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 CompletionQueue;
48 } // namespace grpc_impl
51 class GenericServerContext;
52 class ServerInterface;
53 template <class W, class R>
54 class ServerAsyncReader;
56 class ServerAsyncWriter;
58 class ServerAsyncResponseWriter;
59 template <class W, class R>
60 class ServerAsyncReaderWriter;
67 template <class W, class R>
68 class ServerReaderWriterBody;
69 template <class ServiceType, class RequestType, class ResponseType>
70 class RpcMethodHandler;
71 template <class ServiceType, class RequestType, class ResponseType>
72 class ClientStreamingHandler;
73 template <class ServiceType, class RequestType, class ResponseType>
74 class ServerStreamingHandler;
75 template <class ServiceType, class RequestType, class ResponseType>
76 class BidiStreamingHandler;
77 template <class RequestType, class ResponseType>
78 class CallbackUnaryHandler;
79 template <class RequestType, class ResponseType>
80 class CallbackClientStreamingHandler;
81 template <class RequestType, class ResponseType>
82 class CallbackServerStreamingHandler;
83 template <class RequestType, class ResponseType>
84 class CallbackBidiHandler;
85 template <class Streamer, bool WriteNeeded>
86 class TemplatedBidiStreamingHandler;
87 template <StatusCode code>
88 class ErrorMethodHandler;
91 } // namespace internal
93 class ServerInterface;
95 class InteropServerContextInspector;
96 class ServerContextTestSpouse;
97 } // namespace testing
99 /// A ServerContext allows the person implementing a service handler to:
101 /// - Add custom initial and trailing metadata key-value pairs that will
102 /// propagated to the client side.
103 /// - Control call settings such as compression and authentication.
104 /// - Access metadata coming from the client.
105 /// - Get performance metrics (ie, census).
107 /// Context settings are only relevant to the call handler they are supplied to,
108 /// that is to say, they aren't sticky across multiple calls. Some of these
109 /// settings, such as the compression options, can be made persistent at server
110 /// construction time by specifying the appropriate \a ChannelArguments
111 /// to a \a grpc::ServerBuilder, via \a ServerBuilder::AddChannelArgument.
113 /// \warning ServerContext instances should \em not be reused across rpcs.
114 class ServerContext {
116 ServerContext(); // for async calls
119 /// Return the deadline for the server call.
120 std::chrono::system_clock::time_point deadline() const {
121 return Timespec2Timepoint(deadline_);
124 /// Return a \a gpr_timespec representation of the server call's deadline.
125 gpr_timespec raw_deadline() const { return deadline_; }
127 /// Add the (\a key, \a value) pair to the initial metadata
128 /// associated with a server call. These are made available at the client side
129 /// by the \a grpc::ClientContext::GetServerInitialMetadata() method.
131 /// \warning This method should only be called before sending initial metadata
132 /// to the client (which can happen explicitly, or implicitly when sending a
133 /// a response message or status to the client).
135 /// \param key The metadata key. If \a value is binary data, it must
137 /// \param value The metadata value. If its value is binary, the key name
138 /// must end in "-bin".
140 /// Metadata must conform to the following format:
141 /// Custom-Metadata -> Binary-Header / ASCII-Header
142 /// Binary-Header -> {Header-Name "-bin" } {binary value}
143 /// ASCII-Header -> Header-Name ASCII-Value
144 /// Header-Name -> 1*( %x30-39 / %x61-7A / "_" / "-" / ".") ; 0-9 a-z _ - .
145 /// ASCII-Value -> 1*( %x20-%x7E ) ; space and printable ASCII
146 void AddInitialMetadata(const grpc::string& key, const grpc::string& value);
148 /// Add the (\a key, \a value) pair to the initial metadata
149 /// associated with a server call. These are made available at the client
150 /// side by the \a grpc::ClientContext::GetServerTrailingMetadata() method.
152 /// \warning This method should only be called before sending trailing
153 /// metadata to the client (which happens when the call is finished and a
154 /// status is sent to the client).
156 /// \param key The metadata key. If \a value is binary data,
157 /// it must end in "-bin".
158 /// \param value The metadata value. If its value is binary, the key name
159 /// must end in "-bin".
