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Propeople Blog: Varnish Tips and Tricks

Planet Drupal - Wed, 18/02/2015 - 06:02

In this article we would like to share some use cases and recipes for configuring Varnish.

Use custom data for building varnish cache hash

By default, Varnish uses URL as a parameter for caching. In the VCL file, it is also possible to add custom data (for example: location, or custom header value) to hashing by using the sub vcl_hash{} configuration part. But there is yet another solution to be used that Varnish comes equipped with out of the box. We can set a Vary header that is respected. So, if we want our cache to be based on header X-MyCustomHeader in Drupal, then we can set the header to

Vary: Cookie,Accept-Encoding,X-MyCustomHeader. This way, different values of our custom header will have different cache records in Varnish.

Limit access to the site by ip address

When we build an intranet website, we can limit access to it on the Varnish level. This can be done in following way:

First we define list of allowed IP addresses:

acl offices {

   "localhost";

   "127.0.0.1";

   "1.2.3.4";`

   "5.6.7.8";

}

Then we restrict access to non matching addresses:

sub vcl_recv {

   if ( req.http.host ~ "(intranet\.example\.com)$" && !(client.ip ~ offices) ) {

        error 403 "Access denied";

   }

}

SSL termination

As Varnish is not handling https traffic, we need to terminate SSL before it hits Varnish. For that we can use nginx. Here is a list of links to articles that dive deeper into this topic:

https://www.digitalocean.com/community/tutorials/how-to-configure-varnish-cache-4-0-with-ssl-termination-on-ubuntu-14-04

http://edoceo.com/howto/nginx-varnish-ssl

http://mikkel.hoegh.org/2012/07/24/varnish-as-reverse-proxy-with-nginx-as-web-server-and-ssl-terminator/

https://wiki.deimos.fr/Nginx_%2B_Varnish_:_Cache_even_in_HTTPS_by_offloading_SSL

ESI

On a recent Propeople project, we had the requirement to include a block with data from an external website without any caching. The tricky part was that the external site was providing XML with the data. The solution we implemented was to use ESI block pointing to the custom php file that was pulling that XML and parsing it on the fly.

Hiding js requests to external domains

If we need to do some CORS (http://en.wikipedia.org/wiki/Cross-origin_resource_sharing) requests instead of our Javascript doing requests directly to external domain, we can do requests to our site, but with a specific URL. Then, on the Varnish level, we can redirect that request to external domain. In this case, Varnish will act like a proxy. This can be achieved with backend options.

backend google {

 .host = "209.85.147.106";

 .port = "80";

}

sub vcl_fetch {

 if (req.url ~ "^/masq") {

   set req.backend = google;

   set req.http.host = "www.google.com";

   set req.url = regsub(req.url, "^/masq", "");

   remove req.http.Cookie;

   return(deliver);

 }

}

This is an example from a brilliant book: https://www.varnish-software.com/static/book/

Multiple backends, load balancing

It is possible to define multiple backends for Varnish and switch between them. Most basic implementation is round robin or random. Here is an example:

backend web01 {

   .host = "example1";

   .port = "80";

   .connect_timeout = 120s;

   .first_byte_timeout = 300s;

   .between_bytes_timeout = 60s;

   .max_connections = 50;

   .probe = {

    .url = "/";

    .timeout = 10s;

    .interval = 20s;

    .window = 5;

    .threshold = 3;

   }

}

 

backend web02 {

   .host = "example2";

   .port = "80";

   .max_connections = 100;

   .connect_timeout = 120s;

   .first_byte_timeout = 300s;

   .between_bytes_timeout = 60s;

   .probe = {

       .url = "/";

       .timeout = 10s;          

       .interval = 20s;       

       .window = 5;

       .threshold = 3;

   }

}

 

director apache round-robin {

 { .backend = web01; }

 { .backend = web02; }

}

 

sub vcl_recv {

 set req.backend = apache;

}

 

It is also possible to set a specific backend for visitors coming from specific IP addresses. This can have a number of helpful uses, such as making sure that the editors team has  adedicated backend server.

if (client.ip ~ offices) {

 set req.backend = web03;

}


I hope you have enjoyed our tips regarding Varnish configuration. Please feel free to share your own thoughts and tips on Varnish in the comments below!

Tags: VarnishService category: TechnologyCheck this option to include this post in Planet Drupal aggregator: planetTopics: Tech & Development
Categories: Elsewhere

Four Kitchens: Announcing SANDcamp Training for Advanced Responsive Web Design

Planet Drupal - Wed, 18/02/2015 - 00:44

Patrick Coffey and I have been busy building a new version of the popular Advanced Responsive Web Design all-day training program and are excited to host it at San Diego’s SANDcamp next week. Registration is open and there are several spaces remaining and we would love for you to join us!

Responsive Web Design is on everyone’s mind at the moment, and for good reason. The old techniques we have used to create pixel perfect sites for desktop audiences have already become a thing of the past as mobile usage accelerates.

Training Drupal Camp Drupal
Categories: Elsewhere

Isovera Ideas & Insights: When Do You Make the Move to Drupal 8?

Planet Drupal - Tue, 17/02/2015 - 21:54
Lately, whenever we start a project at Isovera, we are typically asked, "would you build this with Drupal 8"? It's a good question. There are many good reasons to get a leg up with the (currently) beta release, but there are also good reasons to keep your head down and stick with Drupal 7. The official release of Drupal 8 is rapidly approaching. What might this mean to you?
Categories: Elsewhere

Phase2: The Pros And Cons of Headless Drupal

Planet Drupal - Tue, 17/02/2015 - 19:38

Drupal is an excellent content management system. Nodes and fields allow site administrators the ability to create complex datasets and models without having to write a singe mysql query. Unfortunately Drupal’s theming system isn’t as flexible. Complete control over the dom is nearly impossible without a lot of work. Headless Drupal bridges the gap and gives us the best of both worlds.

What is headless Drupal?

Headless Drupal is an approach that decouples Drupal’s backend from the frontend theme. Drupal is used as a content store and admin interface. Using the services module in Drupal 7 or Core in Drupal 8, a rest web service can be created. Visitors to the site don’t view a traditional Drupal theme instead they are presented with pages created with Ember.js, Angular.js, or even a custom framework. Using the web service the chosen framework can be used to transfer data from Drupal to the front end and vice versa.

Pros

So what makes Headless Drupal so great? For one thing it allows frontend developers full control over the page markup. Page speed also increases since display logic is on the client side instead of the server. Sites can also become much more interactive with page transitions and animations. But most importantly the Drupal admin can also be used to power not only web apps but also mobile applications including Android and iOS.

Cons

Unfortunately Headless Drupal is not without its drawbacks. For one layout control for editors becomes much more difficult. Something that could be done easily via context or panels now requires a lot of custom fronted logic. Also if proper caching isn’t utilized and the requests aren’t batched properly lots of roundtrips can occur, causing things to slow down drastically.

Want to learn more about Headless Drupal?  Check out the Headless Drupal Initiative on Drupal.org.  And on a related topic, check out “Drupal 8 And The Changing CMS Landscape.

Categories: Elsewhere

Cameron Eagans: Use the Force!

Planet Drupal - Tue, 17/02/2015 - 18:00

Python developers have Jedi. Go developers have gocode. Hack developers have the built-in autocomplete functionality in hhvm. PHP developers have….nothing.

