Load fewer posts when the android platform is detected

app/assets/javascripts/admin/models/site_setting.js

@@ -1,11 +1,3 @@
-/**
-  Our data model for interacting with site settings.
-
-  @class SiteSetting
-  @extends Discourse.Model
-  @namespace Discourse
-  @module Discourse
-**/
 Discourse.SiteSetting = Discourse.Model.extend({
 
   validationMessage: null,

app/assets/javascripts/discourse/models/post_stream.js

@@ -1,59 +1,17 @@
-/**
-  We use this class to keep on top of streaming and filtering posts within a topic.
-
-  @class PostStream
-  @extends Ember.Object
-  @namespace Discourse
-  @module Discourse
-**/
 Discourse.PostStream = Em.Object.extend({
 
-  /**
-    Are we currently loading posts in any way?
-
-    @property loading
-  **/
   loading: Em.computed.or('loadingAbove', 'loadingBelow', 'loadingFilter', 'stagingPost'),
-
   notLoading: Em.computed.not('loading'),
-
   filteredPostsCount: Em.computed.alias("stream.length"),
 
-  /**
-    Have we loaded any posts?
-
-    @property hasPosts
-  **/
-  hasPosts: function(){
+  hasPosts: function() {
     return this.get('posts.length') > 0;
   }.property("posts.@each"),
 
-  /**
-    Do we have a stream list of post ids?
-
-    @property hasStream
-  **/
   hasStream: Em.computed.gt('filteredPostsCount', 0),
-
-  /**
-    Can we append more posts to our current stream?
-
-    @property canAppendMore
-  **/
   canAppendMore: Em.computed.and('notLoading', 'hasPosts', 'lastPostNotLoaded'),
-
-  /**
-    Can we prepend more posts to our current stream?
-
-    @property canPrependMore
-  **/
   canPrependMore: Em.computed.and('notLoading', 'hasPosts', 'firstPostNotLoaded'),
 
-  /**
-    Have we loaded the first post in the stream?
-
-    @property firstPostPresent
-  **/
   firstPostPresent: function() {
     if (!this.get('hasLoadedData')) { return false; }
     return !!this.get('posts').findProperty('id', this.get('firstPostId'));
@@ -61,47 +19,22 @@ Discourse.PostStream = Em.Object.extend({
 
   firstPostNotLoaded: Em.computed.not('firstPostPresent'),
 
-  /**
-    The first post that we have loaded. Useful for checking to see if we should scroll upwards
-
-    @property firstLoadedPost
-  **/
   firstLoadedPost: function() {
     return _.first(this.get('posts'));
   }.property('posts.@each'),
 
-  /**
-    The last post we have loaded. Useful for checking to see if we should load more
-
-    @property lastLoadedPost
-  **/
   lastLoadedPost: function() {
     return _.last(this.get('posts'));
   }.property('posts.@each'),
 
-  /**
-    Returns the id of the first post in the set
-
-    @property firstPostId
-  **/
   firstPostId: function() {
     return this.get('stream')[0];
   }.property('stream.@each'),
 
-  /**
-    Returns the id of the last post in the set
-
-    @property lastPostId
-  **/
   lastPostId: function() {
     return _.last(this.get('stream'));
   }.property('stream.@each'),
 
-  /**
-    Have we loaded the last post in the stream?
-
-    @property loadedAllPosts
-  **/
   loadedAllPosts: function() {
     if (!this.get('hasLoadedData')) { return false; }
     return !!this.get('posts').findProperty('id', this.get('lastPostId'));
@@ -149,7 +82,7 @@ Discourse.PostStream = Em.Object.extend({
     var firstIndex = this.indexOf(firstPost);
     if (firstIndex === -1) { return []; }
 
-    var startIndex = firstIndex - Discourse.SiteSettings.posts_chunksize;
+    var startIndex = firstIndex - this.get('topic.chunk_size');
     if (startIndex < 0) { startIndex = 0; }
     return stream.slice(startIndex, firstIndex);
 
@@ -173,7 +106,7 @@ Discourse.PostStream = Em.Object.extend({
     if ((lastIndex + 1) >= this.get('highest_post_number')) { return []; }
 
     // find our window of posts
-    return stream.slice(lastIndex+1, lastIndex+Discourse.SiteSettings.posts_chunksize+1);
+    return stream.slice(lastIndex+1, lastIndex + this.get('topic.chunk_size') + 1);
   }.property('lastLoadedPost', 'stream.@each'),
 
 

app/assets/javascripts/discourse/models/site.js

@@ -1,11 +1,3 @@
-/**
-  A data model representing the site (instance of Discourse)
-
-  @class Site
-  @extends Discourse.Model
-  @namespace Discourse
-  @module Discourse
-**/
 Discourse.Site = Discourse.Model.extend({
 
   isReadOnly: Em.computed.alias('is_readonly'),

app/controllers/topics_controller.rb

@@ -47,6 +47,7 @@ class TopicsController < ApplicationController
     opts = params.slice(:username_filters, :filter, :page, :post_number, :show_deleted)
     username_filters = opts[:username_filters]
 
