caddy/middleware/replacer.go

109 lines
2.6 KiB
Go

package middleware
import (
"net"
"net/http"
"strconv"
"strings"
"time"
)
// Replacer is a type which can replace placeholder
// substrings in a string with actual values from a
// http.Request and responseRecorder. Always use
// NewReplacer to get one of these.
type Replacer interface {
Replace(string) string
}
type replacer struct {
replacements map[string]string
emptyValue string
}
// NewReplacer makes a new replacer based on r and rr.
// Do not create a new replacer until r and rr have all
// the needed values, because this function copies those
// values into the replacer.
func NewReplacer(r *http.Request, rr *responseRecorder, emptyValue string) Replacer {
rep := replacer{
replacements: map[string]string{
"{method}": r.Method,
"{scheme}": func() string {
if r.TLS != nil {
return "https"
}
return "http"
}(),
"{host}": r.Host,
"{path}": r.URL.Path,
"{query}": r.URL.RawQuery,
"{fragment}": r.URL.Fragment,
"{proto}": r.Proto,
"{remote}": func() string {
if fwdFor := r.Header.Get("X-Forwarded-For"); fwdFor != "" {
return fwdFor
}
host, _, err := net.SplitHostPort(r.RemoteAddr)
if err != nil {
return r.RemoteAddr
}
return host
}(),
"{port}": func() string {
_, port, err := net.SplitHostPort(r.RemoteAddr)
if err != nil {
return ""
}
return port
}(),
"{uri}": r.URL.RequestURI(),
"{when}": func() string {
return time.Now().Format(timeFormat)
}(),
},
emptyValue: emptyValue,
}
if rr != nil {
rep.replacements["{status}"] = strconv.Itoa(rr.status)
rep.replacements["{size}"] = strconv.Itoa(rr.size)
rep.replacements["{latency}"] = time.Since(rr.start).String()
}
// Header placeholders
for header, val := range r.Header {
rep.replacements[headerReplacer+header+"}"] = strings.Join(val, ",")
}
return rep
}
// Replace performs a replacement of values on s and returns
// the string with the replaced values.
func (r replacer) Replace(s string) string {
for placeholder, replacement := range r.replacements {
if replacement == "" {
replacement = r.emptyValue
}
s = strings.Replace(s, placeholder, replacement, -1)
}
// Replace any header placeholders that weren't found
for strings.Contains(s, headerReplacer) {
idxStart := strings.Index(s, headerReplacer)
endOffset := idxStart + len(headerReplacer)
idxEnd := strings.Index(s[endOffset:], "}")
if idxEnd > -1 {
s = s[:idxStart] + r.emptyValue + s[endOffset+idxEnd+1:]
} else {
break
}
}
return s
}
const (
timeFormat = "02/Jan/2006:15:04:05 -0700"
headerReplacer = "{>"
)