Introduce group basic federation, event new page and notifications

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/service/rich_media/parser.ex

@@ -0,0 +1,278 @@
+# Portions of this file are derived from Pleroma:
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Mobilizon.Service.RichMedia.Parser do
+  @moduledoc """
+  Module to parse data in HTML pages
+  """
+  @options [
+    max_body: 2_000_000,
+    timeout: 10_000,
+    recv_timeout: 20_000,
+    follow_redirect: true,
+    # TODO: Remove me once Hackney/HTTPoison fixes their shit with TLS1.3 and OTP 23
+    ssl: [{:versions, [:"tlsv1.2"]}]
+  ]
+
+  alias Mobilizon.Config
+  alias Mobilizon.Service.RichMedia.Favicon
+  alias Plug.Conn.Utils
+  require Logger
+
+  defp parsers do
+    Mobilizon.Config.get([:rich_media, :parsers])
+  end
+
+  def parse(nil), do: {:error, "No URL provided"}
+
+  @spec parse(String.t()) :: {:ok, map()} | {:error, any()}
+  def parse(url) do
+    case Cachex.fetch(:rich_media_cache, url, fn _ ->
+           case parse_url(url) do
+             {:ok, data} -> {:commit, data}
+             {:error, err} -> {:ignore, err}
+           end
+         end) do
+      {status, value} when status in [:ok, :commit] ->
+        {:ok, value}
+
+      {_, err} ->
+        {:error, err}
+    end
+  rescue
+    e ->
+      {:error, "Cachex error: #{inspect(e)}"}
+  end
+
+  @spec parse_url(String.t(), List.t()) :: {:ok, map()} | {:error, any()}
+  defp parse_url(url, options \\ []) do
+    user_agent = Keyword.get(options, :user_agent, Config.instance_user_agent())
+    headers = [{"User-Agent", user_agent}]
+    Logger.debug("Fetching content at address #{inspect(url)}")
+
+    try do
+      with {:ok, _} <- prevent_local_address(url),
+           {:ok, %HTTPoison.Response{body: body, status_code: code, headers: response_headers}}
+           when code in 200..299 <-
+             HTTPoison.get(
+               url,
+               headers,
+               @options
+             ),
+           {:is_html, _response_headers, true} <-
+             {:is_html, response_headers, is_html(response_headers)} do
+        body
+        |> parse_html()
+        |> maybe_parse()
+        |> Map.put(:url, url)
+        |> maybe_add_favicon()
+        |> clean_parsed_data()
+        |> check_parsed_data()
+        |> check_remote_picture_path()
+      else
+        {:is_html, response_headers, false} ->
+          data = get_data_for_media(response_headers, url)
+
+          {:ok, data}
+
+        {:error, err} ->
+          Logger.debug("HTTP error: #{inspect(err)}")
+          {:error, "HTTP error: #{inspect(err)}"}
+      end
+    rescue
+      e ->
+        {:error, "Parsing error: #{inspect(e)} #{inspect(__STACKTRACE__)}"}
+    end
+  end
+
+  @spec get_data_for_media(List.t(), String.t()) :: map()
+  defp get_data_for_media(response_headers, url) do
+    data = %{title: get_filename_from_headers(response_headers) || get_filename_from_url(url)}
+
+    if is_image(response_headers) do
+      Map.put(data, :image_remote_url, url)
+    else
+      data
+    end
+  end
+
+  @spec is_html(List.t()) :: boolean
+  defp is_html(headers) do
+    headers
+    |> get_header("Content-Type")
+    |> content_type_header_matches(["text/html", "application/xhtml"])
+  end
+
+  @spec is_image(List.t()) :: boolean
+  defp is_image(headers) do
+    headers
+    |> get_header("Content-Type")
+    |> content_type_header_matches(["image/"])
+  end
+
+  @spec content_type_header_matches(String.t() | nil, List.t()) :: boolean
+  defp content_type_header_matches(header, content_types)
+  defp content_type_header_matches(nil, _content_types), do: false
+
+  defp content_type_header_matches(header, content_types) when is_binary(header) do
+    Enum.any?(content_types, fn content_type -> String.starts_with?(header, content_type) end)
+  end
+
+  @spec get_header(List.t(), String.t()) :: String.t() | nil
+  defp get_header(headers, key) do
+    case List.keyfind(headers, key, 0) do
+      {^key, value} -> String.downcase(value)
+      nil -> nil
+    end
+  end
+
+  @spec get_filename_from_headers(List.t()) :: String.t() | nil
