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Copy pathhtml.go
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653 lines (609 loc) · 18 KB
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package minify // import "github.com/tdewolff/minify"
import (
"bytes"
"io"
hash "github.com/tdewolff/parse/html"
"golang.org/x/net/html"
)
var specialTagMap = map[hash.Hash]bool{
hash.Code: true,
hash.Noscript: true,
hash.Pre: true,
hash.Script: true,
hash.Style: true,
hash.Textarea: true,
}
var inlineTagMap = map[hash.Hash]bool{
hash.A: true,
hash.Abbr: true,
hash.Acronym: true,
hash.B: true,
hash.Bdo: true,
hash.Big: true,
hash.Cite: true,
hash.Button: true,
hash.Dfn: true,
hash.Em: true,
hash.I: true,
hash.Img: true,
hash.Input: true,
hash.Kbd: true,
hash.Label: true,
hash.Map: true,
hash.Object: true,
hash.Q: true,
hash.Samp: true,
hash.Select: true,
hash.Small: true,
hash.Span: true,
hash.Strong: true,
hash.Sub: true,
hash.Sup: true,
hash.Tt: true,
hash.Var: true,
}
var booleanAttrMap = map[hash.Hash]bool{
hash.Allowfullscreen: true,
hash.Async: true,
hash.Autofocus: true,
hash.Autoplay: true,
hash.Checked: true,
hash.Compact: true,
hash.Controls: true,
hash.Declare: true,
hash.Default: true,
hash.DefaultChecked: true,
hash.DefaultMuted: true,
hash.DefaultSelected: true,
ha
8000
sh.Defer: true,
hash.Disabled: true,
hash.Draggable: true,
hash.Enabled: true,
hash.Formnovalidate: true,
hash.Hidden: true,
hash.Inert: true,
hash.Ismap: true,
hash.Itemscope: true,
hash.Multiple: true,
hash.Muted: true,
hash.Nohref: true,
hash.Noresize: true,
hash.Noshade: true,
hash.Novalidate: true,
hash.Nowrap: true,
hash.Open: true,
hash.Pauseonexit: true,
hash.Readonly: true,
hash.Required: true,
hash.Reversed: true,
hash.Scoped: true,
hash.Seamless: true,
hash.Selected: true,
hash.Sortable: true,
hash.Spellcheck: true,
hash.Translate: true,
hash.Truespeed: true,
hash.Typemustmatch: true,
hash.Undeterminate: true,
hash.Visible: true,
}
var caseInsensitiveAttrMap = map[hash.Hash]bool{
hash.Accept_Charset: true,
hash.Accept: true,
hash.Align: true,
hash.Alink: true,
hash.Axis: true,
hash.Bgcolor: true,
hash.Charset: true,
hash.Clear: true,
hash.Codetype: true,
hash.Color: true,
hash.Dir: true,
hash.Enctype: true,
hash.Face: true,
hash.Frame: true,
hash.Hreflang: true,
hash.Http_Equiv: true,
hash.Lang: true,
hash.Language: true,
hash.Link: true,
hash.Media: true,
hash.Method: true,
hash.Rel: true,
hash.Rev: true,
hash.Rules: true,
hash.Scope: true,
hash.Scrolling: true,
hash.Shape: true,
hash.Target: true,
hash.Text: true,
hash.Type: true,
hash.Valign: true,
hash.Valuetype: true,
hash.Vlink: true,
}
var urlAttrMap = map[hash.Hash]bool{
hash.Action: true,
hash.Background: true,
hash.Cite: true,
hash.Classid: true,
hash.Codebase: true,
hash.Data: true,
hash.Formaction: true,
hash.Href: true,
hash.Icon: true,
hash.Longdesc: true,
hash.Manifest: true,
hash.Poster: true,
hash.Profile: true,
hash.Src: true,
hash.Usemap: true,
hash.Xmlns: true,
}
////////////////////////////////////////////////////////////////
// replaceMultipleWhitespace replaces any series of whitespace characters by a single space.
