77 lines
1.3 KiB
Go
77 lines
1.3 KiB
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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// See page 122.
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//!+main
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// Findlinks1 prints the links in an HTML document read from standard input.
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package main
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import (
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"fmt"
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"os"
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"golang.org/x/net/html"
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)
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func main() {
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doc, err := html.Parse(os.Stdin)
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if err != nil {
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fmt.Fprintf(os.Stderr, "findlinks1: %v\n", err)
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os.Exit(1)
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}
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for _, link := range visit(nil, doc) {
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fmt.Println(link)
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}
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}
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//!-main
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//!+visit
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// visit appends to links each link found in n and returns the result.
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func visit(links []string, n *html.Node) []string {
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if n.Type == html.ElementNode && n.Data == "a" {
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for _, a := range n.Attr {
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if a.Key == "href" {
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links = append(links, a.Val)
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}
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}
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}
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for c := n.FirstChild; c != nil; c = c.NextSibling {
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links = visit(links, c)
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}
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return links
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}
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//!-visit
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/*
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//!+html
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package html
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type Node struct {
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Type NodeType
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Data string
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Attr []Attribute
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FirstChild, NextSibling *Node
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}
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type NodeType int32
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const (
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ErrorNode NodeType = iota
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TextNode
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DocumentNode
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ElementNode
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CommentNode
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DoctypeNode
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)
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type Attribute struct {
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Key, Val string
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}
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func Parse(r io.Reader) (*Node, error)
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//!-html
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*/
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