Integrating with WordPress via XML-RPC Max Cutler WordCamp NYC 2012 

Who am I? • http://maxcutler.com • @maxcutler • Student • WordPress for Windows Phone • Core Contributor for XML-RPC in 3.4 

Motivation What is XML-RPC? WordPress & XML-RPC Examples Tips for plugin and theme authors What’s next? 

Motivation What is XML-RPC? WordPress & XML-RPC Examples Tips for plugin and theme authors What’s next? 

Cross-system interoperability 

Escape the data silo 

Motivation What is XML-RPC? WordPress & XML-RPC Examples Tips for plugin and theme authors What’s next? 

“Simple cross-platform distributed computing, based on the standards of the Internet.” xmlrpc.com 

RPC using XML serialization 

Sample Exchange - Request POST /xmlrpc.php HTTP/1.0 User-Agent: Max’s API Client Host: maxcutler.com Content-Type: text/xml wp.getUsersBlogs maxcutler L1nk3d1nr0ck$ 

Sample Exchange - Response HTTP/1.0 200 OK Content-Type: text/xml isAdmin 1 url http://www.maxcutler.com/ blogid 1 blogName Max Cutler xmlrpc http://www.maxcutler.com/xmlrpc.php 

Libraries for every language • PHP/WordPress – IXR • Python – xmlrpclib • Ruby – XMLRPC::Client • Perl – RPC::XML • C# - XML-RPC.NET • Java – ws-xmlrpc • JavaScript – Mimic, node-xmlrpc • And many more… 

Motivation What is XML-RPC? WordPress & XML-RPC Examples Tips for plugin and theme authors What’s next? 

xmlrpc.php • WordPress.com • Off-by-default on WordPress.org • wp-includes/class- wp-xmlrpc-server.php 

History • r1348 (May 2004) – xmlrpc.php born • 1.5 – Blogger, MovableType, metaWeblog, and pingback APIs • 2.2 - Pages • 2.5 – Categories, Custom Fields • 2.6 – Options/Settings • 2.7 – Comments • 3.1 – Media Library (read or upload) 

History – 3.3 blogger.getUsersBlogs blogger.getUserInfo blogger.getPost blogger.getRecentPosts blogger.newPost blogger.editPost blogger.deletePost metaWeblog.newPost metaWeblog.editPost metaWeblog.deletePost metaWeblog.getPost metaWeblog.getRecentPosts metaWeblog.getCategories metaWeblog.newMediaObject metaWeblog.getUsersBlogs pingback.ping pingback.extensions mt.getCategoryList mt.getRecentPostTitles mt.getPostCategories mt.setPostCategories mt.publishPost mt.getTrackbackPings wp.getUsersBlogs wp.getAuthors wp.getPage wp.getPages wp.newPage wp.editPage wp.deletePage wp.getPageList wp.getPageTemplates wp.getPageStatusList wp.getCategories wp.getTags wp.newCategory wp.deleteCategory wp.suggestCategories wp.getCommentCount wp.getComment wp.getComments wp.newComment wp.getCommentStatusList wp.getOptions wp.setOptions wp.uploadFile wp.getMediaItem wp.getMediaLibrary wp.getPostFormats wp.getPostStatusList demo.sayHello demo.addTwoNumbers system.listMethods 

Can we clean this up? • Limited or no support for 3.x core features • Widespread inconsistency of parameters and return values • Abuse of legacy method fields postid title description dateCreated date_created_gmt permaLink link title description mt_excerpt mt_text_more wp_more_text mt_allow_comments mt_allow_pings mt_keywords categories wp_slug wp_password userid wp_author_id wp_author_display_name post_status custom_fields wp_post_format sticky enclosure 

Today – 3.4 • Unified post types • Unified taxonomies • More useful media • Actions & filters • Bug-fixes • Unit tests (!!!) http://codex.wordpress.org/XML-RPC_WordPress_API wp.getPost wp.getPosts wp.newPost wp.editPost wp.deletePost wp.getPostType wp.getPostTypes wp.getPostFormats wp.getPostStatusList wp.getTaxonomy wp.getTaxonomies wp.getTerm wp.getTerms wp.newTerm wp.editTerm wp.deleteTerm wp.getMediaItem wp.getMediaLibrary wp.uploadFile wp.getCommentCount wp.getComment wp.getComments wp.newComment wp.editComment wp.deleteComment wp.getCommentStatusList wp.getOptions wp.setOptions wp.getUsersBlogs wp.getAuthors 

Method analogies WordPress Core API XML-RPC Method get_posts wp.getPost, wp.getPosts wp_insert_post wp.newPost, wp.editPost get_taxonomy wp.getTaxonomy, wp.getTaxonomies get_terms wp.getTerm, wp.getTerms wp_insert_term wp.newTerm wp_update_term wp.editTerm get_post_types wp.getPostType, wp.getPostTypes get_comments wp.getComment, wp.getComments 

Motivation What is XML-RPC? WordPress & XML-RPC Examples Tips for plugin and theme authors What’s next? 