func replaceMultipleWhitespace(s []byte) []byte {
i := 0
t := make([]byte, len(s))
previousSpace := false
for _, x := range s {
if isWhitespace(x) {
if !previousSpace {
previousSpace = true
t[i] = ' '
i++
}
} else {
previousSpace = false
t[i] = x
i++
}
}
return t[:i]
}
func normalizeContentType(s []byte) []byte {
s = bytes.ToLower(bytes.TrimSpace(replaceMultipleWhitespace(s)))
t := make([]byte, len(s))
w := 0
start := 0
for j, x := range s {
if x == ' ' && (s[j-1] == ';' || s[j-1] == ',') {
w += copy(t[w:], s[start:j])
start = j + 1
}
}
w += copy(t[w:], s[start:])
return t[:w]
}
// escapeText escapes ampersands.
func escapeText(s []byte) []byte {
amps := 0
for _, x := range s {
if x == '&' {
amps++
}
}
t := make([]byte, len(s)+amps*4)
w := 0
start := 0
for j, x := range s {
if x == '&' {
w += copy(t[w:], s[start:j])
w += copy(t[w:], []byte("&"))
start = j + 1
}
}
copy(t[w:], s[start:])
return t
}
// escapeAttrVal returns the escape attribute value bytes without quotes.
func escapeAttrVal(s []byte) []byte {
if len(s) == 0 {
return []byte("\"\"")
}
amps := 0
singles := 0
doubles := 0
unquoted := true
for _, x := range s {
if x == '&' {
amps++
} else if x == '"' {
doubles++
} else if x == '\'' {
singles++
} else if unquoted && (x == '/' || x == '`' || x == '<' || x == '=' || x == '>' || isWhitespace(x)) {
// no slash either because it causes difficulties!
unquoted = false
}
}
if !unquoted || doubles > 0 || singles > 0 {
// quoted
c := amps + doubles
quote := byte('"')
escapedQuote := []byte(""")
if doubles > singles {
c = amps + singles
quote = byte('\'')
escapedQuote = []byte("'")
}
t := make([]byte, len(s)+c*4+2)
t[0] = quote
w := 1
start := 0
for j, x := range s {
if x == '&' {
w += copy(t[w:], s[start:j])
w += copy(t[w:], []byte("&"))
start = j + 1
} else if x == quote {
w += copy(t[w:], s[start:j])
w += copy(t[w:], escapedQuote)
start = j + 1
}
}
copy(t[w:], s[start:])
t[len(t)-1] = quote
return t
} else {
// unquoted
c := amps
t := make([]byte, len(s)+c*4)
w := 0
start := 0
for j, x := range s {
if x == '&' {
w += copy(t[w:], s[start:j])
w += copy(t[w:], []byte("&"))
start = j + 1
}
}
copy(t[w:], s[start:])
return t
}
}
// isWhitespace returns true for space, \n, \t, \f, \r.
func isWhitespace(x byte) bool {
return x == ' ' || x == '\t' || x == '\n' || x == '\r' || x == '\f'
}
// copyBytes copies bytes to the same position.
// This is required because the referenced slices from the tokenizer might be overwritten on subsequent Next calls.
