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- package cacheobject
- import (
- "errors"
- "math"
- "net/http"
- "net/textproto"
- "strconv"
- "strings"
- )
- var (
- ErrQuoteMismatch = errors.New("Missing closing quote")
- ErrMaxAgeDeltaSeconds = errors.New("Failed to parse delta-seconds in `max-age`")
- ErrSMaxAgeDeltaSeconds = errors.New("Failed to parse delta-seconds in `s-maxage`")
- ErrMaxStaleDeltaSeconds = errors.New("Failed to parse delta-seconds in `min-fresh`")
- ErrMinFreshDeltaSeconds = errors.New("Failed to parse delta-seconds in `min-fresh`")
- ErrNoCacheNoArgs = errors.New("Unexpected argument to `no-cache`")
- ErrNoStoreNoArgs = errors.New("Unexpected argument to `no-store`")
- ErrNoTransformNoArgs = errors.New("Unexpected argument to `no-transform`")
- ErrOnlyIfCachedNoArgs = errors.New("Unexpected argument to `only-if-cached`")
- ErrMustRevalidateNoArgs = errors.New("Unexpected argument to `must-revalidate`")
- ErrPublicNoArgs = errors.New("Unexpected argument to `public`")
- ErrProxyRevalidateNoArgs = errors.New("Unexpected argument to `proxy-revalidate`")
-
- ErrImmutableNoArgs = errors.New("Unexpected argument to `immutable`")
- ErrStaleIfErrorDeltaSeconds = errors.New("Failed to parse delta-seconds in `stale-if-error`")
- ErrStaleWhileRevalidateDeltaSeconds = errors.New("Failed to parse delta-seconds in `stale-while-revalidate`")
- )
- func whitespace(b byte) bool {
- if b == '\t' || b == ' ' {
- return true
- }
- return false
- }
- func parse(value string, cd cacheDirective) error {
- var err error = nil
- i := 0
- for i < len(value) && err == nil {
-
- if whitespace(value[i]) || value[i] == ',' {
- i++
- continue
- }
- j := i + 1
- for j < len(value) {
- if !isToken(value[j]) {
- break
- }
- j++
- }
- token := strings.ToLower(value[i:j])
- tokenHasFields := hasFieldNames(token)
-
- if j+1 < len(value) && value[j] == '=' {
- k := j + 1
-
- if k < len(value) && value[k] == '"' {
- eaten, result := httpUnquote(value[k:])
- if eaten == -1 {
- return ErrQuoteMismatch
- }
- i = k + eaten
- err = cd.addPair(token, result)
- } else {
- z := k
- for z < len(value) {
- if tokenHasFields {
- if whitespace(value[z]) {
- break
- }
- } else {
- if whitespace(value[z]) || value[z] == ',' {
- break
- }
- }
- z++
- }
- i = z
- result := value[k:z]
- if result != "" && result[len(result)-1] == ',' {
- result = result[:len(result)-1]
- }
- err = cd.addPair(token, result)
- }
- } else {
- if token != "," {
- err = cd.addToken(token)
- }
- i = j
- }
- }
- return err
- }
- type DeltaSeconds int32
- func parseDeltaSeconds(v string) (DeltaSeconds, error) {
- n, err := strconv.ParseUint(v, 10, 32)
- if err != nil {
- if numError, ok := err.(*strconv.NumError); ok {
- if numError.Err == strconv.ErrRange {
- return DeltaSeconds(math.MaxInt32), nil
- }
- }
- return DeltaSeconds(-1), err
- } else {
- if n > math.MaxInt32 {
- return DeltaSeconds(math.MaxInt32), nil
- } else {
- return DeltaSeconds(n), nil
- }
- }
- }
- type FieldNames map[string]bool
- type cacheDirective interface {
- addToken(s string) error
- addPair(s string, v string) error
- }
- type RequestCacheDirectives struct {
-
-
-
-
-
-
-
- MaxAge DeltaSeconds
-
-
-
-
-
-
-
-
-
- MaxStale DeltaSeconds
-
-
-
-
-
-
-
- MinFresh DeltaSeconds
-
-
-
-
-
- NoCache bool
-
-
-
-
-
- NoStore bool
-
-
-
-
-
- NoTransform bool
-
-
-
-
- OnlyIfCached bool
-
-
-
-
-
- Extensions []string
- }
- func (cd *RequestCacheDirectives) addToken(token string) error {
- var err error = nil
- switch token {
- case "max-age":
- err = ErrMaxAgeDeltaSeconds
- case "max-stale":
- err = ErrMaxStaleDeltaSeconds
- case "min-fresh":
- err = ErrMinFreshDeltaSeconds
- case "no-cache":
- cd.NoCache = true
- case "no-store":
- cd.NoStore = true
- case "no-transform":
- cd.NoTransform = true
- case "only-if-cached":
- cd.OnlyIfCached = true
- default:
- cd.Extensions = append(cd.Extensions, token)
- }
- return err
- }
- func (cd *RequestCacheDirectives) addPair(token string, v string) error {
