defimpl Mobilizon.Service.Metadata, for: Mobilizon.Events.Event do
alias Phoenix.HTML
alias Phoenix.HTML.Tag
alias Mobilizon.Actors.Actor
alias Mobilizon.Addresses.Address
alias Mobilizon.Events.{Event, EventOptions}
alias Mobilizon.Web.Endpoint
alias Mobilizon.Web.JsonLD.ObjectView
use Mobilizon.Web, :verified_routes
import Mobilizon.Service.Metadata.Utils,
only: [
process_description: 2,
strip_tags: 1,
datetime_to_string: 2,
render_address!: 1,
escape_text: 1
]
def build_tags(%Event{} = event, locale \\ "en") do
formatted_description = description(event, locale)
tags = [
Tag.content_tag(:title, escape_text(event.title) <> " - Mobilizon"),
Tag.tag(:meta, name: "description", content: process_description(event.description, locale)),
Tag.tag(:meta, property: "og:title", content: escape_text(event.title)),
Tag.tag(:meta, property: "og:url", content: event.url),
Tag.tag(:meta, property: "og:description", content: formatted_description),
Tag.tag(:meta, property: "og:type", content: "website"),
# Tell Search Engines what's the origin
Tag.tag(:link, rel: "canonical", href: event.url)
]
tags =
if is_nil(event.picture) do
tags
else
tags ++
[
Tag.tag(:meta,
property: "og:image",
content: event.picture.file.url
)
]
end
breadcrumbs =
if event.attributed_to do
[
%{
"@context" => "https://schema.org",
"@type" => "BreadcrumbList",
"itemListElement" => [
%{
"@type" => "ListItem",
"position" => 1,
"name" => event.attributed_to |> Actor.display_name() |> escape_text(),
"item" =>
~p"/@#{Actor.preferred_username_and_domain(event.attributed_to)}"
|> url()
|> URI.decode()
},
%{
"@type" => "ListItem",
"position" => 2,
"name" => event.title
}
]
}
]
else
[]
end
breadcrumbs =
breadcrumbs ++
[
%{
"@context" => "https://schema.org",
"@type" => "BreadcrumbList",
"itemListElement" => [
%{
"@type" => "ListItem",
"position" => 1,
"name" => "Events",
"item" => "#{Endpoint.url()}/search"
},
%{
"@type" => "ListItem",
"position" => 2,
"name" => escape_text(event.title)
}
]
}
]
tags ++
[
Tag.tag(:meta, property: "twitter:card", content: "summary_large_image"),
~s{}
|> HTML.raw(),
~s{} |> HTML.raw()
]
end
# Insert JSON-LD schema by hand because Tag.content_tag wants to escape it
defp json(%Event{title: title} = event) do
"event.json"
|> ObjectView.render(%{event: %{event | title: strip_tags(title)}})
|> Jason.encode!()
end
defp description(
%Event{
description: description,
begins_on: begins_on,
physical_address: address,
options: %EventOptions{timezone: timezone},
language: language
},
locale
) do
language = build_language(language, locale)
begins_on = build_begins_on(begins_on, timezone)
begins_on
|> datetime_to_string(language)
|> (&[&1]).()
|> add_timezone(begins_on)
|> maybe_build_address(address)
|> build_description(description, language)
|> Enum.join(" - ")
end
@spec build_language(String.t() | nil, String.t()) :: String.t()
defp build_language(language, locale), do: language || locale
@spec build_begins_on(DateTime.t(), String.t() | nil) :: DateTime.t()
defp build_begins_on(begins_on, nil), do: begins_on
defp build_begins_on(begins_on, timezone) do
case DateTime.shift_zone(begins_on, timezone) do
{:ok, begins_on} -> begins_on
{:error, _err} -> begins_on
end
end
defp add_timezone(elements, %DateTime{} = begins_on) do
elements ++ [Cldr.DateTime.Formatter.zone_gmt(begins_on)]
end
@spec maybe_build_address(list(String.t()), Address.t() | nil) :: list(String.t())
defp maybe_build_address(elements, %Address{} = address) do
elements ++ [render_address!(address)]
rescue
# If the address is not renderable
e in ArgumentError ->
require Logger
Logger.error(Exception.format(:error, e, __STACKTRACE__))
elements
end
defp maybe_build_address(elements, _address), do: elements
@spec build_description(list(String.t()), String.t(), String.t()) :: list(String.t())
defp build_description(elements, description, language) do
elements ++ [process_description(description, language)]
end
end