philomena/lib/philomena_proxy/scrapers/tumblr.ex

111 lines
2.9 KiB
Elixir

defmodule PhilomenaProxy.Scrapers.Tumblr do
@moduledoc false
alias PhilomenaProxy.Scrapers.Scraper
alias PhilomenaProxy.Scrapers
@behaviour Scraper
@url_regex ~r|\Ahttps?://(?:.*)/(?:image\|post)/(\d+)(?:\z\|[/?#])|
@media_regex ~r|https?://(?:\d+\.)?media\.tumblr\.com/[a-f\d]+/[a-f\d]+-[a-f\d]+/s\d+x\d+/[a-f\d]+\.(?:png\|jpe?g\|gif)|i
@size_regex ~r|_(\d+)(\..+)\z|
@sizes [1280, 540, 500, 400, 250, 100, 75]
@tumblr_ranges [
InetCidr.parse_cidr!("66.6.32.0/24"),
InetCidr.parse_cidr!("66.6.33.0/24"),
InetCidr.parse_cidr!("66.6.44.0/24"),
InetCidr.parse_cidr!("74.114.152.0/24"),
InetCidr.parse_cidr!("74.114.153.0/24"),
InetCidr.parse_cidr!("74.114.154.0/24"),
InetCidr.parse_cidr!("74.114.155.0/24")
]
@spec can_handle?(URI.t(), String.t()) :: true | false
def can_handle?(uri, url) do
String.match?(url, @url_regex) and tumblr_domain?(uri.host)
end
@spec scrape(URI.t(), Scrapers.url()) :: Scrapers.scrape_result()
def scrape(uri, url) do
[post_id] = Regex.run(@url_regex, url, capture: :all_but_first)
api_url =
"https://api.tumblr.com/v2/blog/#{uri.host}/posts/photo?id=#{post_id}&api_key=#{tumblr_api_key()}"
PhilomenaProxy.Http.get(api_url)
|> json!()
|> process_response!()
end
defp json!({:ok, %Tesla.Env{body: body, status: 200}}),
do: Jason.decode!(body)
defp process_response!(%{"response" => %{"posts" => [post | _rest]}}),
do: process_post!(post)
defp process_post!(%{"type" => "photo"} = post) do
images =
post["photos"]
|> Enum.map(fn photo ->
image = upsize(photo["original_size"]["url"])
%{"url" => preview} =
Enum.find(photo["alt_sizes"], &(&1["width"] == 400)) || %{"url" => image}
%{url: image, camo_url: PhilomenaProxy.Camo.image_url(preview)}
end)
add_meta(post, images)
end
defp process_post!(%{"type" => "text"} = post) do
images =
@media_regex
|> Regex.scan(post["body"])
|> Enum.map(fn [url | _captures] ->
%{url: url, camo_url: PhilomenaProxy.Camo.image_url(url)}
end)
add_meta(post, images)
end
defp upsize(image_url) do
@sizes
|> Enum.map(&String.replace(image_url, @size_regex, "_#{&1}\\2"))
|> Enum.find(&url_ok?/1)
end
defp url_ok?(url) do
match?({:ok, %Tesla.Env{status: 200}}, PhilomenaProxy.Http.head(url))
end
defp add_meta(post, images) do
source = post["post_url"]
author = post["blog_name"]
description = post["summary"]
%{
source_url: source,
author_name: author,
description: description,
images: images
}
end
defp tumblr_domain?(host) do
host
|> String.to_charlist()
|> :inet_res.lookup(:in, :a)
|> case do
[address | _rest] ->
Enum.any?(@tumblr_ranges, &InetCidr.contains?(&1, address))
_ ->
false
end
end
defp tumblr_api_key do
Application.get_env(:philomena, :tumblr_api_key)
end
end