Files
mangaBookmark/backend/internal/userscript/userscript.go
T
sulthan b0bf6fe770 feat: register any guild member as a Reader (#27)
Guild membership is now the whole gate: discordCallback checks membership
(and DISCORD_REQUIRED_ROLE when set), then Store.EnsureReader creates the
Reader on first sight and returns the same row on every later login. The
refusal returns before EnsureReader, so nothing is created as a side
effect of being turned away. OWNER_DISCORD_ID keeps seeding the owner, but
only as the administrator — it no longer gates sign-in.

The cutover grace path is gone with it: API_TOKEN, API_TOKEN_GRACE_UNTIL
and the legacy branch in httpmw.ResolveReader are deleted, so a credential
authenticates exactly one Reader or nothing. That also lets
userscript.Handler drop the re-derivation — the resolved path segment is
already the credential to substitute.

New surfaces: an empty library offers both install links instead of
describing a filter (listView.Fresh, which also hides the action key it has
nothing to name), and the owner alone gets a Readers panel with
POST /readers/{id}/revoke (404 for anyone else) to sign a Reader out
everywhere.

Isolation is asserted from both directions rather than by counting one
Reader's rows, and the shared-series invariant is pinned: two Readers on
one series produce one series row, two independent progresses, one poll
per due cycle, and one Reader's delete leaves the other's bookmark and the
poll intact.
2026-08-08 20:01:42 +07:00

101 lines
4.1 KiB
Go

package userscript
import (
"bytes"
"log"
"net/http"
"os"
"regexp"
"time"
"bookmarkmanager/backend/internal/httpmw"
"bookmarkmanager/backend/internal/store"
)
// tokenPlaceholder is what the bindmounted userscript carries where the
// Reader's credential goes: in the API_TOKEN constant and in the @downloadURL
// and @updateURL metadata lines. The handler substitutes the requesting
// Reader's credential for it at serve time, so no credential literal is ever
// committed or deployed, and each Reader's copy carries exactly their own.
var tokenPlaceholder = []byte("__API_TOKEN__")
// versionLine matches the userscript metadata block's @version directive.
var versionLine = regexp.MustCompile(`(?m)^// @version[ \t]+.*$`)
// stampVersion replaces the served @version with one derived from the file's
// mtime, discarding whatever the file body says.
//
// Violentmonkey only updates when the served version sorts higher than the
// installed one. Deriving it from the body means one accidental downgrade or
// typo freezes updates forever; an mtime-derived version is monotonic by
// construction, so any later write always outranks any earlier one.
//
// A file with no @version line is returned untouched: such a script never
// auto-updates anyway, and inventing a metadata block is not this handler's job.
func stampVersion(src []byte, mod time.Time) []byte {
return versionLine.ReplaceAll(src, []byte("// @version "+mod.UTC().Format("2006.01.02.1504")))
}
// substituteToken replaces every tokenPlaceholder with the Reader's
// credential. A file without the placeholder is returned unchanged so Render
// can warn about it rather than silently serving a credential-less script.
func substituteToken(src []byte, credential string) []byte {
return bytes.ReplaceAll(src, tokenPlaceholder, []byte(credential))
}
// Render writes one userscript file with the credential substituted and the
// mtime-derived version stamped. Shared by the download path (Handler) and
// the web UI's install endpoints, so both serve byte-identical scripts.
//
// The file is read per request — that is what lets a bindmounted copy be
// edited on the host without a restart. It is ~50 KB and polled about once a
// day.
func Render(w http.ResponseWriter, r *http.Request, path, credential string) {
info, err := os.Stat(path)
if err != nil {
log.Printf("userscript: stat %s: %v", path, err)
http.NotFound(w, r)
return
}
src, err := os.ReadFile(path)
if err != nil {
log.Printf("userscript: read %s: %v", path, err)
http.NotFound(w, r)
return
}
rendered := substituteToken(src, credential)
if bytes.Equal(rendered, src) {
// The bindmounted file was not built for per-Reader rendering. Serving
// it as written is the operator's freedom, but a credential-less copy
// is a deployment bug worth one log line — the symptom (silent 401s on
// every device) is otherwise indistinguishable from a network fault.
log.Printf("userscript: %s has no %s placeholder; serving as written", path, tokenPlaceholder)
}
w.Header().Set("Content-Type", "text/javascript; charset=utf-8")
w.Header().Set("Cache-Control", "no-cache")
w.Write(stampVersion(rendered, info.ModTime()))
}
// Handler serves the userscript to Violentmonkey's updater, rendered for the
// Reader whose credential is in the path.
//
// The credential lives in the path because the update poll sends no
// Authorization header, and the rendered file embeds the credential in
// plaintext, so an open path would hand it to anyone who guessed the URL. A
// mismatch answers 404 rather than 401: a prober learns nothing about whether
// the route exists. The same credential authenticates the API bearer header,
// so the two are one secret with one blast radius.
//
// The path segment is the credential itself, so once it resolves it is also
// exactly what the served copy must carry — no re-derivation needed.
func Handler(s *store.Store, path string) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
cred := r.PathValue("token")
if _, ok := httpmw.ResolveReader(s, cred); !ok {
http.NotFound(w, r)
return
}
Render(w, r, path, cred)
}
}