Clients • Language • Standard Library • 3rd-party libraries & wrappers – PHP: IXR_Client (ships with WordPress) – Python: python-wordpress-xmlrpc – Node.js: node-wordpress – C#/.NET: JoeBlogs 

Post Querying • wp.getPosts – Filter • post_type, number, offset, order, orderby – Fields • Meta-fields: post, taxonomies, custom_fields • Individual fields – post_id, post_title, post_date, post_date_gmt, post_modified, post_modified_gmt, post_status, post_type, post_name, post_author, post_password, post_excerpt, post_content, link, comment_status, ping_status, sticky, post_format, terms, custom_fields, enclosure 

Post Querying wp.getPosts( 0, username, password, array( ‘post_type’ => ‘product’, ‘orderby’ => ‘title’, ‘order’ => ‘ASC’ ), array( ‘post_title’, ‘date_modified_gmt’, ‘link’ ) ) 

Post Creation wp.newPost( 0, username, password, array( ‘post_title’ => ‘Hello world’, ‘post_content’ => …, ‘terms_names’ => array( ‘post_tag’ => array( ‘day1’ ), ‘category’ => array( ‘introductions’ ) ) ) ) 

Post Creation (2) wp.newPost( 0, username, password, array( ‘post_type’ => ‘product’, ‘post_title’ => ‘ACME’, ‘post_content’ => …, ‘custom_fields’ => array( array( ‘key’ => ‘price’, ‘value’ => 15 ) ) ) ) 

Real world examples 

Mobile Apps http://wordpress.org/extend/mobile/ 

Offline Writing Applications Windows Live Writer, MarsEdit, ecto, etc. 

Jetpack 

Chicago Tribune News Apps Varnish Caching Unit Tests http://blog.apps.chicagotribune.com/2011/06/28/dont-break-the-homepage-using-unit-tests- to-validate-your-wordpress-varnish-caching-strategy/ 

Generate WordPress site using build tools https://github.com/scottgonzalez/grunt-wordpress github.com/jquery/api.jquery.com (XML files in git repo) grunt-wordpress (XML-RPC bridge) api.jquery.com (WordPress site) 

External Search Django + Haystack + Solr 

Camayak Editorial content production with multiple-site remote publishing Camayak WordPress InDesign NITF Drupal 

Motivation What is XML-RPC? WordPress & XML-RPC Examples Tips for plugin and theme authors What’s next? 

http://codex.wordpress.org/ XML-RPC_Support http://codex.wordpress.org/ XML-RPC_Extending 

Add/remove methods xmlrpc_methods filter function mynamespace_subtractTwoNumbers( $args ) { $number1 = (int) $args[0]; $number2 = (int) $args[1]; return $number1 - $number2; } function mynamespace_new_xmlrpc_methods( $methods ) { $methods['mynamespace.subtractTwoNumbers'] = 'mynamespace_subtractTwoNumbers'; return $methods; } add_filter( 'xmlrpc_methods', mynamespace_new_xmlrpc_methods'); 

Adjust return values • xmlrpc_default_*_fields – post, posttype, taxonomy • xmlrpc_prepare_* – post, post_type, taxonomy, term, media_item, comment, page • xmlrpc_blog_options • wp_handle_upload • Use the source, Luke! 

PSA: Omit Trailing “?>” 

Motivation What is XML-RPC? WordPress & XML-RPC Examples Tips for plugin and theme authors What’s next? 

Using 3.3 or earlier? Shim for 3.4 additions in my plugin: http://wordpress.org/extend/plugins /xml-rpc-modernization/ 

WordPress 3.5? User management Even more media enhancements Improved custom fields JSON Serialization 

REST API v1 on http://developer.wordpress.com v2 in core? TBD 

http://codex.wordpress.org/ XML-RPC_Support 

Thanks! Q&A