linkify/lib/linkify/parser.ex
2020-10-06 21:43:04 +02:00

368 lines
11 KiB
Elixir

defmodule Linkify.Parser do
@moduledoc """
Module to handle parsing the the input string.
"""
alias Linkify.Builder
@invalid_url ~r/(\.\.+)|(^(\d+\.){1,2}\d+$)/
@match_url ~r{^(?:\W*)?(?<url>(?:https?:\/\/)?[\w.-]+(?:\.[\w\.-]+)+[\w\-\._~%:\/?#[\]@!\$&'\(\)\*\+,;=.]+$)}u
@match_hostname ~r{^\W*(?<scheme>https?:\/\/)?(?:[^@\n]+\\w@)?(?<host>[^:#~\/\n?]+)}u
@match_ip ~r"^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$"
# @user
# @user@example.com
@match_mention ~r"^@[a-zA-Z\d_-]+@[a-zA-Z0-9_-](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*|@[a-zA-Z\d_-]+"u
# https://www.w3.org/TR/html5/forms.html#valid-e-mail-address
@match_email ~r"^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$"u
@match_hashtag ~r/^(?<tag>\#[[:word:]_]*[[:alpha:]_·][[:word:]_·\p{M}]*)/u
@match_skipped_tag ~r/^(?<tag>(a|code|pre)).*>*/
@prefix_extra [
"magnet:?",
"dweb://",
"dat://",
"gopher://",
"ipfs://",
"ipns://",
"irc://",
"ircs://",
"irc6://",
"mumble://",
"ssb://"
]
@tlds "./priv/tlds.txt" |> File.read!() |> String.split("\n", trim: true) |> MapSet.new()
@default_opts %{
url: true,
validate_tld: true
}
@doc """
Parse the given string, identifying items to link.
Parses the string, replacing the matching urls with an html link.
## Examples
iex> Linkify.Parser.parse("Check out google.com")
~s{Check out <a href="http://google.com">google.com</a>}
"""
@types [:url, :email, :hashtag, :mention, :extra]
def parse(input, opts \\ %{})
def parse(input, opts) when is_binary(input), do: {input, %{}} |> parse(opts) |> elem(0)
def parse(input, list) when is_list(list), do: parse(input, Enum.into(list, %{}))
def parse(input, opts) do
opts = Map.merge(@default_opts, opts)
{buffer, user_acc} = do_parse(input, opts, {"", [], :parsing})
if opts[:iodata] do
{buffer, user_acc}
else
{IO.iodata_to_binary(buffer), user_acc}
end
end
defp accumulate(acc, buffer),
do: [buffer | acc]
defp accumulate(acc, buffer, trailing),
do: [trailing, buffer | acc]
defp do_parse({"", user_acc}, _opts, {"", acc, _}),
do: {Enum.reverse(acc), user_acc}
defp do_parse({"@" <> text, user_acc}, opts, {buffer, acc, :skip}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, "@"), :skip})
defp do_parse(
{"<" <> text, user_acc},
%{hashtag: true} = opts,
{"#" <> _ = buffer, acc, :parsing}
) do
{buffer, user_acc} = link(buffer, opts, user_acc)
case Regex.run(@match_skipped_tag, text, capture: [:tag]) do
[tag] ->
text = String.trim_leading(text, tag)
do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, "<#{tag}"), :skip})
nil ->
do_parse({text, user_acc}, opts, {"<", acc, {:open, 1}})
end
end
defp do_parse({"<a" <> text, user_acc}, opts, {buffer, acc, :parsing}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, "<a"), :skip})
defp do_parse({"<pre" <> text, user_acc}, opts, {buffer, acc, :parsing}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, "<pre"), :skip})
defp do_parse({"<code" <> text, user_acc}, opts, {buffer, acc, :parsing}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, "<code"), :skip})
defp do_parse({"</a>" <> text, user_acc}, opts, {buffer, acc, :skip}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, "</a>"), :parsing})
defp do_parse({"</pre>" <> text, user_acc}, opts, {buffer, acc, :skip}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, "</pre>"), :parsing})
defp do_parse({"</code>" <> text, user_acc}, opts, {buffer, acc, :skip}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, "</code>"), :parsing})
