github.com/captn3m0/cosmere-books.git

# MyHTML

[![Build Status](https://github.com/kostya/myhtml/actions/workflows/ci.yml/badge.svg)](https://github.com/kostya/myhtml/actions/workflows/ci.yml?query=branch%3Amaster+event%3Apush)

Fast HTML5 Parser (Crystal binding for awesome lexborisov's [myhtml](https://github.com/lexborisov/myhtml) and [Modest](https://github.com/lexborisov/Modest)). This shard used in production to parse millions of pages per day, very stable and fast.

## Installation


Add this to your application's `shard.yml`:

```yaml
dependencies:
  myhtml:
    github: kostya/myhtml
```

And run `shards install`

## Usage example

```crystal
require "myhtml"

html = <<-HTML
  <html>
    <body>
      <div id="t1" class="red">
        <a href="/#">O_o</a>
      </div>
      <div id="t2"></div>
    </body>
  </html>
HTML

myhtml = Myhtml::Parser.new(html)

myhtml.nodes(:div).each do |node|
  id = node.attribute_by("id")

  if first_link = node.scope.nodes(:a).first?
    href = first_link.attribute_by("href")
    link_text = first_link.inner_text

    puts "div with id #{id} have link [#{link_text}](#{href})"
  else
    puts "div with id #{id} have no links"
  end
end

# Output:
#   div with id t1 have link [O_o](/#)
#   div with id t2 have no links
```

## Css selectors example

```crystal
require "myhtml"

html = <<-HTML
  <html>
    <body>
      <table id="t1">
        <tr><td>Hello</td></tr>
      </table>
      <table id="t2">
        <tr><td>123</td><td>other</td></tr>
        <tr><td>foo</td><td>columns</td></tr>
        <tr><td>bar</td><td>are</td></tr>
        <tr><td>xyz</td><td>ignored</td></tr>
      </table>
    </body>
  </html>
HTML

myhtml = Myhtml::Parser.new(html)

p myhtml.css("#t2 tr td:first-child").map(&.inner_text).to_a
# => ["123", "foo", "bar", "xyz"]

p myhtml.css("#t2 tr td:first-child").map(&.to_html).to_a
# => ["<td>123</td>", "<td>foo</td>", "<td>bar</td>", "<td>xyz</td>"]
```

## More Examples

[examples](https://github.com/kostya/myhtml/tree/master/examples)

## Development Setup:

```shell
git clone https://github.com/kostya/myhtml.git
cd myhtml
make
crystal spec
```

## Benchmark

Parse 1000 times google page(600Kb), and 1000 times css select. [myhtml-program](https://github.com/kostya/myhtml/tree/master/bench/test-myhtml.cr), [crystagiri-program](https://github.com/kostya/myhtml/tree/master/bench/test-libxml.cr), [nokogiri-program](https://github.com/kostya/myhtml/tree/master/bench/test-libxml.rb)

| Lang     | Shard      | Lib             | Parse time, s | Css time, s | Memory, MiB |
| -------- | ---------- | --------------- | ------------- | ----------- | ----------- |
| Crystal  | lexbor     | lexbor          | 2.54          | 0.099       | 7.8         |
| Crystal  | myhtml     | myhtml(+modest) | 3.17          | 0.16        | 8.4         |
| Ruby 2.7 | Nokogiri   | libxml2         | 9.19          | 10.76       | 139.8       |
| Crystal  | Crystagiri | libxml2         | 11.27         | -           | 25.0        |