Categories: Elsewhere

Cheeky Monkey Media: How to add typekit fonts to your drupal website

Planet Drupal - Tue, 17/02/2015 - 18:00

So you just got the latest design from your graphics department. Now it’s up to you, the drupal developer, to take that design and turn it into reality. The problem is that they used some fancy pants new font and you need to make sure it works on every browser and mobile device.

There are a few solid options to choose from, including Google fonts and the popular @font-your-face drupal module. However, one of the services that I have been using lately is Adobe Typekit. They offer thousands of fonts and make it easy to scale. Typekit offers a basic free account as well as paid...Read More

Categories: Elsewhere

Appnovation Technologies: Export Data From Views to CSV File

Planet Drupal - Tue, 17/02/2015 - 17:55

It is sometimes useful to be able to save our view results into a document to allow non-technical people to manipulate the data.

Categories: Elsewhere

Tag1 Consulting: How to Maintain Contrib Modules for Drupal and Backdrop at the Same Time - Part 2

Planet Drupal - Tue, 17/02/2015 - 17:00

This is the second in a series of blog posts about the relationship between Drupal and Backdrop CMS, a recently-released fork of Drupal. The goal of the series is to explain how a module (or theme) developer can take a Drupal project they currently maintain and support it for Backdrop as well, while keeping duplicate work to a minimum.

read more

Categories: Elsewhere

Clemens Tolboom: Delete and edit comments on closed node

Planet Drupal - Tue, 17/02/2015 - 16:29

Having a forum you needs quick deletions of improper comments.

In Drupal 7 and Drupal 8 you have to visit admin/content/comments to do so. But then you loose the thread.

You could review and use this patch or add this to your custom module. The first needs review and testing. The later needs a Drupal coder.

Categories: Elsewhere

Drupal Commerce: Using OpenID Connect for Single Sign-On with Drupal

Planet Drupal - Tue, 17/02/2015 - 16:03

At Commerce Guys we provide a varied range of services, including our cloud PaaS Platform.sh, this Drupal Commerce community website, support, and the Commerce Marketplace.

Our users may need to log in to any of these services, and sometimes several at the same time. So we needed to have a shared authentication system, a way of synchronizing user accounts, and single sign-on (SSO) functionality.

After a lot of research on the existing methods, such as CAS, we found that there was no generic open-source solution which would cover all of our current needs and would also allow us to grow and scale in the future when adding new features or applications.

We decided to implement the OAuth 2.0 and OpenID Connect protocols, which were designed to be flexible, yet simple and standardized - exactly what we wanted.

Categories: Elsewhere

Drupal @ Penn State: Autopost to Facebook

Planet Drupal - Tue, 17/02/2015 - 15:15

I ran into an issue with the Drupal for Facebook module, both for D6 and D7, where I wanted articles to auomatically be posted to Facebook when they are submitted.  There appeared to be no way to do this via the module and I had played around with Rules to see if that would work, but no luck.

Categories: Elsewhere

Colan Schwartz: Integrating remote data into Drupal 7 and exposing it to Views

Planet Drupal - Mon, 16/02/2015 - 20:45
Topics: 

Drupal's strength as a content management framework is in its ability to effectively manage and display structured content through its Web user interface. However, the out-of-the-box system assumes all data is local (stored in the database). This can present challenges when attempting to integrate remote data stored in other systems. You cannot, by default, display non-local records as pages. While setting this up is in itself a challenge, it is an even bigger challenge to manipulate, aggregate and display this data through Views.

I've split this article into the following sections and subsections. Click on any of these to jump directly to the one of them.

  1. Introduction
  2. What's Changed
  3. Architecture
    1. Remote entity definition
    2. Access to remote properties
    3. Remote property definition
    4. Entity instances as Web pages
    5. Web services integration
    6. Temporary local storage
    7. Implementing the remote connection class
    8. Implementing the remote query class
  4. Views support
    1. Basic set-up
    2. Converting from an EntityFieldQuery
  5. Alternatives
  6. References
Introduction

This exposition is effectively a follow-up to some excellent articles from years past:

I'd recommend reading them for background information.

The first article (written in the Drupal 6 days) describes a "Wipe/rebuild import" method (Method 3) to bring remote data into Drupal. That's basically what we'll be discussing here, but there is now a standard method for doing so. What's interesting is that future plans mentioned there included per-field storage engines (with some being remote). The idea never made it very far. This is most likely because grabbing field data from multiple locations is far too inefficient (multiple Web-service calls) compared to fetching an entire record from a single location.

Taking a look at the second article, you can now see that Drupal 7 is dominant, and we have more tools at our disposal, but at the time this one was written, we still didn't have all of them in place. We did, however, have the following APIs for dealing with entities.

  1. The entity API in Drupal Core
  2. The Entity API contributed module
What's Changed

We now have another API, the Remote Entity API, which was inspired by Florian's article. As you can imagine, this API is dependent on the Entity API which is in turn dependent on the Drupal Core's entity functionality.

I recently added support for this new API to EntityFieldQuery Views Backend, the module allowing Views to work with data stored outside of the local SQL database. Previously, it supported non-SQL data, but still assumed that this data was local. Tying these two components together gives us what we need to achieve our goal.

Architecture

So we really need to take advantage of the three (3) entity APIs to load and display individual remote records.

  1. The entity API in Drupal Core
  2. The Entity API contributed module
  3. The Remote Entity API contributed module

The first provides basic entity functionality in Drupal. The second adds enhanced functionality for custom entities. The third and final API adds additional handling mechanisms for working with any remote data.

We'll need the following contributed modules to make all of this work.

In addition to the above, a new custom module is necessary. I recommend something like siteshortname_entities_remote for the machine name. You can have another one, siteshortname_entities_local, for local entities without all of the remote code if necessary. In the .info file, add remote_entity (the Remote Entity API) as a dependency.

You'll want to divide your module file into at least three (3) parts:

  1. Entity APIs: Code for defining remote entities through any of the above entity APIs. (Part I)
  2. Drupal Core: Code for implementing Drupal Core hooks. This is basically a hook_menu() implementation with some helper functions to get your entity instances to show up at specific paths based on the remote entity IDs. (Part II)
  3. Web Service Clients: Code for implementing what's necessary for the Web Service Clients module, a prerequisite for the Remote Entity API. It's essentially the external communications component for accessing your remote data. (Part III)

Most of the code will be in PHP class files you'll want in a classes subdirectory (autoloaded by defining these in your .info file), but you'll still need some code in your main module file.

We'll be adding only one new entity in this exercise, but the code is extensible enough to allow for more. Once one of these is set up, adding more is (in most cases) trivial.

Remote entity definition

Your basic remote entity definitions will exist in the Entity APIs section of your module file, Part I. Within the hook_entity_info() implementation, you'll see that different properties within the definition will be used by different layers, the three APIs.

For the following examples, let's assume we have a remote event data type.