defp do_parse({"<" <> text, user_acc}, opts, {"", acc, :parsing}),
do: do_parse({text, user_acc}, opts, {"<", acc, {:open, 1}})
defp do_parse({"<" <> text, user_acc}, opts, {"", acc, {:html, level}}) do
do_parse({text, user_acc}, opts, {"<", acc, {:open, level + 1}})
end
defp do_parse({">" <> text, user_acc}, opts, {buffer, acc, {:attrs, _level}}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, ">"), :parsing})
defp do_parse({<<ch::8>> <> text, user_acc}, opts, {"", acc, {:attrs, level}}) do
do_parse({text, user_acc}, opts, {"", accumulate(acc, <<ch::8>>), {:attrs, level}})
end
defp do_parse({"</" <> text, user_acc}, opts, {buffer, acc, {:html, level}}) do
{buffer, user_acc} = link(buffer, opts, user_acc)
do_parse(
{text, user_acc},
opts,
{"", accumulate(acc, buffer, "</"), {:close, level}}
)
end
defp do_parse({">" <> text, user_acc}, opts, {buffer, acc, {:close, 1}}),
do: do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer, ">"), :parsing})
defp do_parse({">" <> text, user_acc}, opts, {buffer, acc, {:close, level}}),
do:
do_parse(
{text, user_acc},
opts,
{"", accumulate(acc, buffer, ">"), {:html, level - 1}}
)
defp do_parse({text, user_acc}, opts, {buffer, acc, {:open, level}}) do
do_parse({text, user_acc}, opts, {"", accumulate(acc, buffer), {:attrs, level}})
end
defp do_parse(
{<<char::bytes-size(1), text::binary>>, user_acc},
opts,
{buffer, acc, state}
)
when char in [" ", "\r", "\n"] do
{buffer, user_acc} = link(buffer, opts, user_acc)
do_parse(
{text, user_acc},
opts,
{"", accumulate(acc, buffer, char), state}
)
end
defp do_parse({<<ch::8>>, user_acc}, opts, {buffer, acc, state}) do
{buffer, user_acc} = link(buffer <> <<ch::8>>, opts, user_acc)
do_parse(
{"", user_acc},
opts,
{"", accumulate(acc, buffer), state}
)
end
defp do_parse({<<ch::8>> <> text, user_acc}, opts, {buffer, acc, state}),
do: do_parse({text, user_acc}, opts, {buffer <> <<ch::8>>, acc, state})
def check_and_link(:url, buffer, opts, _user_acc) do
str =
buffer
|> String.split("<")
|> List.first()
|> strip_parens()
if url?(str, opts) do
case @match_url |> Regex.run(str, capture: [:url]) |> hd() do
^buffer ->
link_url(buffer, opts)
url ->
buffer
|> String.split(url)
|> Enum.intersperse(link_url(url, opts))
|> if(opts[:iodata], do: & &1, else: &Enum.join(&1)).()
end
else
:nomatch
end
end
def check_and_link(:email, buffer, opts, _user_acc) do
if email?(buffer, opts), do: link_email(buffer, opts), else: :nomatch
end
def check_and_link(:mention, buffer, opts, user_acc) do
buffer
|> match_mention
|> link_mention(buffer, opts, user_acc)
end
def check_and_link(:hashtag, buffer, opts, user_acc) do
buffer
|> match_hashtag
|> link_hashtag(buffer, opts, user_acc)
end
def check_and_link(:extra, "xmpp:" <> handle, opts, _user_acc) do
if email?(handle, opts), do: link_extra("xmpp:" <> handle, opts), else: handle
end
def check_and_link(:extra, buffer, opts, _user_acc) do
if String.starts_with?(buffer, @prefix_extra), do: link_extra(buffer, opts), else: :nomatch
end
defp strip_parens("(" <> buffer) do
~r/[^\)]*/ |> Regex.run(buffer) |> hd()
end
defp strip_parens(buffer), do: buffer
def url?(buffer, opts) do
valid_url?(buffer) && Regex.match?(@match_url, buffer) && valid_tld?(buffer, opts)
end
def email?(buffer, opts) do
valid_url?(buffer) && Regex.match?(@match_email, buffer) && valid_tld?(buffer, opts)
end
defp valid_url?(url), do: !Regex.match?(@invalid_url, url)
@doc """
Validates a URL's TLD. Returns a boolean.
