mobilizon/lib/federation/node_info.ex

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defmodule Mobilizon.Federation.NodeInfo do
@moduledoc """
Performs NodeInfo requests
"""
alias Mobilizon.Service.HTTP.WebfingerClient
require Logger
import Mobilizon.Service.HTTP.Utils, only: [content_type_matches?: 2]
@application_uri "https://www.w3.org/ns/activitystreams#Application"
@nodeinfo_rel_2_0 "http://nodeinfo.diaspora.software/ns/schema/2.0"
@nodeinfo_rel_2_1 "http://nodeinfo.diaspora.software/ns/schema/2.1"
@env Application.compile_env(:mobilizon, :env)
@spec application_actor(String.t()) :: String.t() | nil
def application_actor(host) do
Logger.debug("Fetching application actor from NodeInfo data for domain #{host}")
case fetch_nodeinfo_endpoint(host) do
{:ok, body} ->
extract_application_actor(body)
{:error, _err} ->
nil
end
end
@spec nodeinfo(String.t()) :: {:ok, map()} | {:error, atom()}
def nodeinfo(host) do
Logger.debug("Fetching NodeInfo details for domain #{host}")
with {:ok, endpoint} when is_binary(endpoint) <- fetch_nodeinfo_details(host),
:ok <- Logger.debug("Going to get NodeInfo information from URL #{endpoint}"),
{:ok, %{body: body, status: code, headers: headers}} when code in 200..299 <-
WebfingerClient.get(endpoint),
{:ok, body} <- validate_json_response(body, headers) do
Logger.debug("Found nodeinfo information for domain #{host}")
{:ok, body}
else
{:error, err} ->
{:error, err}
err ->
Logger.debug("Failed to fetch NodeInfo data from endpoint #{inspect(err)}")
{:error, :node_info_endpoint_http_error}
end
end
defp extract_application_actor(body) do
body
|> Map.get("links", [])
|> Enum.find(%{"rel" => @application_uri, "href" => nil}, fn %{"rel" => rel, "href" => href} ->
rel == @application_uri and is_binary(href)
end)
|> Map.get("href")
end
@spec fetch_nodeinfo_endpoint(String.t()) :: {:ok, map()} | {:error, atom()}
defp fetch_nodeinfo_endpoint(host) do
prefix = if @env !== :dev, do: "https", else: "http"
case WebfingerClient.get("#{prefix}://#{host}/.well-known/nodeinfo") do
{:ok, %{body: body, status: code, headers: headers}} when code in 200..299 ->
validate_json_response(body, headers)
err ->
Logger.debug("Failed to fetch NodeInfo data #{inspect(err)}")
{:error, :node_info_meta_http_error}
end
end
@spec fetch_nodeinfo_details(String.t()) :: {:ok, String.t()} | {:error, atom()}
defp fetch_nodeinfo_details(host) do
with {:ok, body} <- fetch_nodeinfo_endpoint(host) do
extract_nodeinfo_endpoint(body)
end
end
@spec extract_nodeinfo_endpoint(map()) ::
{:ok, String.t()}
| {:error, :no_node_info_endpoint_found | :no_valid_node_info_endpoint_found}
defp extract_nodeinfo_endpoint(body) do
links = Map.get(body, "links", [])
relation =
find_nodeinfo_relation(links, @nodeinfo_rel_2_1) ||
find_nodeinfo_relation(links, @nodeinfo_rel_2_0)
if is_nil(relation) do
{:error, :no_node_info_endpoint_found}
else
endpoint = Map.get(relation, "href")
if is_nil(endpoint) do
{:error, :no_valid_node_info_endpoint_found}
else
{:ok, endpoint}
end
end
end
defp find_nodeinfo_relation(links, relation) do
Enum.find(links, fn %{"rel" => rel, "href" => href} ->
rel == relation and is_binary(href)
end)
end
@spec validate_json_response(map() | String.t(), list()) ::
{:ok, String.t()} | {:error, :bad_content_type | :body_not_json}
defp validate_json_response(body, headers) do
cond do
!content_type_matches?(headers, "application/json") ->
{:error, :bad_content_type}
!is_map(body) ->
{:error, :body_not_json}
true ->
{:ok, body}
end
end
end