func copyBytes(src []byte) []byte {
dst := make([]byte, len(src))
copy(dst, src)
return dst
}
////////////////////////////////////////////////////////////////
type attribute struct {
key hash.Hash
keyRaw, val []byte
}
type token struct {
tt html.TokenType
token hash.Hash
tokenRaw []byte
text []byte
attr []attribute
attrKey map[hash.Hash]int
}
func (t *token) getAttrVal(a hash.Hash) []byte {
if i, ok := t.attrKey[a]; ok {
return t.attr[i].val
}
return []byte{}
}
type tokenFeed struct {
z *html.Tokenizer
buf []*token
}
func newTokenFeed(z *html.Tokenizer) *tokenFeed {
return &tokenFeed{z: z}
}
func (tf *tokenFeed) shift() *token {
if len(tf.buf) > 0 {
tf.buf = tf.buf[1:]
}
return tf.peek(0)
}
func (tf *tokenFeed) peek(pos int) *token {
if pos == len(tf.buf) {
if len(tf.buf) > 0 {
t := tf.buf[len(tf.buf)-1]
t.tokenRaw = copyBytes(t.tokenRaw)
t.text = copyBytes(t.text)
for _, attr := range t.attr {
attr.keyRaw = copyBytes(attr.keyRaw)
attr.val = copyBytes(attr.val)
}
}
t := &token{tf.z.Next(), 0, nil, nil, nil, nil}
switch t.tt {
case html.TextToken, html.CommentToken, html.DoctypeToken:
t.text = tf.z.Text()
case html.StartTagToken, html.SelfClosingTagToken, html.EndTagToken:
var moreAttr bool
var keyRaw, val []byte
t.tokenRaw, moreAttr = tf.z.TagName()
t.token = hash.ToHash(t.tokenRaw)
if moreAttr {
t.attr = make([]attribute, 0, 3)
t.attrKey = make(map[hash.Hash]int)
for moreAttr {
keyRaw, val, moreAttr = tf.z.TagAttr()
key := hash.ToHash(keyRaw)
t.attr = append(t.attr, attribute{key, keyRaw, bytes.TrimSpace(val)})
t.attrKey[key] = len(t.attr) - 1
}
}
}
tf.buf = append(tf.buf, t)
return t
}
return tf.buf[pos]
}
func (tf tokenFeed) err() error {
return tf.z.Err()
}
////////////////////////////////////////////////////////////////
// HTML minifies HTML5 files, it reads from r and writes to w.
// Removes unnecessary whitespace, tags, attributes, quotes and comments and typically saves 10% in size.
func (m Minifier) HTML(w io.Writer, r io.Reader) error {
var specialTag []*token // stack array of special tags it is in
precededBySpace := true // on true the next text token must not start with a space
defaultScriptType := "text/javascript"
defaultStyleType := "text/css"
tf := newTokenFeed(html.NewTokenizer(r))
for {
t := tf.shift()
switch t.tt {
case html.ErrorToken:
if tf.err() == io.EOF {
return nil
}
return tf.err()
case html.DoctypeToken:
if _, err := w.Write([]byte("<!doctype html>")); err != nil {
return err
}
case html.CommentToken:
// TODO: ensure that nested comments are handled properly (tokenizer doesn't handle this!)
var text []byte
if bytes.HasPrefix(t.text, []byte("[if")) {
text = append(append([]byte("<!--"), t.text...), []byte("-->")...)
} else if bytes.HasSuffix(t.text, []byte("--")) {
// only occurs when mixed up with conditional comments
text = append(append([]byte("<!"), t.text...), '>')
}
if _, err := w.Write(text); err != nil {
return err
}
case html.TextToken:
// CSS and JS minifiers for inline code
if len(specialTag) > 0 {
token := specialTag[len(specialTag)-1].token
if token == hash.Style || token == hash.Script {
var mediatype string
mediatypeRaw := specialTag[len(specialTag)-1].getAttrVal(hash.Type)
if len(mediatypeRaw) > 0 {
mediatype = string(mediatypeRaw)
} else if token == hash.Script {
mediatype = defaultScriptType
} else {
mediatype = defaultStyleType
}
