mirror of https://github.com/ethereum/go-ethereum
Bas van Kervel
9 years ago
parent
6d3cd03a03
commit
a7bae3b2a6
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language: go |
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go: |
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- 1.3 |
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- 1.4 |
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Copyright (c) 2014 Olivier Poitrey <rs@dailymotion.com> |
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|
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Permission is hereby granted, free of charge, to any person obtaining a copy |
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of this software and associated documentation files (the "Software"), to deal |
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in the Software without restriction, including without limitation the rights |
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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copies of the Software, and to permit persons to whom the Software is furnished |
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to do so, subject to the following conditions: |
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|
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The above copyright notice and this permission notice shall be included in all |
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copies or substantial portions of the Software. |
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|
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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THE SOFTWARE. |
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# Go CORS handler [](https://godoc.org/github.com/rs/cors) [](https://raw.githubusercontent.com/rs/cors/master/LICENSE) [](https://travis-ci.org/rs/cors) |
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|
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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. |
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|
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## Getting Started |
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|
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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`. |
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|
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```go |
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package main |
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|
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import ( |
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"net/http" |
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|
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"github.com/rs/cors" |
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) |
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|
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func main() { |
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h := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
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w.Header().Set("Content-Type", "application/json") |
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w.Write([]byte("{\"hello\": \"world\"}")) |
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}) |
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|
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// cors.Default() setup the middleware with default options being |
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// all origins accepted with simple methods (GET, POST). See |
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// documentation below for more options. |
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handler = cors.Default().Handler(h) |
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http.ListenAndServe(":8080", handler) |
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} |
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``` |
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|
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Install `cors`: |
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|
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go get github.com/rs/cors |
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Then run your server: |
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go run server.go |
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The server now runs on `localhost:8080`: |
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|
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$ curl -D - -H 'Origin: http://foo.com' http://localhost:8080/ |
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HTTP/1.1 200 OK |
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Access-Control-Allow-Origin: foo.com |
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Content-Type: application/json |
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Date: Sat, 25 Oct 2014 03:43:57 GMT |
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Content-Length: 18 |
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{"hello": "world"} |
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|
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### More Examples |
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* `net/http`: [examples/nethttp/server.go](https://github.com/rs/cors/blob/master/examples/nethttp/server.go) |
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* [Goji](https://goji.io): [examples/goji/server.go](https://github.com/rs/cors/blob/master/examples/goji/server.go) |
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* [Martini](http://martini.codegangsta.io): [examples/martini/server.go](https://github.com/rs/cors/blob/master/examples/martini/server.go) |
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* [Negroni](https://github.com/codegangsta/negroni): [examples/negroni/server.go](https://github.com/rs/cors/blob/master/examples/negroni/server.go) |
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* [Alice](https://github.com/justinas/alice): [examples/alice/server.go](https://github.com/rs/cors/blob/master/examples/alice/server.go) |
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|
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## Parameters |
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Parameters are passed to the middleware thru the `cors.New` method as follow: |
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```go |
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c := cors.New(cors.Options{ |
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AllowedOrigins: []string{"http://foo.com"}, |
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AllowCredentials: true, |
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}) |
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|
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// Insert the middleware |
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handler = c.Handler(handler) |
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``` |
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|
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* **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. The default value is `*`. |
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* **AllowedMethods** `[]string`: A list of methods the client is allowed to use with cross-domain requests. |
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* **AllowedHeaders** `[]string`: A list of non simple headers the client is allowed to use with cross-domain requests. Default value is simple methods (`GET` and `POST`) |
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* **ExposedHeaders** `[]string`: Indicates which headers are safe to expose to the API of a CORS API specification |
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* **AllowCredentials** `bool`: Indicates whether the request can include user credentials like cookies, HTTP authentication or client side SSL certificates. The default is `false`. |
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* **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. |
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See [API documentation](http://godoc.org/github.com/rs/cors) for more info. |
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|
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## Licenses |
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All source code is licensed under the [MIT License](https://raw.github.com/rs/cors/master/LICENSE). |
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@ -0,0 +1,308 @@ |
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/* |
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Package cors is net/http handler to handle CORS related requests |
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as defined by http://www.w3.org/TR/cors/
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You can configure it by passing an option struct to cors.New: |
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c := cors.New(cors.Options{ |
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AllowedOrigins: []string{"foo.com"}, |
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AllowedMethods: []string{"GET", "POST", "DELETE"}, |
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AllowCredentials: true, |
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}) |
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Then insert the handler in the chain: |
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handler = c.Handler(handler) |
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See Options documentation for more options. |
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The resulting handler is a standard net/http handler. |
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*/ |
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package cors |
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import ( |
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"log" |
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"net/http" |
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"os" |
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"strconv" |
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"strings" |
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) |
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// Options is a configuration container to setup the CORS middleware.
