├── .gitignore ├── LICENSE ├── README.md └── cors.go /.gitignore: -------------------------------------------------------------------------------- 1 | # Compiled Object files, Static and Dynamic libs (Shared Objects) 2 | *.o 3 | *.a 4 | *.so 5 | 6 | # Folders 7 | _obj 8 | _test 9 | 10 | # Architecture specific extensions/prefixes 11 | *.[568vq] 12 | [568vq].out 13 | 14 | *.cgo1.go 15 | *.cgo2.c 16 | _cgo_defun.c 17 | _cgo_gotypes.go 18 | _cgo_export.* 19 | 20 | _testmain.go 21 | 22 | *.exe 23 | *.test 24 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright {yyyy} {name of copyright owner} 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | cors 2 | ==== 3 | 4 | CORS middleware for Go 5 | 6 | 7 | ``` 8 | corsHandler := cors.New(myHandler) 9 | corsHandler.RemoveMethod("PUT") 10 | corsHandler.RemoveMethod("DELETE") 11 | max_age := 60 * time.Second 12 | corsHandler.SetMaxAge(max_age.Seconds()) 13 | 14 | http.Handle("/", corsHandler) 15 | 16 | http.ListenAndServe("localhost:9999", nil) 17 | 18 | ``` 19 | -------------------------------------------------------------------------------- /cors.go: -------------------------------------------------------------------------------- 1 | package cors 2 | 3 | import ( 4 | "fmt" 5 | "net/http" 6 | "strings" 7 | ) 8 | 9 | type CorsHandler struct { 10 | ALLOWED_METHODS []string 11 | ALLOWED_ORIGINS []string 12 | ALLOWED_HEADERS []string 13 | EXPOSED_HEADERS []string 14 | ALLOW_CREDENTIALS string 15 | MAX_AGE float64 16 | handler http.Handler 17 | } 18 | 19 | func New(handler http.Handler) *CorsHandler { 20 | return &CorsHandler{ 21 | ALLOWED_METHODS: []string{"GET", "POST", "PUT", "DELETE", "HEAD", "OPTIONS"}, 22 | ALLOWED_ORIGINS: []string{"*"}, 23 | ALLOWED_HEADERS: []string{"Content-Type"}, 24 | EXPOSED_HEADERS: []string{"Content-Type"}, 25 | ALLOW_CREDENTIALS: "true", 26 | MAX_AGE: 0, 27 | handler: handler, 28 | } 29 | } 30 | func (cors *CorsHandler) AllowOrigin(origin string) { 31 | if origin == "*" { 32 | cors.ALLOWED_ORIGINS = []string{"*"} 33 | } 34 | for i := 0; i < len(cors.ALLOWED_ORIGINS); i++ { 35 | if origin == cors.ALLOWED_ORIGINS[i] { 36 | return 37 | } 38 | } 39 | cors.ALLOWED_ORIGINS = append(cors.ALLOWED_ORIGINS, origin) 40 | } 41 | func (cors *CorsHandler) AllowMethod(method string) { 42 | method = strings.ToUpper(method) 43 | for i := 0; i < len(cors.ALLOWED_METHODS); i++ { 44 | if method == cors.ALLOWED_METHODS[i] { 45 | return 46 | } 47 | } 48 | cors.ALLOWED_METHODS = append(cors.ALLOWED_METHODS, method) 49 | } 50 | func (cors *CorsHandler) AllowHeader(header string) { 51 | for i := 0; i < len(cors.ALLOWED_HEADERS); i++ { 52 | if header == cors.ALLOWED_HEADERS[i] { 53 | return 54 | } 55 | } 56 | cors.ALLOWED_HEADERS = append(cors.ALLOWED_HEADERS, header) 57 | 58 | } 59 | 60 | func (cors *CorsHandler) ExposeHeader(header string) { 61 | for _, exposedHeader := range cors.EXPOSED_HEADERS { 62 | if header == exposedHeader { 63 | return 64 | } 65 | } 66 | cors.EXPOSED_HEADERS = append(cors.EXPOSED_HEADERS, header) 67 | } 68 | 69 | func (cors *CorsHandler) AllowCredentials(creds bool) { 70 | if creds { 71 | cors.ALLOW_CREDENTIALS = "true" 72 | } else { 73 | cors.ALLOW_CREDENTIALS = "false" 74 | } 75 | } 76 | func (cors *CorsHandler) RemoveOrigin(origin string) { 77 | for i := 0; i < len(cors.ALLOWED_ORIGINS); i++ { 78 | if origin == cors.ALLOWED_ORIGINS[i] { 79 | cors.ALLOWED_ORIGINS = cors.ALLOWED_ORIGINS[:i+copy(cors.ALLOWED_ORIGINS[i:], cors.ALLOWED_ORIGINS[i+1:])] 80 | } 81 | } 82 | 83 | } 84 | func (cors *CorsHandler) RemoveMethod(method string) { 85 | method = strings.ToUpper(method) 86 | for i := 0; i < len(cors.ALLOWED_METHODS); i++ { 87 | if method == cors.ALLOWED_METHODS[i] { 88 | cors.ALLOWED_METHODS = cors.ALLOWED_METHODS[:i+copy(cors.ALLOWED_METHODS[i:], cors.ALLOWED_METHODS[i+1:])] 89 | } 90 | } 91 | } 92 | func (cors *CorsHandler) RemoveHeader(header string) { 93 | for i := 0; i < len(cors.ALLOWED_HEADERS); i++ { 94 | if header == cors.ALLOWED_HEADERS[i] { 95 | cors.ALLOWED_HEADERS = cors.ALLOWED_HEADERS[:i+copy(cors.ALLOWED_HEADERS[i:], cors.ALLOWED_HEADERS[i+1:])] 96 | } 97 | } 98 | } 99 | 100 | func (cors *CorsHandler) RemoveExposedHeader(header string) { 101 | for i, elem := range cors.EXPOSED_HEADERS { 102 | if header == elem { 103 | cors.EXPOSED_HEADERS = cors.EXPOSED_HEADERS[:i+copy(cors.EXPOSED_HEADERS[i:], cors.EXPOSED_HEADERS[i+1:])] 104 | } 105 | } 106 | } 107 | 108 | func (cors *CorsHandler) IsOriginAllowed(origin string) bool { 109 | for i := 0; i < len(cors.ALLOWED_ORIGINS); i++ { 110 | if "*" == cors.ALLOWED_ORIGINS[i] { 111 | return true 112 | } else if origin == cors.ALLOWED_ORIGINS[i] { 113 | return true 114 | } 115 | } 116 | return false 117 | } 118 | func (cors *CorsHandler) IsMethodAllowed(method string) bool { 119 | method = strings.ToUpper(method) 120 | for i := 0; i < len(cors.ALLOWED_METHODS); i++ { 121 | if method == cors.ALLOWED_METHODS[i] { 122 | return true 123 | } 124 | } 125 | return false 126 | } 127 | func (cors *CorsHandler) IsHeaderAllowed(header string) bool { 128 | for i := 0; i < len(cors.ALLOWED_HEADERS); i++ { 129 | if header == cors.ALLOWED_HEADERS[i] { 130 | return true 131 | } 132 | } 133 | return false 134 | } 135 | func (cors *CorsHandler) AllowedMethods() string { 136 | methods := "" 137 | for i := 0; i < len(cors.ALLOWED_METHODS); i++ { 138 | if methods == "" { 139 | methods = cors.ALLOWED_METHODS[i] 140 | } else { 141 | methods = fmt.Sprintf("%s, %s", methods, cors.ALLOWED_METHODS[i]) 142 | } 143 | } 144 | return methods 145 | } 146 | func (cors *CorsHandler) AllowedHeaders() string { 147 | headers := "" 148 | for i := 0; i < len(cors.ALLOWED_HEADERS); i++ { 149 | if headers == "" { 150 | headers = cors.ALLOWED_HEADERS[i] 151 | } else { 152 | headers = fmt.Sprintf("%s, %s", headers, cors.ALLOWED_HEADERS[i]) 153 | } 154 | } 155 | return headers 156 | } 157 | 158 | func (cors *CorsHandler) ExposedHeaders() string { 159 | headers := "" 160 | for _, header := range cors.EXPOSED_HEADERS { 161 | if headers == "" { 162 | headers = header 163 | } else { 164 | headers = fmt.Sprintf("%s, %s", headers, header) 165 | } 166 | } 167 | return headers 168 | } 169 | 170 | func (cors *CorsHandler) SetMaxAge(age float64) { 171 | cors.MAX_AGE = age 172 | } 173 | func (cors *CorsHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) { 174 | origin := req.Header.Get("Origin") 175 | if origin != "" && cors.IsOriginAllowed(origin) { 176 | w.Header().Add("Access-Control-Allow-Origin", origin) 177 | w.Header().Add("Access-Control-Allow-Methods", cors.AllowedMethods()) 178 | w.Header().Add("Access-Control-Allow-Headers", cors.AllowedHeaders()) 179 | w.Header().Add("Access-Control-Expose-Headers", cors.ExposedHeaders()) 180 | w.Header().Add("Access-Control-Allow-Credentials", cors.ALLOW_CREDENTIALS) 181 | if cors.MAX_AGE > 0 { 182 | w.Header().Add("Access-Control-Max-Age", fmt.Sprintf("%9.f", cors.MAX_AGE)) 183 | } 184 | } 185 | cors.handler.ServeHTTP(w, req) 186 | } 187 | --------------------------------------------------------------------------------