/* * * Copyright 2015, Google Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ // The gRPC protocol is an RPC protocol on top of HTTP2. // // While the most common type of RPC receives only one request message and returns only one response // message, the protocol also supports RPCs that return multiple individual messages in a streaming // fashion, RPCs that accept a stream of request messages, or RPCs with both streaming requests and // responses. // // Conceptually, each gRPC call consists of a bidirectional stream of binary messages, with RPCs of // the "non-streaming type" sending only one message in the corresponding direction (the protocol // doesn't make any distinction). // // Each RPC uses a different HTTP2 stream, and thus multiple simultaneous RPCs can be multiplexed // transparently on the same TCP connection. #import #import // Key used in |NSError|'s |userInfo| dictionary to store the response metadata sent by the server. extern id const kGRPCStatusMetadataKey; // Represents a single gRPC remote call. @interface GRPCCall : GRXWriter // These HTTP headers will be passed to the server as part of this call. Each HTTP header is a // name-value pair with string names and either string or binary values. // // The passed dictionary has to use NSString keys, corresponding to the header names. The // value associated to each can be a NSString object or a NSData object. E.g.: // // call.requestMetadata = @{@"Authorization": @"Bearer ..."}; // // call.requestMetadata[@"SomeBinaryHeader"] = someData; // // After the call is started, modifying this won't have any effect. // // For convenience, the property is initialized to an empty NSMutableDictionary, and the setter // accepts (and copies) both mutable and immutable dictionaries. - (NSMutableDictionary *)requestMetadata; // nonatomic - (void)setRequestMetadata:(NSDictionary *)requestMetadata; // nonatomic, copy // This dictionary is populated with the HTTP headers received from the server. When the RPC ends, // the HTTP trailers received are added to the dictionary too. It has the same structure as the // request metadata dictionary. // // The first time this object calls |writeValue| on the writeable passed to |startWithWriteable|, // the |responseMetadata| dictionary already contains the response headers. When it calls // |writesFinishedWithError|, the dictionary contains both the response headers and trailers. @property(atomic, readonly) NSDictionary *responseMetadata; // The request writer has to write NSData objects into the provided Writeable. The server will // receive each of those separately and in order. // A gRPC call might not complete until the request writer finishes. On the other hand, the // request finishing doesn't necessarily make the call to finish, as the server might continue // sending messages to the response side of the call indefinitely (depending on the semantics of // the specific remote method called). // To finish a call right away, invoke cancel. - (instancetype)initWithHost:(NSString *)host path:(NSString *)path requestsWriter:(GRXWriter *)requestsWriter NS_DESIGNATED_INITIALIZER; // Finishes the request side of this call, notifies the server that the RPC // should be cancelled, and finishes the response side of the call with an error // of code CANCELED. - (void)cancel; // TODO(jcanizales): Let specify a deadline. As a category of GRXWriter? @end