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Abstracting functionality with Centralised Content<br />Michael Peacock<br />

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About me<br />Senior Web Developer<br />M.D. of design agency Peacock Carter<br />Technical director for an online retailer<br />Author<br />www.michaelpeacock.co.uk<br />me@michaelpeacock.co.uk<br />@michaelpeacock<br />

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What's in store?<br />Setting the scene – a look at the problem centralised content solves<br />Centralised content – what is it and how can it solve this problem<br />Implementation – How we implemented centralised content with PHP and MySQL<br />

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A sample bespoke CMS / basic e-commerce website<br />Pages<br />Blog entries<br />Blog categories<br />News articles<br />Products<br />Product Categories<br />Events<br />Users can buy products<br />Users can rate products<br />Users can comment on / review products<br />Users can comment on blog entries<br />

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Commenting<br />Needed for both blog entries and products<br />Create a simple library or function to create a comment for us<br />Comments table in our database<br />Table to link them to blog entries<br />Table to link them to products<br />

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Database<br />

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What about searching<br />Do we have search boxes for different aspects of the site?<br />Do we use a complex searching system?<br />Should we just let Google do it for us?<br />“Can’t someone else do it?” Homer J Simpson<br />

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What if in the future, once development is complete…<br />Users need to be able to rate blog entries<br />Users need to be able to purchase (book onto) events<br />… and comment on them<br />… … and rate them…<br />Sounds like a pain!<br />

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Let’s take a step back…<br />And centralise our content!<br />

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Centralised Content<br />Useful architecture; especially for CMS projects<br />MVC brings out the best in it<br />Drupal<br />“node”<br />MVC would be nice, Drupal<br />Used extensively in our own CMS and frameworks for the past year and a half;<br />

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Content<br />Typical content found on a CMS powered site:<br />Pages<br />Blog entries<br />News articles<br />Job vacancies<br />Products<br />Events<br />Photographs / Image gallery<br />

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Pages<br />Name<br />Heading<br />Page content<br />Meta data / title<br />URL<br />

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Blog Entries<br />Name<br />Heading<br />Blog entry<br />Meta data / title<br />Leading image<br />Leading paragraph<br />Author<br />URL<br />

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News articles<br />Name<br />Heading<br />News article<br />Meta data / title<br />Leading image<br />Leading paragraph<br />Author<br />URL<br />

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Job Vacancies<br />Name<br />Heading<br />Job description<br />Location<br />Application deadline<br />Salary<br />Meta data / title<br />Author<br />URL<br />

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Products<br />Name<br />Heading<br />Product description<br />Price<br />Weight<br />Image<br />Meta data / title<br />Author<br />URL<br />

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Events<br />Name<br />Heading<br />Event description<br />Location<br />Date<br />Start / End time<br />Meta data / title<br />Author<br />URL<br />

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Gallery Images<br />Name<br />Heading<br />Image caption / description<br />Camera data<br />Location<br />Image location<br />Meta data / title<br />Author<br />URL<br />

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Its all the same! (well, almost…)<br />Name<br />Heading<br />Title<br />URL / Path / Search Engine friendly name<br />Primary content / description / details<br />Meta data<br />Creator / Author <br />Active / Enabled<br />Comments enabled / disabled<br />

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…with extra bits depending on the type<br />Products<br />Price; Stock level; SKU; Weight<br />Events<br />Venue; Spaces; Price; Date; Start time; End time<br />Gallery image<br />Image file location; Camera details; Location<br />Job vacancy<br />Salary; Location; Start date; Type; Application date<br />

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Content versions<br />With content being centralised we can implement versioning more easily<br />Record all versions of content<br />Static content IDs which relate to the active version<br />

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So; let’s centralise it!<br />Core fields will make up our main table of content (content_versions)<br />Content types will have their own table, containing type specific fields content_versions_*<br />A content table (content) will store static data, such as author, creation date, ID, and reference the current active version certain toggle-able fields (active, commentable) should go here<br />Regardless of the version in play, the content ID can be used to access the element, and won’t change.<br />

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Core database<br />

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Within MVC<br />Content model<br />Models for each content type, extending the content model<br />For administrative tasks (CMS) content controller to perform shared operations: toggle active, toggle comments, delete<br />Content type controllers extend<br />

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Content model<br />Deals exclusively with content and content versions tables<br />Getters and setters for core content fields<br />Creating content:<br />Create new content version<br />Create new content record, pointing to the version<br />Editing content<br />Create new content version<br />Log the old version ID in a versions log<br />Update the content record to point to the new version<br />

