/
html.go
457 lines (429 loc) · 15.5 KB
/
html.go
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// Package html minifies HTML5 following the specifications at http://www.w3.org/TR/html5/syntax.html.
package html // import "github.com/tdewolff/minify/html"
import (
"bytes"
"io"
"github.com/tdewolff/minify"
"github.com/tdewolff/parse"
"github.com/tdewolff/parse/buffer"
"github.com/tdewolff/parse/html"
)
var (
gtBytes = []byte(">")
isBytes = []byte("=")
spaceBytes = []byte(" ")
doctypeBytes = []byte("<!doctype html>")
jsMimeBytes = []byte("application/javascript")
cssMimeBytes = []byte("text/css")
htmlMimeBytes = []byte("text/html")
svgMimeBytes = []byte("image/svg+xml")
mathMimeBytes = []byte("application/mathml+xml")
dataSchemeBytes = []byte("data:")
jsSchemeBytes = []byte("javascript:")
httpBytes = []byte("http")
inlineParams = map[string]string{"inline": "1"}
)
////////////////////////////////////////////////////////////////
// DefaultMinifier is the default minifier.
var DefaultMinifier = &Minifier{}
// Minifier is an HTML minifier.
type Minifier struct {
KeepConditionalComments bool
KeepDefaultAttrVals bool
KeepDocumentTags bool
KeepEndTags bool
KeepWhitespace bool
}
// Minify minifies HTML data, it reads from r and writes to w.
func Minify(m *minify.M, w io.Writer, r io.Reader, params map[string]string) error {
return DefaultMinifier.Minify(m, w, r, params)
}
// Minify minifies HTML data, it reads from r and writes to w.
func (o *Minifier) Minify(m *minify.M, w io.Writer, r io.Reader, _ map[string]string) error {
var rawTagHash html.Hash
var rawTagMediatype []byte
omitSpace := true // if true the next leading space is omitted
inPre := false
attrMinifyBuffer := buffer.NewWriter(make([]byte, 0, 64))
attrByteBuffer := make([]byte, 0, 64)
l := html.NewLexer(r)
defer l.Restore()
tb := NewTokenBuffer(l)
for {
t := *tb.Shift()
SWITCH:
switch t.TokenType {
case html.ErrorToken:
if l.Err() == io.EOF {
return nil
}
return l.Err()
case html.DoctypeToken:
if _, err := w.Write(doctypeBytes); err != nil {
return err
}
case html.CommentToken:
if o.KeepConditionalComments && len(t.Text) > 6 && (bytes.HasPrefix(t.Text, []byte("[if ")) || bytes.HasSuffix(t.Text, []byte("[endif]")) || bytes.HasSuffix(t.Text, []byte("[endif]--"))) {
// [if ...] is always 7 or more characters, [endif] is only encountered for downlevel-revealed
// see https://msdn.microsoft.com/en-us/library/ms537512(v=vs.85).aspx#syntax
if bytes.HasPrefix(t.Data, []byte("<!--[if ")) && bytes.HasSuffix(t.Data, []byte("<![endif]-->")) { // downlevel-hidden
begin := bytes.IndexByte(t.Data, '>') + 1
end := len(t.Data) - len("<![endif]-->")
if _, err := w.Write(t.Data[:begin]); err != nil {
return err
}
if err := o.Minify(m, w, buffer.NewReader(t.Data[begin:end]), nil); err != nil {
return err
}
if _, err := w.Write(t.Data[end:]); err != nil {
return err
}
} else if _, err := w.Write(t.Data); err != nil { // downlevel-revealed or short downlevel-hidden
return err
}
}
case html.SvgToken:
if err := m.MinifyMimetype(svgMimeBytes, w, buffer.NewReader(t.Data), nil); err != nil {
if err != minify.ErrNotExist {
return err
} else if _, err := w.Write(t.Data); err != nil {
return err
}
}
case html.MathToken:
if err := m.MinifyMimetype(mathMimeBytes, w, buffer.NewReader(t.Data), nil); err != nil {
if err != minify.ErrNotExist {
return err
} else if _, err := w.Write(t.Data); err != nil {
return err
}
}
case html.TextToken:
