defmodule Floki do
alias Floki.{Finder, HTMLParser, FilterOut, HTMLTree}
@moduledoc """
Floki is a simple HTML parser that enables search for nodes using CSS selectors.
## Example
Assuming that you have the following HTML:
```html
```
Examples of queries that you can perform:
* Floki.find(html, "#content")
* Floki.find(html, ".headline")
* Floki.find(html, "a")
* Floki.find(html, "[data-model=user]")
* Floki.find(html, "#content a")
* Floki.find(html, ".headline, a")
Each HTML node is represented by a tuple like:
{tag_name, attributes, children_nodes}
Example of node:
{"p", [{"class", "headline"}], ["Floki"]}
So even if the only child node is the element text, it is represented
inside a list.
You can write a simple HTML crawler (with support of [HTTPoison](https://github.com/edgurgel/httpoison)) with a few lines of code:
html
|> Floki.find(".pages a")
|> Floki.attribute("href")
|> Enum.map(fn(url) -> HTTPoison.get!(url) end)
It is simple as that!
"""
@type html_tree :: tuple | list
@doc """
Parses a HTML string.
## Examples
iex> Floki.parse("hello world
")
{"div", [{"class", "js-action"}], ["hello world"]}
iex> Floki.parse("first
second
")
[{"div", [], ["first"]}, {"div", [], ["second"]}]
"""
@spec parse(binary) :: html_tree | String.t()
def parse(html) do
HTMLParser.parse(html)
end
@doc """
Converts HTML tree to raw HTML.
Note that the resultant HTML may be different from the original one.
Spaces after tags and doctypes are ignored.
## Examples
iex> Floki.parse(~s(my content
)) |> Floki.raw_html
~s(my content
)
"""
@spec raw_html(html_tree | binary) :: binary
defdelegate raw_html(html_tree), to: Floki.RawHTML
@doc """
Find elements inside a HTML tree or string.
## Examples
iex> Floki.find("hello
", ".hint")
[{"span", [{"class", "hint"}], ["hello"]}]
iex> Floki.find("", "#important")
[{"div", [{"id", "important"}], [{"div", [], ["Content"]}]}]
iex> Floki.find("Google
", "a")
[{"a", [{"href", "https://google.com"}], ["Google"]}]
iex> Floki.find([{ "div", [], [{"a", [{"href", "https://google.com"}], ["Google"]}]}], "div a")
[{"a", [{"href", "https://google.com"}], ["Google"]}]
"""
@spec find(binary | html_tree, binary) :: html_tree
def find(html, selector) when is_binary(html) do
html_as_tuple = parse(html)
{tree, results} = Finder.find(html_as_tuple, selector)
Enum.map(results, fn html_node -> HTMLTree.to_tuple(tree, html_node) end)
end
def find(html_tree_as_tuple, selector) do
{tree, results} = Finder.find(html_tree_as_tuple, selector)
Enum.map(results, fn html_node -> HTMLTree.to_tuple(tree, html_node) end)
end
@doc """
Changes the attribute values of the elements matched by `selector`
with the function `mutation` and returns the whole element tree
## Examples
iex> Floki.attr("", "#a", "id", fn(id) -> String.replace(id, "a", "b") end)
[{"div", [{"id", "b"}], []}]
iex> Floki.attr("", "div", "id", fn _ -> "b" end)
[{"div", [{"id", "b"}, {"class", "class_name"}], []}]
"""
@spec attr(binary | html_tree, binary, binary, (binary -> binary)) :: html_tree
def attr(html_elem_tuple, selector, attribute_name, mutation) when is_tuple(html_elem_tuple) do
attr([html_elem_tuple], selector, attribute_name, mutation)
end
def attr(html_str, selector, attribute_name, mutation) when is_binary(html_str) do
attr(parse(html_str), selector, attribute_name, mutation)
end
def attr(html_tree_list, selector, attribute_name, mutation) when is_list(html_tree_list) do
{tree, results} = Finder.find(html_tree_list, selector)
mutate_attrs(html_tree_list, tree, results, attribute_name, mutation)
end
defp add_nodes_to_tree(tree, [html_node]) do
nodes = Map.put(tree.nodes, html_node.node_id, html_node)
Map.put(tree, :nodes, nodes)
end
defp add_nodes_to_tree(tree, [html_node | tail]) do
nodes = Map.put(tree.nodes, html_node.node_id, html_node)
tree
|> Map.put(:nodes, nodes)
|> add_nodes_to_tree(tail)
end
defp mutate_attrs(html_tree_list, _, [], _, _), do: html_tree_list
defp mutate_attrs(_, tree, results, attribute_name, mutation_fn) do
mutated_nodes =
Enum.map(results, fn result ->
mutated_attributes =
if Enum.any?(result.attributes, &match?({^attribute_name, _}, &1)) do
Enum.map(result.attributes, fn attribute ->
with {^attribute_name, attribute_value} <- attribute do
{attribute_name, mutation_fn.(attribute_value)}
end
end)
else
[{attribute_name, mutation_fn.(nil)} | result.attributes]
end
Map.put(result, :attributes, mutated_attributes)
end)
tree = add_nodes_to_tree(tree, mutated_nodes)
tree.nodes
|> Map.values()
|> Enum.filter(fn actual_node -> is_nil(actual_node.parent_node_id) end)
|> Enum.map(fn html_node -> HTMLTree.to_tuple(tree, html_node) end)
end
@doc """
It receives a HTML tree structure as tuple and maps
through all nodes with a given function that receives
a tuple with {name, attributes}.
