Tìm Hiểu về Wordpress - part 21 pptx

187 6.3.4 Number of Posts While configuring your feed for either full or partial post display, you should also consider the number of posts included in your feed. In the WordPress Admin, under Settings > Reading, you will see two fields, “Blog pages show at most…” and “Syndication feeds show the most recent…”, which enable you to specify how many posts should appear on your home page and in your feed, respectively. These numbers may be the same or completely different. Here you may set any number of posts for your feed – this may be different than the number set for your archive posts. Note that when it comes to your feeds, the number of posts specified in the WordPress Admin applies to every feed produced by your site, including comment feeds! 6.3.5 WordPress Feed Formats WordPress Post-feed formats for permalinks If you have permalinks enabled on your site, your Posts feed is accessible via the following URLs: http://domain.tld/feed/ - RSS 2.0 format http://domain.tld/feed/rss2/ - RSS 2.0 format http://domain.tld/feed/rss/ - RSS 0.92 format http://domain.tld/feed/rdf/ - RDF/RSS 1.0 format http://domain.tld/feed/atom/ - Atom format Finding Balance When choosing the number of posts to display on your home and archive pages, try to nd the right balance between providing plenty of content and delivering speedy web pages. Too much content can slow things down for users with slow connections, but not enough content can leave your site looking empty. If you host your own RSS feeds (rather than use something like FeedBurner) also consider balance. The more articles you show in your feed, the more bandwidth intensive serving that feed is. 188 WordPress Post-feed formats for default URLs (non-permalink) By default, your Posts feed is accessible via the following file-based URLs (even when you have permalinks enabled): http://domain.tld/wp-rss2.php - RSS 2.0 format http://domain.tld/wp-rss.php - RSS 0.92 format http://domain.tld/wp-rdf.php - RDF/RSS 1.0 format http://domain.tld/wp-atom.php - Atom format WordPress Post-feed formats via query string (non-permalink) Alternately, your Posts feed is also available at the following query-string-based URLs (even when you have permalinks enabled): http://domain.tld/?feed=rss2 - RSS 2.0 format http://domain.tld/?feed=rss - RSS 0.92 format http://domain.tld/?feed=rdf - RDF/RSS 1.0 format http://domain.tld/?feed=atom - Atom format Display default Post-feed URLs To determine/display the default posts feed URL for your blog’s main content, place any or all of these template tags into a useful location in one of your theme files: <?php bloginfo('rss2_url'); ?> - RSS 2.0 format <?php bloginfo('rss_url'); ?> - RSS 0.92 format <?php bloginfo('rdf_url'); ?> - RDF/RSS 1.0 format <?php bloginfo('atom_url'); ?> - Atom format 189 WordPress main comments feed Your blog’s main comments feed is available only in RSS 2.0 format, but there are several URL options from which to choose: http://domain.tld/comments/feed/ - Permalink format http://domain.tld/wp-commentsrss2.php - Default le-based format http://domain.tld/?feed=commentsrss2 - Query-string format Display main comments feed URL To display the default URL for your main comments feed, add this template tag to your theme file and load the page in your browser: <?php bloginfo('comments_rss2_url'); ?> Post-specific comment feeds By default, every post also delivers its own feed featuring all of its comments. To display feed URLs for individual, post-specific comment feeds, place this template tag anywhere in the main post loop or comment loop: <?php comments_rss_link('Subscribe to comments on this post via RSS'); ?> Alternately, to display the comment-feed URL for any specific post, simply append either of the following to the original post URL: feed/ - Permalink format ?feed=rss2 - Default format Here is an example of each method for a generalized post URL: http://domain.tld/individual-post/feed/ - Permalink format http://domain.tld/individual-post/?feed=rss2 - Default format What is my Feed URL? For a complete online reference of all available WordPress feed formats, types, and possibilities, check out this article: http://digwp.com/u/380 190 When using default (non-permalink) URLs, the post-specific comment feeds are available via the following format: http://domain.tld/?feed=rss2&p=123 …where “p=123” references the post ID. Category Feeds To display individual category feed URLs, use either of the following formats: http://domain.tld/category/categoryname/feed/ - Permalink format http://domain.tld/wp-rss2.php?cat=33 - Default format Whew! As you can see, WordPress provides a ton of feed formats and configuration options. And these are just the standard formats available by default. Later in section 6.6.5, we’ll show you how to rig up just about any feed imaginable. 