// CSS and JS minifiers for inline code
if rawTagHash != 0 {
if rawTagHash == html.Style || rawTagHash == html.Script || rawTagHash == html.Iframe {
var mimetype []byte
var params map[string]string
if rawTagHash == html.Iframe {
mimetype = htmlMimeBytes
} else if len(rawTagMediatype) > 0 {
mimetype, params = parse.Mediatype(rawTagMediatype)
} else if rawTagHash == html.Script {
mimetype = jsMimeBytes
} else if rawTagHash == html.Style {
mimetype = cssMimeBytes
}
if err := m.MinifyMimetype(mimetype, w, buffer.NewReader(t.Data), params); err != nil {
if err != minify.ErrNotExist {
return err
} else if _, err := w.Write(t.Data); err != nil {
return err
}
}
} else if _, err := w.Write(t.Data); err != nil {
return err
}
} else if inPre {
if _, err := w.Write(t.Data); err != nil {
return err
}
} else {
t.Data = parse.ReplaceMultipleWhitespace(t.Data)
// whitespace removal; trim left
if omitSpace && (t.Data[0] == ' ' || t.Data[0] == '\n') {
t.Data = t.Data[1:]
}
// whitespace removal; trim right
omitSpace = false
if len(t.Data) == 0 {
omitSpace = true
} else if t.Data[len(t.Data)-1] == ' ' || t.Data[len(t.Data)-1] == '\n' {
omitSpace = true
i := 0
for {
next := tb.Peek(i)
// trim if EOF, text token with leading whitespace or block token
if next.TokenType == html.ErrorToken {
t.Data = t.Data[:len(t.Data)-1]
omitSpace = false
break
} else if next.TokenType == html.TextToken {
// this only happens when a comment, doctype or phrasing end tag (only for !o.KeepWhitespace) was in between
// remove if the text token starts with a whitespace
if len(next.Data) > 0 && parse.IsWhitespace(next.Data[0]) {
t.Data = t.Data[:len(t.Data)-1]
omitSpace = false
}
break
} else if next.TokenType == html.StartTagToken || next.TokenType == html.EndTagToken {
if o.KeepWhitespace {
break
}
// remove when followed up by a block tag
if next.Traits&nonPhrasingTag != 0 {
t.Data = t.Data[:len(t.Data)-1]
omitSpace = false
break
} else if next.TokenType == html.StartTagToken {
break
}
}
i++
}
}
if _, err := w.Write(t.Data); err != nil {
return err
}
}
case html.StartTagToken, html.EndTagToken:
rawTagHash = 0
hasAttributes := false
if t.TokenType == html.StartTagToken {
if next := tb.Peek(0); next.TokenType == html.AttributeToken {
hasAttributes = true
}
if t.Traits&rawTag != 0 {
// ignore empty script and style tags
if !hasAttributes && (t.Hash == html.Script || t.Hash == html.Style) {
if next := tb.Peek(1); next.TokenType == html.EndTagToken {
tb.Shift()
tb.Shift()
break
}
}
rawTagHash = t.Hash
rawTagMediatype = nil
}
} else if t.Hash == html.Template {
omitSpace = true // EndTagToken
}
if t.Hash == html.Pre {
inPre = t.TokenType == html.StartTagToken
}
// remove superfluous tags, except for html, head and body tags when KeepDocumentTags is set
if !hasAttributes && (!o.KeepDocumentTags && (t.Hash == html.Html || t.Hash == html.Head || t.Hash == html.Body) || t.Hash == html.Colgroup) {
break
} else if t.TokenType == html.EndTagToken {
if !o.KeepEndTags {
if t.Hash == html.Thead || t.Hash == html.Tbody || t.Hash == html.Tfoot || t.Hash == html.Tr || t.Hash == html.Th || t.Hash == html.Td ||
t.Hash == html.Optgroup || t.Hash == html.Option || t.Hash == html.Dd || t.Hash == html.Dt ||
t.Hash == html.Li || t.Hash == html.Rb || t.Hash == html.Rt || t.Hash == html.Rtc || t.Hash == html.Rp {
break
} else if t.Hash == html.P {
i := 0
for {
next := tb.Peek(i)
i++
// continue if text token is empty or whitespace