if err := m.Minify(mediatype, w, bytes.NewBuffer(t.text)); err != nil {
if err == ErrNotExist {
// no minifier, write the original
if _, err := w.Write(t.text); err != nil {
return err
}
} else {
return err
}
}
} else if token == hash.Noscript {
if err := m.HTML(w, bytes.NewBuffer(t.text)); err != nil {
return err
}
} else if _, err := w.Write(t.text); err != nil {
return err
}
} else if t.text = escapeText(replaceMultipleWhitespace(t.text)); len(t.text) > 0 {
// whitespace removal; trim left
if t.text[0] == ' ' && precededBySpace {
t.text = t.text[1:]
}
// whitespace removal; trim right
precededBySpace = false
if len(t.text) == 0 {
precededBySpace = true
} else if t.text[len(t.text)-1] == ' ' {
precededBySpace = true
trim := false
i := 1
for {
next := tf.peek(i)
// trim if EOF, text token with whitespace begin or block token
if next.tt == html.ErrorToken {
trim = true
break
} else if next.tt == html.TextToken {
// remove if the text token starts with a whitespace
trim = (len(next.text) > 0 && isWhitespace(next.text[0]))
break
} else if next.tt == html.StartTagToken || next.tt == html.EndTagToken || next.tt == html.SelfClosingTagToken {
if !inlineTagMap[next.token] {
trim = true
break
} else if next.tt == html.StartTagToken {
break
}
}
i++
}
if trim {
t.text = t.text[:len(t.text)-1]
precededBySpace = false
}
}
if _, err := w.Write(t.text); err != nil {
return err
}
}
case html.StartTagToken, html.EndTagToken, html.SelfClosingTagToken:
if !inlineTagMap[t.token] {
precededBySpace = true
if specialTagMap[t.token] {
if t.tt == html.StartTagToken {
specialTag = append(specialTag, t)
} else if t.tt == html.EndTagToken && len(specialTag) > 0 && specialTag[len(specialTag)-1].token == t.token {
specialTag = specialTag[:len(specialTag)-1]
}
// ignore empty script and style tags
if t.attr == nil && (t.token == hash.Script || t.token == hash.Style) {
if next := tf.peek(1); next.tt == html.EndTagToken {
tf.shift()
break
}
}
}
// remove superfluous ending tags
if t.attr == nil && (t.token == hash.Html || t.token == hash.Head || t.token == hash.Body ||
t.tt == html.EndTagToken && (t.token == hash.Td || t.token == hash.Tr || t.token == hash.Th || t.token == hash.Thead || t.token == hash.Tbody || t.token == hash.Tfoot ||
t.token == hash.Option || t.token == hash.Colgroup || t.token == hash.Dd || t.token == hash.Dt)) {
break
} else if t.tt == html.EndTagToken && (t.token == hash.P || t.token == hash.Li) {
remove := false
i := 1
for {
next := tf.peek(i)
i++
// continue if text token is empty or whitespace
if next.tt == html.TextToken && (len(next.text) == 0 || isWhitespace(next.text[0]) && len(replaceMultipleWhitespace(next.text)) == 1) {
continue
}
remove = (next.tt == html.ErrorToken || next.tt == html.EndTagToken || next.tt == html.StartTagToken && next.token == t.token)
break
}
if remove {
break
}
}
// rewrite meta tag with charset
if t.attr != nil && t.token == hash.Meta {
if _, ok := t.attrKey[hash.Charset]; !ok {
if iHttpEquiv, ok := t.attrKey[hash.Http_Equiv]; ok && bytes.Equal(bytes.ToLower(t.attr[iHttpEquiv].val), []byte("content-type")) {
if iContent, ok := t.attrKey[hash.Content]; ok && bytes.Equal(normalizeContentType(t.attr[iContent].val), []byte("text/html;charset=utf-8")) {
delete(t.attrKey, hash.Http_Equiv)
delete(t.attrKey, hash.Content)
t.attr = append(t.attr[:iContent], t.attr[iContent+1:]...)
