k8s.io/apiserver@v0.31.1/pkg/util/flushwriter/writer.go (about)

     1  /*
     2  Copyright 2014 The Kubernetes 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 flushwriter
    18  
    19  import (
    20  	"io"
    21  	"net/http"
    22  )
    23  
    24  // Wrap wraps an io.Writer into a writer that flushes after every write if
    25  // the writer implements the Flusher interface.
    26  func Wrap(w io.Writer) io.Writer {
    27  	fw := &flushWriter{
    28  		writer: w,
    29  	}
    30  	if flusher, ok := w.(http.Flusher); ok {
    31  		fw.flusher = flusher
    32  	}
    33  	return fw
    34  }
    35  
    36  // flushWriter provides wrapper for responseWriter with HTTP streaming capabilities
    37  type flushWriter struct {
    38  	flusher http.Flusher
    39  	writer  io.Writer
    40  }
    41  
    42  // Write is a FlushWriter implementation of the io.Writer that sends any buffered
    43  // data to the client.
    44  func (fw *flushWriter) Write(p []byte) (n int, err error) {
    45  	n, err = fw.writer.Write(p)
    46  	if err != nil {
    47  		return
    48  	}
    49  	if fw.flusher != nil {
    50  		fw.flusher.Flush()
    51  	}
    52  	return
    53  }