philomena/lib/philomena/scrapers/twitter.ex
2021-08-01 22:10:25 -04:00

75 lines
2.2 KiB
Elixir

defmodule Philomena.Scrapers.Twitter do
@gt_regex ~r|decodeURIComponent\("gt=(\d+);|
@url_regex ~r|\Ahttps?://(?:mobile\.)?twitter.com/([A-Za-z\d_]+)/status/([\d]+)/?|
@script_regex ~r|="(https://abs.twimg.com/responsive-web/client-web(?:-legacy)?/main\.[\da-z]+\.js)"|
@bearer_regex ~r|"(AAAAAAAAAAAAA[^"]*)"|
@spec can_handle?(URI.t(), String.t()) :: true | false
def can_handle?(_uri, url) do
String.match?(url, @url_regex)
end
def scrape(_uri, url) do
api_response!(url)
|> extract_data()
end
defp extract_data(tweet) do
images =
tweet["entities"]["media"]
|> Enum.map(
&%{
url: &1["media_url_https"] <> "?format=jpg&name=4096x4096",
camo_url: Camo.Image.image_url(&1["media_url_https"])
}
)
%{
source_url: tweet["url"],
author_name: tweet["user"],
description: tweet["text"] || tweet["full_text"],
images: images
}
end
# We'd like to use the API anonymously. In order to do this, we need to
# extract the anonymous bearer token. Fortunately, this is pretty easy
# to identify in the minified mobile script source.
def api_response!(url) do
[user, status_id] = Regex.run(@url_regex, url, capture: :all_but_first)
page_url = "https://twitter.com/#{user}/status/#{status_id}"
api_url =
"https://api.twitter.com/2/timeline/conversation/#{status_id}.json?tweet_mode=extended"
url = "https://twitter.com/#{user}/status/#{status_id}"
{gt, bearer} =
Philomena.Http.get(page_url)
|> extract_guest_token_and_bearer()
{:ok, api_resp} =
Philomena.Http.get(api_url, [{"Authorization", "Bearer #{bearer}"}, {"x-guest-token", gt}])
api_resp
|> Map.get(:body)
|> Jason.decode!()
|> Map.get("globalObjects")
|> Map.get("tweets")
|> Map.get(status_id)
|> Map.put("user", user)
|> Map.put("url", url)
end
defp extract_guest_token_and_bearer({:ok, %Tesla.Env{body: page}}) do
[gt] = Regex.run(@gt_regex, page, capture: :all_but_first)
[script | _] = Regex.run(@script_regex, page, capture: :all_but_first)
{:ok, %{body: body}} = Philomena.Http.get(script)
[bearer] = Regex.run(@bearer_regex, body, capture: :all_but_first)
{gt, bearer}
end
end