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# Pleroma: A lightweight social networking server
# Copyright © 2015-2020 Tymon Tobolski <https://github.com/teamon/tesla/blob/master/lib/tesla/middleware/follow_redirects.ex>
# Copyright © 2020 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.HTTP.Middleware.FollowRedirects do
@moduledoc """
Pool-aware version of https://github.com/teamon/tesla/blob/master/lib/tesla/middleware/follow_redirects.ex
Follow 3xx redirects
## Options
- `:max_redirects` - limit number of redirects (default: `5`)
"""
alias Pleroma.Gun.ConnectionPool
@behaviour Tesla.Middleware
@max_redirects 5
@redirect_statuses [301, 302, 303, 307, 308]
@impl Tesla.Middleware
def call(env, next, opts \\ []) do
max = Keyword.get(opts, :max_redirects, @max_redirects)
redirect(env, next, max)
end
defp redirect(env, next, left) do
opts = env.opts[:adapter]
case Tesla.run(env, next) do
{:ok, %{status: status} = res} when status in @redirect_statuses and left > 0 ->
release_conn(opts)
case Tesla.get_header(res, "location") do
nil ->
{:ok, res}
location ->
location = parse_location(location, res)
case get_conn(location, opts) do
{:ok, opts} ->
%{env | opts: Keyword.put(env.opts, :adapter, opts)}
|> new_request(res.status, location)
|> redirect(next, left - 1)
e ->
e
end
end
{:ok, %{status: status}} when status in @redirect_statuses ->
release_conn(opts)
{:error, {__MODULE__, :too_many_redirects}}
{:error, _} = e ->
release_conn(opts)
e
other ->
unless opts[:body_as] == :chunks do
release_conn(opts)
end
other
end
end
defp get_conn(location, opts) do
uri = URI.parse(location)
case ConnectionPool.get_conn(uri, opts) do
{:ok, conn} ->
{:ok, Keyword.merge(opts, conn: conn)}
e ->
e
end
end
defp release_conn(opts) do
ConnectionPool.release_conn(opts[:conn])
end
# The 303 (See Other) redirect was added in HTTP/1.1 to indicate that the originally
# requested resource is not available, however a related resource (or another redirect)
# available via GET is available at the specified location.
# https://tools.ietf.org/html/rfc7231#section-6.4.4
defp new_request(env, 303, location), do: %{env | url: location, method: :get, query: []}
# The 307 (Temporary Redirect) status code indicates that the target
# resource resides temporarily under a different URI and the user agent
# MUST NOT change the request method (...)
# https://tools.ietf.org/html/rfc7231#section-6.4.7
defp new_request(env, 307, location), do: %{env | url: location}
defp new_request(env, _, location), do: %{env | url: location, query: []}
defp parse_location("https://" <> _rest = location, _env), do: location
defp parse_location("http://" <> _rest = location, _env), do: location
defp parse_location(location, env) do
env.url
|> URI.parse()
|> URI.merge(location)
|> URI.to_string()
end
end
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