Enable controller to have CORS

2026-07-20 04:30:26 +03:00 · 2015-08-31 01:47:05 -07:00
parent dcf0c71ca3
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+# Go CORS handler [![godoc](http://img.shields.io/badge/godoc-reference-blue.svg?style=flat)](https://godoc.org/github.com/rs/cors) [![license](http://img.shields.io/badge/license-MIT-red.svg?style=flat)](https://raw.githubusercontent.com/rs/cors/master/LICENSE) [![build](https://img.shields.io/travis/rs/cors.svg?style=flat)](https://travis-ci.org/rs/cors)
+
+CORS is a `net/http` handler implementing [Cross Origin Resource Sharing W3 specification](http://www.w3.org/TR/cors/) in Golang.
+
+## Getting Started
+
+After installing Go and setting up your [GOPATH](http://golang.org/doc/code.html#GOPATH), create your first `.go` file. We'll call it `server.go`.
+
+```go
+package main
+
+import (
+    "net/http"
+
+    "github.com/rs/cors"
+)
+
+func main() {
+    mux := http.NewServeMux()
+    mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+        w.Header().Set("Content-Type", "application/json")
+        w.Write([]byte("{\"hello\": \"world\"}"))
+    })
+
+    // cors.Default() setup the middleware with default options being
+    // all origins accepted with simple methods (GET, POST). See
+    // documentation below for more options.
+    handler := cors.Default().Handler(mux)
+    http.ListenAndServe(":8080", handler)
+}
+```
+
+Install `cors`:
+
+    go get github.com/rs/cors
+
+Then run your server:
+
+    go run server.go
+
+The server now runs on `localhost:8080`:
+
+    $ curl -D - -H 'Origin: http://foo.com' http://localhost:8080/
+    HTTP/1.1 200 OK
+    Access-Control-Allow-Origin: foo.com
+    Content-Type: application/json
+    Date: Sat, 25 Oct 2014 03:43:57 GMT
+    Content-Length: 18
+
+    {"hello": "world"}
+
+### More Examples
+
+* `net/http`: [examples/nethttp/server.go](https://github.com/rs/cors/blob/master/examples/nethttp/server.go)
+* [Goji](https://goji.io): [examples/goji/server.go](https://github.com/rs/cors/blob/master/examples/goji/server.go)
+* [Martini](http://martini.codegangsta.io): [examples/martini/server.go](https://github.com/rs/cors/blob/master/examples/martini/server.go)
+* [Negroni](https://github.com/codegangsta/negroni): [examples/negroni/server.go](https://github.com/rs/cors/blob/master/examples/negroni/server.go)
+* [Alice](https://github.com/justinas/alice): [examples/alice/server.go](https://github.com/rs/cors/blob/master/examples/alice/server.go)
+
+## Parameters
+
+Parameters are passed to the middleware thru the `cors.New` method as follow:
+
+```go
+c := cors.New(cors.Options{
+    AllowedOrigins: []string{"http://foo.com"},
+    AllowCredentials: true,
+})
+
+// Insert the middleware
+handler = c.Handler(handler)
+```
+
+* **AllowedOrigins** `[]string`: A list of origins a cross-domain request can be executed from. If the special `*` value is present in the list, all origins will be allowed. An origin may contain a wildcard (`*`) to replace 0 or more characters (i.e.: `http://*.domain.com`). Usage of wildcards implies a small performance penality. Only one wildcard can be used per origin. The default value is `*`.
+* **AllowOriginFunc** `func (origin string) bool`: A custom function to validate the origin. It take the origin as argument and returns true if allowed or false otherwise. If this option is set, the content of `AllowedOrigins` is ignored
+* **AllowedMethods** `[]string`: A list of methods the client is allowed to use with cross-domain requests. Default value is simple methods (`GET` and `POST`).
+* **AllowedHeaders** `[]string`: A list of non simple headers the client is allowed to use with cross-domain requests.
+* **ExposedHeaders** `[]string`: Indicates which headers are safe to expose to the API of a CORS API specification
+* **AllowCredentials** `bool`: Indicates whether the request can include user credentials like cookies, HTTP authentication or client side SSL certificates. The default is `false`.
+* **MaxAge** `int`: Indicates how long (in seconds) the results of a preflight request can be cached. The default is `0` which stands for no max age.
+* **OptionsPassthrough** `bool`: Instructs preflight to let other potential next handlers to process the `OPTIONS` method. Turn this on if your application handles `OPTIONS`.
+* **Debug** `bool`: Debugging flag adds additional output to debug server side CORS issues.
+
+See [API documentation](http://godoc.org/github.com/rs/cors) for more info.
+
+## Benchmarks
+
+    BenchmarkWithout          20000000    64.6 ns/op      8 B/op    1 allocs/op
+    BenchmarkDefault          3000000      469 ns/op    114 B/op    2 allocs/op
+    BenchmarkAllowedOrigin    3000000      608 ns/op    114 B/op    2 allocs/op
+    BenchmarkPreflight        20000000    73.2 ns/op      0 B/op    0 allocs/op
+    BenchmarkPreflightHeader  20000000    73.6 ns/op      0 B/op    0 allocs/op
+    BenchmarkParseHeaderList  2000000      847 ns/op    184 B/op    6 allocs/op
+    BenchmarkParse…Single     5000000      290 ns/op     32 B/op    3 allocs/op
+    BenchmarkParse…Normalized 2000000      776 ns/op    160 B/op    6 allocs/op
+
+## Licenses
+
+All source code is licensed under the [MIT License](https://raw.github.com/rs/cors/master/LICENSE).