<?php
/****************************************************************************
 ** Entity APIs
 ****************************************************************************/

/**
 * Implements hook_entity_info().
 *
 * @todo Add 'bundles' for different types of remote content.
 * @todo Add 'entity keys' => 'needs remote save' if remote saving required.
 * @todo Remove 'static cache' and 'field cache' settings after development.
 */
function siteshortname_entities_remote_entity_info() {
  $entities['siteshortname_entities_remote_event'] = array(

    // Core properties.
    'label' => t('Event'),
    'controller class' => 'RemoteEntityAPIDefaultController',
    'base table' => 'siteshortname_entities_remote_events',
    'uri callback' => 'entity_class_uri',
    'label callback' => 'remote_entity_entity_label',
    'fieldable' => FALSE,
    'entity keys' => array(
      'id' => 'eid',
      'label' => 'event_name',
    ),
    'view modes' => array(
      'full' => array(
        'label' => t('Full content'),
        'custom settings' => FALSE,
      ),
    ),
    'static cache' => FALSE,
    'field cache' => FALSE,

    // Entity API properties.
    'entity class' => 'SiteshortnameEvent',
    'module' => 'siteshortname_entities_remote',
    'metadata controller class' => 'RemoteEntityAPIDefaultMetadataController',
    'views controller class' => 'EntityDefaultViewsController',

    // Remote Entity API properties.
    'remote base table' => 'siteshortname_entities_remote_events',
    'remote entity keys' => array(
      'remote id' => 'event_id',
      'label' => 'event_name',
    ),
    'expiry' => array(
      // Number of seconds before a locally cached instance must be refreshed
      // from the remote source.
      'expiry time' => 600,
      // A boolean indicating whether or not to delete expired local entities
      // on cron.
      'purge' => FALSE,
    ),
  );

  // Get the property map data.
  $remote_properties = siteshortname_entities_remote_get_remote_properties();

  // Assign each map to its corresponding entity.
  foreach ($entities as $key => $einfo) {
    $entities[$key]['property map'] =
      drupal_map_assoc(array_keys($remote_properties[$key]));
  }

  // Return all of the entity information.
  return $entities;
}
?>
Notes
  1. Just like the entity type node, which is subdivided into content types (generically referred to as bundles in Drupal-speak), we can subdivide remote entities into their own bundles. In this case, we could have a "High-school event" bundle and a "College event" bundle that vary slightly, but instances of both would still be members of the entity type Event. We won't be setting this up here though.
  2. In this article, we won't be covering remote saving (only remote loading), but it is possible through the remote API.
  3. Make sure to adjust the cache settings properly once development is complete.
  4. Detailed documentation on the APIs is available for the Core entity API, the Entity API, and the the Remote Entity API.
Access to remote properties

As we're not using the Field API to attach information to our entities, we need to do it with properties. The code below exposes the data we'll define shortly.

<?php
/**
 * Implements hook_entity_property_info_alter().
 *
 * This is needed to use wrappers to access the remote entity
 * data in the entity_data property of remote entities.
 *
 * @see: Page 107 of the Programming Drupal 7 Entities book.  The code below is
 *   a variation on it.
 * @todo: Remove whenever this gets added to the remote_entity module.
 */
function siteshortname_entities_remote_entity_property_info_alter(&$info) {

  // Set the entity types and get their properties.
  $entity_types = array(
    'siteshortname_entities_remote_event',
  );

  $remote_properties = siteshortname_entities_remote_get_remote_properties();

  // Assign the property data to each entity.
  foreach ($entity_types as $entity_type) {
    $properties = &$info[$entity_type]['properties'];
    $entity_data = &$properties['entity_data'];
    $pp = &$remote_properties[$entity_type];
    $entity_data['type'] = 'remote_entity_' . $entity_type;

    // Set the default getter callback for each property.
    foreach ($pp as $key => $pinfo) {
      $pp[$key]['getter callback'] = 'entity_property_verbatim_get';
    }

    // Assign the updated property info to the entity info.
    $entity_data['property info'] = $pp;
  }
}
?>
Remote property definition

This is where we define the field (or in this case property) information, the data attached to each entity, that we exposed above.

<?php
/**
 * Get remote property information for remote entities.
 *
 * @return
 *   An array of property information keyed by entity type.
 */
function siteshortname_entities_remote_get_remote_properties() {

  // Initialize a list of entity properties.
  $properties = array();

  // Define properties for the entity type.
  $properties['siteshortname_entities_remote_event'] = array(

    // Event information.
    'event_id' => array(
      'label' => 'Remote Event ID',
      'type' => 'integer',
      'description' => 'The remote attribute "id".',
      'views' => array(
        'filter' => 'siteshortname_entities_remote_views_handler_filter_event_id',
      ),
    ),
    'event_date' => array(
      'label' => 'Date',
      'type' => 'date',
      'description' => 'The remote attribute "date".',
      'views' => array(
        'filter' => 'siteshortname_entities_remote_views_handler_filter_event_date',
      ),
    ),
    'event_details' => array(
      'label' => 'Details',
      'type' => 'text',
      'description' => 'The remote attribute "details".',
    ),
  );

  // Return all of the defined property info.
  return $properties;
}
?>
Notes
  1. Try to remember the distinction between local and remote entity IDs. At the moment, we're only interested in remote properties so we don't don't need to worry about local IDs just yet.
  2. Don't worry too much about the Views filters. These are Views filter handler classes. They're only necessary if you'd like custom filters for the respective properties.
Entity instances as Web pages

This starts the Core Hooks section of the module file, Part II. In this section, we're providing each remote data instance as a Web page just like standard local content within Drupal via nodes.

The hook_menu() implementation responds to hits to the event/EVENT_ID path, loads the object, themes all of the data, and then returns it for display as a page. We're assuming all of your HTML output will be in a template in the includes/siteshortname_entities_remote.theme.inc file in your module's directory.

<?php
/****************************************************************************
 ** Drupal Core
 ****************************************************************************/

/**
 * Implements hook_menu().
 */
function siteshortname_entities_remote_menu() {
  $items = array();

  $items['event/%siteshortname_entities_remote_event'] = array(
    'title' => 'Remote Event',
    'page callback' => 'siteshortname_entities_remote_event_view',
    'page arguments' => array(1),
    'access arguments' => array('access content'),
  );

  return $items;
}

/**
 * Menu autoloader wildcard for path 'event/REMOTE_ID'.
 *
 * @see hook_menu() documentation.
 * @param $remote_id
 *   The remote ID of the record to load.
 * @return
 *   The loaded object, or FALSE on failure.
 */
function siteshortname_entities_remote_event_load($remote_id) {
  return remote_entity_load_by_remote_id('siteshortname_entities_remote_event', $remote_id);
}

/**
 * Page callback for path 'event/%remote_id'.
 *
 * @param $event
 *   The auto-loaded object.
 * @return
 *   The themed output for the event page.
 */
function siteshortname_entities_remote_event_view($event) {
  $fullname = $event->name;
  drupal_set_title($fullname);
  $event_output = theme('siteshortname_entities_remote_event', array(
    'event' => $event,
  ));
  return $event_output;
}

/**
 * Implements hook_theme().
 */
function siteshortname_entities_remote_theme() {
  return array(
    'siteshortname_entities_remote_event' => array(
      'variables' => array('event' => NULL),
      'file' => 'includes/siteshortname_entities_remote.theme.inc',
    ),
  );
}
?>

There's one more thing to do here. In our hook_entity_info() implementation, we stated the following:

<?php
    'entity class' => 'SiteshortnameEvent',
?>

We could have used Entity here instead of SiteshortnameEvent, but we want a custom class here so that we can override the URL path for these entities. So add the following class:

<?php
class SiteshortnameEvent extends Entity {
  /**
   * Override defaultUri().
   */
  protected function defaultUri() {
    return array('path' => 'event/' . $this->remote_id);
  }
}
?>
Web services integration We're now onto Part III, setting up Web-service endpoints and associating remote resources with entities. This is done through the implementation of a few Web Service Clients hooks. <?php
/****************************************************************************
 ** Web Service Clients
 ****************************************************************************/

/**
 * Implements hook_clients_connection_type_info().
 */
function siteshortname_entities_remote_clients_connection_type_info() {
  return array(
    'our_rest' => array(
      'label'  => t('REST Data Services'),
      'description' => t('Connects to our data service using REST endpoints.'),
      'tests' => array(
        'event_retrieve_raw' => 'SiteshortnameEntitiesRemoteConnectionTestEventRetrieveRaw',
      ),
      'interfaces' => array(
        'ClientsRemoteEntityInterface',
      ),
    ),
  );
}

/**
 * Implements hook_clients_default_connections().
 */
function siteshortname_entities_remote_clients_default_connections() {

  $connections['my_rest_connection'] = new clients_connection_our_rest(array(
    'endpoint' => 'https://data.example.com',
    'configuration' => array(
      'username' => '',
      'password' => '',
    ),
    'label' => 'Our REST Service',
    'type' => 'our_rest',
  ), 'clients_connection');

  return $connections;
}

/**
 * Implements hook_clients_default_resources().
 */
function siteshortname_entities_remote_clients_default_resources() {
  $resources['siteshortname_entities_remote_event'] = new clients_resource_remote_entity(array(
    'component' => 'siteshortname_entities_remote_event',
    'connection' => 'my_rest_connection',
    'label' => 'Resource for remote events',
    'type' => 'remote_entity',
  ), 'clients_resource');

  return $resources;
}
?>

In the first function, we're adding metadata for the connection. In the second one, we're setting the endpoint and its credentials. The third function is what ties our remote entity, defined earlier, with the remote resource. There's some information on this documentation page, but there's more in the README file.

Temporary local storage

We'll need to store the remote data in a local table as a non-authoritative cache. The frequency with which it gets refreshed is up to you, as described earlier in this article. We'll need one table per entity. The good news is that we don't need to worry about the details; this is handled by the Remote Entity API. It provides a function returning the default schema. If you want to do anything different here, you are welcome to define your own.

The argument provided in the call is used for the table description as "The base table for [whatever you provide]". This will go in your siteshortname_entities_remote.install file.

<?php
/**
 * Implementation of hook_schema().
 */
function siteshortname_entities_remote_schema() {
  $schema = array(
    'siteshortname_entities_remote_events' => remote_entity_schema_table('our remote event entity type'),
  );

  return $schema;
}
?>

If you don't actually want to save one or more of your remote entities locally (say because you have private data you'd rather not have stored on your publicly-accessible Web servers), you can alter this default behaviour by defining your own controller which overrides the save() method.

<?php
/**
 * Entity controller extending RemoteEntityAPIDefaultController
 *
 * For most of our cases the default controller is fine, but we can use
 * this one for entities we don't want stored locally.  Override the save
 * behaviour and do not keep a local cached copy.
 */
class SiteshortnameEntitiesRemoteNoLocalAPIController extends RemoteEntityAPIDefaultController {

  /**
   * Don't actually save anything.
   */
  public function save($entity, DatabaseTransaction $transaction = NULL) {
    $entity->eid = uniqid();
  }
}
?>
Implementing the remote connection class

Create a file for the connection class.

<?php
/**
 * @file
 * Contains the clients_connection_our_rest class.
 */

/**
 * Set up a client connection to our REST services.
 *
 *  @todo Make private functions private once development is done.
 */
class clients_connection_our_rest extends clients_connection_base
  implements ClientsConnectionAdminUIInterface, ClientsRemoteEntityInterface {

}
?>

We'll now divide the contents of said file into three (3) sections, ClientsRemoteEntityInterface implementations, clients_connection_base overrides and local methods.

ClientsRemoteEntityInterface implementations

As you can see below, we've got three (3) methods here.

  • remote_entity_load() will load a remote entity with the provided remote ID.
  • entity_property_type_map() is supposedly required to map remote properties to local ones, but it wasn't clear to me how this gets used.
  • getRemoteEntityQuery() returns a query object, either a "select", "insert" or "update" based on whichever one was requested.
<?php
  /**************************************************************************
   * ClientsRemoteEntityInterface implementations.
   **************************************************************************/

  /**
   * Load a remote entity.
   *
   * @param $entity_type
   *   The entity type to load.
   * @param $id
   *   The (remote) ID of the entity.
   *
   * @return
   *  An entity object.
   */
  function remote_entity_load($entity_type, $id) {
    $query = $this->getRemoteEntityQuery('select');
    $query->base($entity_type);
    $query->entityCondition('entity_id', $id);
    $result = $query->execute();

    // There's only one. Same pattern as entity_load_single().
    return reset($result);
  }

  /**
   * Provide a map of remote property types to Drupal types.
   *
   * Roughly analogous to _entity_metadata_convert_schema_type().
   *
   * @return
   *   An array whose keys are remote property types as used as types for fields
   *   in hook_remote_entity_query_table_info(), and whose values are types
   *   recognized by the Entity Metadata API (as listed in the documentation for
   *   hook_entity_property_info()).
   *   If a remote property type is not listed here, it will be mapped to 'text'
   *   by default.
   */
  function entity_property_type_map() {
    return array(
      'EntityCollection' => 'list<string>',
    );
  }

  /**
   * Get a new RemoteEntityQuery object appropriate for the connection.
   *
   * @param $query_type
   *  (optional) The type of the query. Defaults to 'select'.
   *
   * @return
   *  A remote query object of the type appropriate to the query type.
   */
  function getRemoteEntityQuery($query_type = 'select') {
    switch ($query_type) {
      case 'select':
        return new OurRestRemoteSelectQuery($this);
      case 'insert':
        return new OurRestRemoteInsertQuery($this);
      case 'update':
        return new OurRestRemoteUpdateQuery($this);
    }
  }
?>
Parent overrides

The only method we need to worry about here is callMethodArray(). Basically, it sets up the remote call.

<?php
  /**************************************************************************
   * clients_connection_base overrides
   **************************************************************************/

  /**
   * Call a remote method with an array of parameters.
   *
   * This is intended for internal use from callMethod() and
   * clients_connection_call().
   * If you need to call a method on given connection object, use callMethod
   * which has a nicer form.
   *
   * Subclasses do not necessarily have to override this method if their
   * connection type does not make sense with this.
   *
   * @param $method
   *  The name of the remote method to call.
   * @param $method_params
   *  An array of parameters to passed to the remote method.
   *
   * @return
   *  Whatever is returned from the remote site.
   *
   * @throws Exception on error from the remote site.
   *  It's up to subclasses to implement this, as the test for an error and
   *  the way to get information about it varies according to service type.
   */
  function callMethodArray($method, $method_params = array()) {

    switch ($method) {
      case 'makeRequest':

        // Set the parameters.
        $resource_path = $method_params[0];
        $http_method = $method_params[1];
        $data = isset($method_params[2]) ? $method_params[2] : array();

        // Make the request.
        $results = $this->makeRequest($resource_path, $http_method, $data);
        break;
    }

    return $results;
  }
?>
Local methods We're assuming REST here, but you can use any protocol.

We have a makeRequest() method, which actually performs the remote call, and handleRestError() which deals with any errors which are returned.