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type Options struct { |
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// AllowedOrigins is a list of origins a cross-domain request can be executed from.
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// If the special "*" value is present in the list, all origins will be allowed.
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// Default value is ["*"]
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AllowedOrigins []string |
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// AllowedMethods is a list of methods the client is allowed to use with
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// cross-domain requests. Default value is simple methods (GET and POST)
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AllowedMethods []string |
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// AllowedHeaders is list of non simple headers the client is allowed to use with
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// cross-domain requests.
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// If the special "*" value is present in the list, all headers will be allowed.
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// Default value is [] but "Origin" is always appended to the list.
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AllowedHeaders []string |
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// ExposedHeaders indicates which headers are safe to expose to the API of a CORS
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// API specification
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ExposedHeaders []string |
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// AllowCredentials indicates whether the request can include user credentials like
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// cookies, HTTP authentication or client side SSL certificates.
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AllowCredentials bool |
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// MaxAge indicates how long (in seconds) the results of a preflight request
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// can be cached
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MaxAge int |
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// Debugging flag adds additional output to debug server side CORS issues
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Debug bool |
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// log object to use when debugging
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log *log.Logger |
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} |
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type Cors struct { |
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// The CORS Options
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options Options |
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} |
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// New creates a new Cors handler with the provided options.
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func New(options Options) *Cors { |
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// Normalize options
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// Note: for origins and methods matching, the spec requires a case-sensitive matching.
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// As it may error prone, we chose to ignore the spec here.
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normOptions := Options{ |
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AllowedOrigins: convert(options.AllowedOrigins, strings.ToLower), |
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AllowedMethods: convert(options.AllowedMethods, strings.ToUpper), |
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// Origin is always appended as some browsers will always request
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// for this header at preflight
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AllowedHeaders: convert(append(options.AllowedHeaders, "Origin"), http.CanonicalHeaderKey), |
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ExposedHeaders: convert(options.ExposedHeaders, http.CanonicalHeaderKey), |
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AllowCredentials: options.AllowCredentials, |
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MaxAge: options.MaxAge, |
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Debug: options.Debug, |
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log: log.New(os.Stdout, "[cors] ", log.LstdFlags), |
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} |
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if len(normOptions.AllowedOrigins) == 0 { |
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// Default is all origins
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normOptions.AllowedOrigins = []string{"*"} |
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} |
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if len(normOptions.AllowedHeaders) == 1 { |
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// Add some sensible defaults
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normOptions.AllowedHeaders = []string{"Origin", "Accept", "Content-Type"} |
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} |
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if len(normOptions.AllowedMethods) == 0 { |
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// Default is simple methods
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normOptions.AllowedMethods = []string{"GET", "POST"} |
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} |
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if normOptions.Debug { |
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normOptions.log.Printf("Options: %v", normOptions) |
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} |
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return &Cors{ |
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options: normOptions, |
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} |
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} |
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// Default creates a new Cors handler with default options
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func Default() *Cors { |
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return New(Options{}) |
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} |
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// Handler apply the CORS specification on the request, and add relevant CORS headers
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// as necessary.