if next.TokenType == html.TextToken && parse.IsAllWhitespace(next.Data) {
continue
}
if next.TokenType == html.ErrorToken || next.TokenType == html.EndTagToken && next.Traits&keepPTag == 0 || next.TokenType == html.StartTagToken && next.Traits&omitPTag != 0 {
break SWITCH // omit p end tag
}
break
}
}
}
if o.KeepWhitespace || t.Traits&objectTag != 0 {
omitSpace = false
} else if t.Traits&nonPhrasingTag != 0 {
omitSpace = true // omit spaces after block elements
}
if len(t.Data) > 3+len(t.Text) {
t.Data[2+len(t.Text)] = '>'
t.Data = t.Data[:3+len(t.Text)]
}
if _, err := w.Write(t.Data); err != nil {
return err
}
break
}
if o.KeepWhitespace || t.Traits&objectTag != 0 {
omitSpace = false
} else if t.Traits&nonPhrasingTag != 0 {
omitSpace = true // omit spaces after block elements
}
if _, err := w.Write(t.Data); err != nil {
return err
}
if hasAttributes {
if t.Hash == html.Meta {
attrs := tb.Attributes(html.Content, html.Http_Equiv, html.Charset, html.Name)
if content := attrs[0]; content != nil {
if httpEquiv := attrs[1]; httpEquiv != nil {
if charset := attrs[2]; charset == nil && parse.EqualFold(httpEquiv.AttrVal, []byte("content-type")) {
content.AttrVal = minify.Mediatype(content.AttrVal)
if bytes.Equal(content.AttrVal, []byte("text/html;charset=utf-8")) {
httpEquiv.Text = nil
content.Text = []byte("charset")
content.Hash = html.Charset
content.AttrVal = []byte("utf-8")
}
}
}
if name := attrs[3]; name != nil {
if parse.EqualFold(name.AttrVal, []byte("keywords")) {
content.AttrVal = bytes.Replace(content.AttrVal, []byte(", "), []byte(","), -1)
} else if parse.EqualFold(name.AttrVal, []byte("viewport")) {
content.AttrVal = bytes.Replace(content.AttrVal, []byte(" "), []byte(""), -1)
for i := 0; i < len(content.AttrVal); i++ {
if content.AttrVal[i] == '=' && i+2 < len(content.AttrVal) {
i++
if n := parse.Number(content.AttrVal[i:]); n > 0 {
minNum := minify.Number(content.AttrVal[i:i+n], -1)
if len(minNum) < n {
copy(content.AttrVal[i:i+len(minNum)], minNum)
copy(content.AttrVal[i+len(minNum):], content.AttrVal[i+n:])
content.AttrVal = content.AttrVal[:len(content.AttrVal)+len(minNum)-n]
}
i += len(minNum)
}
i-- // mitigate for-loop increase
}
}
}
}
}
} else if t.Hash == html.Script {
attrs := tb.Attributes(html.Src, html.Charset)
if attrs[0] != nil && attrs[1] != nil {
attrs[1].Text = nil
}
} else if t.Hash == html.Input {
attrs := tb.Attributes(html.Type, html.Value)
if t, value := attrs[0], attrs[1]; t != nil && value != nil {
isRadio := parse.EqualFold(t.AttrVal, []byte("radio"))
if !isRadio && len(value.AttrVal) == 0 {
value.Text = nil
} else if isRadio && parse.EqualFold(value.AttrVal, []byte("on")) {
value.Text = nil
}
}
}
// write attributes
htmlEqualIdName := false
for {
attr := *tb.Shift()
if attr.TokenType != html.AttributeToken {
break
} else if attr.Text == nil {
continue // removed attribute
}
if t.Hash == html.A && (attr.Hash == html.Id || attr.Hash == html.Name) {
if attr.Hash == html.Id {
if name := tb.Attributes(html.Name)[0]; name != nil && bytes.Equal(attr.AttrVal, name.AttrVal) {
htmlEqualIdName = true
}
} else if htmlEqualIdName {
continue
} else if id := tb.Attributes(html.Id)[0]; id != nil && bytes.Equal(id.AttrVal, attr.AttrVal) {
continue
}
}
val := attr.AttrVal
if len(val) == 0 && (attr.Hash == html.Class ||
attr.Hash == html.Dir ||
attr.Hash == html.Id ||
attr.Hash == html.Lang ||
attr.Hash == html.Name ||
attr.Hash == html.Title ||
attr.Hash == html.Action && t.Hash == html.Form) {
