knative.dev/pkg@v0.0.0-20260602142205-ac97e43f6622/websocket/hijack.go (about)

     1  /*
     2  Copyright 2019 The Knative Authors
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package websocket
    18  
    19  import (
    20  	"bufio"
    21  	"fmt"
    22  	"net"
    23  	"net/http"
    24  )
    25  
    26  // HijackIfPossible calls Hijack() on the given http.ResponseWriter if it implements
    27  // http.Hijacker interface, which is required for net/http/httputil/reverseproxy
    28  // to handle connection upgrade/switching protocol.  Otherwise returns an error.
    29  func HijackIfPossible(w http.ResponseWriter) (net.Conn, *bufio.ReadWriter, error) {
    30  	hj, ok := w.(http.Hijacker)
    31  	if !ok {
    32  		return nil, nil, fmt.Errorf("wrapped writer of type %T can't be hijacked", w)
    33  	}
    34  	return hj.Hijack()
    35  }