package transform
import (
htmltran "code.google.com/p/go-html-transform/html/transform"
"io"
"net/url"
)
type AbsURL struct {
BaseURL string
}
func (t *AbsURL) Apply(w io.Writer, r io.Reader) (err error) {
var tr *htmltran.Transformer
if tr, err = htmltran.NewFromReader(r); err != nil {
return
}
if err = t.absUrlify(tr, elattr{"a", "href"}, elattr{"script", "src"}); err != nil {
return
}
return tr.Render(w)
}
type elattr struct {
tag, attr string
}
func (t *AbsURL) absUrlify(tr *htmltran.Transformer, selectors ...elattr) (err error) {
var baseURL, inURL *url.URL
if baseURL, err = url.Parse(t.BaseURL); err != nil {
return
}
replace := func(in string) string {
if inURL, err = url.Parse(in); err != nil {
return in + "?"
}
if fragmentOnly(inURL) {
return in
}
return baseURL.ResolveReference(inURL).String()
}
for _, el := range selectors {
if err = tr.Apply(htmltran.TransformAttrib(el.attr, replace), el.tag); err != nil {
return
}
}
return
}
func fragmentOnly(u *url.URL) bool {
return u.Fragment != "" && u.Scheme == "" && u.Opaque == "" && u.User == nil && u.Host == "" && u.Path == "" && u.Path == "" && u.RawQuery == ""
}