6.4.1 Using FeedBurner For Feed Delivery There are many ways to track your feed statistics. Perhaps the most popular method of doing so involves the free feed-delivery service provided by FeedBurner http://digwp.com/u/166. Millions of site owners and bloggers redirect their feeds to FeedBurner, which in turn delivers the feeds to all of your subscribers. In the process of delivering your feed, FeedBurner maintains an excellent set of statistics for many aspects of your feeds. We use and recommend FeedBurner for all of our feed-delivery needs, so we want to take a moment to discuss why it’s cool, how to use it, and some of the awesome things that it can do. 191 6.4.2 Benefits of Using FeedBurner Perhaps the best reason to use FeedBurner is its immense popularity. With millions of users, the chance of FeedBurner closing shop is next to nil. Further, FeedBurner belongs to Google since 2007, and it is unlikely that anyone will be snatching it from their able hands. To be sure, Google has dropped the ball a few times for their FeedBurner service, but the issues are usually resolved within a bearable amount of time (it could be better), and with Google, you know that there are always people around to fix things when they break. If that wasn’t quite convincing enough, let us just emphasize the vast amount of data that is collected by FeedBurner. Everything that you could want to know about your feeds is available to you from an elaborate user-interface in your FeedBurner account’s Admin area. Here is a rundown of some of the best features that are available when you host your feed(s) at FeedBurner: • Awesome analytical tools - Comprehensive subscriber statistics, click- throughs, and many other key statistics for your feed • Integrated Adsense advertising - Google makes it easy to manage and monetize your feeds with Adsense • Universal feed delivery - FeedBurner’s SmartFeed formats your feed to work perfectly with virtually any feed reader • Tons of optimization options - FeedFlares, Link Splicing, Geotagging, and many more savvy optimization tools • Great tools to publicize your feed - Headline animator, Email subscriptions, feed branding, and everything else you need to help spread the word • Easy exportation of data - You can export your feed stats via Excel or CSV file for easy analysis with your favorite spreadsheet or statistical software Even better, FeedBurner is simple to set up and use, tracks everything automatically, is easily configurable, and costs absolutely nothing. Sure there are periods of downtime, but so far these have been few and far between, with consistent and reliable FeedBurner service being the norm. 192 6.4.3 Setting Up and Configuring a FeedBurner Account To “burn” your feed using the FeedBurner service, you must do the following: • Register for a Google account (a single account may host multiple feeds) • Enter the URL of the feed that you would like to burn • Pick a FeedBurner feed URL for each of your feeds • Redirect your original feed URL to its corresponding FeedBurner counterpart For the last step – redirecting your feed to FeedBurner, there are several options, including redirecting via plugin, HTAccess (or Apache configuration file), or PHP. Let’s take a look at each of these methods. 6.4.4 Redirecting to FeedBurner via Plugin Two great options for redirecting your feeds to FeedBurner are the Feedsmith plugin – http://digwp.com/u/167 (direct download link, zip file) – and the FD FeedBurner plugin – http://digwp.com/u/168. Either of these plugins do a good job at automatically redirecting your site’s main feed and, optionally, your main comments feed. As Easy as it Gets Installing and using the Feedsmith plugin is a no- brainer: simply enter your feed URL(s) in the plugin options section and click save. Nothing more to do – everything else happens automagically behind the scenes. 193 Simply install either plugin, navigate to the plugin options page, and enter your FeedBurner feed URL(s) in the fields provided. Once done, save the options and check that everything is working as expected. 6.4.5 Redirecting to FeedBurner via HTAccess One of the limitations of using a plugin to redirect your site’s feeds to FeedBurner is the lack of customization and configurational control over which feeds are redirected. By default, either of the currently available FeedBurner-redirect plugins will redirect all of your WordPress feeds to your FeedBurner URL. For multi-topic or multi-author blogs, this may prevent you from delivering topic-specific feeds to your readers. For example, what if you wanted to redirect your individual category feeds to their corresponding FeedBurner counterparts? With these plugins, this is not possible. Fortunately, we can use Apache’s powerful HTAccess directives to get the job done quickly and easily. To see an example of how HTAccess enables a more flexible collection of feed offerings, let’s assume the following hypothetical collection of WordPress/ FeedBurner feed URLs: • Main feed: http://domain.tld/feed/ =redirects to=> http://feeds.feedburner.com/main-feed • Comments feed: http://domain.tld/comments/feed/ =redirects to=> http://feeds.feedburner.com/comments-feed • “Business” category feed: http://domain.tld/category/business/feed/ =redirects to=> http://feeds.feedburner.com/business-feed • “Pleasure” category feed: http://domain.tld/category/pleasure/feed/ =redirects to=> http://feeds.feedburner.com/pleasure-feed • “Nonsense” category feed: http://domain.tld/category/nonsense/feed/ =redirects to=> http://feeds.feedburner.com/nonsense-feed 194 Currently, there is not a plugin that will handle this scenario, but by placing the following Apache directives into our site’s root HTAccess file (or httpd.conf file) we can get the job done quite