t.attr[iHttpEquiv] = attribute{hash.Charset, []byte("charset"), []byte("utf-8")}
t.attrKey[hash.Charset] = iHttpEquiv
}
}
}
}
}
// write tag
if t.tt == html.EndTagToken {
if _, err := w.Write([]byte("</")); err != nil {
return err
}
} else {
if _, err := w.Write([]byte("<")); err != nil {
return err
}
}
if _, err := w.Write(t.tokenRaw); err != nil {
return err
}
// write attributes
for _, attr := range t.attr {
val := attr.val
if caseInsensitiveAttrMap[attr.key] {
val = bytes.ToLower(val)
if attr.key == hash.Enctype || attr.key == hash.Codetype || attr.key == hash.Accept || attr.key == hash.Type && (t.token == hash.A || t.token == hash.Link || t.token == hash.Object || t.token == hash.Param || t.token == hash.Script || t.token == hash.Style || t.token == hash.Source) {
val = normalizeContentType(val)
}
}
// default attribute values can be ommited
if attr.key == hash.Type && (t.token == hash.Script && bytes.Equal(val, []byte("text/javascript")) ||
t.token == hash.Style && bytes.Equal(val, []byte("text/css")) ||
t.token == hash.Link && bytes.Equal(val, []byte("text/css")) ||
t.token == hash.Input && bytes.Equal(val, []byte("text")) ||
t.token == hash.Button && bytes.Equal(val, []byte("submit"))) ||
attr.key == hash.Method && bytes.Equal(val, []byte("get")) ||
attr.key == hash.Enctype && bytes.Equal(val, []byte("application/x-www-form-urlencoded")) ||
attr.key == hash.Colspan && bytes.Equal(val, []byte("1")) ||
attr.key == hash.Rowspan && bytes.Equal(val, []byte("1")) ||
attr.key == hash.Shape && bytes.Equal(val, []byte("rect")) ||
attr.key == hash.Span && bytes.Equal(val, []byte("1")) ||
attr.key == hash.Clear && bytes.Equal(val, []byte("none")) ||
attr.key == hash.Frameborder && bytes.Equal(val, []byte("1")) ||
attr.key == hash.Scrolling && bytes.Equal(val, []byte("auto")) ||
attr.key == hash.Valuetype && bytes.Equal(val, []byte("data")) ||
attr.key == hash.Language && t.token == hash.Script && bytes.Equal(val, []byte("javascript")) {
continue
}
if _, err := w.Write([]byte(" ")); err != nil {
return err
}
if _, err := w.Write(attr.keyRaw); err != nil {
return err
}
// booleans have no value
if !booleanAttrMap[attr.key] {
if len(val) == 0 {
continue
}
var err error
if _, err := w.Write([]byte("=")); err != nil {
return err
}
// CSS and JS minifiers for attribute inline code
if attr.key == hash.Style {
val, err = m.MinifyBytes(defaultStyleType, val)
if err != nil && err != ErrNotExist {
return err
}
} else if len(attr.keyRaw) > 2 && attr.keyRaw[0] == 'o' && attr.keyRaw[1] == 'n' {
if len(val) >= 11 && bytes.Equal(bytes.ToLower(val[:11]), []byte("javascript:")) {
val = val[11:]
}
val, err = m.MinifyBytes(defaultScriptType, val)
if err != nil && err != ErrNotExist {
return err
}
} else if urlAttrMap[attr.key] {
if len(val) >= 5 && bytes.Equal(bytes.ToLower(val[:5]), []byte("http:")) {
val = val[5:]
}
} else if t.token == hash.Meta && attr.key == hash.Content {
httpEquiv := t.getAttrVal(hash.Http_Equiv)
if bytes.Equal(httpEquiv, []byte("content-type")) {
val = normalizeContentType(val)
} else if bytes.Equal(httpEquiv, []byte("content-style-type")) {
defaultStyleType = string(normalizeContentType(val))
} else if bytes.Equal(httpEquiv, []byte("content-script-type")) {
defaultScriptType = string(normalizeContentType(val))
}
name := bytes.ToLower(t.getAttrVal(hash.Name))
if bytes.Equal(name, []byte("keywords")) {
val = bytes.Replace(val, []byte(", "), []byte(","), -1)
} else if bytes.Equal(name, []byte("viewport")) {
val = bytes.Replace(val, []byte(" "), []byte(""), -1)
}
}
// no quotes if possible, else prefer single or double depending on which occurs more often in value
val = escapeAttrVal(val)
if _, err := w.Write(val); err != nil {
return err
}
}
}
if _, err := w.Write([]byte(">")); err != nil {
return err
}
}
}
}