FEATURE: post chunk size should not be configurable

If people need to configure post chunk size use a plugin
Core only supports out of the box settings, if changed can lead to
severe performance issues.

config/locales/server.en.yml

@@ -739,8 +739,6 @@ en:
     track_external_right_clicks: "Track external links that are right clicked (eg: open in new tab) disabled by default because it rewrites URLs"
     topics_per_page: "How many topics are loaded by default on the topic list, and when scrolling down to load more topics"
     slow_topics_per_page: "The amount of topics per page on slow devices such as Android"
-    posts_chunksize: "How many posts are loaded by default on a topic, and when scrolling down to load more posts"
-    posts_slow_chunksize: "Like `posts_chunksize` but for slow platforms (such as Android)"
     site_contact_username: "All automated private messages will be from this user; if left blank the default System account will be used."
     send_welcome_message: "Send all new users a welcome private message with a quick start guide."
     suppress_reply_directly_below: "Don't show the expandable reply count on a post when there is only a single reply directly below this post."

config/locales/server.es.yml

@@ -668,7 +668,6 @@ es:
     share_links: "Determina qué elementos aparecen en el cuadro de compartir y en qué orden"
     track_external_right_clicks: "Hacer seguimiento de los enlaces externos en los que se ha hecho clic con el botón derecho (ej: abrir en nueva pestaña) desactivado por defecto porque reescribe URLs"
     topics_per_page: "Cuántos temas se cargan por defecto en la lista de temas y cuando se hace scroll hacia abajo para cargar más temas"
-    posts_chunksize: "Cuantos posts son cargados por default en un tema, y cuando se desplaza hacia abajo para cargar mas posts."
     site_contact_username: "Todos los mensajes privados automatizados serán de este usuario. Si es dejado en blanco, el la cuenta del Sistema por defecto será utilizada."
     send_welcome_message: "Enviar a todos los nuevos usuarios un mensaje privado de bienvenida con una guía rápida para comenzar."
     suppress_reply_directly_below: "No mostrar el contador de respuestas desplegable en un post si solo hay una única respuesta y está justamente debajo del post en cuestión."

config/locales/server.fi.yml

@@ -668,7 +668,6 @@ fi:
     share_links: "Mitkä painikkeet näytetään Jaa-valikossa ja missä järjestyksessä."
     track_external_right_clicks: "Seuraa pois sivustolta vieviä linkkejä, jotka avataan hiiren oikealla näppäimellä (esim. avaa uudessa välilehdessä) oletuksena poistettu käytöstä, koska tämä kirjoittaa URL:n uudelleen"
     topics_per_page: "Kuinka monta ketjua ladataan avattaessa ketjulista ja kerrallaan lisää vieritettäessä sivua alaspäin"
-    posts_chunksize: "Kuinka monta viestiä ladataa avattaessa viestiketju ja kerrallaan lisää vieritetäessä sivua alaspäin"
     site_contact_username: "Kaikki automaattiset yksityisviestit lähetetään tämän käyttäjän nimissä; jos jätetään tyhjäksi oletuksena on System-käyttäjä."
     send_welcome_message: "Lähetä kaikille uusille käyttäjille yksityinen tervetuliaisviesti, jossa on pikakäyttöopas."
     suppress_reply_directly_below: "Älä näytä vastausten lukumäärää viestissä, jos ainoa vastaus on seuraavassa viestissä."

config/locales/server.fr.yml

@@ -663,7 +663,6 @@ fr:
     share_links: "Choix des éléments qui doivent apparaître dans la fenêtre de partage, et leur ordre."
     track_external_right_clicks: "Suivi des clics sur les liens externes (ex: ouverture dans un nouvel onglet) désactivé par défaut car nécessite une ré-écriture de toutes les urls"
     topics_per_page: "Combien de sujets seront chargés par défaut sur la liste des sujets et lors du défilement vers le bas pour charger des sujets supplémentaires"
-    posts_chunksize: "Combien de messages seront chargés par défaut sur un sujet, et quand défiler vers le bas pour charger des messages supplémentaires."
     site_contact_username: "Tous les messages privés automatisés le seront depuis cet utilisateur; si non renseigné, le compte par défaut System sera utilisé."
     send_welcome_message: "Envoyer à tous les nouveaux utilisateurs un message privé avec un guide de démarrage rapide."
     suppress_reply_directly_below: "Ne pas afficher le panneau extensible des réponses d'un message quand la seule réponse est juste en dessous ce dernier."