easily: Notice that the first two RewriteCond directives redirect your main feed and comments feed to their respective FeedBurner URLs. Simply edit the specified FeedBurner URL in both of these lines to your actual FeedBurner URLs. After that, the next three RewriteCond directives redirect each of our three hypothetical category URLs to its respective FeedBurner URL. For each of these lines, edit both the category name and its associated FeedBurner feed URL according to your actual values. Further, including additional categories is as easy as replicating one of the last three RewriteCond directives. Copy and paste a new line, edit accordingly, and done! Likewise, to remove any unnecessary category feeds, simply use the lines that are needed and delete the others. Thus, if you only want to redirect your site’s main and comments feeds, your code would look like this: <IfModule mod_rewrite.c> RewriteEngine on RewriteCond %{HTTP_USER_AGENT} !^.*(FeedBurner|FeedValidator) [NC] # Redirect Wordpress Feeds to FeedBurner <IfModule mod_rewrite.c> RewriteEngine on RewriteCond %{HTTP_USER_AGENT} !^.*(FeedBurner|FeedValidator) [NC] RewriteRule ^feed/?.*$ http://feeds.feedburner.com/main-feed [L,NC,R=302] RewriteRule ^comments/?.*$ http://feeds.feedburner.com/comments-feed [L,NC,R=302] RewriteRule ^category/business/feed/?.*$ http://feeds.feedburner.com/business-feed [L,NC,R=302] RewriteRule ^category/pleasure/feed/?.*$ http://feeds.feedburner.com/pleasure-feed [L,NC,R=302] RewriteRule ^category/nonsense/feed/?.*$ http://feeds.feedburner.com/nonsense-feed [L,NC,R=302] </IfModule> 195 RewriteRule ^feed/?.*$ http://feeds.feedburner.com/main-feed [L,NC,R=302] RewriteRule ^comments/?.*$ http://feeds.feedburner.com/comments-feed [L,NC,R=302] </IfModule> With that code in place (and properly edited), your server will redirect all requests for your blog’s Posts Feed and Comments Feed to their respectively associated FeedBurner URLs. All other types of feeds (tag feeds, individual post-comment feeds, author feeds, etc.) will not be affected and will appear as normal when requested. And the best part? With this HTAccess method, there is no need to install an additional plugin – this method takes care of everything you need to redirect your feeds properly. 6.4.6 Redirecting to FeedBurner via PHP If the thought of using HTAccess to redirect your feeds makes your skin crawl, don’t sweat it – here is an alternate version for redirecting your feeds to FeedBurner using good ‘ol-fashioned PHP. 1. Add the following code to your active theme’s functions.php file: function custom_feed_link($output, $feed) { $feed_url = 'http://feeds.feedburner.com/your-feedburner-feed'; $feed_array = array( 'rss' => $feed_url, 'rss2' => $feed_url, 'atom' => $feed_url, 'rdf' => $feed_url, 'comments_rss2' => '' ); $feed_array[$feed] = $feed_url; Look Ma, No Plugin! To redirect your feeds to FeedBurner without using a plugin, copy the code featured on this page and paste it into your site’s root .htaccess le. This snippet of code gets the job done without any PHP processing from the server. Credit Thanks to Justin Tadlock for sharing this PHP-redirection technique with the WordPress Community! http://digwp.com/u/88 196 $output = $feed_array[$feed]; return $output; } add_lter('feed_link','custom_feed_link', 1, 2); 2. Edit the $feed_url with the URL of your FeedBurner feed. Once in place, this code will redirect all of your site’s main feeds – in all formats – to your corresponding FeedBurner counterpart. Additionally, you may also redirect other types of feeds as well. For example, here is the code used (in your functions. php file) to redirect your category, author, tag, and search feeds as well: function other_feed_links($link) { $link = 'http://feeds.feedburner.com/your-feedburner-feed'; return $link; } add_lter('category_feed_link', 'other_feed_links'); add_lter('author_feed_link', 'other_feed_links'); add_lter('tag_feed_link','other_feed_links'); add_lter('search_feed_link','other_feed_links'); This code may be customized according to your specific needs. For example, if you only need to redirect your category feeds, simply delete the three other add_lter lines in the code. Likewise, if you need to add additional feed types, simply replicate one of the add_lter lines and specify the feed type in the first PHP parameter. Whatever you do, remember to test, test, test that everything is working properly. The <link> While this code doesn't redirect feeds in the sense of literally changing the URL being accessed (the other methods do), it does change the <link> element which is what tells browsers and feed reading applications where the RSS feed lives. . enabled): http://domain.tld/wp-rss2.php - RSS 2.0 format http://domain.tld/wp-rss.php - RSS 0.92 format http://domain.tld/wp-rdf.php - RDF/RSS 1.0 format http://domain.tld/wp-atom.php - Atom format WordPress Post-feed. choose: http://domain.tld/comments/feed/ - Permalink format http://domain.tld/wp-commentsrss2.php - Default le-based format http://domain.tld/?feed=commentsrss2 - Query-string format Display main comments. URLs: http://domain.tld/feed/ - RSS 2.0 format http://domain.tld/feed/rss2/ - RSS 2.0 format http://domain.tld/feed/rss/ - RSS 0.92 format http://domain.tld/feed/rdf/ - RDF/RSS 1.0 format http://domain.tld/feed/atom/ -