<?php
  /**************************************************************************
   * Local methods
   **************************************************************************/

  /**
   * Make a REST request.
   *
   * Originally from clients_connection_drupal_services_rest_7->makeRequest().
   * Examples:
   * Retrieve an event:
   *  makeRequest('event?eventId=ID', 'GET');
   * Update a node:
   *  makeRequest('node/NID', 'POST', $data);
   *
   * @param $resource_path
   *  The path of the resource. Eg, 'node', 'node/1', etc.
   * @param $http_method
   *  The HTTP method. One of 'GET', 'POST', 'PUT', 'DELETE'. For an explanation
   *  of how the HTTP method affects the resource request, see the Services
   *  documentation at http://drupal.org/node/783254.
   * @param $data = array()
   *  (Optional) An array of data to pass to the request.
   * @param boolean $data_as_headers
   *   Data will be sent in the headers if this is set to TRUE.
   *
   * @return
   *  The data from the request response.
   *
   *  @todo Update the first two test classes to not assume a SimpleXMLElement.
   */
  function makeRequest($resource_path, $http_method, $data = array(), $data_as_headers = FALSE) {

    // Tap into this function's cache if there is one.
    $request_cache_map = &drupal_static(__FUNCTION__);

    // Set the options.
    $options = array(
      'headers' => $this->getHeaders(),  // Define if you need it.
      'method'  => $http_method,
      'data'    => $data,
    );

    // If cached, we have already issued this request during this page request so
    // just use the cached value.
    $request_path = $this->endpoint . $context_path . '/' . $resource_path;

    // Either get the data from the cache or send a request for it.
    if (isset($request_cache_map[$request_path])) {
      // Use the cached copy.
      $response = $request_cache_map[$request_path];
    } else {
      // Not cached yet so fire off the request.
      $response = drupal_http_request($request_path, $options);

      // And then cache to avoid duplicate calls within the page request.
      $request_cache_map[$request_path] = $response;
    }

    // Handle any errors and then return the response.
    $this->handleRestError($request_path, $response);
    return $response;
  }

  /**
   * Common helper for reacting to an error from a REST call.
   *
   * Originally from clients_connection_drupal_services_rest_7->handleRestError().
   * Gets the error from the response, logs the error message,
   * and throws an exception, which should be caught by the module making use
   * of the Clients connection API.
   *
   * @param $response
   *  The REST response data, decoded.
   *
   * @throws Exception
   */
  function handleRestError($request, $response) {

    // Report and throw an error if we get anything unexpected.
    if (!in_array($response->code, array(200, 201, 202, 204, 404))) {

      // Report error to the logs.
      watchdog('clients', 'Error with REST request (@req). Error was code @code with error "@error" and message "@message".', array(
        '@req'      => $request,
        '@code'     => $response->code,
        '@error'    => $response->error,
        '@message'  => isset($response->status_message) ? $response->status_message : '(no message)',
      ), WATCHDOG_ERROR);

      // Throw an error with which callers must deal.
      throw new Exception(t("Clients connection error, got message '@message'.", array(
        '@message' => isset($response->status_message) ? $response->status_message : $response->error,
      )), $response->code);
    }
  }
?>
Implementing the remote query class

This is where the magic happens. We need a new class file, OurRestRemoteSelectQuery.class.php, that will assemble the select query and execute it based on any set conditions.

Class variables and constructor

First, let's define the class, its variables and its constructor. It's a subclass of the RemoteEntityQuery class. Most of the standard conditions would be added to the $conditions array, but conditions handled in a special way (say those dealing with metadata) can be set up as variables themselves. In the example below, the constructor sets the active user as it can affect which data is returned. You can, however, set whatever you need to initialize your subclass, or leave it out entirely.

<?php
/**
 * @file
 * Contains the OurRestRemoteSelectQuery class.
 */

/**
 * Select query for our remote data.
 *
 * @todo Make vars protected once no longer developing.
 */
class OurRestRemoteSelectQuery extends RemoteEntityQuery {

  /**
   * Determines whether the query is RetrieveMultiple or Retrieve.
   *
   * The query is Multiple by default, until an ID condition causes it to be
   * single.
   */
  public $retrieve_multiple = TRUE;

  /**
   * An array of conditions on the query. These are grouped by the table they
   * are on.
   */
  public $conditions = array();

  /**
   * The from date filter for event searches
   */
  public $from_date = NULL;

  /**
   * The to date filter for event searches
   */
  public $to_date = NULL;

  /**
   * The user id.
   */
  public $user_id = NULL;

  /**
   * Constructor to generically set up the user id condition if
   * there is a current user.
   *
   * @param $connection
   */
  function __construct($connection) {
    parent::__construct($connection);
    if (user_is_logged_in()) {
      global $user;
      $this->useridCondition($user->name);
    }
  }
}
?>
Setting conditions

We have three (3) methods which set conditions within the query. entityCondition() sets conditions affecting entities in general. (The only entity condition supported here is the entity ID.) propertyCondition() sets conditions related to properties specific to the type of data. For example, this could be a location filter for one or more events. Finally, we have useridCondition() which sets the query to act on behalf of a specific user. Here we simply record the current Drupal user.

<?php
  /**
   * Add a condition to the query.
   *
   * Originally based on the entityCondition() method in EntityFieldQuery, but
   * largely from USDARemoteSelectQuery (Programming Drupal 7 Entities) and
   * MSDynamicsSoapSelectQuery.
   *
   * @param $name
   *  The name of the entity property.
   */
  function entityCondition($name, $value, $operator = NULL) {

    // We only support the entity ID for now.
    if ($name == 'entity_id') {

      // Get the remote field name of the entity ID.
      $field = $this->entity_info['remote entity keys']['remote id'];

      // Set the remote ID field to the passed value.
      $this->conditions[$this->remote_base][] = array(
        'field' => $field,
        'value' => $value,
        'operator' => $operator,
      );

      // Record that we'll only be retrieving a single item.
      if (is_null($operator) || ($operator == '=')) {
        $this->retrieve_multiple = FALSE;
      }
    }
    else {

      // Report an invalid entity condition.
      $this->throwException(
        'OURRESTREMOTESELECTQUERY_INVALID_ENTITY_CONDITION',
        'The query object can only accept the \'entity_id\' condition.'
      );
    }
  }

  /**
   * Add a condition to the query, using local property keys.
   *
   * Based on MSDynamicsSoapSelectQuery::propertyCondition().
   *
   * @param $property_name
   *  A local property. Ie, a key in the $entity_info 'property map' array.
   */
  function propertyCondition($property_name, $value, $operator = NULL) {

    // Make sure the entity base has been set up.
    if (!isset($this->entity_info)) {
      $this->throwException(
        'OURRESTREMOTESELECTQUERY_ENTITY_BASE_NOT_SET',
        'The query object was not set with an entity type.'
      );
    }

    // Make sure that the provided property is valid.
    if (!isset($this->entity_info['property map'][$property_name])) {
      $this->throwException(
        'OURRESTREMOTESELECTQUERY_INVALID_PROPERY',
        'The query object cannot set a non-existent property.'
      );
    }

    // Adding a field condition (probably) automatically makes this a multiple.
    // TODO: figure this out for sure!
    $this->retrieve_multiple = TRUE;

    // Use the property map to determine the remote field name.
    $remote_field_name = $this->entity_info['property map'][$property_name];

    // Set the condition for use during execution.
    $this->conditions[$this->remote_base][] = array(
      'field' => $remote_field_name,
      'value' => $value,
      'operator' => $operator,
    );
  }

  /**
   * Add a user id condition to the query.
   *
   * @param $user_id
   *   The user to search for appointments.
   */
  function useridCondition($user_id) {
    $this->user_id = $user_id;
  }
?>
Executing the remote query

The execute() method marshals all of the conditions, passes the built request to the connection's makeRequest() that we saw earlier, calls parseEventResponse() (which we'll investigate below) and then returns the list of remote entities that can now be used by Drupal.