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func (cors *Cors) Handler(h http.Handler) http.Handler { |
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
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if r.Method == "OPTIONS" { |
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cors.logf("Handler: Preflight request") |
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cors.handlePreflight(w, r) |
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// Preflight requests are standalone and should stop the chain as some other
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// middleware may not handle OPTIONS requests correctly. One typical example
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// is authentication middleware ; OPTIONS requests won't carry authentication
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// headers (see #1)
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} else { |
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cors.logf("Handler: Actual request") |
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cors.handleActualRequest(w, r) |
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h.ServeHTTP(w, r) |
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} |
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}) |
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} |
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|
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// Martini compatible handler
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func (cors *Cors) HandlerFunc(w http.ResponseWriter, r *http.Request) { |
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if r.Method == "OPTIONS" { |
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cors.logf("HandlerFunc: Preflight request") |
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cors.handlePreflight(w, r) |
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} else { |
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cors.logf("HandlerFunc: Actual request") |
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cors.handleActualRequest(w, r) |
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} |
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} |
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|
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// Negroni compatible interface
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func (cors *Cors) ServeHTTP(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) { |
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if r.Method == "OPTIONS" { |
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cors.logf("ServeHTTP: Preflight request") |
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cors.handlePreflight(w, r) |
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// Preflight requests are standalone and should stop the chain as some other
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// middleware may not handle OPTIONS requests correctly. One typical example
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// is authentication middleware ; OPTIONS requests won't carry authentication
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// headers (see #1)
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} else { |
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cors.logf("ServeHTTP: Actual request") |
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cors.handleActualRequest(w, r) |
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next(w, r) |
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} |
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} |
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// handlePreflight handles pre-flight CORS requests
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func (cors *Cors) handlePreflight(w http.ResponseWriter, r *http.Request) { |
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options := cors.options |
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headers := w.Header() |
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origin := r.Header.Get("Origin") |
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if r.Method != "OPTIONS" { |
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cors.logf(" Preflight aborted: %s!=OPTIONS", r.Method) |
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return |
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} |
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if origin == "" { |
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cors.logf(" Preflight aborted: empty origin") |
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return |
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} |
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if !cors.isOriginAllowed(origin) { |
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cors.logf(" Preflight aborted: origin '%s' not allowed", origin) |
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return |
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} |
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reqMethod := r.Header.Get("Access-Control-Request-Method") |
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if !cors.isMethodAllowed(reqMethod) { |
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cors.logf(" Preflight aborted: method '%s' not allowed", reqMethod) |
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return |
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} |
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reqHeaders := parseHeaderList(r.Header.Get("Access-Control-Request-Headers")) |
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if !cors.areHeadersAllowed(reqHeaders) { |
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cors.logf(" Preflight aborted: headers '%v' not allowed", reqHeaders) |
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return |
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} |
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headers.Set("Access-Control-Allow-Origin", origin) |
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headers.Add("Vary", "Origin") |
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// Spec says: Since the list of methods can be unbounded, simply returning the method indicated
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// by Access-Control-Request-Method (if supported) can be enough
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headers.Set("Access-Control-Allow-Methods", strings.ToUpper(reqMethod)) |
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if len(reqHeaders) > 0 { |
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// Spec says: Since the list of headers can be unbounded, simply returning supported headers
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// from Access-Control-Request-Headers can be enough
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headers.Set("Access-Control-Allow-Headers", strings.Join(reqHeaders, ", ")) |
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} |
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if options.AllowCredentials { |
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headers.Set("Access-Control-Allow-Credentials", "true") |
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} |
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if options.MaxAge > 0 { |
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headers.Set("Access-Control-Max-Age", strconv.Itoa(options.MaxAge)) |
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} |
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cors.logf(" Preflight response headers: %v", headers) |
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} |
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// handleActualRequest handles simple cross-origin requests, actual request or redirects
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func (cors *Cors) handleActualRequest(w http.ResponseWriter, r *http.Request) { |
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options := cors.options |
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headers := w.Header() |
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origin := r.Header.Get("Origin") |
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if r.Method == "OPTIONS" { |
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cors.logf(" Actual request no headers added: method == %s", r.Method) |
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return |
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} |
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if origin == "" { |
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cors.logf(" Actual request no headers added: missing origin") |
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return |
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} |
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if !cors.isOriginAllowed(origin) { |
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cors.logf(" Actual request no headers added: origin '%s' not allowed", origin) |
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return |
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} |
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// Note that spec does define a way to specifically disallow a simple method like GET or
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// POST. Access-Control-Allow-Methods is only used for pre-flight requests and the
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// spec doesn't instruct to check the allowed methods for simple cross-origin requests.
