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
19package grpcutil
20
21import (
22 "errors"
23 "strings"
24)
25
26// ParseMethod splits service and method from the input. It expects format
27// "/service/method".
28func 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 its 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.
46const 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.
61func 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
83func ContentType(contentSubtype string) string {
84 if contentSubtype == "" {
85 return baseContentType
86 }
87 return baseContentType + "+" + contentSubtype
88}