Feel free to ignore the authentication code if it's not required for your implementation. I left it in as an extended example of how this could be done.

<?php
  /**
   * Run the query and return a result.
   *
   * @return
   *  Remote entity objects as retrieved from the remote connection.
   */
  function execute() {

    // If there are any validation errors, don't perform a search.
    if (form_set_error()) {
      return array();
    }

    $querystring = array();

    $path = variable_get($this->base_entity_type . '_resource_name', '');

    // Iterate through all of the conditions and add them to the query.
    if (isset($this->conditions[$this->remote_base])) {
      foreach ($this->conditions[$this->remote_base] as $condition) {
        switch ($condition['field']) {
          case 'event_id':
            $querystring['eventId'] = $condition['value'];
            break;
          case 'login_id':
            $querystring['userId'] = $condition['value'];
            break;
        }
      }
    }

    // "From date" parameter.
    if (isset($this->from_date)) {
      $querystring['startDate'] = $this->from_date;
    }

    // "To date" parameter.
    if (isset($this->to_date)) {
      $querystring['endDate'] = $this->to_date;
    }

    // Add user id based filter if present.
    if (isset($this->user_id)) {
      $querystring['userId'] = $this->user_id;
    }

    // Assemble all of the query parameters.
    if (count($querystring)) {
      $path .= '?' . drupal_http_build_query($querystring);
    }

    // Make the request.
    try {
      $response = $this->connection->makeRequest($path, 'GET');
    } catch (Exception $e) {
      if ($e->getCode() == OUR_REST_LOGIN_REQUIRED_NO_SESSION) {
        drupal_set_message($e->getMessage());
        drupal_goto('user/login', array('query' => drupal_get_destination()));
      }
      elseif ($e->getCode() == OUR_REST_LOGIN_REQUIRED_TOKEN_EXPIRED) {

        // Logout
        global $user;
        module_invoke_all('user_logout', $user);
        session_destroy();

        // Redirect
        drupal_set_message($e->getMessage());
        drupal_goto('user/login', array('query' => drupal_get_destination()));
      }
    }

    switch($this->base_entity_type) {
      case 'siteshortname_entities_remote_event' :
        $entities = $this->parseEventResponse($response);
        break;
    }

    // Return the list of results.
    return $entities;
  }
?>
Unmarshalling the response data and returning it

Here, in the parseEventResponse method, we decode the response data (if there is any), and do any additional work required to get each entity's data into an object. They're all returned as a single list (array) of entity objects. If the response provides information on the format (XML, JSON, etc.), you can unmarshal the data differently based on what the server returned.

<?php
  /**
   * Helper for execute() which parses the JSON response for event entities.
   *
   * May also set the $total_record_count property on the query, if applicable.
   *
   * @param $response
   *  The JSON/XML/whatever response from the REST server.
   *
   * @return
   *  An list of entity objects, keyed numerically.
   *  An empty array is returned if the response contains no entities.
   *
   * @throws
   *  Exception if a fault is received when the REST call was made.
   */
  function parseEventResponse($response) {

    // Fetch the list of events.
    if ($response->code == 404) {
      // No data was returned so let's provide an empty list.
      $events = array();
    }
    else /* we have response data */ {

      // Convert the JSON (assuming that's what we're getting) into a PHP array.
      // Do any unmarshalling to convert the response data into a PHP array.
      $events = json_decode($response->data, TRUE);
    }

    // Initialize an empty list of entities for returning.
    $entities = array();

    // Iterate through each event.
    foreach ($events as $event) {
      $entities[] = (object) array(

        // Set event information.
        'event_id' => isset($event['id']) ? $event['id'] : NULL,
        'event_name' => isset($event['name']) ? $event['name'] : NULL,
        'event_date' => isset($event['date']) ? $event['date'] : NULL,
      );
    }

    // Return the newly-created list of entities.
    return $entities;
  }
?>
Error handling

We provide a helper method dealing with errors raised in other methods. It records the specific error message in the log and throws an exception based on the message and the code.

<?php
  /**
   * Throw an exception when there's a problem.
   *
   * @param string $code
   *   The error code.
   *
   * @param string $message
   *   A user-friendly message describing the problem.
   *
   * @throws Exception
   */
  function throwException($code, $message) {

    // Report error to the logs.
    watchdog('siteshortname_entities_remote', 'ERROR: OurRestRemoteSelectQuery: "@code", "@message".', array(
      '@code' => $code,
      '@message' => $message,
    ));

    // Throw an error with which callers must deal.
   throw new Exception(t("OurRestRemoteSelectQuery error, got message '@message'.", array(
      '@message' => $message,
    )), $code);
  }
?>

Everything we've covered so far gets our remote data into Drupal. Below, we'll expose it to Views.

Views support Basic set-up

At the beginning of this article, I stated that we required the EntityFieldQuery Views Backend module. This allows us to replace the default Views query back-end, a local SQL database, with one that supports querying entities fetchable through the Remote Entity API. Make sure to add it, efq_views, to your custom remote entity module as a dependency.

For the curious, the changes I made to EFQ Views Backend to add this support can be found in the issue Add support for remote entities.

I added official documentation for all of this to the Remote Entity API README (via Explain how to integrate remote querying through Views). As it may not be obvious, when creating a new view of your remote entities, make sure that the base entity is the EntityFieldQuery version, not simply the entity itself. When selecting the entity type on which to base the view, you should see each entity twice: the standard one (via the default query back-end) and the EFQ version.

As stated in the documentation, you need to a add a buildFromEFQ() method to your RemoteEntityQuery subclass (which we went over in the previous section). We'll review why this is necessary and give an example next.

Converting from an EntityFieldQuery

As EFQ Views only builds EntityFieldQuery objects, we need to convert that type of query to an instance of our RemoteEntityQuery subclass. If EFQ Views stumbles upon a remote query instead of a local one, it will run the execute() method on one of these objects instead.

So we need to tell our subclass how to generate an instance of itself when provided with an EntityFieldQuery object. The method below handles the conversion, which EFQ Views calls when necessary.