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Content: save<br />public function save()<br />{<br /> // are we creating a new content item?<br /> if( $this->id == 0 )<br /> {<br />/** create the content versions record */<br /> $this->registry->getObject('db')->insertRecords( 'content_versions', $insert );<br />// record the ID<br /> $this->revisionID = $this->registry->getObject('db')->lastInsertID();<br />/** insert the content record */<br /> $this->registry->getObject('db')->insertRecords( 'content', $insert );<br />// record the ID<br /> $this->id = $this->registry->getObject('db')->lastInsertID();<br /> }<br /> else<br /> {<br />// have we changed the revision, or just something from the content table?<br /> if( $this->revisionChanged == true )<br /> {<br />// make a note of the old revision ID for the history<br /> $this->oldRevisionID = $this->revisionID;<br />/** insert the new content_versions record */<br /> $this->registry->getObject('db')->insertRecords( 'content_versions', $insert );<br />// update the revisionID<br /> $this->revisionID = $this->registry->getObject('db')->lastInsertID();<br />/** record the history */<br /> $this->registry->getObject('db')->insertRecords( 'content_versions_history', $insert);<br /> }<br />/* update the content table */<br /> $this->registry->getObject('db')->updateRecords('content', $update, 'ID=' . $this->id );<br /> }<br />}<br />

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Product (i.e. a content type) model<br />Extends content model<br />Getters and setters for extended data for the content type<br />Creating product<br />

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Product: save<br />public function save()<br />{<br />// Creating a new product<br /> if( $this->getID() == 0 )<br /> {<br />parent::setType( $this->typeID );<br /> parent::save();<br /> $this->saveProduct();<br /> }<br /> else<br /> {<br /> // tells the parent, that the revision has changed, <br /> // i.e. that we didn't just toggle active / change something from the _content_table!<br />$this->setRevisionChanged( true );<br /> parent::save();<br /> $this->saveProduct();<br /> }<br />}<br />

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Product: Saving product data<br />private function saveProduct()<br />{<br />/** insert product specific data */<br /> // product version ID should be the same as the content version ID for easy maping<br /> $insert['version_id'] = $this->getRevisionID();<br /> $this->registry->getObject('db')->insertRecords( 'content_versions_store_products', $insert );<br /> // get the content ID<br /> $pid = $this->getID();<br /> // categories<br /> // delete all associations with this product ID<br /> // insert new ones based off user input; $pid to reference product<br /> // shipping costs<br /> // delete all associations with this ID<br /> // insert new ones based off user input; $pid to reference product<br />}<br />

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A load of CRUD!<br />Creating<br />New features / content types we only need to code for the extended fields<br />Reading<br /> Custom constructor in the child model<br />Call setters for content type specific fields<br />Call parent setters for core content<br />Child method to iterate through / process fields to go to the template engine<br />

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A load of CRUD!<br />Updating<br />Parent deals with all the core fields (no new work!)<br />Insert (versions) extended fields<br />Use the ID the parent gives to the content version, to make table mapping easier<br />Deleting<br />Assuming “deleting” just hides content from front and back-end<br />Parent object updates content record to deleted – no extra work!<br />

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Commenting<br />Requires just one database table<br />Can be used, without additional work, for all content types<br />Each comment relates to a record in the content table<br />

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... commenting<br />private function postComment( $id )<br />{<br />require_once( FRAMEWORK_PATH . 'models/comment/comment.php');<br /> $comment = new Commentmodel( $this->registry, 0 );<br /> // tell the comment which content element it relates to<br /> $comment->setContent( $id );<br /> $comment->setName( isset( $_POST['comment_name'] ) ? $_POST['comment_name']: '' );<br /> $comment->setEmail( isset( $_POST['comment_email'] ) ? $_POST['comment_email']: '' );<br /> $comment->setURL( isset( $_POST['comment_url'] ) ? $_POST['comment_url']: '' );<br /> $comment->setComment( isset( $_POST['comment_comment'] ) ? $_POST['comment_comment']: '' );<br /> $comment->setIPAddress( $_SERVER['REMOTE_ADDR'] );<br /> $comment->setCommentsAutoPublished( $this->registry->getSetting('blog.comments_approved') );<br /> $comment->setPageURL( $this->registry->getURLBits() );<br /> if( $comment->checkForErrors() )<br /> {<br /> /** error processing */<br /> }<br /> else<br /> {<br /> // save the post<br /> $comment->save();<br />/** Redirect to the controller the user was on before, based on the URL */<br /> }<br />}<br />

