mirror of
https://github.com/acaloiaro/garbagespeak.com
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124 lines
2.5 KiB
Go
124 lines
2.5 KiB
Go
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package html_parser
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import (
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"bytes"
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"io"
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"log"
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"strings"
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"golang.org/x/net/html"
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)
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func htmlGetAttr(n *html.Node, key string) (string, bool) {
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for _, attr := range n.Attr {
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if attr.Key == key {
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return attr.Val, true
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}
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}
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return "", false
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}
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// htmlRenderNode renders a node, excluding its children
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func htmlRenderNode(n *html.Node) string {
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var buf bytes.Buffer
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w := io.Writer(&buf)
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// walk backwards through the document tree to find the root
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for {
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if n.Parent != nil {
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n = n.Parent
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continue
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}
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break
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}
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err := html.Render(w, n)
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if err != nil {
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return ""
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}
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return buf.String()
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}
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func htmlHasID(n *html.Node, id string) bool {
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if n.Type == html.ElementNode {
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s, ok := htmlGetAttr(n, "id")
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if ok && s == id {
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return true
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}
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}
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return false
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}
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func htmlWalkTree(n *html.Node, id string) *html.Node {
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if htmlHasID(n, id) {
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return n
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}
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for c := n.FirstChild; c != nil; c = c.NextSibling {
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res := htmlWalkTree(c, id)
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if res != nil {
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return res
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}
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}
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return nil
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}
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func htmlGetByID(n *html.Node, id string) *html.Node {
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return htmlWalkTree(n, id)
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}
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// ParseAndSplice parses HTML within 'file' and splices `htmlContent` into its node tree at `id`
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//
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// Returns rendered HTML content as a string
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func ParseAndSplice(file io.Reader, id, htmlContent string) (content string) {
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doc, err := html.Parse(file)
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if err != nil {
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log.Fatal(err)
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}
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doc = htmlGetByID(doc, id)
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if doc == nil {
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return
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}
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// Get rid of the element's children, as we want to swap our own content in as this element's _only_ content
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doc.FirstChild = nil
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doc.LastChild = nil
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// Parse the content we're swapping in
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// This creates a "well-formed" tree, meaning that it adds <html><head></head><body><our node/></body></html>
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// but we don't want a well-formed tree, we want our new content as a single Node. The tree parents will be
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// removed
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newHtml, err := html.Parse(strings.NewReader(htmlContent))
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if err != nil {
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log.Fatal(err)
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}
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// Remove the tree parents, as we do not want a "well-formed" tree
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for {
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if newHtml.LastChild == nil {
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break
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}
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newHtml = newHtml.LastChild
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}
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// We've walked all the way down the new tree to the lowermost node of our new HTML tree.
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// Get its parent to get the outermost element of the new content (spliced in nodes should
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// not consist of nested node)
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newHtml = newHtml.Parent
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// "detach" the new node so it can be spliced into the tree
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newHtml.Parent = nil
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newHtml.PrevSibling = nil
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newHtml.NextSibling = nil
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doc.AppendChild(newHtml)
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content = htmlRenderNode(doc)
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return
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}
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