<?php
  /**
   * Build the query from an EntityFieldQuery object.
   *
   * To have our query work with Views using the EntityFieldQuery Views module,
   * which assumes EntityFieldQuery query objects, it's necessary to convert
   * from the EFQ so that we may execute this one instead.
   *
   * @param $efq
   *   The built-up EntityFieldQuery object.
   *
   * @return
   *   The current object.  Helpful for chaining methods.
   */
  function buildFromEFQ($efq) {

    // Copy all of the conditions.
    foreach ($efq->propertyConditions as $condition) {

      // Handle various conditions in different ways.
      switch ($condition['column']) {

        // Get the from date.
        case 'from_date' :
          $from_date = $condition['value'];
          // Convert the date to the correct format for the REST service
          $result = $from_date->format('Y/m/d');
          // The above format() can return FALSE in some cases, so add a check
          if ( $result ) {
            $this->from_date = $result;
          }
          break;

        // Get the to date.
        case 'to_date':
          $to_date = $condition['value'];
          // Convert the date to the correct format for the REST service
          $result = $to_date->format('Y/m/d');
          // The above format() can return FALSE in some cases, so add a check
          if ( $result ) {
            $this->to_date = $result;
          }
          break;

        // Get the user ID.
        case 'user_id':
          $this->user_id = $condition['value'];
          break;

        default:
          $this->conditions[$this->remote_base][] = array(
            'field' => $condition['column'],
            'value' => $condition['value'],
            'operator' => isset($condition['operator']) ? $condition['operator'] : NULL,
          );
          break;
      }
    }

    return $this;
  }
?>

That should be it! You'll now need to spend some time (if you haven't already) getting everything connected as above to fit your specific situation. If you can get these details sorted, you'll then be ready to go.

Alternatives

At the time of this writing, there appears to be only one alternative to the Remote Entity API (not including custom architectures). It's the Web Service Data suite. The main difference between the modules is that Web Service Data doesn't store a local cache of remote data; the data is always passed through directly.

If this more closely matches what you'd like to do, be aware that there is currently no EntityFieldQuery support:

Support for EntityFieldQuery (coming soon) will allow developers to make entity field queries with web service data.

This is very clearly stated on the main project page, but I wasn't able to find an issue in the queue tracking progress. So if you choose this method, you may have to add EFQ support yourself, or you may not be able to use Views with your remote entities.

References

This article, Integrating remote data into Drupal 7 and exposing it to Views, appeared first on the Colan Schwartz Consulting Services blog.

Categories: Elsewhere

DrupalCon News: Making website magic with the DrupalCon site building track

Planet Drupal - Mon, 16/02/2015 - 19:45

In honor of this year’s DrupalCon in Tinseltown, we invite you to indulge in a bit of Drupal movie magic.

Imagine the scene…

NARRATOR
You are about to enter another dimension, a dimension not only of configuration and security but of UI. A journey into a wondrous land of complex sites without custom development. Next stop, the Drupal Zone!

THE SCENE
Intl. Acme, Inc. Meeting Room - it is day

FADE IN

Categories: Elsewhere

Chromatic: Atomic Drupal Development: Building Pieces Before Pages

Planet Drupal - Mon, 16/02/2015 - 18:12

Many designers are praising the benefits of Atomic Design. Rather than designing pages, Atomic Design focuses on designing systems of individual, reusable components. Designers aren’t – or at least shouldn’t be – the only ones thinking this way. From content strategy to QA, the entire team must be on the same atomic page.

Development is one area of a project that stands to benefit the most from this change in thought. Organizing a codebase by individual components keeps developers out of each other’s hair, reducing the code and effort overlap that often occurs when building by page or section. It also makes the codebase much easier to understand and maintain. Developers will know where to find code and how to fix, alter, or extend it, regardless of the original author. After enforcing coding standards, only git’s history will know who wrote what. This all saves time and money.

Because there are many ways to do anything in Drupal, building every component with the same approach is crucial. In the Drupal world, this approach is known as “the Drupal way”.

Building a component the Drupal way

Individual blocks, panel panes, or other UI elements would be examples of a component in Drupal. They are placed into regions within layouts to build pages. Other pages may use the same component in the same or different regions. A given component may vary across pages, but the design and intended functionality are similar. A simple search form is a good example, but they can be much more complex.

Design deliverables often arrive as complete pages. If the designers haven’t already, identify the components that each page consists of. Break up the page’s layout into regions and those regions into components. Determine which components live on more than one page and if they vary between them. It also helps to identify different components that share design or functionality with others. It’s important to recognize early if they will be sharing code.

Before writing a line of code, determine where in the codebase the component will live. Organize custom modules by content types or sections and add relevant components to the same modules. A module exported with Features should be treated no differently than one created by hand; don’t be afraid to add custom code to them (please do). The end goal is to have all back-end and (most) front-end code for a given component living in the same module.

Warning: This article is about to move fast and cover more ground than it should. It will move from back-end to front-end. There are many wonderful resources about each topic covered below, so they will be linked to rather than recreated. This will instead provide a high level overview of how they fit together and will highlight the most important pieces.

Component containers and placement

The most common container for a custom component is a block, created with a series of hooks. Contributed modules like Context can help place them on the page. More complex projects may choose to build pages with the Panels module. For pages built with Panels, custom panel page plugins are a component’s container of choice.

The decision between blocks and Context, Panels, or another approach is important to make early in the project. It is also important to stick with the same approach for every component. This article will focus less on this decision and more on how to construct the markup within the container of choice.

View modes and entity_view()

If the component displays information from a node or another type of entity, render it with a view mode. View modes can render different information from the same entity in different ways. Among other benefits, this helps display content in similar ways among different components.

Create a view mode with hook_entity_info_alter() or with the Entity view modes contributed module. This module also provide template suggestions for each entity type in each view mode. Render an individual piece of information with a view mode inside of a component using entity_view() (you’ll need the Entity API module) or node_view(). Alter the entity’s information as needed using a preprocess function and adjust the markup in a template. Those pieces will be discussed later.

If a component lists more than one entity or node, build a view with the Views contributed module. It is best if the view renders content with view modes using the Format options. Create Views components with the Block (or Content pane for Panels) display(s). Views also provides template suggestions to further customize the markup of the component. The exported view should live in the same module as the code that customizes it. EntityFieldQuery might be worth considering as an alternative to using Views.

hook_theme() and render arrays

If the component does not display information from an entity, such as a UI element, build it with hook_theme(). Drupal core and contributed modules use hook_theme() to build elements like links and item lists. This allows other modules to override and alter the information used to render the element. Default theme functions and templates can also be overridden to alter their markup.

Choose a name for the element that will identify it throughout the codebase. Outline what information the element will need to build the desired output. Use these decisions to define it using hook_theme(). Again, keep this hook in the same custom module as the rest of the code for the component.

To render a hook_theme() implementation, construct a render array. This array should contain the name of the implementation to render and any data it needs as input. Build and return this array to render the element as markup. The theme() function is a common alternative to render arrays, but it has been deprecated in Drupal 8. There are advantages to using render arrays instead, as explained in Render Arrays in Drupal 7.

Custom templates

Drupal renders all markup through templates and theme functions. Use templates to construct markup instead of theme functions. Doing so makes it easier for front-end developers to build and alter the markup they need.

Templates place variables provided by entity_view(), render arrays, and preprocess functions into the markup. They should live in the “templates” directory of the same module as the rest of the component’s code. The name of a template will come from theme hook suggestions. Underscores get replaced with dashes. Tell hook_theme() about the template for each element it defines.

There should be no logic in the template and they should not have to dig deep into Drupal’s objects or arrays. They should only use an if statement to determine if a variable has a value before printing its markup and value. They can also use a foreach to loop through an array of data. Further manipulation or function calls should happen in a preprocess function.

Preprocess functions

Use preprocess functions to extract and manipulate data such as field values and prepare them for the template. They are the middleman between the input and the output.