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// We think it's a nice feature to be able to have control on those methods though.
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if !cors.isMethodAllowed(r.Method) { |
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if cors.options.Debug { |
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cors.logf(" Actual request no headers added: method '%s' not allowed", |
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r.Method) |
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} |
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return |
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} |
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headers.Set("Access-Control-Allow-Origin", origin) |
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headers.Add("Vary", "Origin") |
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if len(options.ExposedHeaders) > 0 { |
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headers.Set("Access-Control-Expose-Headers", strings.Join(options.ExposedHeaders, ", ")) |
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} |
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if options.AllowCredentials { |
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headers.Set("Access-Control-Allow-Credentials", "true") |
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} |
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cors.logf(" Actual response added headers: %v", headers) |
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} |
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// convenience method. checks if debugging is turned on before printing
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func (cors *Cors) logf(format string, a ...interface{}) { |
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if cors.options.Debug { |
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cors.options.log.Printf(format, a...) |
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} |
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} |
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// isOriginAllowed checks if a given origin is allowed to perform cross-domain requests
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// on the endpoint
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func (cors *Cors) isOriginAllowed(origin string) bool { |
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allowedOrigins := cors.options.AllowedOrigins |
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origin = strings.ToLower(origin) |
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for _, allowedOrigin := range allowedOrigins { |
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switch allowedOrigin { |
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case "*": |
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return true |
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case origin: |
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return true |
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} |
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} |
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return false |
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} |
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|
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// isMethodAllowed checks if a given method can be used as part of a cross-domain request
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// on the endpoing
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func (cors *Cors) isMethodAllowed(method string) bool { |
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allowedMethods := cors.options.AllowedMethods |
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if len(allowedMethods) == 0 { |
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// If no method allowed, always return false, even for preflight request
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return false |
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} |
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method = strings.ToUpper(method) |
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if method == "OPTIONS" { |
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// Always allow preflight requests
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return true |
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} |
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for _, allowedMethod := range allowedMethods { |
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if allowedMethod == method { |
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return true |
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} |
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} |
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return false |
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} |
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|
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// areHeadersAllowed checks if a given list of headers are allowed to used within
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// a cross-domain request.
