1 /* 2 * 3 * Copyright 2018 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 package grpcutil 20 21 import ( 22 "errors" 23 "strings" 24 ) 25 26 // ParseMethod splits service and method from the input. It expects format 27 // "/service/method". 28 func ParseMethod(methodName string) (service, method string, _ error) { 29 if !strings.HasPrefix(methodName, "/") { 30 return "", "", errors.New("invalid method name: should start with /") 31 } 32 methodName = methodName[1:] 33 34 pos := strings.LastIndex(methodName, "/") 35 if pos < 0 { 36 return "", "", errors.New("invalid method name: suffix /method is missing") 37 } 38 return methodName[:pos], methodName[pos+1:], nil 39 } 40 41 // baseContentType is the base content-type for gRPC. This is a valid 42 // content-type on it's own, but can also include a content-subtype such as 43 // "proto" as a suffix after "+" or ";". See 44 // https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests 45 // for more details. 46 const baseContentType = "application/grpc" 47 48 // ContentSubtype returns the content-subtype for the given content-type. The 49 // given content-type must be a valid content-type that starts with 50 // "application/grpc". A content-subtype will follow "application/grpc" after a 51 // "+" or ";". See 52 // https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for 53 // more details. 54 // 55 // If contentType is not a valid content-type for gRPC, the boolean 56 // will be false, otherwise true. If content-type == "application/grpc", 57 // "application/grpc+", or "application/grpc;", the boolean will be true, 58 // but no content-subtype will be returned. 59 // 60 // contentType is assumed to be lowercase already. 61 func ContentSubtype(contentType string) (string, bool) { 62 if contentType == baseContentType { 63 return "", true 64 } 65 if !strings.HasPrefix(contentType, baseContentType) { 66 return "", false 67 } 68 // guaranteed since != baseContentType and has baseContentType prefix 69 switch contentType[len(baseContentType)] { 70 case '+', ';': 71 // this will return true for "application/grpc+" or "application/grpc;" 72 // which the previous validContentType function tested to be valid, so we 73 // just say that no content-subtype is specified in this case 74 return contentType[len(baseContentType)+1:], true 75 default: 76 return "", false 77 } 78 } 79 80 // ContentType builds full content type with the given sub-type. 81 // 82 // contentSubtype is assumed to be lowercase 83 func ContentType(contentSubtype string) string { 84 if contentSubtype == "" { 85 return baseContentType 86 } 87 return baseContentType + "+" + contentSubtype 88 } 89