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Rating<br />Again, just one table<br />Directly relates to the appropriate content element<br />Create it once; works for all content types – no future work for new content types<br />

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Geo-tagging<br />Either extend the content / versions tableOR<br />Create a co-ordinates table and map it to the content table<br />

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What else?<br />Keyword tagging<br />Keywords table<br />Content keywords associations table<br />Central functionality to add keywords and delete orphaned keywords<br />Categories<br />A content type (up for debate) – why?<br />New table to map content to content<br />Central functionality to manage associations<br />

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Purchasing<br />Provided content types have consistent cost / shipping fields, they can slot into the order pipeline<br />Won’t work for all content types<br />Makes conversion easy<br />Make event purchasable?<br />Make gallery image purchasable?<br />Just add price fields, and indicate the content type can be purchased<br />

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Purchasing<br />By giving an image a price field, pre-existing e-commerce functionality can process it<br />Piece of cake<br />

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Hierarchies and ordering<br />Ordering pages within the sites menu<br />Moving pages within another page<br />Ordering product categories<br />Ordering blog entries<br />Ordering news articles<br />

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Searching<br />Search the content & content versions table<br />LEFT JOIN content_versions_* tables where appropriate<br />Designate searchable fields<br />Execute the query<br />Enjoy integrated search results!<br />

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Searching: Define our extended search fields<br />private $extendedTablesAndFields = array( <br /> 'content_versions_news' => array( 'joinfield' => 'version_id', 'fields' => array( 'lead_paragraph' ) ) <br />);<br />

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Searching: Build our left joins<br />$joins = "";<br />$selects = "";<br />$wheres = " ";<br />$priority = 4;<br />$orders = "";<br />foreach( $this->extendedTablesAndFields as $table => $data )<br />{<br /> $field = $data['joinfield'];<br /> $joins .= " LEFT JOIN {$table} ON content.current_revision={$table}.{$field} "; <br />foreach( $data['fields'] as $field )<br /> {<br /> $wheres .= " IF( {$table}.{$field} LIKE '%{$phrase}%', 0, 1 ) <> 1 OR ";<br /> $selects .= ", IF( {$table}.{$field} LIKE '%{$phrase}%', 0, 1 ) as priority{$priority} ";<br /> $orders .= " priority{$priority} ASC, ";<br /> $priority++;<br /> }<br />}<br />

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Searching: Query!<br />$sql = "SELECT *, <br /> IF(content_types.reference='page',content.path,CONCAT(content_types.view_path,'/',content.path ) ) as access_path, <br /> REPLACE(substr(content_versions.content,1,100),'<p>','') as snippet, <br /> content_types.name as ct, <br /> IF( content_versions.name LIKE '%{$phrase}%', 0, 1 ) as priority0, <br /> IF( content_versions.title LIKE '%{$phrase}%', 0, 1 ) as priority1, <br /> IF( content_versions.heading LIKE '%{$phrase}%', 0, 1 ) as priority2, <br /> IF( content_versions.content LIKE '%{$phrase}%', 0, 1 ) as priority3 <br />{$selects} <br />FROM <br /> content <br /> LEFT JOIN <br />content_types ON content.type=content_types.ID<br />{$joins} <br /> LEFT JOIN <br />content_versions ON content.current_revision=content_versions.ID <br />WHERE <br />content.active=1 AND <br />content.deleted=0 AND <br /> ( IF( content_versions.name LIKE '%{$phrase}%', 0, 1 ) <> 1 OR <br /> IF( content_versions.title LIKE '%{$phrase}%', 0, 1 ) <> 1 OR <br /> IF( content_versions.heading LIKE '%{$phrase}%', 0, 1 ) <> 1 OR <br /> IF( content_versions.content LIKE '%{$phrase}%', 0, 1 ) <> 1 OR<br />{$wheres} <br /> ) <br />ORDER BY <br /> priority0 ASC, <br /> priority1 ASC, <br /> priority2 ASC, <br /> priority3 ASC, <br />{$orders} 1";<br />

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Searching: Results<br />

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Simple access permissions<br />public function isAuthorised( $user )<br />{<br /> if( $this->requireAuthorisation == false )<br /> {<br /> return true;<br /> }<br />elseif( $user->loggedIn == false )<br /> {<br /> return false;<br /> }<br />elseif( count( array_intersect( $this->authorisedGroups, $user->groups ) ) > 0 )<br /> {<br /> return true;<br /> }<br /> else<br /> {<br /> return false;<br /> }<br />}<br />