It returns that structure transformed by the function.
## Examples
iex> html = {"div", [{"class", "foo"}], ["text"]}
iex> Floki.map(html, fn({name, attrs}) -> {name, [{"data-name", "bar"} | attrs]} end)
{"div", [{"data-name", "bar"}, {"class", "foo"}], ["text"]}
"""
def map(html_tree_list, fun) when is_list(html_tree_list) do
Enum.map(html_tree_list, &Finder.map(&1, fun))
end
def map(html_tree, fun), do: Finder.map(html_tree, fun)
@doc """
Returns the text nodes from a HTML tree.
By default, it will perform a deep search through the HTML tree.
You can disable deep search with the option `deep` assigned to false.
You can include content of script tags with the option `js` assigned to true.
You can specify a separator between nodes content.
## Examples
iex> Floki.text("hello world
")
"hello world"
iex> Floki.text("hello world
", deep: false)
" world"
iex> Floki.text(" world
")
" world"
iex> Floki.text(" world
", js: true)
"hello world"
iex> Floki.text("", sep: " ")
"hello world"
iex> Floki.text([{"div", [], ["hello world"]}])
"hello world"
iex> Floki.text([{"p", [], ["1"]},{"p", [], ["2"]}])
"12"
"""
@spec text(html_tree | binary) :: binary
def text(html, opts \\ [deep: true, js: false, sep: ""]) do
html_tree =
if is_binary(html) do
parse(html)
else
html
end
cleaned_html_tree =
case opts[:js] do
true -> html_tree
_ -> filter_out(html_tree, "script")
end
search_strategy =
case opts[:deep] do
false -> Floki.FlatText
_ -> Floki.DeepText
end
case opts[:sep] do
nil -> search_strategy.get(cleaned_html_tree)
sep -> search_strategy.get(cleaned_html_tree, sep)
end
end
@doc """
Returns a list with attribute values for a given selector.
## Examples
iex> Floki.attribute("Google", "a", "href")
["https://google.com"]
iex> Floki.attribute([{"a", [{"href", "https://google.com"}], ["Google"]}], "a", "href")
["https://google.com"]
"""
@spec attribute(binary | html_tree, binary, binary) :: list
def attribute(html, selector, attribute_name) do
html
|> find(selector)
|> attribute_values(attribute_name)
end
@doc """
Returns a list with attribute values from elements.
## Examples
iex> Floki.attribute("Google", "href")
["https://google.com"]
iex> Floki.attribute([{"a", [{"href", "https://google.com"}], ["Google"]}], "href")
["https://google.com"]
"""
@spec attribute(binary | html_tree, binary) :: list
def attribute(html_tree, attribute_name) when is_binary(html_tree) do
html_tree
|> parse
|> attribute_values(attribute_name)
end
def attribute(elements, attribute_name) do
attribute_values(elements, attribute_name)
end
defp attribute_values(element, attr_name) when is_tuple(element) do
attribute_values([element], attr_name)
end
defp attribute_values(elements, attr_name) do
values =
Enum.reduce(elements, [], fn {_, attributes, _}, acc ->
case attribute_match?(attributes, attr_name) do
{_attr_name, value} ->
[value | acc]
_ ->
acc
end
end)
Enum.reverse(values)
end
defp attribute_match?(attributes, attribute_name) do
Enum.find(attributes, fn {attr_name, _} ->
attr_name == attribute_name
end)
end
@doc """
Returns the nodes from a HTML tree that don't match the filter selector.
## Examples
iex> Floki.filter_out(" world
", "script")
{"div", [], [" world"]}
iex> Floki.filter_out([{"body", [], [{"script", [], []},{"div", [], []}]}], "script")
[{"body", [], [{"div", [], []}]}]
iex> Floki.filter_out(" text
", :comment)
{"div", [], [" text"]}
"""
@spec filter_out(binary | html_tree, binary) :: list
def filter_out(html_tree, selector) when is_binary(html_tree) do
html_tree
|> parse
|> FilterOut.filter_out(selector)
end
def filter_out(elements, selector) do
FilterOut.filter_out(elements, selector)
end
end