debianize-mobilizon/lib/federation/web_finger/web_finger.ex
Thomas Citharel 280f461ba7
Refactor the ActivityPub module
Signed-off-by: Thomas Citharel <tcit@tcit.fr>
2021-04-22 19:29:47 +02:00

221 lines
6.8 KiB
Elixir

# Portions of this file are derived from Pleroma:
# Copyright © 2017-2018 Pleroma Authors <https://pleroma.social>
# SPDX-License-Identifier: AGPL-3.0-only
# Upstream: https://git.pleroma.social/pleroma/pleroma/blob/develop/lib/pleroma/web/web_finger/web_finger.ex
defmodule Mobilizon.Federation.WebFinger do
@moduledoc """
Performs the WebFinger requests and responses (JSON only).
"""
alias Mobilizon.Actors
alias Mobilizon.Actors.Actor
alias Mobilizon.Federation.ActivityPub.Actor, as: ActivityPubActor
alias Mobilizon.Federation.WebFinger.XmlBuilder
alias Mobilizon.Service.HTTP.{HostMetaClient, WebfingerClient}
alias Mobilizon.Web.Endpoint
alias Mobilizon.Web.Router.Helpers, as: Routes
require Jason
require Logger
import SweetXml
def host_meta do
base_url = Endpoint.url()
%URI{host: host} = URI.parse(base_url)
{
:XRD,
%{
xmlns: "http://docs.oasis-open.org/ns/xri/xrd-1.0",
"xmlns:hm": "http://host-meta.net/ns/1.0"
},
[
{
:"hm:Host",
host
},
{
:Link,
%{
rel: "lrdd",
type: "application/jrd+json",
template: "#{base_url}/.well-known/webfinger?resource={uri}"
}
}
]
}
|> XmlBuilder.to_doc()
end
def webfinger(resource, "JSON") do
host = Endpoint.host()
regex = ~r/(acct:)?(?<name>\w+)@#{host}/
with %{"name" => name} <- Regex.named_captures(regex, resource),
%Actor{} = actor <- Actors.get_local_actor_by_name(name) do
{:ok, represent_actor(actor, "JSON")}
else
_e ->
case ActivityPubActor.get_or_fetch_actor_by_url(resource) do
{:ok, %Actor{} = actor} when not is_nil(actor) ->
{:ok, represent_actor(actor, "JSON")}
_e ->
{:error, "Couldn't find actor"}
end
end
end
@spec represent_actor(Actor.t()) :: struct()
def represent_actor(%Actor{} = actor), do: represent_actor(actor, "JSON")
@spec represent_actor(Actor.t(), String.t()) :: struct()
def represent_actor(%Actor{} = actor, "JSON") do
links =
[
%{"rel" => "self", "type" => "application/activity+json", "href" => actor.url},
%{
"rel" => "http://ostatus.org/schema/1.0/subscribe",
"template" => "#{Routes.page_url(Endpoint, :interact, uri: nil)}{uri}"
}
]
|> maybe_add_avatar(actor)
|> maybe_add_profile_page(actor)
%{
"subject" => "acct:#{actor.preferred_username}@#{Endpoint.host()}",
"aliases" => [actor.url],
"links" => links
}
end
defp maybe_add_avatar(data, %Actor{avatar: avatar}) when not is_nil(avatar) do
data ++
[
%{
"rel" => "http://webfinger.net/rel/avatar",
"type" => avatar.content_type,
"href" => avatar.url
}
]
end
defp maybe_add_avatar(data, _actor), do: data
defp maybe_add_profile_page(data, %Actor{type: :Group, url: url}) do
data ++
[
%{
"rel" => "http://webfinger.net/rel/profile-page/",
"type" => "text/html",
"href" => url
}
]
end
defp maybe_add_profile_page(data, _actor), do: data
@doc """
Finger an actor to retreive it's ActivityPub ID/URL
Fetches the Extensible Resource Descriptor endpoint `/.well-known/host-meta` to find the Webfinger endpoint (usually `/.well-known/webfinger?resource=`) with `find_webfinger_endpoint/1` and then performs a Webfinger query to get the ActivityPub ID associated to an actor.
"""
@spec finger(String.t()) :: {:ok, String.t()} | {:error, atom()}
def finger(actor) do
actor = String.trim_leading(actor, "@")
with address when is_binary(address) <- apply_webfinger_endpoint(actor),
false <- address_invalid(address),
{:ok, %{body: body, status: code}} when code in 200..299 <-
WebfingerClient.get(address),
{:ok, %{"url" => url}} <- webfinger_from_json(body) do
{:ok, url}
else
e ->
Logger.debug("Couldn't finger #{actor}")
Logger.debug(inspect(e))
{:error, e}
end
end
@doc """
Fetches the Extensible Resource Descriptor endpoint `/.well-known/host-meta` to find the Webfinger endpoint (usually `/.well-known/webfinger?resource=`)
"""
@spec find_webfinger_endpoint(String.t()) :: String.t()
def find_webfinger_endpoint(domain) when is_binary(domain) do
with {:ok, %{body: body}} <- fetch_document("http://#{domain}/.well-known/host-meta"),
link_template <- find_link_from_template(body) do
{:ok, link_template}
end
end
@spec apply_webfinger_endpoint(String.t()) :: String.t() | {:error, :host_not_found}
defp apply_webfinger_endpoint(actor) do
with {:ok, domain} <- domain_from_federated_actor(actor) do
case find_webfinger_endpoint(domain) do
{:ok, link_template} ->
String.replace(link_template, "{uri}", "acct:#{actor}")
_ ->
"http://#{domain}/.well-known/webfinger?resource=acct:#{actor}"
end
end
end
@spec domain_from_federated_actor(String.t()) :: {:ok, String.t()} | {:error, :host_not_found}
defp domain_from_federated_actor(actor) do
case String.split(actor, "@") do
[_name, domain] ->
{:ok, domain}
_e ->
host = URI.parse(actor).host
if is_nil(host), do: {:error, :host_not_found}, else: {:ok, host}
end
end
@spec webfinger_from_json(map() | String.t()) ::
{:ok, map()} | {:error, :webfinger_information_not_json}
defp webfinger_from_json(doc) when is_map(doc) do
data =
Enum.reduce(doc["links"], %{"subject" => doc["subject"]}, fn link, data ->
case {link["type"], link["rel"]} do
{"application/activity+json", "self"} ->
Map.put(data, "url", link["href"])
_ ->
Logger.debug(fn ->
"Unhandled type to finger: #{inspect(link["type"])}"
end)
data
end
end)
{:ok, data}
end
defp webfinger_from_json(_doc), do: {:error, :webfinger_information_not_json}
@spec find_link_from_template(String.t()) :: String.t() | {:error, :link_not_found}
defp find_link_from_template(doc) do
with res when res in [nil, ""] <-
xpath(doc, ~x"//Link[@rel=\"lrdd\"][@type=\"application/json\"]/@template"s),
res when res in [nil, ""] <- xpath(doc, ~x"//Link[@rel=\"lrdd\"]/@template"s),
do: {:error, :link_not_found}
end
@spec fetch_document(String.t()) :: Tesla.Env.result()
defp fetch_document(endpoint) do
with {:error, err} <- HostMetaClient.get(endpoint), do: {:error, err}
end
@spec address_invalid(String.t()) :: false | {:error, :invalid_address}
defp address_invalid(address) do
with %URI{host: host, scheme: scheme} <- URI.parse(address),
true <- is_nil(host) or is_nil(scheme) do
{:error, :invalid_address}
end
end
end