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-rw-r--r--lib/htmlparser/htmlparser.go108
1 files changed, 108 insertions, 0 deletions
diff --git a/lib/htmlparser/htmlparser.go b/lib/htmlparser/htmlparser.go
new file mode 100644
index 0000000..fb4e012
--- /dev/null
+++ b/lib/htmlparser/htmlparser.go
@@ -0,0 +1,108 @@
+// gomuks - A terminal Matrix client written in Go.
+// Copyright (C) 2018 Tulir Asokan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+package htmlparser
+
+import (
+ "io"
+ "strings"
+
+ "golang.org/x/net/html"
+)
+
+type HTMLProcessor interface {
+ Preprocess()
+ HandleStartTag(tagName string, attrs map[string]string)
+ HandleSelfClosingTag(tagName string, attrs map[string]string)
+ HandleText(text string)
+ HandleEndTag(tagName string)
+ ReceiveError(err error)
+ Postprocess()
+}
+
+type HTMLParser struct {
+ *html.Tokenizer
+ processor HTMLProcessor
+}
+
+func NewHTMLParserFromTokenizer(z *html.Tokenizer, processor HTMLProcessor) HTMLParser {
+ return HTMLParser{
+ z,
+ processor,
+ }
+}
+
+func NewHTMLParserFromReader(reader io.Reader, processor HTMLProcessor) HTMLParser {
+ return NewHTMLParserFromTokenizer(html.NewTokenizer(reader), processor)
+}
+
+func NewHTMLParserFromString(html string, processor HTMLProcessor) HTMLParser {
+ return NewHTMLParserFromReader(strings.NewReader(html), processor)
+}
+
+var SelfClosingTags = []string{"img", "br", "hr", "area", "base", "basefont", "input", "link", "meta"}
+
+func (parser HTMLParser) mapAttrs() map[string]string {
+ attrs := make(map[string]string)
+ hasMore := true
+ for hasMore {
+ var key, val []byte
+ key, val, hasMore = parser.TagAttr()
+ attrs[string(key)] = string(val)
+ }
+ return attrs
+}
+
+func (parser HTMLParser) isSelfClosing(tag string) bool {
+ for _, selfClosingTag := range SelfClosingTags {
+ if tag == selfClosingTag {
+ return true
+ }
+ }
+ return false
+}
+
+func (parser HTMLParser) Process() {
+ parser.processor.Preprocess()
+Loop:
+ for {
+ tt := parser.Next()
+ switch tt {
+ case html.ErrorToken:
+ parser.processor.ReceiveError(parser.Err())
+ break Loop
+ case html.TextToken:
+ parser.processor.HandleText(string(parser.Text()))
+ case html.StartTagToken, html.SelfClosingTagToken:
+ tagb, _ := parser.TagName()
+ attrs := parser.mapAttrs()
+ tag := string(tagb)
+
+ selfClosing := tt == html.SelfClosingTagToken || parser.isSelfClosing(tag)
+
+ if selfClosing {
+ parser.processor.HandleSelfClosingTag(tag, attrs)
+ } else {
+ parser.processor.HandleStartTag(tag, attrs)
+ }
+ case html.EndTagToken:
+ tagb, _ := parser.TagName()
+ parser.processor.HandleEndTag(string(tagb))
+ }
+ }
+
+ parser.processor.Postprocess()
+}