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func (cors *Cors) areHeadersAllowed(requestedHeaders []string) bool { |
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if len(requestedHeaders) == 0 { |
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return true |
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} |
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for _, header := range requestedHeaders { |
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found := false |
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for _, allowedHeader := range cors.options.AllowedHeaders { |
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if allowedHeader == "*" || allowedHeader == header { |
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found = true |
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break |
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} |
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} |
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if !found { |
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return false |
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} |
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} |
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return true |
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} |
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@ -0,0 +1,27 @@ |
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package cors |
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|
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import ( |
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"net/http" |
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"strings" |
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) |
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|
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type converter func(string) string |
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|
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// convert converts a list of string using the passed converter function
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func convert(s []string, c converter) []string { |
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out := []string{} |
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for _, i := range s { |
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out = append(out, c(i)) |
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} |
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return out |
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} |
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|
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func parseHeaderList(headerList string) (headers []string) { |
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for _, header := range strings.Split(headerList, ",") { |
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header = http.CanonicalHeaderKey(strings.TrimSpace(header)) |
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if header != "" { |
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headers = append(headers, header) |
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} |
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} |
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return headers |
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} |
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@ -0,0 +1,7 @@ |
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language: go |
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go: |
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- 1.5 |
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- tip |
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matrix: |
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allow_failures: |
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- go: tip |
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@ -0,0 +1,19 @@ |
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Copyright (c) 2015 Olivier Poitrey <rs@dailymotion.com> |
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|
||||
Permission is hereby granted, free of charge, to any person obtaining a copy |
||||
of this software and associated documentation files (the "Software"), to deal |
||||
in the Software without restriction, including without limitation the rights |
||||
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
||||
copies of the Software, and to permit persons to whom the Software is furnished |
||||
to do so, subject to the following conditions: |
||||
|
||||
The above copyright notice and this permission notice shall be included in all |
||||
copies or substantial portions of the Software. |
||||
|
||||
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
||||
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
||||
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
||||
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
||||
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
||||
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
||||
THE SOFTWARE. |
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@ -0,0 +1,134 @@ |
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# XHandler |
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|
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[](https://godoc.org/github.com/rs/xhandler) [](https://raw.githubusercontent.com/rs/xhandler/master/LICENSE) [](https://travis-ci.org/rs/xhandler) [](http://gocover.io/github.com/rs/xhandler) |
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|
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XHandler is a bridge between [net/context](https://godoc.org/golang.org/x/net/context) and `http.Handler`. |
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|
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It lets you enforce `net/context` in your handlers without sacrificing compatibility with existing `http.Handlers` nor imposing a specific router. |
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|
