Files
kage/asset/css.go
T
Duc-Tam Nguyen e6afa91e09 Add the clone engine, CLI, tests, CI, and docs
kage renders every page in headless Chrome, snapshots the final
DOM, strips all JavaScript, and localises CSS, images, and fonts
so a site can be browsed offline as a plain folder of files.

The engine is split into small packages:

  urlx      deterministic URL to local-path mapping and scope rules
  sanitize  remove scripts, on* handlers, and javascript: URLs
  asset     rewrite HTML and CSS references, download assets
  browser   headless Chrome pool over the DevTools protocol
  robots    robots.txt matcher
  clone     the orchestrator: a polite resumable breadth-first crawl

The cli package wires a cobra and fang command surface with two
commands, clone and serve. Every pure package has table tests; the
browser and clone packages add Chrome-driven end-to-end tests that
skip when no browser is present or under -short.

CI runs gofmt, vet, build, race tests, golangci-lint, govulncheck,
and a tidy check on Linux and macOS. A goreleaser config fans one
tag out to archives, deb/rpm/apk, a Chromium-bundled GHCR image,
and the package managers. A tago docs site builds to Pages and
Cloudflare.
2026-06-14 18:22:25 +07:00

70 lines
2.2 KiB
Go

package asset
import (
"net/url"
"regexp"
"strings"
"github.com/tamnd/kage/urlx"
)
// RefSink registers a resolved asset/page URL with the cloner and returns the
// string to write back into the markup or CSS — a relative local path for
// things kage saves, or the absolute URL for anything it leaves on the live web.
type RefSink func(u *url.URL, kind urlx.Kind) string
var (
// url( ... ) with optional single/double quotes or bare token.
cssURLRe = regexp.MustCompile(`url\(\s*("[^"]*"|'[^']*'|[^)'"]*)\s*\)`)
// @import "..." / @import '...' (the @import url(...) form is caught by cssURLRe).
cssImportRe = regexp.MustCompile(`@import\s+("[^"]*"|'[^']*')`)
)
// RewriteCSS rewrites every url(...) and @import in a stylesheet so its
// references point at local files. base is the stylesheet's own URL (so relative
// references resolve correctly); sink maps each absolute URL to its local path.
// data: URLs and unparseable references are left untouched.
func RewriteCSS(css []byte, base *url.URL, sink RefSink) []byte {
s := string(css)
s = cssImportRe.ReplaceAllStringFunc(s, func(m string) string {
raw := cssImportRe.FindStringSubmatch(m)[1]
ref := unquote(raw)
if newRef, ok := resolveRef(base, ref, sink); ok {
return `@import "` + newRef + `"`
}
return m
})
s = cssURLRe.ReplaceAllStringFunc(s, func(m string) string {
raw := cssURLRe.FindStringSubmatch(m)[1]
ref := unquote(raw)
if newRef, ok := resolveRef(base, ref, sink); ok {
return `url("` + newRef + `")`
}
return m
})
return []byte(s)
}
// resolveRef normalises ref against base and runs it through the sink. It
// reports ok=false (leave the original text) for empty, data:, or unparseable
// references.
func resolveRef(base *url.URL, ref string, sink RefSink) (string, bool) {
ref = strings.TrimSpace(ref)
if ref == "" || strings.HasPrefix(strings.ToLower(ref), "data:") || strings.HasPrefix(ref, "#") {
return "", false
}
u, err := urlx.Normalize(base, ref)
if err != nil {
return "", false
}
return sink(u, urlx.Asset), true
}
func unquote(s string) string {
s = strings.TrimSpace(s)
if len(s) >= 2 && (s[0] == '"' || s[0] == '\'') && s[len(s)-1] == s[0] {
return s[1 : len(s)-1]
}
return s
}