- var err error = nil
- switch token {
- case "max-age":
- cd.MaxAge, err = parseDeltaSeconds(v)
- if err != nil {
- err = ErrMaxAgeDeltaSeconds
- }
- case "max-stale":
- cd.MaxStale, err = parseDeltaSeconds(v)
- if err != nil {
- err = ErrMaxStaleDeltaSeconds
- }
- case "min-fresh":
- cd.MinFresh, err = parseDeltaSeconds(v)
- if err != nil {
- err = ErrMinFreshDeltaSeconds
- }
- case "no-cache":
- err = ErrNoCacheNoArgs
- case "no-store":
- err = ErrNoStoreNoArgs
- case "no-transform":
- err = ErrNoTransformNoArgs
- case "only-if-cached":
- err = ErrOnlyIfCachedNoArgs
- default:
-
- cd.Extensions = append(cd.Extensions, token+"="+v)
- }
- return err
- }
- func ParseRequestCacheControl(value string) (*RequestCacheDirectives, error) {
- cd := &RequestCacheDirectives{
- MaxAge: -1,
- MaxStale: -1,
- MinFresh: -1,
- }
- err := parse(value, cd)
- if err != nil {
- return nil, err
- }
- return cd, nil
- }
- type ResponseCacheDirectives struct {
-
-
-
-
-
- MustRevalidate bool
-
-
-
-
-
-
-
-
-
-
-
-
- NoCache FieldNames
-
-
-
-
-
- NoCachePresent bool
-
-
-
-
-
- NoStore bool
-
-
-
-
-
- NoTransform bool
-
-
-
-
-
- Public bool
-
-
-
-
-
-
-
-
-
-
-
-
- Private FieldNames
-
-
-
-
-
- PrivatePresent bool
-
-
-
-
-
- ProxyRevalidate bool
-
-
-
-
-
- MaxAge DeltaSeconds
-
-
-
-
-
-
-
- SMaxAge DeltaSeconds
-
-
-
-
-
-
- Immutable bool
-
- StaleIfError DeltaSeconds
-
- StaleWhileRevalidate DeltaSeconds
-
-
-
-
-
- Extensions []string
- }
- func ParseResponseCacheControl(value string) (*ResponseCacheDirectives, error) {
- cd := &ResponseCacheDirectives{
- MaxAge: -1,
- SMaxAge: -1,
-
- StaleIfError: -1,
- StaleWhileRevalidate: -1,
- }
- err := parse(value, cd)
- if err != nil {
- return nil, err
- }
- return cd, nil
- }
- func (cd *ResponseCacheDirectives) addToken(token string) error {
- var err error = nil
- switch token {
- case "must-revalidate":
- cd.MustRevalidate = true
- case "no-cache":
- cd.NoCachePresent = true
- case "no-store":
- cd.NoStore = true
- case "no-transform":
- cd.NoTransform = true
- case "public":
- cd.Public = true
- case "private":
- cd.PrivatePresent = true
- case "proxy-revalidate":
- cd.ProxyRevalidate = true
- case "max-age":
- err = ErrMaxAgeDeltaSeconds
- case "s-maxage":
- err = ErrSMaxAgeDeltaSeconds
-
- case "immutable":
- cd.Immutable = true
- case "stale-if-error":
- err = ErrMaxAgeDeltaSeconds
- case "stale-while-revalidate":
- err = ErrMaxAgeDeltaSeconds
- default:
- cd.Extensions = append(cd.Extensions, token)
- }
- return err
- }
- func hasFieldNames(token string) bool {
- switch token {
- case "no-cache":
- return true
- case "private":
- return true
- }
- return false
- }
- func (cd *ResponseCacheDirectives) addPair(token string, v string) error {
- var err error = nil
- switch token {
- case "must-revalidate":
- err = ErrMustRevalidateNoArgs
- case "no-cache":
- cd.NoCachePresent = true
- tokens := strings.Split(v, ",")
- if cd.NoCache == nil {
- cd.NoCache = make(FieldNames)
- }
- for _, t := range tokens {
- k := http.CanonicalHeaderKey(textproto.TrimString(t))
- cd.NoCache[k] = true
- }
- case "no-store":
- err = ErrNoStoreNoArgs
- case "no-transform":
- err = ErrNoTransformNoArgs
- case "public":
- err = ErrPublicNoArgs
- case "private":
- cd.PrivatePresent = true
- tokens := strings.Split(v, ",")
- if cd.Private == nil {
- cd.Private = make(FieldNames)
- }
- for _, t := range tokens {
- k := http.CanonicalHeaderKey(textproto.TrimString(t))
- cd.Private[k] = true
- }
- case "proxy-revalidate":
- err = ErrProxyRevalidateNoArgs
- case "max-age":
- cd.MaxAge, err = parseDeltaSeconds(v)
- case "s-maxage":
- cd.SMaxAge, err = parseDeltaSeconds(v)
-
- case "immutable":
- err = ErrImmutableNoArgs
- case "stale-if-error":
- cd.StaleIfError, err = parseDeltaSeconds(v)
- case "stale-while-revalidate":
- cd.StaleWhileRevalidate, err = parseDeltaSeconds(v)
- default:
-
-
- cd.Extensions = append(cd.Extensions, token+"="+v)
- }
- return err
- }
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