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mirror of https://github.com/DNSCrypt/dnscrypt-proxy.git synced 2025-01-14 02:25:52 +01:00

Have fetchFromCache support a TTL parameter

Partially
fixes #854
This commit is contained in:
Frank Denis 2019-06-13 11:24:15 +02:00
parent df24db9b9d
commit d27171f62b

View File

@ -27,7 +27,7 @@ const (
)
const (
SourcesUpdateDelay = time.Duration(24) * time.Hour
MinSourcesUpdateDelay = time.Duration(24) * time.Hour
)
type Source struct {
@ -36,8 +36,11 @@ type Source struct {
in string
}
func fetchFromCache(cacheFile string) (in string, expired bool, delayTillNextUpdate time.Duration, err error) {
func fetchFromCache(cacheFile string, refreshDelay time.Duration) (in string, expired bool, delayTillNextUpdate time.Duration, err error) {
expired = false
if refreshDelay < MinSourcesUpdateDelay {
refreshDelay = MinSourcesUpdateDelay
}
fi, err := os.Stat(cacheFile)
if err != nil {
dlog.Debugf("Cache file [%s] not present", cacheFile)
@ -45,9 +48,9 @@ func fetchFromCache(cacheFile string) (in string, expired bool, delayTillNextUpd
return
}
elapsed := time.Since(fi.ModTime())
if elapsed < SourcesUpdateDelay {
if elapsed < refreshDelay {
dlog.Debugf("Cache file [%s] is still fresh", cacheFile)
delayTillNextUpdate = SourcesUpdateDelay - elapsed
delayTillNextUpdate = refreshDelay - elapsed
} else {
dlog.Debugf("Cache file [%s] needs to be refreshed", cacheFile)
delayTillNextUpdate = time.Duration(0)
@ -65,10 +68,10 @@ func fetchFromCache(cacheFile string) (in string, expired bool, delayTillNextUpd
return
}
func fetchWithCache(xTransport *XTransport, urlStr string, cacheFile string) (in string, cached bool, delayTillNextUpdate time.Duration, err error) {
func fetchWithCache(xTransport *XTransport, urlStr string, cacheFile string, refreshDelay time.Duration) (in string, cached bool, delayTillNextUpdate time.Duration, err error) {
cached = false
expired := false
in, expired, delayTillNextUpdate, err = fetchFromCache(cacheFile)
in, expired, delayTillNextUpdate, err = fetchFromCache(cacheFile, refreshDelay)
if err == nil && !expired {
dlog.Debugf("Delay till next update: %v", delayTillNextUpdate)
cached = true
@ -110,7 +113,7 @@ func fetchWithCache(xTransport *XTransport, urlStr string, cacheFile string) (in
err = nil
cached = false
in = string(bin)
delayTillNextUpdate = SourcesUpdateDelay
delayTillNextUpdate = refreshDelay
return
}
@ -125,7 +128,6 @@ type URLToPrefetch struct {
}
func NewSource(xTransport *XTransport, urls []string, minisignKeyStr string, cacheFile string, formatStr string, refreshDelay time.Duration) (Source, []URLToPrefetch, error) {
_ = refreshDelay
source := Source{urls: urls}
if formatStr == "v2" {
source.format = SourceFormatV2
@ -146,14 +148,14 @@ func NewSource(xTransport *XTransport, urls []string, minisignKeyStr string, cac
var sigErr error
var preloadURL string
if len(urls) <= 0 {
in, cached, delayTillNextUpdate, err = fetchWithCache(xTransport, "", cacheFile)
sigStr, sigCached, sigDelayTillNextUpdate, sigErr = fetchWithCache(xTransport, "", sigCacheFile)
in, cached, delayTillNextUpdate, err = fetchWithCache(xTransport, "", cacheFile, refreshDelay)
sigStr, sigCached, sigDelayTillNextUpdate, sigErr = fetchWithCache(xTransport, "", sigCacheFile, refreshDelay)
} else {
preloadURL = urls[0]
for _, url := range urls {
sigURL := url + ".minisig"
in, cached, delayTillNextUpdate, err = fetchWithCache(xTransport, url, cacheFile)
sigStr, sigCached, sigDelayTillNextUpdate, sigErr = fetchWithCache(xTransport, sigURL, sigCacheFile)
in, cached, delayTillNextUpdate, err = fetchWithCache(xTransport, url, cacheFile, refreshDelay)
sigStr, sigCached, sigDelayTillNextUpdate, sigErr = fetchWithCache(xTransport, sigURL, sigCacheFile, refreshDelay)
if err == nil && sigErr == nil {
preloadURL = url
break
@ -268,7 +270,7 @@ func (source *Source) parseV2(prefix string) ([]RegisteredServer, error) {
}
func PrefetchSourceURL(xTransport *XTransport, urlToPrefetch *URLToPrefetch) error {
in, cached, delayTillNextUpdate, err := fetchWithCache(xTransport, urlToPrefetch.url, urlToPrefetch.cacheFile)
in, cached, delayTillNextUpdate, err := fetchWithCache(xTransport, urlToPrefetch.url, urlToPrefetch.cacheFile, MinSourcesUpdateDelay)
if err == nil && !cached {
AtomicFileWrite(urlToPrefetch.cacheFile, []byte(in))
}