config/locales/server.he.yml

@@ -658,7 +658,6 @@ he:
     share_links: "החלט אילו פריטים יופיעו בתיבת השיתוף, ובאיזה סדר."
     track_external_right_clicks: "Track external links that are right clicked (eg: open in new tab) disabled by default because it rewrites URLs"
     topics_per_page: "כמה נושאים נטענים כברירת מחדל ברשימת הנושאים, ומתי גלילה למטה טוענת נושאים נוספים"
-    posts_chunksize: "כמה פרסומים לטעון כברירת מחדל תחת נושא מסוים, וכאשר יש גלילה למטה ייטענו פרסומים נוספים."
     site_contact_username: "כל המסרים האישיים האוטומטיים יהיו ממשתמש זה; אם תשאירו ריק, יעשה שימוש בחשבון ברירת המחדל של המערכת."
     send_welcome_message: "שלחו כל המשתמשים החדשים הודעת \"ברוכים הבאים\" פרטים עם הדרכה ראשונית כיצד להתחיל."
     suppress_reply_directly_below: "אל תציגו את סך התגובות המצטבר בפרסום כאשר ישנה תגובה ישירה אחת לפרסום זה."

config/locales/server.ru.yml

@@ -662,7 +662,6 @@ ru:
     share_links: "Определите, какие элементы должны отображаться в окне  'Поделиться' и в какой последовательности."
     track_external_right_clicks: "Отслеживать внешние ссылки, открытые правой кнопкой мыши (например: открыть в новой вкладке), по умолчанию отключено, так как это перезаписывает пути"
     topics_per_page: "Сколько тем показывать сразу в списках тем, и подгружать за один раз при прокручивании списка вниз."
-    posts_chunksize: "Сколько сообщений показывать сразу на странице темы и подгружать за один раз при ее прокручивании вниз."
     site_contact_username: "Все личные сообщения, отправляемые форумчанам автоматически, будут отправляться от имени этого пользователя. Если оставить пустым, то будет использован системный пользователь по-умолчанию - system."
     send_welcome_message: "Отправлять новым зарегистрировавшимся пользователям приватное сообщение с короткой инструкцией по возможностям форума."
     redirect_users_to_top_page: "Автоматически перенаправлять новых и давно отсутствующих пользователей к началу страницы."

config/locales/server.sq.yml

@@ -667,7 +667,6 @@ sq:
     share_links: "Determine which items appear on the share dialog, and in what order."
     track_external_right_clicks: "Track external links that are right clicked (eg: open in new tab) disabled by default because it rewrites URLs"
     topics_per_page: "How many topics are loaded by default on the topic list, and when scrolling down to load more topics"
-    posts_chunksize: "How many posts are loaded by default on a topic, and when scrolling down to load more posts"
     site_contact_username: "All automated private messages will be from this user; if left blank the default System account will be used."
     send_welcome_message: "Send all new users a welcome private message with a quick start guide."
     suppress_reply_directly_below: "Don't show the expandable reply count on a post when there is only a single reply directly below this post."

config/locales/server.tr_TR.yml

@@ -622,7 +622,6 @@ tr_TR:
     share_links: "Paylaşım penceresinde hangi maddelerin ne sırada gözükeceğini belirleyin."
     track_external_right_clicks: "URL'leri tekrar yazdığı için, sağ tıklanan dış bağlantıların (ör: yeni bir sekmede aç) takibi varsayılan ayarlarda devre dışı bırakılmıştır."
     topics_per_page: "Konu listesinde gözüken ve daha fazla konu görmek için sayfa aşağı kaydırıldığında yüklenen konu sayısı"
-    posts_chunksize: "Bir konuda gözüken ve daha fazla gönderi görmek için sayfa aşağı kaydırıldığında yüklenen gönderi sayısı"
     site_contact_username: "Tüm otomatik özel mesajlar bu kullanıcıdan gönderilecek; boş bırakılırsa varsayılan Sistem hesabı kullanılır. "
     send_welcome_message: "Tüm yeni kullanıcılara bir hoşgeldiniz özel mesajı ile beraber hızlı başlangıç kılavuzu gönderin."
     suppress_reply_directly_below: "Bu gönderinin direk altında sadece tek bir cevap varsa, gönderideki açılabilir cevap sayısı bölümünü gösterme."