+  defp get_filename_from_headers(headers) do
+    case get_header(headers, "Content-Disposition") do
+      nil -> nil
+      content_disposition -> parse_content_disposition(content_disposition)
+    end
+  end
+
+  @spec get_filename_from_url(String.t()) :: String.t()
+  defp get_filename_from_url(url) do
+    %URI{path: path} = URI.parse(url)
+
+    path
+    |> String.split("/", trim: true)
+    |> Enum.at(-1)
+    |> URI.decode()
+  end
+
+  # The following is taken from https://github.com/elixir-plug/plug/blob/65986ad32f9aaae3be50dc80cbdd19b326578da7/lib/plug/parsers/multipart.ex#L207
+  @spec parse_content_disposition(String.t()) :: String.t() | nil
+  defp parse_content_disposition(disposition) do
+    with [_, params] <- :binary.split(disposition, ";"),
+         %{"name" => _name} = params <- Utils.params(params) do
+      handle_disposition(params)
+    else
+      _ -> nil
+    end
+  end
+
+  @spec handle_disposition(map()) :: String.t() | nil
+  defp handle_disposition(params) do
+    case params do
+      %{"filename" => ""} ->
+        nil
+
+      %{"filename" => filename} ->
+        filename
+
+      %{"filename*" => ""} ->
+        nil
+
+      %{"filename*" => "utf-8''" <> filename} ->
+        URI.decode(filename)
+
+      _ ->
+        nil
+    end
+  end
+
+  defp parse_html(html), do: Floki.parse_document!(html)
+
+  defp maybe_parse(html) do
+    Enum.reduce_while(parsers(), %{}, fn parser, acc ->
+      case parser.parse(html, acc) do
+        {:ok, data} -> {:halt, data}
+        {:error, _msg} -> {:cont, acc}
+      end
+    end)
+  end
+
+  defp check_parsed_data(%{title: title} = data)
+       when is_binary(title) and byte_size(title) > 0 do
+    {:ok, data}
+  end
+
+  defp check_parsed_data(data) do
+    {:error, "Found metadata was invalid or incomplete: #{inspect(data)}"}
+  end
+
+  defp clean_parsed_data(data) do
+    data
+    |> Enum.reject(fn {key, val} ->
+      case Jason.encode(%{key => val}) do
+        {:ok, _} -> false
+        _ -> true
+      end
+    end)
+    |> Map.new()
+  end
+
+  defp prevent_local_address(url) do
+    case URI.parse(url) do
+      %URI{host: host} when not is_nil(host) ->
+        host = String.downcase(host)
+
+        if validate_hostname_not_localhost(host) && validate_hostname_only(host) &&
+             validate_ip(host) do
+          {:ok, url}
+        else
+          {:error, "Host violates local access rules"}
+        end
+
+      _ ->
+        {:error, "Could not detect any host"}
+    end
+  end
+
+  defp validate_hostname_not_localhost(hostname),
+    do:
+      hostname != "localhost" && !String.ends_with?(hostname, ".local") &&
+        !String.ends_with?(hostname, ".localhost")
+
+  defp validate_hostname_only(hostname),
+    do: hostname |> String.graphemes() |> Enum.count(&(&1 == "o")) > 0
+
+  defp validate_ip(hostname) do
+    case hostname |> String.to_charlist() |> :inet.parse_address() do
+      {:ok, address} ->
+        !IpReserved.is_reserved?(address)
+
+      # Not a valid IP
+      {:error, _} ->
+        true
+    end
+  end
+
+  @spec maybe_add_favicon(map()) :: map()
+  defp maybe_add_favicon(%{url: url} = data) do
+    case Favicon.fetch(url) do
+      {:ok, favicon_url} ->
+        Logger.debug("Adding favicon #{favicon_url} to metadata")
+        Map.put(data, :favicon_url, favicon_url)
+
+      err ->
+        Logger.debug("Failed to add favicon to metadata")
+        Logger.debug(inspect(err))
+        data
+    end
+  end
+
+  @spec check_remote_picture_path(map()) :: map()
+  defp check_remote_picture_path(%{image_remote_url: image_remote_url, url: url} = data) do
+    Logger.debug("Checking image_remote_url #{image_remote_url}")
+    image_uri = URI.parse(image_remote_url)
+    uri = URI.parse(url)
+
+    image_remote_url =
+      cond do
+        is_nil(image_uri.host) -> "#{uri.scheme}://#{uri.host}#{image_remote_url}"
+        is_nil(image_uri.scheme) -> "#{uri.scheme}:#{image_remote_url}"
+        true -> image_remote_url
+      end
+
+    Map.put(data, :image_remote_url, image_remote_url)
+  end
+
+  defp check_remote_picture_path(data), do: data
+end