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- package cacheobject
- import (
- "net/http"
- "time"
- )
- type Object struct {
- CacheIsPrivate bool
- RespDirectives *ResponseCacheDirectives
- RespHeaders http.Header
- RespStatusCode int
- RespExpiresHeader time.Time
- RespDateHeader time.Time
- RespLastModifiedHeader time.Time
- ReqDirectives *RequestCacheDirectives
- ReqHeaders http.Header
- ReqMethod string
- NowUTC time.Time
- }
- type ObjectResults struct {
- OutReasons []Reason
- OutWarnings []Warning
- OutExpirationTime time.Time
- OutErr error
- }
- func CachableObject(obj *Object, rv *ObjectResults) {
- rv.OutReasons = nil
- rv.OutWarnings = nil
- rv.OutErr = nil
- switch obj.ReqMethod {
- case "GET":
- break
- case "HEAD":
- break
- case "POST":
-
- if !hasFreshness(obj.ReqDirectives, obj.RespDirectives, obj.RespHeaders, obj.RespExpiresHeader, obj.CacheIsPrivate) {
- rv.OutReasons = append(rv.OutReasons, ReasonRequestMethodPOST)
- }
- case "PUT":
- rv.OutReasons = append(rv.OutReasons, ReasonRequestMethodPUT)
- case "DELETE":
- rv.OutReasons = append(rv.OutReasons, ReasonRequestMethodDELETE)
- case "CONNECT":
- rv.OutReasons = append(rv.OutReasons, ReasonRequestMethodCONNECT)
- case "OPTIONS":
- rv.OutReasons = append(rv.OutReasons, ReasonRequestMethodOPTIONS)
- case "TRACE":
- rv.OutReasons = append(rv.OutReasons, ReasonRequestMethodTRACE)
-
-
-
-
- default:
- rv.OutReasons = append(rv.OutReasons, ReasonRequestMethodUnkown)
- }
- if obj.ReqDirectives.NoStore {
- rv.OutReasons = append(rv.OutReasons, ReasonRequestNoStore)
- }
-
- authz := obj.ReqHeaders.Get("Authorization")
- if authz != "" {
- if obj.RespDirectives.MustRevalidate ||
- obj.RespDirectives.Public ||
- obj.RespDirectives.SMaxAge != -1 {
-
- } else {
- rv.OutReasons = append(rv.OutReasons, ReasonRequestAuthorizationHeader)
- }
- }
- if obj.RespDirectives.PrivatePresent && !obj.CacheIsPrivate {
- rv.OutReasons = append(rv.OutReasons, ReasonResponsePrivate)
- }
- if obj.RespDirectives.NoStore {
- rv.OutReasons = append(rv.OutReasons, ReasonResponseNoStore)
- }
-
- expires := obj.RespHeaders.Get("Expires") != ""
- statusCachable := cachableStatusCode(obj.RespStatusCode)
- if expires ||
- obj.RespDirectives.MaxAge != -1 ||
- (obj.RespDirectives.SMaxAge != -1 && !obj.CacheIsPrivate) ||
- statusCachable ||
- obj.RespDirectives.Public {
-
- } else {
- rv.OutReasons = append(rv.OutReasons, ReasonResponseUncachableByDefault)
- }
- }
- var twentyFourHours = time.Duration(24 * time.Hour)
- const debug = false
- func ExpirationObject(obj *Object, rv *ObjectResults) {
-
-
- var expiresTime time.Time
- if obj.RespDirectives.SMaxAge != -1 && !obj.CacheIsPrivate {
- expiresTime = obj.NowUTC.Add(time.Second * time.Duration(obj.RespDirectives.SMaxAge))
- } else if obj.RespDirectives.MaxAge != -1 {
- expiresTime = obj.NowUTC.UTC().Add(time.Second * time.Duration(obj.RespDirectives.MaxAge))
- } else if !obj.RespExpiresHeader.IsZero() {
- serverDate := obj.RespDateHeader
- if serverDate.IsZero() {
-
-
- serverDate = obj.NowUTC
- }
- expiresTime = obj.NowUTC.Add(obj.RespExpiresHeader.Sub(serverDate))
- } else if !obj.RespLastModifiedHeader.IsZero() {
-
- rv.OutWarnings = append(rv.OutWarnings, WarningHeuristicExpiration)
-
-
-
-
-
-
-
- since := obj.RespLastModifiedHeader.Sub(obj.NowUTC)
- since = time.Duration(float64(since) * -0.1)
- if since > twentyFourHours {
- expiresTime = obj.NowUTC.Add(twentyFourHours)
- } else {