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Thanks to `net/context` deadline management, `xhandler` is able to enforce a per request deadline and will cancel the context when the client closes the connection unexpectedly. |
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|
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You may create your own `net/context` aware handler pretty much the same way as you would do with http.Handler. |
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|
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Read more about xhandler on [Dailymotion engineering blog](http://engineering.dailymotion.com/our-way-to-go/). |
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|
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## Installing |
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|
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go get -u github.com/rs/xhandler |
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|
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## Usage |
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|
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```go |
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package main |
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|
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import ( |
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"log" |
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"net/http" |
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"time" |
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|
||||
"github.com/rs/cors" |
||||
"github.com/rs/xhandler" |
||||
"golang.org/x/net/context" |
||||
) |
||||
|
||||
type myMiddleware struct { |
||||
next xhandler.HandlerC |
||||
} |
||||
|
||||
func (h myMiddleware) ServeHTTPC(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
ctx = context.WithValue(ctx, "test", "World") |
||||
h.next.ServeHTTPC(ctx, w, r) |
||||
} |
||||
|
||||
func main() { |
||||
c := xhandler.Chain{} |
||||
|
||||
// Add close notifier handler so context is cancelled when the client closes |
||||
// the connection |
||||
c.UseC(xhandler.CloseHandler) |
||||
|
||||
// Add timeout handler |
||||
c.UseC(xhandler.TimeoutHandler(2 * time.Second)) |
||||
|
||||
// Middleware putting something in the context |
||||
c.UseC(func(next xhandler.HandlerC) xhandler.HandlerC { |
||||
return myMiddleware{next: next} |
||||
}) |
||||
|
||||
// Mix it with a non-context-aware middleware handler |
||||
c.Use(cors.Default().Handler) |
||||
|
||||
// Final handler (using handlerFuncC), reading from the context |
||||
xh := xhandler.HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
value := ctx.Value("test").(string) |
||||
w.Write([]byte("Hello " + value)) |
||||
}) |
||||
|
||||
// Bridge context aware handlers with http.Handler using xhandler.Handle() |
||||
http.Handle("/test", c.Handler(xh)) |
||||
|
||||
if err := http.ListenAndServe(":8080", nil); err != nil { |
||||
log.Fatal(err) |
||||
} |
||||
} |
||||
``` |
||||
|
||||
### Using xmux |
||||
|
||||
Xhandler comes with an optional context aware [muxer](https://github.com/rs/xmux) forked from [httprouter](https://github.com/julienschmidt/httprouter): |
||||
|
||||
```go |
||||
package main |
||||
|
||||
import ( |
||||
"fmt" |
||||
"log" |
||||
"net/http" |
||||
"time" |
||||
|
||||
"github.com/rs/xhandler" |
||||
"github.com/rs/xmux" |
||||
"golang.org/x/net/context" |
||||
) |
||||
|
||||
func main() { |
||||
c := xhandler.Chain{} |
||||
|
||||
// Append a context-aware middleware handler |
||||
c.UseC(xhandler.CloseHandler) |
||||
|
||||
// Another context-aware middleware handler |
||||
c.UseC(xhandler.TimeoutHandler(2 * time.Second)) |
||||
|
||||
mux := xmux.New() |
||||
|
||||
// Use c.Handler to terminate the chain with your final handler |
||||
mux.GET("/welcome/:name", xhandler.HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, req *http.Request) { |
||||
fmt.Fprintf(w, "Welcome %s!", xmux.Params(ctx).Get("name")) |
||||
})) |
||||
|
||||
if err := http.ListenAndServe(":8080", c.Handler(mux)); err != nil { |
||||
log.Fatal(err) |
||||
} |
||||
} |
||||
``` |
||||
|
||||
See [xmux](https://github.com/rs/xmux) for more examples. |
||||
|
||||
## Context Aware Middleware |
||||
|
||||
Here is a list of `net/context` aware middleware handlers implementing `xhandler.HandlerC` interface. |
||||
|
||||
Feel free to put up a PR linking your middleware if you have built one: |
||||
|
||||
| Middleware | Author | Description | |
||||
| ---------- | ------ | ----------- | |
||||
| [xmux](https://github.com/rs/xmux) | [Olivier Poitrey](https://github.com/rs) | HTTP request muxer | |
||||
| [xlog](https://github.com/rs/xlog) | [Olivier Poitrey](https://github.com/rs) | HTTP handler logger | |
||||
| [xstats](https://github.com/rs/xstats) | [Olivier Poitrey](https://github.com/rs) | A generic client for service instrumentation | |
||||
| [xaccess](https://github.com/rs/xaccess) | [Olivier Poitrey](https://github.com/rs) | HTTP handler access logger with [xlog](https://github.com/rs/xlog) and [xstats](https://github.com/rs/xstats) | |
||||
| [cors](https://github.com/rs/cors) | [Olivier Poitrey](https://github.com/rs) | [Cross Origin Resource Sharing](http://www.w3.org/TR/cors/) (CORS) support | |
||||
|
||||
## Licenses |
||||
|
||||
All source code is licensed under the [MIT License](https://raw.github.com/rs/xhandler/master/LICENSE). |
||||
@ -0,0 +1,93 @@ |
||||
package xhandler |
||||
|
||||
import ( |
||||
"net/http" |
||||
|
||||
"github.com/ethereum/go-ethereum/Godeps/_workspace/src/golang.org/x/net/context" |
||||
) |
||||
|
||||
// Chain is an helper to chain middleware handlers together for an easier
|
||||
// management.
|
||||
type Chain []func(next HandlerC) HandlerC |
||||
|
||||
// UseC appends a context-aware handler to the middleware chain.
|
||||
func (c *Chain) UseC(f func(next HandlerC) HandlerC) { |
||||
*c = append(*c, f) |
||||
} |
||||
|
||||
// Use appends a standard http.Handler to the middleware chain without
|
||||
// lossing track of the context when inserted between two context aware handlers.
