html

package
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Published: Apr 4, 2024 License: BSD-3-Clause Imports: 5 Imported by: 2

Documentation

Overview

Package html extends the golang.org/x/net/html by providing simplified methods to Node.

The x/net/html package currently only provide bare raw functionalities to iterate tree, there is no check for empty node, and no function to get attribute by name without looping it manually.

This package extends the parent package by adding methods to get node's attribute by name, get the first non-empty child, get the next non-empty sibling, and method to iterate the tree.

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

func NormalizeForID

func NormalizeForID(in string) (out string)

NormalizeForID given an input string normalize it to HTML ID. The normalization follow Mozilla specification rules,

  • it must not contain whitespace (spaces, tabs etc.),
  • only ASCII letters, digits, '_', and '-' should be used, and
  • it should start with a letter.

This function,

  • Return "_" if input is empty string,
  • replace unknown characters with '_',
  • prefix output with '_' unless it start with '-', '_', or letters, and
  • convert letters to lower cases.
Example
fmt.Println(NormalizeForID(""))
fmt.Println(NormalizeForID(" id "))
fmt.Println(NormalizeForID(" ID "))
fmt.Println(NormalizeForID("_id.1"))
fmt.Println(NormalizeForID("1-d"))
fmt.Println(NormalizeForID(".123 ABC def"))
fmt.Println(NormalizeForID("test 123"))
fmt.Println(NormalizeForID("⌘"))
Output:

_
_id_
_id_
_id_1
_1-d
_123_abc_def
test_123
___

func Sanitize

func Sanitize(in []byte) (plain []byte)

Sanitize the content of HTML into plain text.

Example
input := `
<html>
	<title>Test</title>
	<head>
	</head>
	<body>
		This
		<p> is </p>
		a
		<a href="/">link</a>.
		An another
		<a href="/">link</a>.
	</body>
</html>
`

out := Sanitize([]byte(input))
fmt.Printf("%s", out)
Output:

This is a link. An another link.

Types

type Node

type Node struct {
	*html.Node
}

Node extends the html.Node.

func NewNode

func NewNode(el *html.Node) *Node

NewNode create new node by embedding html.Node "el".

func (*Node) GetAttrValue

func (node *Node) GetAttrValue(key string) string

GetAttrValue get the value of node's attribute with specific key or empty if key not found.

func (*Node) GetFirstChild

func (node *Node) GetFirstChild() *Node

GetFirstChild get the first non-empty child of node or nil if no child left.

func (*Node) GetNextSibling

func (node *Node) GetNextSibling() *Node

GetNextSibling get the next non-empty sibling of node or nil if no more sibling left.

func (*Node) IsElement

func (node *Node) IsElement() bool

IsElement will return true if node type is html.ElementNode.

type NodeIterator

type NodeIterator struct {
	// contains filtered or unexported fields
}

NodeIterator simplify iterating each node from top to bottom.

func Parse

func Parse(r io.Reader) (iter *NodeIterator, err error)

Parse returns the NodeIterator to iterate through HTML tree.

Example
rawHTML := `
<ul>
	<li>
		<b>item</b>
		<span>one</span>
	</li>
</ul>
`

r := strings.NewReader(rawHTML)

iter, err := Parse(r)
if err != nil {
	log.Fatal(err)
}

for node := iter.Next(); node != nil; node = iter.Next() {
	if node.IsElement() {
		fmt.Printf("%s\n", node.Data)
	} else {
		fmt.Printf("\t%s\n", node.Data)
	}
}
Output:

html
head
body
ul
li
b
	item
b
span
	one
span
li
ul
body
html

func (*NodeIterator) Next

func (iter *NodeIterator) Next() *Node

Next return the first child or the next sibling of current node. If no more node in the tree, it will return nil.

func (*NodeIterator) SetNext

func (iter *NodeIterator) SetNext(el *Node)

SetNext set the node for iteration to Node "el" only if its not nil.

Example
rawHTML := `
<ul>
	<li>
		<b>item</b>
		<span>one</span>
	</li>
</ul>
<h2>Jump here</h2>
`

r := strings.NewReader(rawHTML)

iter, err := Parse(r)
if err != nil {
	log.Fatal(err)
}

for node := iter.Next(); node != nil; node = iter.Next() {
	if node.IsElement() {
		if node.Data == "ul" {
			// Skip iterating the "ul" element.
			iter.SetNext(node.GetNextSibling())
			continue
		}
		fmt.Printf("%s\n", node.Data)
	} else {
		fmt.Printf("\t%s\n", node.Data)
	}
}
Output:

html
head
body
h2
	Jump here
h2
body
html

func (*NodeIterator) SetNextNode

func (iter *NodeIterator) SetNextNode(el *html.Node)

SetNextNode set the next iteration node to html.Node "el" only if its not nil.

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