- expiresTime = obj.NowUTC.Add(since)
- }
- if debug {
- println("Now UTC: ", obj.NowUTC.String())
- println("Last-Modified: ", obj.RespLastModifiedHeader.String())
- println("Since: ", since.String())
- println("TwentyFourHours: ", twentyFourHours.String())
- println("Expiration: ", expiresTime.String())
- }
- } else {
-
- }
- rv.OutExpirationTime = expiresTime
- }
- func UsingRequestResponse(req *http.Request,
- statusCode int,
- respHeaders http.Header,
- privateCache bool) ([]Reason, time.Time, error) {
- reasons, time, _, _, err := UsingRequestResponseWithObject(req, statusCode, respHeaders, privateCache)
- return reasons, time, err
- }
- func UsingRequestResponseWithObject(req *http.Request,
- statusCode int,
- respHeaders http.Header,
- privateCache bool) ([]Reason, time.Time, []Warning, *Object, error) {
- var reqHeaders http.Header
- var reqMethod string
- var reqDir *RequestCacheDirectives = nil
- respDir, err := ParseResponseCacheControl(respHeaders.Get("Cache-Control"))
- if err != nil {
- return nil, time.Time{}, nil, nil, err
- }
- if req != nil {
- reqDir, err = ParseRequestCacheControl(req.Header.Get("Cache-Control"))
- if err != nil {
- return nil, time.Time{}, nil, nil, err
- }
- reqHeaders = req.Header
- reqMethod = req.Method
- }
- var expiresHeader time.Time
- var dateHeader time.Time
- var lastModifiedHeader time.Time
- if respHeaders.Get("Expires") != "" {
- expiresHeader, err = http.ParseTime(respHeaders.Get("Expires"))
- if err != nil {
-
-
- expiresHeader = time.Time{}
- }
- expiresHeader = expiresHeader.UTC()
- }
- if respHeaders.Get("Date") != "" {
- dateHeader, err = http.ParseTime(respHeaders.Get("Date"))
- if err != nil {
- return nil, time.Time{}, nil, nil, err
- }
- dateHeader = dateHeader.UTC()
- }
- if respHeaders.Get("Last-Modified") != "" {
- lastModifiedHeader, err = http.ParseTime(respHeaders.Get("Last-Modified"))
- if err != nil {
- return nil, time.Time{}, nil, nil, err
- }
- lastModifiedHeader = lastModifiedHeader.UTC()
- }
- obj := Object{
- CacheIsPrivate: privateCache,
- RespDirectives: respDir,
- RespHeaders: respHeaders,
- RespStatusCode: statusCode,
- RespExpiresHeader: expiresHeader,
- RespDateHeader: dateHeader,
- RespLastModifiedHeader: lastModifiedHeader,
- ReqDirectives: reqDir,
- ReqHeaders: reqHeaders,
- ReqMethod: reqMethod,
- NowUTC: time.Now().UTC(),
- }
- rv := ObjectResults{}
- CachableObject(&obj, &rv)
- if rv.OutErr != nil {
- return nil, time.Time{}, nil, nil, rv.OutErr
- }
- ExpirationObject(&obj, &rv)
- if rv.OutErr != nil {
- return nil, time.Time{}, nil, nil, rv.OutErr
- }
- return rv.OutReasons, rv.OutExpirationTime, rv.OutWarnings, &obj, nil
- }
- func hasFreshness(reqDir *RequestCacheDirectives, respDir *ResponseCacheDirectives, respHeaders http.Header, respExpires time.Time, privateCache bool) bool {
- if !privateCache && respDir.SMaxAge != -1 {
- return true
- }
- if respDir.MaxAge != -1 {
- return true
- }
- if !respExpires.IsZero() || respHeaders.Get("Expires") != "" {
- return true
- }
- return false
- }
- func cachableStatusCode(statusCode int) bool {
-
- switch statusCode {
- case 200:
- return true
- case 203:
- return true
- case 204:
- return true
- case 206:
- return true
- case 300:
- return true
- case 301:
- return true
- case 404:
- return true
- case 405:
- return true
- case 410:
- return true
- case 414:
- return true
- case 501:
- return true
- default:
- return false
- }
- }
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