config/locales/server.zh_CN.yml

@@ -638,7 +638,6 @@ zh_CN:
     share_links: "决定分享对话框中出现的按钮及显示顺序。"
     track_external_right_clicks: "追踪外部链接的右键点击（例如：在浏览器新标签打开），缺省是禁用的，因为它会重写URL"
     topics_per_page: "在主题列表页面，缺省载入多少个主题，以及滚动至什么时候载入更多主题"
-    posts_chunksize: "载入主题时默认载入多少帖子，以及向下滚动时载入多少帖子"
     site_contact_username: "论坛给用户发送自动私信时使用的用户名；如果留空将使用默认的系统账户。"
     send_welcome_message: "给所有用户发送快速开始指导的私信"
     suppress_reply_directly_below: "当一个帖子只有一个回复时，不显示帖子回复数量。"

config/site_settings.yml

@@ -654,12 +654,6 @@ developer:
   verbose_localization:
     default: false
     client: true
-  posts_chunksize:
-    default: 20
-    min: 1
-  posts_slow_chunksize:
-    default: 10
-    min: 1
 
 embedding:
   embeddable_host: ''

lib/topic_view.rb

@@ -8,6 +8,14 @@ class TopicView
   attr_reader :topic, :posts, :guardian, :filtered_posts, :chunk_size
   attr_accessor :draft, :draft_key, :draft_sequence, :user_custom_fields
 
+  def self.slow_chunk_size
+    10
+  end
+
+  def self.chunk_size
+    20
+  end
+
   def initialize(topic_id, user=nil, options={})
     @user = user
     @guardian = Guardian.new(@user)
@@ -20,7 +28,7 @@ class TopicView
 
     @page = @page.to_i
     @page = 1 if @page.zero?
-    @chunk_size = options[:slow_platform] ? SiteSetting.posts_slow_chunksize : SiteSetting.posts_chunksize
+    @chunk_size = options[:slow_platform] ? TopicView.slow_chunk_size : TopicView.chunk_size
     @limit ||= @chunk_size
 
     setup_filtered_posts

spec/components/topic_view_spec.rb

@@ -26,13 +26,13 @@ describe TopicView do
   end
 
   context "chunk_size" do
-    it "returns `posts_chunksize` by default" do
+    it "returns `chunk_size` by default" do
-      TopicView.new(topic.id, coding_horror).chunk_size.should == SiteSetting.posts_chunksize
+      TopicView.new(topic.id, coding_horror).chunk_size.should == TopicView.chunk_size
     end
 
-    it "returns `posts_slow_chunksize` when slow_platform is true" do
+    it "returns `slow_chunk_size` when slow_platform is true" do
       tv = TopicView.new(topic.id, coding_horror, slow_platform: true)
-      tv.chunk_size.should == SiteSetting.posts_slow_chunksize
+      tv.chunk_size.should == TopicView.slow_chunk_size
     end
   end
 
@@ -128,8 +128,8 @@ describe TopicView do
       end
 
       it "generates a canonical correctly for paged results" do
-        SiteSetting.stubs(:posts_chunksize).returns(5)
+        TopicView.new(1234, user, post_number: 10 * TopicView.chunk_size )
-        TopicView.new(1234, user, post_number: 50).canonical_path.should eql("/1234?page=10")
+          .canonical_path.should eql("/1234?page=10")
       end
     end
 
@@ -146,7 +146,7 @@ describe TopicView do
         TopicView.any_instance.expects(:find_topic).with(1234).returns(topic)
         TopicView.any_instance.stubs(:filter_posts)
         TopicView.any_instance.stubs(:last_post).returns(p2)
-        SiteSetting.stubs(:posts_chunksize).returns(2)
+        TopicView.stubs(:chunk_size).returns(2)
       end
 
       it "should return the next page" do
@@ -255,7 +255,7 @@ describe TopicView do
     let!(:p3) { Fabricate(:post, topic: topic, user: first_poster)}
 
     before do
-      SiteSetting.posts_chunksize = 3
+      TopicView.stubs(:chunk_size).returns(3)
 