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(Simple) Access permissions<br />Single table mapping content to groups<br />At content level, for content elements which require – cross reference the users groups with allowed groups<br />

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Downloads / Files / Resources<br />Create them as a content type<br />Searchable based off name / description<br />Store the file outside of the web root<br />Make use of access permissions already implemented<br />Make them purchasable<br />

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Not just “content”!<br />Other entities within an application which are similar<br />Social Networks<br />CRM’s<br />

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Social Networks: Statuses<br />Core table: status<br />Creator<br />Profile status posted on (use it for both statuses and “wall posts”<br />The status<br />Creation date<br />

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Social Networks: Statuses<br />Extended tables:<br />Videos: YouTube Video URL<br />Images: URL, Dimensions<br />Links: URL, Title<br />

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... Build a stream<br />Status streams<br />Recent activity<br />Viewing a profile’s “wall posts”<br />

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Query the stream<br />Part of a stream model<br />SELECT <br />t.type_reference, t.type_name, s.*, <br />p.name as poster_name, r.name as profile_name<br />FROM <br /> statuses s, status_types t, profile p, profile r <br />WHERE <br /> t.ID=s.type AND p.user_id=s.poster AND r.user_id=s.profileAND <br /> ( p.user_id={$user} <br /> OR r.user_id={$user} <br /> OR ( p.user_id IN ({$network}) AND r.user_id IN ({$network}) ) <br /> )<br />ORDER BY <br /> s.ID DESC LIMIT {$offset}, 20<br />

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Generate the stream<br />For each stream record<br />Include a template related to:<br />the stream item type, e.g. video<br />The context, e.g. Posting on your own profile<br />Insert stream record details into that instance of the template bit<br />

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foreach( $streamdata as $data )<br />{ <br /> if( $userUpdatingOwnStatus )<br /> {<br /> // updates to users "wall" by themselves<br /> $template->addBit( 'stream/types/' . $data['type_reference'] . '-me-2-me.tpl.php', $data );<br /> }<br />elseif( $statusesToMe )<br /> {<br /> // updates to users "wall" by someone<br /> $template->addBit( 'stream/types/' . $data['type_reference'] . '-2me.tpl.php', $datatags ); <br /> }<br />elseif( $statusesFromMe )<br /> {<br /> // statuses by user on someone elses wall<br /> $template->addBit( 'stream/types/' . $data['type_reference'] . '-fromme.tpl.php', $datatags ); <br /> }<br /> else<br /> {<br /> // friends posting on another friends wall<br /> $template->addBit( 'stream/types/' . $data['type_reference'] . '-f2f.tpl.php', $datatags ); <br /> }<br />}<br />

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CRM’s<br />People and organisations are very similar<br />Centralise them!<br />Entity<br />Entity_Organisation<br />Entity_Person<br />Record Person <-> organisation relationships in a table mapping entity table onto itself<br />

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Extending: Adding new content types<br />Drop in a model<br />Getters and setters for extended fields<br />Save method to insert extended data<br />Drop in an administrator controller<br />Rely on parent for standard operations<br />Pass CRUD requests / data to the model<br />Drop in a front end controller<br />Viewing: over-ride parent method & extend the select query<br />Anything else: Add specific functionality here<br />

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Why centralise your content / common entities?<br />Eases content versioning<br />Write functionality (commenting, rating, etc) once, and it works for all current and future content types – without the need for additional work<br />Fixing bugs with abstracted features, fixes it for all aspects which use that feature<br />Conversion is relatively easy – e.g. Turn a page into a blog entry. More so if they don’t extend the core table<br />

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Some of the problems<br />Can be a risk of content and content versions tables having too many fields<br />Optimization bottle-neck – poorly performing and optimizing tables will cripple the entire site<br />Versioning: Stores lots of data<br />Sometimes you want functionality to differ across features (e.g. Product reviews <> comments)<br />A bug in an abstract feature will be present in all aspects which use it<br />

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phpMyAdmin is harder<br />Managing content via phpMyAdmin is more difficult<br />MySQL Views can help with listing and viewing content <br />

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Thanks for listening<br />www.michaelpeacock.co.uk<br />me@michaelpeacock.co.uk<br />@michaelpeacock<br /> Please leave feedback!http://joind.in/2065<br />