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http: handle weak etags on comparisons 

When server returns a weak etag, the prefix can
cause a mismatch on direct comparison with old value.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
master
Tonis Tiigi 2022-02-13 21:21:38 -08:00
parent 63eff24da0
commit 4d0a3f9ff3
1 changed files with 8 additions and 2 deletions
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10
source/http/httpsource.go
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@ -181,7 +181,7 @@ func (hs *httpSourceHandler) CacheKey(ctx context.Context, g session.Group, inde
resp, err := client.Do(req)
if err == nil {
if resp.StatusCode == http.StatusOK || resp.StatusCode == http.StatusNotModified {
respETag := resp.Header.Get("ETag")
respETag := etagValue(resp.Header.Get("ETag"))
// If a 304 is returned without an ETag and we had only sent one ETag,
// the response refers to the ETag we asked about.
@ -212,7 +212,7 @@ func (hs *httpSourceHandler) CacheKey(ctx context.Context, g session.Group, inde
return "", "", nil, false, errors.Errorf("invalid response status %d", resp.StatusCode)
}
if resp.StatusCode == http.StatusNotModified {
respETag := resp.Header.Get("ETag")
respETag := etagValue(resp.Header.Get("ETag"))
if respETag == "" && onlyETag != "" {
respETag = onlyETag
@ -350,6 +350,7 @@ func (hs *httpSourceHandler) save(ctx context.Context, resp *http.Response, s se
dgst = digest.NewDigest(digest.SHA256, h)
if respETag := resp.Header.Get("ETag"); respETag != "" {
respETag = etagValue(respETag)
if err := md.setETag(respETag); err != nil {
return nil, "", err
}
@ -471,3 +472,8 @@ func (md cacheRefMetadata) getHTTPModTime() string {
func (md cacheRefMetadata) setHTTPModTime(s string) error {
return md.SetString(keyModTime, s, "")
}
func etagValue(v string) string {
// remove weak for direct comparison
return strings.TrimPrefix(v, "W/")
}