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@loopthrough

loopthrough/remove_script.go

Last active April 14, 2022 11:32
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Removing script tags from HTML
Raw
remove_script.go
package main
import (
"bytes"
"fmt"
"golang.org/x/net/html"
"log"
"strings"
)
var s = `
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" async="" src=""></script>
<script src=""></script>
<script type="text/javascript" async="" src=""></script>
<script type="text/javascript" async="" src=""></script>
<script src="" async=""></script>
<script async="" src=""></script>
<script type="text/javascript" async="" src=""></script>
<script async="" src=""></script>
<link rel="stylesheet" media="screen" href=""/>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<style type="text/css">.at-icon{fill:#fff;border:0}.at-icon-wrapper{display:inline-block;overflow:hidden}</style></head><body></body></html>`
func main() {
doc, err := html.Parse(strings.NewReader(s))
if err != nil {
log.Fatal(err)
}
var content bytes.Buffer
removeScript(doc)
html.Render(&content, doc)
fmt.Printf("%s\n", content.Bytes())
}
func removeScript(n *html.Node) {
// if note is script tag
if n.Type == html.ElementNode && n.Data == "script" {
n.Parent.RemoveChild(n)
return
}
// traverse DOM
for c := n.FirstChild; c != nil; c = c.NextSibling {
defer removeScript(c)
}
}
@loopthrough
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Author

Using defer to eliminate need to remember the references to siblings.
They were originally used because in recursion current node would be removed and would lose siblings so recursion would stop.

@LeMoussel
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With recursion , there are some disadvantages to iterate over parsed tree, namely:

  • Bigger memory consumption
  • Pointy CPU usage

To solve these issues you can process data while reading from the stream.
See Parsing HTML with Go using stream processing (https://mionskowski.pl/html-golang-stream-processing)

@loopthrough
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Author

Thanks for the comment and for the link to the informative article. I guess that in languages which don't optimise recursions it is smart to avoid it for performance reasons where matters more than expressivity of the concept. Streaming the tokens from the tokeniser is a nice idea.

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