Golang程序
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// Copyright 2009 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 http
import (
"log"
"net"
"strconv"
"strings"
"time"
)
// A Cookie represents an HTTP cookie as sent in the Set-Cookie header of an
// HTTP response or the Cookie header of an HTTP request.
//
// See https://tools.ietf.org/html/rfc6265 for details.
type Cookie struct {
Name string
Value string
Path string // optional
Domain string // optional
Expires time.Time // optional
RawExpires string // for reading cookies only
// MaxAge=0 means no 'Max-Age' attribute specified.
// MaxAge<0 means delete cookie now, equivalently 'Max-Age: 0'
// MaxAge>0 means Max-Age attribute present and given in seconds
MaxAge int
Secure bool
HttpOnly bool
SameSite SameSite
Raw string
Unparsed []string // Raw text of unparsed attribute-value pairs
}
// SameSite allows a server to define a cookie attribute making it impossible for
// the browser to send this cookie along with cross-site requests. The main
// goal is to mitigate the risk of cross-origin information leakage, and provide
// some protection against cross-site request forgery attacks.
//
// See https://tools.ietf.org/html/draft-ietf-httpbis-cookie-same-site-00 for details.
type SameSite int
const (
SameSiteDefaultMode SameSite = iota + 1
SameSiteLaxMode
SameSiteStrictMode
)
// readSetCookies parses all "Set-Cookie" values from
// the header h and returns the successfully parsed Cookies.
func readSetCookies(h Header) []*Cookie {
cookieCount := len(h["Set-Cookie"])
if cookieCount == 0 {
return []*Cookie{}
}
cookies := make([]*Cookie, 0, cookieCount)
for _, line := range h["Set-Cookie"] {
parts := strings.Split(strings.TrimSpace(line), ";")
if len(parts) == 1 && parts[0] == "" {
continue
}
parts[0] = strings.TrimSpace(parts[0])
j := strings.Index(parts[0], "=")
if j < 0 {
continue
}
name, value := parts[0][:j], parts[0][j+1:]
if !isCookieNameValid(name) {
continue
}
value, ok := parseCookieValue(value, true)
if !ok {
continue
}
c := &Cookie{
Name: name,
Value: value,
Raw: line,
}
for i := 1; i < len(parts); i++ {
parts[i] = strings.TrimSpace(parts[i])
if len(parts[i]) == 0 {
continue
}
attr, val := parts[i], ""
if j := strings.Index(attr, "="); j >= 0 {
attr, val = attr[:j], attr[j+1:]
}
lowerAttr := strings.ToLower(attr)
val, ok = parseCookieValue(val, false)
if !ok {
c.Unparsed = append(c.Unparsed, parts[i])
continue
}
switch lowerAttr {
case "samesite":
lowerVal := strings.ToLower(val)
switch lowerVal {
case "lax":
c.SameSite = SameSiteLaxMode
case "strict":
c.SameSite = SameSiteStrictMode
default:
c.SameSite = SameSiteDefaultMode
}
continue
case "secure":
c.Secure = true
continue
case "httponly":
c.HttpOnly = true
continue
case "domain":
c.Domain = val
continue
case "max-age":
secs, err := strconv.Atoi(val)
if err != nil || secs != 0 && val[0] == '0' {
break
}
if secs <= 0 {
secs = -1
}
c.MaxAge = secs
continue
case "expires":
c.RawExpires = val
exptime, err := time.Parse(time.RFC1123, val)
if err != nil {
exptime, err = time.Parse("Mon, 02-Jan-2006 15:04:05 MST", val)
if err != nil {
c.Expires = time.Time{}
break
}
}
c.Expires = exptime.UTC()
continue
case "path":
c.Path = val
continue
}
c.Unparsed = append(c.Unparsed, parts[i])
}
cookies = append(cookies, c)
}
return cookies
}
// SetCookie adds a Set-Cookie header to the provided ResponseWriter's headers.
// The provided cookie must have a valid Name. Invalid cookies may be
// silently dropped.
func SetCookie(w ResponseWriter, cookie *Cookie) {
if v := cookie.String(); v != "" {
w.Header().Add("Set-Cookie", v)
}
}
// String returns the serialization of the cookie for use in a Cookie
// header (if only Name and Value are set) or a Set-Cookie response
// header (if other fields are set).
// If c is nil or c.Name is invalid, the empty string is returned.
func (c *Cookie) String() string {
if c == nil || !isCookieNameValid(c.Name) {
return ""
}
var b strings.Builder
b.WriteString(sanitizeCookieName(c.Name))
b.WriteRune('=')
b.WriteString(sanitizeCookieValue(c.Value))
if len(c.Path) > 0 {
b.WriteString("; Path=")
b.WriteString(sanitizeCookiePath(c.Path))
}
if len(c.Domain) > 0 {
if validCookieDomain(c.Domain) {
// A c.Domain containing illegal characters is not
// sanitized but simply dropped which turns the cookie
// into a host-only cookie. A leading dot is okay
// but won't be sent.
d := c.Domain
if d[0] == '.' {
d = d[1:]
}
b.WriteString("; Domain=")
b.WriteString(d)
} else {
log.Printf("net/http: invalid Cookie.Domain %q; dropping domain attribute", c.Domain)
}
}
var buf [len(TimeFormat)]byte
if validCookieExpires(c.Expires) {
b.WriteString("; Expires=")
b.Write(c.Expires.UTC().AppendFormat(buf[:0], TimeFormat))
}
if c.MaxAge > 0 {
b.WriteString("; Max-Age=")
b.Write(strconv.AppendInt(buf[:0], int64(c.MaxAge), 10))
} else if c.MaxAge < 0 {
b.WriteString("; Max-Age=0")
}
if c.HttpOnly {
b.WriteString("; HttpOnly")
}
if c.Secure {
b.WriteString("; Secure")
}
switch c.SameSite {
case SameSiteDefaultMode:
b.WriteString("; SameSite")
case SameSiteLaxMode:
b.WriteString("; SameSite=Lax")
case SameSiteStrictMode:
b.WriteString("; SameSite=Strict")
}
return b.String()
}
// readCookies parses all "Cookie" values from the header h and
// returns the successfully parsed Cookies.
