http: split requests into internal and external requests.

Split requests made by Danbooru::Http into either internal or external
requests. Internal requests are API calls to internal services run by
Danbooru. External requests are requests to external websites, for
example fetching sources or downloading files. External requests may use
a HTTP proxy if one is configured. Internal requests don't.

Fixes a few source extractors not using the HTTP proxy for certain API calls.

app/logical/danbooru/http.rb

@@ -40,21 +40,33 @@ module Danbooru
     attr_accessor :max_size, :http
 
     class << self
-      delegate :get, :head, :put, :post, :delete, :cache, :follow, :max_size, :timeout, :auth, :basic_auth, :headers, :cookies, :use, :public_only, :with_legacy_ssl, :download_media, to: :new
+      delegate :get, :head, :put, :post, :delete, :cache, :follow, :max_size, :timeout, :auth, :basic_auth, :headers, :cookies, :use, :proxy, :public_only, :with_legacy_ssl, :download_media, to: :new
     end
 
-    def initialize
-      @http ||=
-        ::Danbooru::Http::ApplicationClient.new
+    # The default HTTP client.
+    def self.default
+      Danbooru::Http::ApplicationClient.new
         .timeout(DEFAULT_TIMEOUT)
-        .headers("Accept-Encoding" => "gzip")
-        .headers("User-Agent": "#{Danbooru.config.canonical_app_name}/#{Rails.application.config.x.git_hash}")
-        #.headers("User-Agent": Danbooru.config.canonical_app_name)
+        .headers("Accept-Encoding": "gzip")
         .use(:auto_inflate)
         .use(redirector: { max_redirects: MAX_REDIRECTS })
         .use(:session)
     end
 
+    # The default HTTP client for requests to external websites. This includes API calls to external services, fetching source data, and downloading images.
+    def self.external
+      new.proxy.public_only.headers("User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Firefox/102.0")
+    end
+
+    # The default HTTP client for API calls to internal services controlled by Danbooru.
+    def self.internal
+      new.headers("User-Agent": "#{Danbooru.config.canonical_app_name}/#{Rails.application.config.x.git_hash}")
+    end
+
+    def initialize
+      @http ||= Danbooru::Http.default
+    end
+
     def get(url, **options)
       request(:get, url, **options)
     end