       # Update them to the sort order we're checking for
       [p1, p2, p3, p4, p5, p6, p7].each_with_index do |p, idx|
@@ -299,7 +299,7 @@ describe TopicView do
 
 
     describe '#filter_posts_paged' do
-      before { SiteSetting.stubs(:posts_chunksize).returns(2) }
+      before { TopicView.stubs(:chunk_size).returns(2) }
 
       it 'returns correct posts for all pages' do
         topic_view.filter_posts_paged(1).should == [p1, p2]
@@ -372,7 +372,7 @@ describe TopicView do
       end
 
       context "when 'posts per page' exceeds the number of posts" do
-        before { SiteSetting.stubs(:posts_chunksize).returns(100) }
+        before { TopicView.stubs(:chunk_size).returns(100) }
 
         it 'returns all the posts' do
           near_view = topic_view_near(p5)

spec/controllers/topics_controller_spec.rb

@@ -656,19 +656,16 @@ describe TopicsController do
     context 'filters' do
 
       it 'grabs first page when no filter is provided' do
-        SiteSetting.stubs(:posts_chunksize).returns(20)
         TopicView.any_instance.expects(:filter_posts_in_range).with(0, 19)
         xhr :get, :show, topic_id: topic.id, slug: topic.slug
       end
 
       it 'grabs first page when first page is provided' do
-        SiteSetting.stubs(:posts_chunksize).returns(20)
         TopicView.any_instance.expects(:filter_posts_in_range).with(0, 19)
         xhr :get, :show, topic_id: topic.id, slug: topic.slug, page: 1
       end
 
       it 'grabs correct range when a page number is provided' do
-        SiteSetting.stubs(:posts_chunksize).returns(20)
         TopicView.any_instance.expects(:filter_posts_in_range).with(20, 39)
         xhr :get, :show, topic_id: topic.id, slug: topic.slug, page: 2
       end

