danbooru::http: support automatically following redirects.

Replace http.rb's builtin redirect following option with our own
redirect follower. This fixes an issue with http.rb losing cookies after
following a redirect.

app/logical/danbooru/http.rb

@@ -1,5 +1,6 @@
 require "danbooru/http/html_adapter"
 require "danbooru/http/xml_adapter"
+require "danbooru/http/redirector"
 require "danbooru/http/retriable"
 require "danbooru/http/session"
 
@@ -11,12 +12,24 @@ module Danbooru
     DEFAULT_TIMEOUT = 10
     MAX_REDIRECTS = 5
 
-    attr_writer :cache, :max_size, :http
+    attr_accessor :cache, :max_size, :http
 
     class << self
       delegate :get, :head, :put, :post, :delete, :cache, :follow, :max_size, :timeout, :auth, :basic_auth, :headers, :cookies, :use, :public_only, :download_media, to: :new
     end
 
+    def initialize
+      @http ||=
+        ::Danbooru::Http::ApplicationClient.new
+        .timeout(DEFAULT_TIMEOUT)
+        .headers(Danbooru.config.http_headers)
+        .headers("Accept-Encoding" => "gzip")
+        .use(:auto_inflate)
+        .use(:retriable)
+        .use(redirector: { max_redirects: MAX_REDIRECTS })
+        .use(:session)
+    end
+
     def get(url, **options)
       request(:get, url, **options)
     end
@@ -147,16 +160,5 @@ module Danbooru
     def fake_response(status, body)
       ::HTTP::Response.new(status: status, version: "1.1", body: ::HTTP::Response::Body.new(body))
     end
-
-    def http
-      @http ||=
-        ::Danbooru::Http::ApplicationClient.new
-        .follow(strict: false, max_hops: MAX_REDIRECTS)
-        .use(:session)
-        .timeout(DEFAULT_TIMEOUT)
-        .use(:auto_inflate)
-        .headers(Danbooru.config.http_headers)
-        .headers("Accept-Encoding" => "gzip")
-    end
   end
 end

app/logical/danbooru/http/redirector.rb

@@ -0,0 +1,40 @@
+# A HTTP::Feature that automatically follows HTTP redirects.
+# https://developer.mozilla.org/en-US/docs/Web/HTTP/Redirections
+
+module Danbooru
+  class Http
+    class Redirector < HTTP::Feature
+      HTTP::Options.register_feature :redirector, self
+
+      attr_reader :max_redirects
+
+      def initialize(max_redirects: 5)
+        @max_redirects = max_redirects
+      end
+
+      def perform(request, &block)
+        response = yield request
+
+        redirects = max_redirects
+        while response.status.redirect?
+          raise HTTP::Redirector::TooManyRedirectsError if redirects <= 0
+
+          response = yield build_redirect(request, response)
+          redirects -= 1
+        end
+
+        response
+      end
+
+      def build_redirect(request, response)
+        location = response.headers["Location"].to_s
+        uri = HTTP::URI.parse(location)
+
+        verb = request.verb
+        verb = :get if response.status == 303 && !request.verb.in?([:get, :head])
+
+        request.redirect(uri, verb)
+      end
+    end
+  end
+end

app/logical/nico_seiga_api_client.rb

@@ -5,10 +5,11 @@ class NicoSeigaApiClient
   attr_reader :http
 
   # XXX temp disable following redirects.
-  def initialize(work_id:, type:, http: Danbooru::Http.follow(nil))
+  def initialize(work_id:, type:)
     @work_id = work_id
     @work_type = type
-    @http = http
+    @http = Danbooru::Http.new
+    @http.http.default_options.features.reject! { |name, _| name == :redirector }
   end
 
   def image_ids