alice.pds.demo.boltless.dev
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appview,knotserver: use ETag based caching for blobs
this avoids stale raw content from being sent to clients.
Signed-off-by: oppiliappan <me@oppi.li>
author
oppiliappan
committer
Tangled
date
(Aug 21, 2025, 3:06 PM UTC)
commit
6be6a26b
6be6a26b0e5ccce28494ab451f401af655a8ac1b
parent
c4d3a083
c4d3a083f67575da4fdea079ed84047172f9c8e1
+34
-9
+22
-2
appview/repo/repo.go
+22
-2
appview/repo/repo.go
···
734
734
if !rp.config.Core.Dev {
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735
protocol = "https"
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}
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+
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blobURL := fmt.Sprintf("%s://%s/%s/%s/raw/%s/%s", protocol, f.Knot, f.OwnerDid(), f.Repo.Name, ref, filePath)
738
-
resp, err := http.Get(blobURL)
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+
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+
req, err := http.NewRequest("GET", blobURL, nil)
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if err != nil {
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-
log.Println("failed to reach knotserver:", err)
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+
log.Println("failed to create request", err)
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+
return
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+
}
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+
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+
// forward the If-None-Match header
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+
if clientETag := r.Header.Get("If-None-Match"); clientETag != "" {
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+
req.Header.Set("If-None-Match", clientETag)
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+
}
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+
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+
client := &http.Client{}
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+
resp, err := client.Do(req)
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+
if err != nil {
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+
log.Println("failed to reach knotserver", err)
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rp.pages.Error503(w)
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return
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}
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defer resp.Body.Close()
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+
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+
// forward 304 not modified
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+
if resp.StatusCode == http.StatusNotModified {
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+
w.WriteHeader(http.StatusNotModified)
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+
return
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+
}
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if resp.StatusCode != http.StatusOK {
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log.Printf("knotserver returned non-OK status for raw blob %s: %d", blobURL, resp.StatusCode)
+12
-7
knotserver/routes.go
+12
-7
knotserver/routes.go
···
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mimeType = "image/svg+xml"
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}
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+
contentHash := sha256.Sum256(contents)
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+
eTag := fmt.Sprintf("\"%x\"", contentHash)
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+
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// allow image, video, and text/plain files to be served directly
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switch {
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-
case strings.HasPrefix(mimeType, "image/"):
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-
// allowed
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-
case strings.HasPrefix(mimeType, "video/"):
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-
// allowed
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+
case strings.HasPrefix(mimeType, "image/"), strings.HasPrefix(mimeType, "video/"):
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+
if clientETag := r.Header.Get("If-None-Match"); clientETag == eTag {
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+
w.WriteHeader(http.StatusNotModified)
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+
return
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+
}
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+
w.Header().Set("ETag", eTag)
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+
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case strings.HasPrefix(mimeType, "text/plain"):
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-
// allowed
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+
w.Header().Set("Cache-Control", "public, no-cache")
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+
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default:
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l.Error("attempted to serve disallowed file type", "mimetype", mimeType)
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writeError(w, "only image, video, and text files can be accessed directly", http.StatusForbidden)
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return
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}
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-
w.Header().Set("Cache-Control", "public, max-age=86400") // cache for 24 hours
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-
w.Header().Set("ETag", fmt.Sprintf("%x", sha256.Sum256(contents)))
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w.Header().Set("Content-Type", mimeType)
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w.Write(contents)
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}