161 /// Metadata must conform to the following format:
162 /// Custom-Metadata -> Binary-Header / ASCII-Header
163 /// Binary-Header -> {Header-Name "-bin" } {binary value}
164 /// ASCII-Header -> Header-Name ASCII-Value
165 /// Header-Name -> 1*( %x30-39 / %x61-7A / "_" / "-" / ".") ; 0-9 a-z _ - .
166 /// ASCII-Value -> 1*( %x20-%x7E ) ; space and printable ASCII
167 void AddTrailingMetadata(const grpc::string& key, const grpc::string& value);
169 /// IsCancelled is always safe to call when using sync or callback API.
170 /// When using async API, it is only safe to call IsCancelled after
171 /// the AsyncNotifyWhenDone tag has been delivered.
172 bool IsCancelled() const;
174 /// Cancel the Call from the server. This is a best-effort API and
175 /// depending on when it is called, the RPC may still appear successful to
177 /// For example, if TryCancel() is called on a separate thread, it might race
178 /// with the server handler which might return success to the client before
179 /// TryCancel() was even started by the thread.
181 /// It is the caller's responsibility to prevent such races and ensure that if
182 /// TryCancel() is called, the serverhandler must return Status::CANCELLED.
183 /// The only exception is that if the serverhandler is already returning an
184 /// error status code, it is ok to not return Status::CANCELLED even if
185 /// TryCancel() was called.
187 /// Note that TryCancel() does not change any of the tags that are pending
188 /// on the completion queue. All pending tags will still be delivered
189 /// (though their ok result may reflect the effect of cancellation).
190 void TryCancel() const;
192 /// Return a collection of initial metadata key-value pairs sent from the
193 /// client. Note that keys may happen more than
194 /// once (ie, a \a std::multimap is returned).
196 /// It is safe to use this method after initial metadata has been received,
197 /// Calls always begin with the client sending initial metadata, so this is
198 /// safe to access as soon as the call has begun on the server side.
200 /// \return A multimap of initial metadata key-value pairs from the server.
201 const std::multimap<grpc::string_ref, grpc::string_ref>& client_metadata()
203 return *client_metadata_.map();
206 /// Return the compression algorithm to be used by the server call.
207 grpc_compression_level compression_level() const {
208 return compression_level_;
211 /// Set \a level to be the compression level used for the server call.
213 /// \param level The compression level used for the server call.
214 void set_compression_level(grpc_compression_level level) {
215 compression_level_set_ = true;
216 compression_level_ = level;
219 /// Return a bool indicating whether the compression level for this call
220 /// has been set (either implicitly or through a previous call to
221 /// \a set_compression_level.
222 bool compression_level_set() const { return compression_level_set_; }
224 /// Return the compression algorithm the server call will request be used.
225 /// Note that the gRPC runtime may decide to ignore this request, for example,
226 /// due to resource constraints, or if the server is aware the client doesn't
227 /// support the requested algorithm.
228 grpc_compression_algorithm compression_algorithm() const {
229 return compression_algorithm_;
231 /// Set \a algorithm to be the compression algorithm used for the server call.
233 /// \param algorithm The compression algorithm used for the server call.
234 void set_compression_algorithm(grpc_compression_algorithm algorithm);
236 /// Set the serialized load reporting costs in \a cost_data for the call.
237 void SetLoadReportingCosts(const std::vector<grpc::string>& cost_data);
239 /// Return the authentication context for this server call.
241 /// \see grpc::AuthContext.
242 std::shared_ptr<const AuthContext> auth_context() const {
243 if (auth_context_.get() == nullptr) {
244 auth_context_ = CreateAuthContext(call_);
246 return auth_context_;
249 /// Return the peer uri in a string.
250 /// WARNING: this value is never authenticated or subject to any security
251 /// related code. It must not be used for any authentication related
252 /// functionality. Instead, use auth_context.
253 grpc::string peer() const;
255 /// Get the census context associated with this server call.
256 const struct census_context* census_context() const;
258 /// Async only. Has to be called before the rpc starts.
259 /// Returns the tag in completion queue when the rpc finishes.
260 /// IsCancelled() can then be called to check whether the rpc was cancelled.
261 /// TODO(vjpai): Fix this so that the tag is returned even if the call never
262 /// starts (https://github.com/grpc/grpc/issues/10136).
263 void AsyncNotifyWhenDone(void* tag) {
264 has_notify_when_done_tag_ = true;
265 async_notify_when_done_tag_ = tag;
268 /// Should be used for framework-level extensions only.