|
||||
//
|
||||
// Caveat: the f function will be called on each request so you are better to put
|
||||
// any initialization sequence outside of this function.
|
||||
func (c *Chain) Use(f func(next http.Handler) http.Handler) { |
||||
xf := func(next HandlerC) HandlerC { |
||||
return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
n := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
||||
next.ServeHTTPC(ctx, w, r) |
||||
}) |
||||
f(n).ServeHTTP(w, r) |
||||
}) |
||||
} |
||||
*c = append(*c, xf) |
||||
} |
||||
|
||||
// Handler wraps the provided final handler with all the middleware appended to
|
||||
// the chain and return a new standard http.Handler instance.
|
||||
// The context.Background() context is injected automatically.
|
||||
func (c Chain) Handler(xh HandlerC) http.Handler { |
||||
ctx := context.Background() |
||||
return c.HandlerCtx(ctx, xh) |
||||
} |
||||
|
||||
// HandlerFC is an helper to provide a function (HandlerFuncC) to Handler().
|
||||
//
|
||||
// HandlerFC is equivalent to:
|
||||
// c.Handler(xhandler.HandlerFuncC(xhc))
|
||||
func (c Chain) HandlerFC(xhf HandlerFuncC) http.Handler { |
||||
ctx := context.Background() |
||||
return c.HandlerCtx(ctx, HandlerFuncC(xhf)) |
||||
} |
||||
|
||||
// HandlerH is an helper to provide a standard http handler (http.HandlerFunc)
|
||||
// to Handler(). Your final handler won't have access the context though.
|
||||
func (c Chain) HandlerH(h http.Handler) http.Handler { |
||||
ctx := context.Background() |
||||
return c.HandlerCtx(ctx, HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
h.ServeHTTP(w, r) |
||||
})) |
||||
} |
||||
|
||||
// HandlerF is an helper to provide a standard http handler function
|
||||
// (http.HandlerFunc) to Handler(). Your final handler won't have access
|
||||
// the context though.
|
||||
func (c Chain) HandlerF(hf http.HandlerFunc) http.Handler { |
||||
ctx := context.Background() |
||||
return c.HandlerCtx(ctx, HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
hf(w, r) |
||||
})) |
||||
} |
||||
|
||||
// HandlerCtx wraps the provided final handler with all the middleware appended to
|
||||
// the chain and return a new standard http.Handler instance.
|
||||
func (c Chain) HandlerCtx(ctx context.Context, xh HandlerC) http.Handler { |
||||
return New(ctx, c.HandlerC(xh)) |
||||
} |
||||
|
||||
// HandlerC wraps the provided final handler with all the middleware appended to
|
||||
// the chain and returns a HandlerC instance.
|
||||
func (c Chain) HandlerC(xh HandlerC) HandlerC { |
||||
for i := len(c) - 1; i >= 0; i-- { |
||||
xh = c[i](xh) |
||||
} |
||||
return xh |
||||
} |
||||
|
||||
// HandlerCF wraps the provided final handler func with all the middleware appended to
|
||||
// the chain and returns a HandlerC instance.
|
||||
//
|
||||
// HandlerCF is equivalent to:
|
||||
// c.HandlerC(xhandler.HandlerFuncC(xhc))
|
||||
func (c Chain) HandlerCF(xhc HandlerFuncC) HandlerC { |
||||
return c.HandlerC(HandlerFuncC(xhc)) |
||||
} |
||||
@ -0,0 +1,59 @@ |
||||
package xhandler |
||||
|
||||
import ( |
||||
"net/http" |
||||
"time" |
||||
|
||||
"github.com/ethereum/go-ethereum/Godeps/_workspace/src/golang.org/x/net/context" |
||||
) |
||||
|
||||
// CloseHandler returns a Handler cancelling the context when the client
|
||||
// connection close unexpectedly.