Preprocess functions follow the naming convention of hook_theme() implementations. Common base themes often use Drupal core’s preprocess functions, such as hook_preprocess_node(), in their template.php file. Keeping all preprocess functions in one file will create a mess in no time. Instead, place preprocess functions in the modules that define the parts their working with. This might be the custom feature that contains the exported content type.

jQuery/JavaScript files

Create a separate JavaScript file for each component that needs custom JavaScript. Place it in a “js” directory within the module and name the file after the component. Be sure to use the Drupal behavior system and name the behavior after the module and component.

Add the JavaScript file to each page the component will appear on. If the component appears on most pages, it might be best to just add it to every page. This will cause less HTTP requests with JavaScript aggregation enabled. The best way to do so is with hook_page_build(). JavaScript files can also be attached to entities rendered through view modes within hook_entity_view(). The best way to add JavaScript to a hook_theme() implementation is by attaching it to the render array.

Sass components

When using a CSS preprocessor like Sass, there isn’t much of a penalty to dividing the CSS into many files. Create a new Sass partial for each component and give the file the same name as the component. Keep them in a “components” directory within the Sass folder structure. Unlike all other code mentioned in this article, it is often best to keep all CSS for these components within the theme. Only keep CSS that supports the core behavior of the component in the module. Consider what styles should persist if it were a contributed module used with other themes.

In the component’s template, base the class names off of the component’s name as well. This makes it easy to find the component’s Sass after inspecting the element in the source. Follow the popular BEM / SMACSS / OOCSS methodologies from there.

Coming up for air

As mentioned, there are often endless ways to complete the same task in Drupal. This makes learning best practices difficult and “the Drupal way” will vary in the minds of different experts. The best way to grasp what works best is to start building something with other people and learn from mistakes. The approach outlined in this article aligns with common practice, but mileage will vary per project.

Regardless of approach, focusing on components before pages will only become more important. Drupal content is already displayed on everything from watches to car dashboards. The web is not made of pages anymore. Designers have begun to embrace this and Drupal developers should too; everyone will benefit!

Categories: Elsewhere

Makak Media: Taking BackDrop For A Test Drive

Planet Drupal - Mon, 16/02/2015 - 17:41

So the first BackDrop release is out there in the wild ready for a quick test drive! We're excited to see where this fork of Drupal 7 leads as we believe it to be a good complementary system to Drupal with a long term future.

First off we checked under the hood to get things configured and found the settings.php file in the root folder, which makes for easier access. Also all those txt files have been removed including the CHANGELOG.txt file, which we remove by default, as it supplies useful info to any hacker out there!

Naturally the installation process is very similar to Drupal but with a few less settings giving it a simpler feel.

Upon installation you're presented with a responsive admin menu with a slightly different structure to the standard Drupal menu. Responsiveness out of the box is great and the new menu again has a simpler look.

read more

Categories: Elsewhere

DrupalDare: G-WAN as a static Drupal file server

Planet Drupal - Mon, 16/02/2015 - 17:26
So now that we have concluded that it's easy to setup distribution of files on a separate subdomain, what about using a completely other web server (or in this case an application server)? Will it blend?
Categories: Elsewhere

Acquia: Development based on Drupal's Fundamental Particles - Brad Czerniak

Planet Drupal - Mon, 16/02/2015 - 13:34
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Presenter Brad Czerniak caught my eye with a blog post entitled "10 things I learned using Drupal at a hackathon," based on his experiences taking part in the #hackDPL (Detroit Public Library) competitive hackathon. In our podcast interview we talk about that – before moving on to Brad's session about the Drupal development best practices he and his team use at Commercial Progression in Michigan.

Categories: Elsewhere

Annertech: Enlightening - The Dark Art of Solr Search with Drupal

Planet Drupal - Mon, 16/02/2015 - 12:41
Enlightening - The Dark Art of Solr Search with Drupal Why this blog post?

Often when I add a search function to a Drupal website using Apache Solr, I'm amazed at how complex some people think this is. Many developers/site builders are of the belief that this is some kind of very-hard-to-master black art. They could not be more wrong.

So what I want to contribute back to the Drupal community is an understanding of how Solr works, why/how it differs from Drupal Core Search module, and the benefits Solr has over core search.

Categories: Elsewhere

lakshminp.com: The Drupal 8 plugin system - part 2

Planet Drupal - Mon, 16/02/2015 - 11:38

We saw in part 1 how plugins help us in writing reusable functionality in Drupal 8. There are a lot of concepts which plugins share in common with services, like:

  1. limited scope. Do one thing and do it right.
  2. PHP classes which are swappable.

Which begs the question, how exactly are plugins different from services?
If your interface expects implementations to yield the same behaviour, then go for services. Otherwise, you should write it as a plugin. This needs some explaining.
For instance, if you are creating an interface to store data in a persistent system, like MySQL or MongoDB, then it would be implemented as a service. The save() function in your interface interface will be implemented differently for both the services, but the behaviour will be the same, i.e., it takes data as input parameters, stores them in the respective data store and returns a success message.

On the other hand, if you are creating an image effect, it needs to be a plugin. (It already is. Check image effects as plugins). The core concept of image plugins is to take in an image, apply an effect on it and return the modified image. Different image effects yield different behaviours. An image scaling effect might not produce the same behaviour as that of an image rotating effect. Hence, each of these effects need to be implemented as a plugin. If any module wants to create a new image effect, it needs to write a new plugin by extending the ImageEffectBase class.

Plugins used in core

Let's take a look at the major plugin types provided by Drupal 8 core. An example plugin of each plugin types will be the subjects of future blog posts.

  1. Blocks
    Drupal 8 finally got blocks right. Custom blocks can be created from the BlockBase class.

  2. Field Types, Field Widgets and Field Formatters
    Check part 1 for how this is done in Drupal 8.

  3. Actions
    Drupal 8 allows module developers to perform custom actions by implementing the ActionBase class. Blocking a user, unpublishing a comment, making a node sticky etc. are examples of actions.

  4. Image Effects
    Image effects are plugins which manipulate an image. You can create new image effects by extending ImageEffectBase. Examples of core image effects are CropImageEffect and ScaleImageEffect.

  5. Input filters
    User submitted input is passed through a series of filters before it is persisted in the database or output in HTML. These filters are implemented as plugins by implementing the FilterBase class.

  6. Entity Types
    In Drupal parlance, entities are objects that persist content or configuration in the database. Each entity is an instance of an entity type. New entity types can be defined using the annotation discovery mechanism.

  7. Views related plugins
    A large collection of different plugin types are employed by views during the querying, building and rendering stages.

Plugin Discovery

Plugin discovery is the process by which Drupal finds plugins written in your module. Drupal 8 has the following plugin discovery mechanisms:

  1. Annotation based. Plugin classes are annotated and have a directory structure which follows the PSR-4 notation.

  2. Hooks. Plugin modules need to implement a hook to tell the manager about their plugins.

  3. YAML files. Plugins are listed in YAML files. Drupal Core uses this method for discovering local tasks and local actions.

  4. Static. Plugin classes are registered within the plugin manager class itself. This is useful if other modules should not create new plugins of this type.

Annotation based discovery is the most popular plugin discovery method in use. We will briefly look at how we create a new plugin type using this method in the next part.

Categories: Elsewhere

DrupalDare: CDN, Cookieless Requests and Subdomains

Planet Drupal - Mon, 16/02/2015 - 10:52
In this text I will go in to the topic of using a separate domain for serving your static files to avoid the client sending unnecessary cookies in the headers and why it may be or may not be a solution to speed up your website.
Categories: Elsewhere

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