Will return `true` if `:validate_tld` option set to `false`.
Will skip validation and return `true` if `:validate_tld` set to `:no_scheme` and the url has a scheme.
"""
def valid_tld?(url, opts) do
[scheme, host] = Regex.run(@match_hostname, url, capture: [:scheme, :host])
cond do
opts[:validate_tld] == false ->
true
ip?(host) ->
true
# don't validate if scheme is present
opts[:validate_tld] == :no_scheme and scheme != "" ->
true
true ->
tld = host |> String.split(".") |> List.last()
MapSet.member?(@tlds, tld)
end
end
def ip?(buffer), do: Regex.match?(@match_ip, buffer)
def match_mention(buffer) do
case Regex.run(@match_mention, buffer) do
[mention] -> mention
_ -> nil
end
end
def match_hashtag(buffer) do
case Regex.run(@match_hashtag, buffer, capture: [:tag]) do
[hashtag] -> hashtag
_ -> nil
end
end
def link_hashtag(nil, _buffer, _, _user_acc), do: :nomatch
def link_hashtag(hashtag, buffer, %{hashtag_handler: hashtag_handler} = opts, user_acc) do
hashtag
|> hashtag_handler.(buffer, opts, user_acc)
|> maybe_update_buffer(hashtag, buffer)
end
def link_hashtag(hashtag, buffer, opts, _user_acc) do
hashtag
|> Builder.create_hashtag_link(buffer, opts)
|> maybe_update_buffer(hashtag, buffer)
end
def link_mention(nil, _buffer, _, _user_acc), do: :nomatch
def link_mention(mention, buffer, %{mention_handler: mention_handler} = opts, user_acc) do
mention
|> mention_handler.(buffer, opts, user_acc)
|> maybe_update_buffer(mention, buffer)
end
def link_mention(mention, buffer, opts, _user_acc) do
mention
|> Builder.create_mention_link(buffer, opts)
|> maybe_update_buffer(mention, buffer)
end
defp maybe_update_buffer(out, match, buffer) when is_binary(out) do
maybe_update_buffer({out, nil}, match, buffer)
end
defp maybe_update_buffer({out, user_acc}, match, buffer)
when match != buffer and out != buffer do
out = String.replace(buffer, match, out)
{out, user_acc}
end
defp maybe_update_buffer(out, _match, _buffer), do: out
@doc false
def link_url(buffer, opts) do
Builder.create_link(buffer, opts)
end
@doc false
def link_email(buffer, opts) do
Builder.create_email_link(buffer, opts)
end
def link_extra(buffer, opts) do
Builder.create_extra_link(buffer, opts)
end
defp link(buffer, opts, user_acc) do
Enum.reduce_while(@types, {buffer, user_acc}, fn type, _ ->
if opts[type] == true do
check_and_link_reducer(type, buffer, opts, user_acc)
else
{:cont, {buffer, user_acc}}
end
end)
end
defp check_and_link_reducer(type, buffer, opts, user_acc) do
case check_and_link(type, buffer, opts, user_acc) do
:nomatch -> {:cont, {buffer, user_acc}}
{buffer, user_acc} -> {:halt, {buffer, user_acc}}
buffer -> {:halt, {buffer, user_acc}}
end
end
end