+    opts[:slow_platform] = true if request.user_agent =~ /Android/
     opts[:username_filters] = username_filters.split(',') if username_filters.is_a?(String)
 
     begin
@@ -58,7 +59,7 @@ class TopicsController < ApplicationController
     end
 
     page = params[:page].to_i
-    if (page < 0) || ((page - 1) * SiteSetting.posts_chunksize > @topic_view.topic.highest_post_number)
+    if (page < 0) || ((page - 1) * @topic_view.chunk_size > @topic_view.topic.highest_post_number)
       raise Discourse::NotFound
     end
 

app/serializers/topic_view_serializer.rb

@@ -42,8 +42,8 @@ class TopicViewSerializer < ApplicationSerializer
              :has_deleted,
              :actions_summary,
              :expandable_first_post,
-             :is_warning
-
+             :is_warning,
+             :chunk_size
 
   # Define a delegator for each attribute of the topic we want
   attributes(*topic_attributes)
@@ -113,6 +113,9 @@ class TopicViewSerializer < ApplicationSerializer
     result
   end
 
+  def chunk_size
+    object.chunk_size
+  end
 
   def is_warning
     object.topic.private_message? && object.topic.subtype == TopicSubtype.moderator_warning

config/locales/server.en.yml

@@ -739,6 +739,7 @@ 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"
     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/site_settings.yml

@@ -653,9 +653,11 @@ developer:
     default: false
     client: true
   posts_chunksize:
-    client: true
     default: 20
     min: 1
+  posts_slow_chunksize:
+    default: 10
+    min: 1
 
 embedding:
   embeddable_host: ''

lib/topic_view.rb

@@ -5,7 +5,7 @@ require_dependency 'gaps'
 
 class TopicView
 
-  attr_reader :topic, :posts, :guardian, :filtered_posts
+  attr_reader :topic, :posts, :guardian, :filtered_posts, :chunk_size
   attr_accessor :draft, :draft_key, :draft_sequence, :user_custom_fields
 
   def initialize(topic_id, user=nil, options={})
@@ -20,7 +20,8 @@ class TopicView
 
     @page = @page.to_i
     @page = 1 if @page.zero?
-    @limit ||= SiteSetting.posts_chunksize
+    @chunk_size = options[:slow_platform] ? SiteSetting.posts_slow_chunksize : SiteSetting.posts_chunksize
+    @limit ||= @chunk_size
 
     setup_filtered_posts
 

spec/components/topic_view_spec.rb

@@ -25,6 +25,16 @@ describe TopicView do
     lambda { TopicView.new(topic.id, admin) }.should_not raise_error
   end
 
+  context "chunk_size" do
+    it "returns `posts_chunksize` by default" do
+      TopicView.new(topic.id, coding_horror).chunk_size.should == SiteSetting.posts_chunksize
+    end
+
+    it "returns `posts_slow_chunksize` when slow_platform is true" do
+      tv = TopicView.new(topic.id, coding_horror, slow_platform: true)
+      tv.chunk_size.should == SiteSetting.posts_slow_chunksize
+    end
+  end
 
   context "with a few sample posts" do
     let!(:p1) { Fabricate(:post, topic: topic, user: first_poster, percent_rank: 1 )}

test/javascripts/models/post-stream-test.js.es6

@@ -1,7 +1,7 @@
 module("Discourse.PostStream");
 
 var buildStream = function(id, stream) {
-  var topic = Discourse.Topic.create({id: id});
+  var topic = Discourse.Topic.create({id: id, chunk_size: 5});
   var ps = topic.get('postStream');
   if (stream) {
     ps.set('stream', stream);
@@ -20,7 +20,6 @@ test('defaults', function() {
   blank(postStream.get('posts'), "there are no posts in a stream by default");
   ok(!postStream.get('loaded'), "it has never loaded");
   present(postStream.get('topic'));
-
 });
 
 test('appending posts', function() {
@@ -182,7 +181,6 @@ test("loading", function() {
 });
 
 test("nextWindow", function() {
-  Discourse.SiteSettings.posts_chunksize = 5;
   var postStream = buildStream(1234, [1,2,3,5,8,9,10,11,13,14,15,16]);
 
   blank(postStream.get('nextWindow'), 'With no posts loaded, the window is blank');
@@ -199,7 +197,6 @@ test("nextWindow", function() {
 });
 
 test("previousWindow", function() {
-  Discourse.SiteSettings.posts_chunksize = 5;
   var postStream = buildStream(1234, [1,2,3,5,8,9,10,11,13,14,15,16]);
 
   blank(postStream.get('previousWindow'), 'With no posts loaded, the window is blank');