242 lines
5.9 KiB
Go
242 lines
5.9 KiB
Go
package router
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import (
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"bufio"
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"net"
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"net/http"
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"path/filepath"
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"regexp"
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"strings"
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"sync"
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"github.com/drone/routes/exp/context"
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)
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const (
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DELETE = "DELETE"
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GET = "GET"
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HEAD = "HEAD"
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OPTIONS = "OPTIONS"
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PATCH = "PATCH"
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POST = "POST"
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PUT = "PUT"
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)
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type route struct {
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method string
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regex *regexp.Regexp
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params map[int]string
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handler http.HandlerFunc
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}
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type Router struct {
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sync.RWMutex
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routes []*route
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filters []http.HandlerFunc
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params map[string]interface{}
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}
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func New() *Router {
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r := Router{}
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r.params = make(map[string]interface{})
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return &r
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}
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// Get adds a new Route for GET requests.
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func (r *Router) Get(pattern string, handler http.HandlerFunc) {
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r.AddRoute(GET, pattern, handler)
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}
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// Put adds a new Route for PUT requests.
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func (r *Router) Put(pattern string, handler http.HandlerFunc) {
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r.AddRoute(PUT, pattern, handler)
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}
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// Del adds a new Route for DELETE requests.
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func (r *Router) Del(pattern string, handler http.HandlerFunc) {
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r.AddRoute(DELETE, pattern, handler)
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}
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// Patch adds a new Route for PATCH requests.
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func (r *Router) Patch(pattern string, handler http.HandlerFunc) {
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r.AddRoute(PATCH, pattern, handler)
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}
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// Post adds a new Route for POST requests.
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func (r *Router) Post(pattern string, handler http.HandlerFunc) {
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r.AddRoute(POST, pattern, handler)
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}
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// Adds a new Route for Static http requests. Serves
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// static files from the specified directory
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func (r *Router) Static(pattern string, dir string) {
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//append a regex to the param to match everything
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// that comes after the prefix
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pattern = pattern + "(.+)"
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r.Get(pattern, func(w http.ResponseWriter, req *http.Request) {
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path := filepath.Clean(req.URL.Path)
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path = filepath.Join(dir, path)
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http.ServeFile(w, req, path)
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})
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}
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// Adds a new Route to the Handler
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func (r *Router) AddRoute(method string, pattern string, handler http.HandlerFunc) {
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r.Lock()
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defer r.Unlock()
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//split the url into sections
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parts := strings.Split(pattern, "/")
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//find params that start with ":"
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//replace with regular expressions
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j := 0
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params := make(map[int]string)
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for i, part := range parts {
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if strings.HasPrefix(part, ":") {
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expr := "([^/]+)"
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//a user may choose to override the defult expression
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// similar to expressjs: ‘/user/:id([0-9]+)’
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if index := strings.Index(part, "("); index != -1 {
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expr = part[index:]
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part = part[:index]
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}
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params[j] = part[1:]
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parts[i] = expr
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j++
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}
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}
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//recreate the url pattern, with parameters replaced
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//by regular expressions. then compile the regex
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pattern = strings.Join(parts, "/")
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regex := regexp.MustCompile(pattern)
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route := &route{
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method : method,
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regex : regex,
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handler : handler,
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params : params,
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}
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//append to the list of Routes
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r.routes = append(r.routes, route)
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}
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// Filter adds the middleware filter.
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func (r *Router) Filter(filter http.HandlerFunc) {
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r.Lock()
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r.filters = append(r.filters, filter)
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r.Unlock()
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}
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// FilterParam adds the middleware filter iff the URL parameter exists.
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func (r *Router) FilterParam(param string, filter http.HandlerFunc) {
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r.Filter(func(w http.ResponseWriter, req *http.Request) {
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c := context.Get(req)
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if len(c.Params.Get(param)) > 0 { filter(w, req) }
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})
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}
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// FilterPath adds the middleware filter iff the path matches the request.
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func (r *Router) FilterPath(path string, filter http.HandlerFunc) {
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pattern := path
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pattern = strings.Replace(pattern, "*", "(.+)", -1)
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pattern = strings.Replace(pattern, "**", "([^/]+)", -1)
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regex := regexp.MustCompile(pattern)
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r.Filter(func(w http.ResponseWriter, req *http.Request) {
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if regex.MatchString(req.URL.Path) { filter(w, req) }
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})
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}
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// Required by http.Handler interface. This method is invoked by the
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// http server and will handle all page routing
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func (r *Router) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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r.RLock()
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defer r.RUnlock()
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//wrap the response writer in our custom interface
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w := &responseWriter{writer: rw, Router: r}
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//find a matching Route
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for _, route := range r.routes {
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//if the methods don't match, skip this handler
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//i.e if request.Method is 'PUT' Route.Method must be 'PUT'
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if req.Method != route.method {
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continue
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}
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//check if Route pattern matches url
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if !route.regex.MatchString(req.URL.Path) {
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continue
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}
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//get submatches (params)
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matches := route.regex.FindStringSubmatch(req.URL.Path)
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//double check that the Route matches the URL pattern.
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if len(matches[0]) != len(req.URL.Path) {
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continue
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}
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//create the http.Requests context
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c := context.Get(req)
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//add url parameters to the context
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for i, match := range matches[1:] {
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c.Params.Set(route.params[i], match)
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}
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//execute middleware filters
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for _, filter := range r.filters {
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filter(w, req)
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if w.started { return }
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}
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//invoke the request handler
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route.handler(w, req)
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return
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}
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//if no matches to url, throw a not found exception
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if w.started == false {
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http.NotFound(w, req)
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}
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}
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// responseWriter is a wrapper for the http.ResponseWriter to track if
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// response was written to, and to store a reference to the router.
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type responseWriter struct {
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Router *Router
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writer http.ResponseWriter
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started bool
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status int
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}
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// Header returns the header map that will be sent by WriteHeader.
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func (w *responseWriter) Header() http.Header {
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return w.writer.Header()
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}
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// Write writes the data to the connection as part of an HTTP reply,
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// and sets `started` to true
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func (w *responseWriter) Write(p []byte) (int, error) {
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w.started = true
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return w.writer.Write(p)
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}
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// WriteHeader sends an HTTP response header with status code,
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// and sets `started` to true
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func (w *responseWriter) WriteHeader(code int) {
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w.status = code
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w.started = true
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w.writer.WriteHeader(code)
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}
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// The Hijacker interface is implemented by ResponseWriters that allow an
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// HTTP handler to take over the connection.
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func (w *responseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
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return w.writer.(http.Hijacker).Hijack()
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}
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