RichMedia: Do a HEAD request to check content type/length

This shouldn't be too expensive, since the connections are pooled,
but it should save us some bandwidth since we won't fetch non-html
files and files that are too large for us to process (especially
since you can't cancel a request without closing the connection
with HTTP1).
This commit is contained in:
rinpatch 2020-09-14 14:45:58 +03:00
parent f66a15c4a5
commit f70335002d
3 changed files with 91 additions and 1 deletions

View file

@ -87,6 +87,50 @@ def perform(:fetch, %Activity{} = activity) do
def rich_media_get(url) do
headers = [{"user-agent", Pleroma.Application.user_agent() <> "; Bot"}]
Pleroma.HTTP.get(url, headers, @options)
head_check =
case Pleroma.HTTP.head(url, headers, @options) do
# If the HEAD request didn't reach the server for whatever reason,
# we assume the GET that comes right after won't either
{:error, _} = e ->
e
{:ok, %Tesla.Env{status: 200, headers: headers}} ->
with :ok <- check_content_type(headers),
:ok <- check_content_length(headers),
do: :ok
_ ->
:ok
end
with :ok <- head_check, do: Pleroma.HTTP.get(url, headers, @options)
end
defp check_content_type(headers) do
case List.keyfind(headers, "content-type", 0) do
{_, content_type} ->
case Plug.Conn.Utils.media_type(content_type) do
{:ok, "text", "html", _} -> :ok
_ -> {:error, {:content_type, content_type}}
end
_ ->
:ok
end
end
@max_body @options[:max_body]
defp check_content_length(headers) do
case List.keyfind(headers, "content-length", 0) do
{_, maybe_content_length} ->
case Integer.parse(maybe_content_length) do
{content_length, ""} when content_length <= @max_body -> :ok
{_, ""} -> {:error, :body_too_large}
_ -> :ok
end
_ ->
:ok
end
end
end

View file

@ -1262,4 +1262,21 @@ def post(url, query, body, headers) do
inspect(headers)
}"}
end
# Most of the rich media mocks are missing HEAD requests, so we just return 404.
@rich_media_mocks [
"https://example.com/ogp",
"https://example.com/ogp-missing-data",
"https://example.com/twitter-card"
]
def head(url, _query, _body, _headers) when url in @rich_media_mocks do
{:ok, %Tesla.Env{status: 404, body: ""}}
end
def head(url, query, body, headers) do
{:error,
"Mock response not implemented for HEAD #{inspect(url)}, #{query}, #{inspect(body)}, #{
inspect(headers)
}"}
end
end

View file

@ -56,6 +56,27 @@ defmodule Pleroma.Web.RichMedia.ParserTest do
%{method: :get, url: "http://example.com/error"} ->
{:error, :overload}
%{
method: :head,
url: "http://example.com/huge-page"
} ->
%Tesla.Env{
status: 200,
headers: [{"content-length", "2000001"}, {"content-type", "text/html"}]
}
%{
method: :head,
url: "http://example.com/pdf-file"
} ->
%Tesla.Env{
status: 200,
headers: [{"content-length", "1000000"}, {"content-type", "application/pdf"}]
}
%{method: :head} ->
%Tesla.Env{status: 404, body: "", headers: []}
end)
:ok
@ -144,4 +165,12 @@ test "rejects invalid OGP data" do
test "returns error if getting page was not successful" do
assert {:error, :overload} = Parser.parse("http://example.com/error")
end
test "does a HEAD request to check if the body is too large" do
assert {:error, body_too_large} = Parser.parse("http://example.com/huge-page")
end
test "does a HEAD request to check if the body is html" do
assert {:error, {:content_type, _}} = Parser.parse("http://example.com/pdf-file")
end
end