plugeth/vendor/github.com/rs/cors/README.md

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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) [![Coverage](http://gocover.io/_badge/github.com/rs/cors)](http://gocover.io/github.com/rs/cors)
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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) {
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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)
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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.
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* **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.
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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
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## Licenses
All source code is licensed under the [MIT License](https://raw.github.com/rs/cors/master/LICENSE).