continue // omit empty attribute values
}
if attr.Traits&caselessAttr != 0 {
val = parse.ToLower(val)
if attr.Hash == html.Enctype || attr.Hash == html.Codetype || attr.Hash == html.Accept || attr.Hash == html.Type && (t.Hash == html.A || t.Hash == html.Link || t.Hash == html.Object || t.Hash == html.Param || t.Hash == html.Script || t.Hash == html.Style || t.Hash == html.Source) {
val = minify.Mediatype(val)
}
}
if rawTagHash != 0 && attr.Hash == html.Type {
rawTagMediatype = parse.Copy(val)
}
// default attribute values can be omitted
if !o.KeepDefaultAttrVals && (attr.Hash == html.Type && (t.Hash == html.Script && jsMimetypes[string(val)] ||
t.Hash == html.Style && bytes.Equal(val, []byte("text/css")) ||
t.Hash == html.Link && bytes.Equal(val, []byte("text/css")) ||
t.Hash == html.Input && bytes.Equal(val, []byte("text")) ||
t.Hash == html.Button && bytes.Equal(val, []byte("submit"))) ||
attr.Hash == html.Language && t.Hash == html.Script ||
attr.Hash == html.Method && bytes.Equal(val, []byte("get")) ||
attr.Hash == html.Enctype && bytes.Equal(val, []byte("application/x-www-form-urlencoded")) ||
attr.Hash == html.Colspan && bytes.Equal(val, []byte("1")) ||
attr.Hash == html.Rowspan && bytes.Equal(val, []byte("1")) ||
attr.Hash == html.Shape && bytes.Equal(val, []byte("rect")) ||
attr.Hash == html.Span && bytes.Equal(val, []byte("1")) ||
attr.Hash == html.Clear && bytes.Equal(val, []byte("none")) ||
attr.Hash == html.Frameborder && bytes.Equal(val, []byte("1")) ||
attr.Hash == html.Scrolling && bytes.Equal(val, []byte("auto")) ||
attr.Hash == html.Valuetype && bytes.Equal(val, []byte("data")) ||
attr.Hash == html.Media && t.Hash == html.Style && bytes.Equal(val, []byte("all"))) {
continue
}
// CSS and JS minifiers for attribute inline code
if attr.Hash == html.Style {
attrMinifyBuffer.Reset()
if err := m.MinifyMimetype(cssMimeBytes, attrMinifyBuffer, buffer.NewReader(val), inlineParams); err == nil {
val = attrMinifyBuffer.Bytes()
} else if err != minify.ErrNotExist {
return err
}
if len(val) == 0 {
continue
}
} else if len(attr.Text) > 2 && attr.Text[0] == 'o' && attr.Text[1] == 'n' {
if len(val) >= 11 && parse.EqualFold(val[:11], jsSchemeBytes) {
val = val[11:]
}
attrMinifyBuffer.Reset()
if err := m.MinifyMimetype(jsMimeBytes, attrMinifyBuffer, buffer.NewReader(val), nil); err == nil {
val = attrMinifyBuffer.Bytes()
} else if err != minify.ErrNotExist {
return err
}
if len(val) == 0 {
continue
}
} else if len(val) > 5 && attr.Traits&urlAttr != 0 { // anchors are already handled
if parse.EqualFold(val[:4], httpBytes) {
if val[4] == ':' {
if m.URL != nil && m.URL.Scheme == "http" {
val = val[5:]
} else {
parse.ToLower(val[:4])
}
} else if (val[4] == 's' || val[4] == 'S') && val[5] == ':' {
if m.URL != nil && m.URL.Scheme == "https" {
val = val[6:]
} else {
parse.ToLower(val[:5])
}
}
} else if parse.EqualFold(val[:5], dataSchemeBytes) {
val = minify.DataURI(m, val)
}
}
if _, err := w.Write(spaceBytes); err != nil {
return err
}
if _, err := w.Write(attr.Text); err != nil {
return err
}
if len(val) > 0 && attr.Traits&booleanAttr == 0 {
if _, err := w.Write(isBytes); err != nil {
return err
}
// no quotes if possible, else prefer single or double depending on which occurs more often in value
val = html.EscapeAttrVal(&attrByteBuffer, attr.AttrVal, val)
if _, err := w.Write(val); err != nil {
return err
}
}
}
}
if _, err := w.Write(gtBytes); err != nil {
return err
}
}
}
}