|
||||
func CloseHandler(next HandlerC) HandlerC { |
||||
return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
// Cancel the context if the client closes the connection
|
||||
if wcn, ok := w.(http.CloseNotifier); ok { |
||||
var cancel context.CancelFunc |
||||
ctx, cancel = context.WithCancel(ctx) |
||||
defer cancel() |
||||
|
||||
notify := wcn.CloseNotify() |
||||
go func() { |
||||
select { |
||||
case <-notify: |
||||
cancel() |
||||
case <-ctx.Done(): |
||||
} |
||||
}() |
||||
} |
||||
|
||||
next.ServeHTTPC(ctx, w, r) |
||||
}) |
||||
} |
||||
|
||||
// TimeoutHandler returns a Handler which adds a timeout to the context.
|
||||
//
|
||||
// Child handlers have the responsability to obey the context deadline and to return
|
||||
// an appropriate error (or not) response in case of timeout.
|
||||
func TimeoutHandler(timeout time.Duration) func(next HandlerC) HandlerC { |
||||
return func(next HandlerC) HandlerC { |
||||
return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
ctx, _ = context.WithTimeout(ctx, timeout) |
||||
next.ServeHTTPC(ctx, w, r) |
||||
}) |
||||
} |
||||
} |
||||
|
||||
// If is a special handler that will skip insert the condNext handler only if a condition
|
||||
// applies at runtime.
|
||||
func If(cond func(ctx context.Context, w http.ResponseWriter, r *http.Request) bool, condNext func(next HandlerC) HandlerC) func(next HandlerC) HandlerC { |
||||
return func(next HandlerC) HandlerC { |
||||
return HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
if cond(ctx, w, r) { |
||||
condNext(next).ServeHTTPC(ctx, w, r) |
||||
} else { |
||||
next.ServeHTTPC(ctx, w, r) |
||||
} |
||||
}) |
||||
} |
||||
} |
||||
@ -0,0 +1,42 @@ |
||||
// Package xhandler provides a bridge between http.Handler and net/context.
|
||||
//
|
||||
// xhandler enforces net/context in your handlers without sacrificing
|
||||
// compatibility with existing http.Handlers nor imposing a specific router.
|
||||
//
|
||||
// Thanks to net/context deadline management, xhandler is able to enforce
|
||||
// a per request deadline and will cancel the context in when the client close
|
||||
// the connection unexpectedly.
|
||||
//
|
||||
// You may create net/context aware middlewares pretty much the same way as
|
||||
// you would do with http.Handler.
|
||||
package xhandler |
||||
|
||||
import ( |
||||
"net/http" |
||||
|
||||
"github.com/ethereum/go-ethereum/Godeps/_workspace/src/golang.org/x/net/context" |
||||
) |
||||
|
||||
// HandlerC is a net/context aware http.Handler
|
||||
type HandlerC interface { |
||||
ServeHTTPC(context.Context, http.ResponseWriter, *http.Request) |
||||
} |
||||
|
||||
// HandlerFuncC type is an adapter to allow the use of ordinary functions
|
||||
// as a xhandler.Handler. If f is a function with the appropriate signature,
|
||||
// xhandler.HandlerFuncC(f) is a xhandler.Handler object that calls f.
|
||||
type HandlerFuncC func(context.Context, http.ResponseWriter, *http.Request) |
||||
|
||||
// ServeHTTPC calls f(ctx, w, r).
|
||||
func (f HandlerFuncC) ServeHTTPC(ctx context.Context, w http.ResponseWriter, r *http.Request) { |
||||
f(ctx, w, r) |
||||
} |
||||
|
||||
// New creates a conventional http.Handler injecting the provided root
|
||||
// context to sub handlers. This handler is used as a bridge between conventional
|
||||
// http.Handler and context aware handlers.
|
||||
func New(ctx context.Context, h HandlerC) http.Handler { |
||||
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
||||
h.ServeHTTPC(ctx, w, r) |
||||
}) |
||||
} |
||||
Loading…
Reference in new issue