/
betaRedirect.go
75 lines (64 loc) · 2.2 KB
/
betaRedirect.go
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// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package middleware
import (
"net/http"
"net/url"
)
const (
betaPkgGoDevRedirectCookie = "betapkggodev-redirect"
betaPkgGoDevRedirectParam = "betaredirect"
betaPkgGoDevRedirectOn = "on"
betaPkgGoDevRedirectOff = "off"
betaPkgGoDevHost = "beta.pkg.go.dev"
)
// BetaPkgGoDevRedirect redirects requests from pkg.go.dev to beta.pkg.go.dev,
// based on whether a cookie is set for betapkggodev-redirect. The cookie
// can be turned on/off using a query param.
func BetaPkgGoDevRedirect() Middleware {
return func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if userReturningFromBetaPkgGoDev(r) {
h.ServeHTTP(w, r)
return
}
redirectParam := r.FormValue(betaPkgGoDevRedirectParam)
if redirectParam == betaPkgGoDevRedirectOn {
cookie := &http.Cookie{Name: betaPkgGoDevRedirectCookie, Value: redirectParam, Path: "/"}
http.SetCookie(w, cookie)
}
if redirectParam == betaPkgGoDevRedirectOff {
cookie := &http.Cookie{Name: betaPkgGoDevRedirectCookie, Value: "", MaxAge: -1, Path: "/"}
http.SetCookie(w, cookie)
}
if !shouldRedirectToBetaPkgGoDev(r) {
h.ServeHTTP(w, r)
return
}
http.Redirect(w, r, betaPkgGoDevURL(r.URL).String(), http.StatusFound)
})
}
}
func userReturningFromBetaPkgGoDev(req *http.Request) bool {
return req.FormValue("utm_source") == "backtopkggodev"
}
func shouldRedirectToBetaPkgGoDev(req *http.Request) bool {
redirectParam := req.FormValue(betaPkgGoDevRedirectParam)
if redirectParam == betaPkgGoDevRedirectOn || redirectParam == betaPkgGoDevRedirectOff {
return redirectParam == betaPkgGoDevRedirectOn
}
cookie, err := req.Cookie(betaPkgGoDevRedirectCookie)
return (err == nil && cookie.Value == betaPkgGoDevRedirectOn)
}
func betaPkgGoDevURL(sourceURL *url.URL) *url.URL {
values := sourceURL.Query()
values.Del(betaPkgGoDevRedirectParam)
values.Set("utm_source", "pkggodev")
return &url.URL{
Scheme: "https",
Host: betaPkgGoDevHost,
Path: sourceURL.Path,
RawQuery: values.Encode(),
}
}