// Package redirect is middleware for redirecting certain requests
// to other locations.
package redirect
import (
"fmt"
"html"
"net/http"
"net/url"
"path"
"strings"
"github.com/mholt/caddy/middleware"
)
// Redirect is middleware to respond with HTTP redirects
type Redirect struct {
Next middleware.Handler
Rules []Rule
}
// ServeHTTP implements the middleware.Handler interface.
func (rd Redirect) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
for _, rule := range rd.Rules {
if rule.From == "/" {
// Catchall redirect preserves path (TODO: Standardize/formalize this behavior)
toURL, err := url.Parse(rule.To)
if err != nil {
return http.StatusInternalServerError, err
}
newPath := path.Join(toURL.Host, toURL.Path, r.URL.Path)
if strings.HasSuffix(r.URL.Path, "/") {
newPath = newPath + "/"
}
newPath = toURL.Scheme + "://" + newPath
parameters := toURL.Query()
for k, v := range r.URL.Query() {
parameters.Set(k, v[0])
}
if len(parameters) > 0 {
newPath = newPath + "?" + parameters.Encode()
}
if rule.Meta {
fmt.Fprintf(w, metaRedir, html.EscapeString(newPath))
} else {
http.Redirect(w, r, newPath, rule.Code)
}
return 0, nil
}
if r.URL.Path == rule.From {
if rule.Meta {
fmt.Fprintf(w, metaRedir, html.EscapeString(rule.To))
} else {
http.Redirect(w, r, rule.To, rule.Code)
}
return 0, nil
}
}
return rd.Next.ServeHTTP(w, r)
}
// Rule describes an HTTP redirect rule.
type Rule struct {
From, To string
Code int
Meta bool
}
var metaRedir = `<html>
<head>
<meta http-equiv="refresh" content="0;URL='%s'">
</head>
<body>redirecting...</body>
</html>`