test/javascripts/helpers/site-settings.js

@@ -1,3 +1,3 @@
 /*jshint maxlen:10000000 */
-Discourse.SiteSettingsOriginal = {"title":"Discourse Meta","logo_url":"/assets/logo.png","logo_small_url":"/assets/logo-single.png","mobile_logo_url":"","favicon_url":"//meta.discourse.org/uploads/default/2499/79d53726406d87af.ico","allow_user_locale":false,"suggested_topics":7,"track_external_right_clicks":false,"ga_universal_tracking_code":"","ga_universal_domain_name":"auto","ga_tracking_code":"UA-33736483-2","ga_domain_name":"","top_menu":"latest|new|unread|starred|categories|top","post_menu":"like|share|flag|edit|bookmark|delete|admin|reply","post_menu_hidden_items":"edit|delete|admin","share_links":"twitter|facebook|google+|email","category_colors":"BF1E2E|F1592A|F7941D|9EB83B|3AB54A|12A89D|25AAE2|0E76BD|652D90|92278F|ED207B|8C6238|231F20|808281|B3B5B4|283890","enable_mobile_theme":true,"relative_date_duration":14,"category_featured_topics":4,"fixed_category_positions":false,"show_subcategory_list":false,"posts_chunksize":20,"enable_badges":true,"invite_only":false,"login_required":false,"must_approve_users":false,"enable_local_logins":true,"allow_new_registrations":true,"enable_google_logins":true,"enable_google_oauth2_logins":false,"enable_yahoo_logins":true,"enable_twitter_logins":true,"enable_facebook_logins":true,"enable_github_logins":true,"enable_sso":false,"min_username_length":3,"max_username_length":20,"min_password_length":8,"enable_names":true,"invites_shown":30,"delete_user_max_post_age":60,"delete_all_posts_max":15,"min_post_length":20,"min_private_message_post_length":10,"max_post_length":32000,"min_topic_title_length":15,"max_topic_title_length":255,"min_private_message_title_length":2,"allow_uncategorized_topics":true,"min_title_similar_length":10,"min_body_similar_length":15,"edit_history_visible_to_public":true,"delete_removed_posts_after":24,"traditional_markdown_linebreaks":false,"suppress_reply_directly_below":true,"suppress_reply_directly_above":true,"newuser_max_images":0,"newuser_max_attachments":0,"display_name_on_posts":true,"short_progress_text_threshold":10000,"default_code_lang":"lang-auto","autohighlight_all_code":false,"email_in":false,"max_image_size_kb":3072,"max_attachment_size_kb":1024,"authorized_extensions":".jpg|.jpeg|.png|.gif|.svg|.txt|.ico|.yml","max_image_width":690,"max_image_height":500,"allow_profile_backgrounds":true,"allow_uploaded_avatars":true,"allow_animated_avatars":false,"tl1_requires_read_posts":30,"enable_long_polling":true,"polling_interval":3000,"anon_polling_interval":30000,"flush_timings_secs":5,"tos_url":"","privacy_policy_url":"","tos_accept_required":false,"faq_url":"","allow_restore":false,"maximum_backups":7,"version_checks":true,"suppress_uncategorized_badge":true,"min_search_term_length":3,"topic_views_heat_low":1000,"topic_views_heat_medium":2000,"topic_views_heat_high":5000,"global_notice":"","show_create_topics_notice":true,"available_locales":"cs|da|de|en|es|fr|he|id|it|ja|ko|nb_NO|nl|pl_PL|pt|pt_BR|ru|sv|uk|zh_CN|zh_TW"};
+Discourse.SiteSettingsOriginal = {"title":"Discourse Meta","logo_url":"/assets/logo.png","logo_small_url":"/assets/logo-single.png","mobile_logo_url":"","favicon_url":"//meta.discourse.org/uploads/default/2499/79d53726406d87af.ico","allow_user_locale":false,"suggested_topics":7,"track_external_right_clicks":false,"ga_universal_tracking_code":"","ga_universal_domain_name":"auto","ga_tracking_code":"UA-33736483-2","ga_domain_name":"","top_menu":"latest|new|unread|starred|categories|top","post_menu":"like|share|flag|edit|bookmark|delete|admin|reply","post_menu_hidden_items":"edit|delete|admin","share_links":"twitter|facebook|google+|email","category_colors":"BF1E2E|F1592A|F7941D|9EB83B|3AB54A|12A89D|25AAE2|0E76BD|652D90|92278F|ED207B|8C6238|231F20|808281|B3B5B4|283890","enable_mobile_theme":true,"relative_date_duration":14,"category_featured_topics":4,"fixed_category_positions":false,"show_subcategory_list":false,"enable_badges":true,"invite_only":false,"login_required":false,"must_approve_users":false,"enable_local_logins":true,"allow_new_registrations":true,"enable_google_logins":true,"enable_google_oauth2_logins":false,"enable_yahoo_logins":true,"enable_twitter_logins":true,"enable_facebook_logins":true,"enable_github_logins":true,"enable_sso":false,"min_username_length":3,"max_username_length":20,"min_password_length":8,"enable_names":true,"invites_shown":30,"delete_user_max_post_age":60,"delete_all_posts_max":15,"min_post_length":20,"min_private_message_post_length":10,"max_post_length":32000,"min_topic_title_length":15,"max_topic_title_length":255,"min_private_message_title_length":2,"allow_uncategorized_topics":true,"min_title_similar_length":10,"min_body_similar_length":15,"edit_history_visible_to_public":true,"delete_removed_posts_after":24,"traditional_markdown_linebreaks":false,"suppress_reply_directly_below":true,"suppress_reply_directly_above":true,"newuser_max_images":0,"newuser_max_attachments":0,"display_name_on_posts":true,"short_progress_text_threshold":10000,"default_code_lang":"lang-auto","autohighlight_all_code":false,"email_in":false,"max_image_size_kb":3072,"max_attachment_size_kb":1024,"authorized_extensions":".jpg|.jpeg|.png|.gif|.svg|.txt|.ico|.yml","max_image_width":690,"max_image_height":500,"allow_profile_backgrounds":true,"allow_uploaded_avatars":true,"allow_animated_avatars":false,"tl1_requires_read_posts":30,"enable_long_polling":true,"polling_interval":3000,"anon_polling_interval":30000,"flush_timings_secs":5,"tos_url":"","privacy_policy_url":"","tos_accept_required":false,"faq_url":"","allow_restore":false,"maximum_backups":7,"version_checks":true,"suppress_uncategorized_badge":true,"min_search_term_length":3,"topic_views_heat_low":1000,"topic_views_heat_medium":2000,"topic_views_heat_high":5000,"global_notice":"","show_create_topics_notice":true,"available_locales":"cs|da|de|en|es|fr|he|id|it|ja|ko|nb_NO|nl|pl_PL|pt|pt_BR|ru|sv|uk|zh_CN|zh_TW"};
 Discourse.SiteSettings = jQuery.extend(true, {}, Discourse.SiteSettingsOriginal);