go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/server/encryptedcookies/internal/utils.go (about)

     1  // Copyright 2021 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package internal
    16  
    17  import (
    18  	"net/http"
    19  	"net/url"
    20  	"path"
    21  	"strings"
    22  	"time"
    23  
    24  	"go.chromium.org/luci/common/errors"
    25  )
    26  
    27  // NormalizeURL verifies URL is parsable and that it is relative.
    28  func NormalizeURL(dest string) (string, error) {
    29  	if dest == "" {
    30  		return "/", nil
    31  	}
    32  	u, err := url.Parse(dest)
    33  	if err != nil {
    34  		return "", errors.Annotate(err, "bad destination URL %q", dest).Err()
    35  	}
    36  	// Note: '//host/path' is a location on a server named 'host'.
    37  	if u.IsAbs() || !strings.HasPrefix(u.Path, "/") || strings.HasPrefix(u.Path, "//") {
    38  		return "", errors.Reason("bad absolute destination URL %q", u).Err()
    39  	}
    40  	// path.Clean removes trailing slash. It matters for URLs though. Keep it.
    41  	keepSlash := strings.HasSuffix(u.Path, "/")
    42  	u.Path = path.Clean(u.Path)
    43  	if !strings.HasSuffix(u.Path, "/") && keepSlash {
    44  		u.Path += "/"
    45  	}
    46  	if !strings.HasPrefix(u.Path, "/") {
    47  		return "", errors.Reason("bad destination URL %q", u).Err()
    48  	}
    49  	return u.String(), nil
    50  }
    51  
    52  // MakeRedirectURL is used to generate login and logout URLs.
    53  func MakeRedirectURL(base, dest string) (string, error) {
    54  	dest, err := NormalizeURL(dest)
    55  	if err != nil {
    56  		return "", err
    57  	}
    58  	if dest == "/" {
    59  		return base, nil
    60  	}
    61  	v := url.Values{"r": {dest}}
    62  	return base + "?" + v.Encode(), nil
    63  }
    64  
    65  // RemoveCookie sets a cookie to a past expiration date so that the browser can
    66  // remove it.
    67  //
    68  // It also replaces the value with junk, in unlikely case the browser decides
    69  // to ignore the expiration time.
    70  func RemoveCookie(rw http.ResponseWriter, r *http.Request, cookie, path string) {
    71  	http.SetCookie(rw, &http.Cookie{
    72  		Name:    cookie,
    73  		Value:   "deleted",
    74  		Path:    path,
    75  		MaxAge:  -1,
    76  		Expires: time.Unix(1, 0),
    77  	})
    78  }