269 /// Applications never need to call this method.
270 grpc_call* c_call() { return call_; }
273 friend class ::grpc::testing::InteropServerContextInspector;
274 friend class ::grpc::testing::ServerContextTestSpouse;
275 friend class ::grpc::ServerInterface;
276 friend class ::grpc_impl::Server;
277 template <class W, class R>
278 friend class ::grpc::ServerAsyncReader;
280 friend class ::grpc::ServerAsyncWriter;
282 friend class ::grpc::ServerAsyncResponseWriter;
283 template <class W, class R>
284 friend class ::grpc::ServerAsyncReaderWriter;
286 friend class ::grpc::ServerReader;
288 friend class ::grpc::ServerWriter;
289 template <class W, class R>
290 friend class ::grpc::internal::ServerReaderWriterBody;
291 template <class ServiceType, class RequestType, class ResponseType>
292 friend class ::grpc::internal::RpcMethodHandler;
293 template <class ServiceType, class RequestType, class ResponseType>
294 friend class ::grpc::internal::ClientStreamingHandler;
295 template <class ServiceType, class RequestType, class ResponseType>
296 friend class ::grpc::internal::ServerStreamingHandler;
297 template <class Streamer, bool WriteNeeded>
298 friend class ::grpc::internal::TemplatedBidiStreamingHandler;
299 template <class RequestType, class ResponseType>
300 friend class ::grpc::internal::CallbackUnaryHandler;
301 template <class RequestType, class ResponseType>
302 friend class ::grpc::internal::CallbackClientStreamingHandler;
303 template <class RequestType, class ResponseType>
304 friend class ::grpc::internal::CallbackServerStreamingHandler;
305 template <class RequestType, class ResponseType>
306 friend class ::grpc::internal::CallbackBidiHandler;
307 template <StatusCode code>
308 friend class internal::ErrorMethodHandler;
309 friend class ::grpc::ClientContext;
310 friend class ::grpc::GenericServerContext;
313 ServerContext(const ServerContext&);
314 ServerContext& operator=(const ServerContext&);
318 void BeginCompletionOp(internal::Call* call,
319 std::function<void(bool)> callback,
320 internal::ServerReactor* reactor);
321 /// Return the tag queued by BeginCompletionOp()
322 internal::CompletionQueueTag* GetCompletionOpTag();
324 ServerContext(gpr_timespec deadline, grpc_metadata_array* arr);
326 void set_call(grpc_call* call) { call_ = call; }
328 void BindDeadlineAndMetadata(gpr_timespec deadline, grpc_metadata_array* arr);
332 void Setup(gpr_timespec deadline);
334 uint32_t initial_metadata_flags() const { return 0; }
336 void SetCancelCallback(std::function<void()> callback);
337 void ClearCancelCallback();
339 experimental::ServerRpcInfo* set_server_rpc_info(
340 const char* method, internal::RpcMethod::RpcType type,
342 std::unique_ptr<experimental::ServerInterceptorFactoryInterface>>&
344 if (creators.size() != 0) {
345 rpc_info_ = new experimental::ServerRpcInfo(this, method, type);
346 rpc_info_->RegisterInterceptors(creators);
351 CompletionOp* completion_op_;
352 bool has_notify_when_done_tag_;
353 void* async_notify_when_done_tag_;
354 internal::CallbackWithSuccessTag completion_tag_;
356 gpr_timespec deadline_;
358 ::grpc_impl::CompletionQueue* cq_;
359 bool sent_initial_metadata_;
360 mutable std::shared_ptr<const AuthContext> auth_context_;
361 mutable internal::MetadataMap client_metadata_;
362 std::multimap<grpc::string, grpc::string> initial_metadata_;
363 std::multimap<grpc::string, grpc::string> trailing_metadata_;
365 bool compression_level_set_;
366 grpc_compression_level compression_level_;
367 grpc_compression_algorithm compression_algorithm_;
369 internal::CallOpSet<internal::CallOpSendInitialMetadata,
370 internal::CallOpSendMessage>
372 bool has_pending_ops_;
374 experimental::ServerRpcInfo* rpc_info_;
379 #endif // GRPCPP_IMPL_CODEGEN_SERVER_CONTEXT_H