defmodule Html5ever do
@moduledoc """
This is an HTML parser written in Rust.
The project provides a NIF - Native Implemented Function.
It works on top of [a parser of the same name](https://github.com/servo/html5ever)
from the Servo project.
By default this lib will try to use a precompiled NIF
from the GitHub releases page. This way you don't need
to have the Rust toolchain installed.
In case no precompiled file is found and the Mix env is
production then an error is raised.
You can force the compilation to occur by setting the
value of the `HTML5EVER_BUILD` environment variable to
"true" or "1". Alternatively you can also set the application
env `:build_from_source` to `true` in order to force the build:
config :html5ever, Html5ever, build_from_source: true
This project is possible thanks to [Rustler](https://hexdocs.pm/rustler).
"""
@doc """
Parses an HTML document from a string.
This returns a list of tuples representing the HTML tree.
## Example
iex> Html5ever.parse("<!doctype html><html><body><h1>Hello world</h1></body></html>")
{:ok,
[
{:doctype, "html", "", ""},
{"html", [], [{"head", [], []}, {"body", [], [{"h1", [], ["Hello world"]}]}]}
]}
"""
def parse(html) when byte_size(html) > 500 do
parse_async(html)
end
def parse(html) do
parse_sync(html)
end
@doc """
Parses an HTML document from a string and returns a map.
The map contains the document structure.
## Example
iex> Html5ever.flat_parse("<!doctype html><html><body><h1>Hello world</h1></body></html>")
{:ok,
%{
nodes: %{
0 => %{id: 0, parent: nil, type: :document},
1 => %{id: 1, parent: 0, type: :doctype},
2 => %{
attrs: [],
children: [3, 4],
id: 2,
name: "html",
parent: 0,
type: :element
},
3 => %{
attrs: [],
children: [],
id: 3,
name: "head",
parent: 2,
type: :element
},
4 => %{
attrs: [],
children: [5],
id: 4,
name: "body",
parent: 2,
type: :element
},
5 => %{
attrs: [],
children: [6],
id: 5,
name: "h1",
parent: 4,
type: :element
},
6 => %{contents: "Hello world", id: 6, parent: 5, type: :text}
},
root: 0
}}
"""
def flat_parse(html) when byte_size(html) > 500 do
flat_parse_async(html)
end
def flat_parse(html) do
flat_parse_sync(html)
end
defp parse_sync(html) do
case Html5ever.Native.parse_sync(html) do
{:html5ever_nif_result, :ok, result} ->
{:ok, result}
{:html5ever_nif_result, :error, err} ->
{:error, err}
end
end
defp parse_async(html) do
:ok = Html5ever.Native.parse_async(html)
receive do
{:html5ever_nif_result, :ok, result} ->
{:ok, result}
{:html5ever_nif_result, :error, err} ->
{:error, err}
end
end
defp flat_parse_sync(html) do
case Html5ever.Native.flat_parse_sync(html) do
{:html5ever_nif_result, :ok, result} ->
{:ok, result}
{:html5ever_nif_result, :error, err} ->
{:error, err}
end
end
defp flat_parse_async(html) do
:ok = Html5ever.Native.flat_parse_async(html)
receive do
{:html5ever_nif_result, :ok, result} ->
{:ok, result}
{:html5ever_nif_result, :error, err} ->
{:error, err}
end
end
end