//
// if filter isn't empty, only cookies of that name are returned
func readCookies(h Header, filter string) []*Cookie {
lines, ok := h["Cookie"]
if !ok {
return []*Cookie{}
}
cookies := []*Cookie{}
for _, line := range lines {
parts := strings.Split(strings.TrimSpace(line), ";")
if len(parts) == 1 && parts[0] == "" {
continue
}
// Per-line attributes
for i := 0; i < len(parts); i++ {
parts[i] = strings.TrimSpace(parts[i])
if len(parts[i]) == 0 {
continue
}
name, val := parts[i], ""
if j := strings.Index(name, "="); j >= 0 {
name, val = name[:j], name[j+1:]
}
if !isCookieNameValid(name) {
continue
}
if filter != "" && filter != name {
continue
}
val, ok := parseCookieValue(val, true)
if !ok {
continue
}
cookies = append(cookies, &Cookie{Name: name, Value: val})
}
}
return cookies
}
// validCookieDomain reports whether v is a valid cookie domain-value.
func validCookieDomain(v string) bool {
if isCookieDomainName(v) {
return true
}
if net.ParseIP(v) != nil && !strings.Contains(v, ":") {
return true
}
return false
}
// validCookieExpires reports whether v is a valid cookie expires-value.
func validCookieExpires(t time.Time) bool {
// IETF RFC 6265 Section 5.1.1.5, the year must not be less than 1601
return t.Year() >= 1601
}
// isCookieDomainName reports whether s is a valid domain name or a valid
// domain name with a leading dot '.'. It is almost a direct copy of
// package net's isDomainName.
func isCookieDomainName(s string) bool {
if len(s) == 0 {
return false
}
if len(s) > 255 {
return false
}
if s[0] == '.' {
// A cookie a domain attribute may start with a leading dot.
s = s[1:]
}
last := byte('.')
ok := false // Ok once we've seen a letter.
partlen := 0
for i := 0; i < len(s); i++ {
c := s[i]
switch {
default:
return false
case 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z':
// No '_' allowed here (in contrast to package net).
ok = true
partlen++
case '0' <= c && c <= '9':
// fine
partlen++
case c == '-':
// Byte before dash cannot be dot.
if last == '.' {
return false
}
partlen++
case c == '.':
// Byte before dot cannot be dot, dash.
if last == '.' || last == '-' {
return false
}
if partlen > 63 || partlen == 0 {
return false
}
partlen = 0
}
last = c
}
if last == '-' || partlen > 63 {
return false
}
return ok
}
var cookieNameSanitizer = strings.NewReplacer("\n", "-", "\r", "-")
func sanitizeCookieName(n string) string {
return cookieNameSanitizer.Replace(n)
}
// https://tools.ietf.org/html/rfc6265#section-4.1.1
// cookie-value = *cookie-octet / ( DQUOTE *cookie-octet DQUOTE )
// cookie-octet = %x21 / %x23-2B / %x2D-3A / %x3C-5B / %x5D-7E
// ; US-ASCII characters excluding CTLs,
// ; whitespace DQUOTE, comma, semicolon,
// ; and backslash
// We loosen this as spaces and commas are common in cookie values
// but we produce a quoted cookie-value in when value starts or ends
// with a comma or space.
// See https://golang.org/issue/7243 for the discussion.
func sanitizeCookieValue(v string) string {
v = sanitizeOrWarn("Cookie.Value", validCookieValueByte, v)
if len(v) == 0 {
return v
}
if strings.IndexByte(v, ' ') >= 0 || strings.IndexByte(v, ',') >= 0 {
return `"` + v + `"`
}
return v
}
func validCookieValueByte(b byte) bool {
return 0x20 <= b && b < 0x7f && b != '"' && b != ';' && b != '\\'
}
// path-av = "Path=" path-value
// path-value = <any CHAR except CTLs or ";">
func sanitizeCookiePath(v string) string {
return sanitizeOrWarn("Cookie.Path", validCookiePathByte, v)
}
func validCookiePathByte(b byte) bool {
return 0x20 <= b && b < 0x7f && b != ';'
}
func sanitizeOrWarn(fieldName string, valid func(byte) bool, v string) string {
ok := true
for i := 0; i < len(v); i++ {
if valid(v[i]) {
continue
}
log.Printf("net/http: invalid byte %q in %s; dropping invalid bytes", v[i], fieldName)
ok = false
break
}
if ok {
return v
}
buf := make([]byte, 0, len(v))
for i := 0; i < len(v); i++ {
if b := v[i]; valid(b) {
buf = append(buf, b)
}
}
return string(buf)
}
func parseCookieValue(raw string, allowDoubleQuote bool) (string, bool) {
// Strip the quotes, if present.
if allowDoubleQuote && len(raw) > 1 && raw[0] == '"' && raw[len(raw)-1] == '"' {
raw = raw[1 : len(raw)-1]
}
for i := 0; i < len(raw); i++ {
if !validCookieValueByte(raw[i]) {
return "", false
}
}
return raw, true
}
func isCookieNameValid(raw string) bool {
if raw == "" {
return false
}
return strings.IndexFunc(raw, isNotToken) < 0
}