miracle091/dnscrypt-proxy
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dnscrypt-proxy
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Refactor saving downloads to cache 

Moved writing to happen immediately after the download to reduce duplicated code and number of return values from the download function.
This commit is contained in:
William Elwood 2019-10-30 04:45:04 +00:00 committed by Frank Denis
parent 4c156784c8
commit ad92be5b9c
1 changed files with 11 additions and 30 deletions
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41
dnscrypt-proxy/sources.go
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@ -84,18 +84,13 @@ func fetchFromURL(xTransport *XTransport, u *url.URL) (bin []byte, err error) {
return return
} }
func fetchWithCache(xTransport *XTransport, urlStr string, cacheFile string, refreshDelay time.Duration) (in string, cached bool, delayTillNextUpdate time.Duration, err error) { func fetchWithCache(xTransport *XTransport, urlStr string, cacheFile string, refreshDelay time.Duration) (in string, delayTillNextUpdate time.Duration, err error) {
cached = false
expired := false expired := false
in, expired, delayTillNextUpdate, err = fetchFromCache(cacheFile, refreshDelay) in, expired, delayTillNextUpdate, err = fetchFromCache(cacheFile, refreshDelay)
if err == nil && !expired { if err == nil && !expired {
dlog.Debugf("Delay till next update: %v", delayTillNextUpdate) dlog.Debugf("Delay till next update: %v", delayTillNextUpdate)
cached = true
return return
} }
if expired {
cached = true
}
if len(urlStr) == 0 { if len(urlStr) == 0 {
if !expired { if !expired {
err = fmt.Errorf("Cache file [%s] not present and no URL given to retrieve it", cacheFile) err = fmt.Errorf("Cache file [%s] not present and no URL given to retrieve it", cacheFile)
@ -113,7 +108,11 @@ func fetchWithCache(xTransport *XTransport, urlStr string, cacheFile string, ref
if bin, err = fetchFromURL(xTransport, u); err != nil { if bin, err = fetchFromURL(xTransport, u); err != nil {
return return
} }
cached = false if err = AtomicFileWrite(cacheFile, bin); err != nil {
if absPath, err2 := filepath.Abs(cacheFile); err2 == nil {
dlog.Warnf("%s: %s", absPath, err)
}
}
in = string(bin) in = string(bin)
delayTillNextUpdate = MinSourcesUpdateDelay delayTillNextUpdate = MinSourcesUpdateDelay
return return
@ -146,19 +145,18 @@ func NewSource(xTransport *XTransport, urls []string, minisignKeyStr string, cac
sigCacheFile := cacheFile + ".minisig" sigCacheFile := cacheFile + ".minisig"
var sigStr, in string var sigStr, in string
var cached, sigCached bool
var delayTillNextUpdate, sigDelayTillNextUpdate time.Duration var delayTillNextUpdate, sigDelayTillNextUpdate time.Duration
var err, sigErr error var err, sigErr error
var preloadURL string var preloadURL string
if len(urls) <= 0 { if len(urls) <= 0 {
in, cached, delayTillNextUpdate, err = fetchWithCache(xTransport, "", cacheFile, refreshDelay) in, delayTillNextUpdate, err = fetchWithCache(xTransport, "", cacheFile, refreshDelay)
sigStr, sigCached, sigDelayTillNextUpdate, sigErr = fetchWithCache(xTransport, "", sigCacheFile, refreshDelay) sigStr, sigDelayTillNextUpdate, sigErr = fetchWithCache(xTransport, "", sigCacheFile, refreshDelay)
} else { } else {
preloadURL = urls[0] preloadURL = urls[0]
for _, url := range urls { for _, url := range urls {
sigURL := url + ".minisig" sigURL := url + ".minisig"
in, cached, delayTillNextUpdate, err = fetchWithCache(xTransport, url, cacheFile, refreshDelay) in, delayTillNextUpdate, err = fetchWithCache(xTransport, url, cacheFile, refreshDelay)
sigStr, sigCached, sigDelayTillNextUpdate, sigErr = fetchWithCache(xTransport, sigURL, sigCacheFile, refreshDelay) sigStr, sigDelayTillNextUpdate, sigErr = fetchWithCache(xTransport, sigURL, sigCacheFile, refreshDelay)
if err == nil && sigErr == nil { if err == nil && sigErr == nil {
preloadURL = url preloadURL = url
break break
@ -182,20 +180,6 @@ func NewSource(xTransport *XTransport, urls []string, minisignKeyStr string, cac
if err = source.checkSignature(in, sigStr); err != nil { if err = source.checkSignature(in, sigStr); err != nil {
return source, urlsToPrefetch, err return source, urlsToPrefetch, err
} }
if !cached {
if err = AtomicFileWrite(cacheFile, []byte(in)); err != nil {
if absPath, err2 := filepath.Abs(cacheFile); err2 == nil {
dlog.Warnf("%s: %s", absPath, err)
}
}
}
if !sigCached {
if err = AtomicFileWrite(sigCacheFile, []byte(sigStr)); err != nil {
if absPath, err2 := filepath.Abs(sigCacheFile); err2 == nil {
dlog.Warnf("%s: %s", absPath, err)
}
}
}
dlog.Noticef("Source [%s] loaded", cacheFile) dlog.Noticef("Source [%s] loaded", cacheFile)
source.in = in source.in = in
return source, urlsToPrefetch, nil return source, urlsToPrefetch, nil
@ -276,10 +260,7 @@ PartsLoop:
} }
func PrefetchSourceURL(xTransport *XTransport, urlToPrefetch *URLToPrefetch) error { func PrefetchSourceURL(xTransport *XTransport, urlToPrefetch *URLToPrefetch) error {
in, cached, delayTillNextUpdate, err := fetchWithCache(xTransport, urlToPrefetch.url, urlToPrefetch.cacheFile, MinSourcesUpdateDelay) _, delayTillNextUpdate, err := fetchWithCache(xTransport, urlToPrefetch.url, urlToPrefetch.cacheFile, MinSourcesUpdateDelay)
if err == nil && !cached {
AtomicFileWrite(urlToPrefetch.cacheFile, []byte(in))
}
urlToPrefetch.when = timeNow().Add(delayTillNextUpdate) urlToPrefetch.when = timeNow().Add(delayTillNextUpdate)
return err return err
} }