bool has_pending_ops_;
370 experimental::ServerRpcInfo* rpc_info_;
375 #endif // GRPCPP_IMPL_CODEGEN_SERVER_CONTEXT_H