func extractJSONURL(htmlDoc io.Reader) (string, error) { z := html.NewTokenizer(htmlDoc) for { tt := z.Next() switch { case tt == html.ErrorToken: return "", fmt.Errorf("expected alternate <link> not found in fetched HTML document") case tt == html.StartTagToken: t := z.Token() if t.Data == "link" && getAttr(&t, "rel") == "alternate" && getAttr(&t, "type") == "application/asciicast+json" { return getAttr(&t, "href"), nil } } } }
func prescan(content []byte) (e encoding.Encoding, name string) { z := html.NewTokenizer(bytes.NewReader(content)) for { switch z.Next() { case html.ErrorToken: return nil, "" case html.StartTagToken, html.SelfClosingTagToken: tagName, hasAttr := z.TagName() if !bytes.Equal(tagName, []byte("meta")) { continue } attrList := make(map[string]bool) gotPragma := false const ( dontKnow = iota doNeedPragma doNotNeedPragma ) needPragma := dontKnow name = "" e = nil for hasAttr { var key, val []byte key, val, hasAttr = z.TagAttr() ks := string(key) if attrList[ks] { continue } attrList[ks] = true for i, c := range val { if 'A' <= c && c <= 'Z' { val[i] = c + 0x20 } } switch ks { case "http-equiv": if bytes.Equal(val, []byte("content-type")) { gotPragma = true } case "content": if e == nil { name = fromMetaElement(string(val)) if name != "" { e, name = Lookup(name) if e != nil { needPragma = doNeedPragma } } } case "charset": e, name = Lookup(string(val)) needPragma = doNotNeedPragma } } if needPragma == dontKnow || needPragma == doNeedPragma && !gotPragma { continue } if strings.HasPrefix(name, "utf-16") { name = "utf-8" e = encoding.Nop } if e != nil { return e, name } } } }