reverseproxy - http.go

     1  package reverseproxy
     2  
     3  import (
     4  	"bytes"
     5  	"errors"
     6  	"fmt"
     7  	"io"
     8  )
     9  
    10  var (
    11  	eoh  = []byte("\r\n\r\n")
    12  	eol  = eoh[:2]
    13  	host = []byte("\r\nHost: ")
    14  )
    15  
    16  func readHTTPServerName(r io.Reader, buf []byte) (string, []byte, error) {
    17  	n := 1
    18  	h := -1
    19  	l := -1
    20  	for l < 0 {
    21  		m, err := r.Read(buf[n:])
    22  		n += m
    23  		h = bytes.Index(buf[:n], host)
    24  		if e := bytes.Index(buf[:n], eoh); h > 0 && (e > h || e == -1) {
    25  			h += len(host)
    26  			l = bytes.Index(buf[h:n], eol)
    27  		} else if e >= 0 {
    28  			return "", buf, errNoServerHeader
    29  		}
    30  		if err != nil {
    31  			return "", buf, fmt.Errorf("error reading headers: %w", err)
    32  		}
    33  	}
    34  	return string(buf[h : h+l]), buf[:n], nil
    35  }
    36  
    37  var errNoServerHeader = errors.New("no server header")
    38